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Full text of "Byte Magazine Volume 10 Number 01: Through the Hourglass"

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JANUARY 1985 VOL. 10, NO. 1 



$3.50 IN UNITED STATES 

$4.25 In CANADA / £2.10 in U.K. 

A McGRAW-HfLL PUBLICATION 

0360-5280 



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THROUGH 

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Today, there are more Apples in 
schools than any other computer. 

Unfortunately, there are still more 
kids in schools than Apples. 

So innocent youngsters (like your 
own) may have to fend off packs of bully 
nerds to get some time on a computer. 

Which is why it makes good sense 
to buy them an Apple® He Personal 
Computer of their very own. 

The lie is just like the leading com- 
puter in education, the Apple He. Only 
smaller. About the size of a three-ring note- 
book, to be exact. 

Even the price of the lie is small — 
under SHOO* 



Of course, since the He is the legiti- 
mate offspring of the lie, it can access the 
world's largest library of educational soft- 
ware. Everything from Stickybear Shapes™ 



programs in all. More than a few of which 
you might be interested in yourself. 

For example, 3-in-l integrated busi- 
ness software. Home accounting and tax 




With a //c, your kid can do something constructive after school. Like learn to write stories. 
Or team to fly. Or eren learn something slightly mare advanced. Like m all i variable calculus. 



for preschoolers to SAF test preparation 
programs for college hopefuls. 

In fact, the lie can run over 10,000 



programs. Diet and fitness programs. 

Not to mention fun programs for the 
whole family. Like* 'Genetic Mapping" and 



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"Enzyme Kinetics." 

And the Apple He comes complete 
with everything you need to start computing 
in one box. 

Including a free 4-diskette course to 
teach you how— when your kids get tired 
of your questions. 

An RF modulator that can turn almost 
any TV into a monitor. 

As well as a long list of built-in 
features that would add about $800 to the 
cost of a smaller-minded computer. 

128K of internal memory— twice 



the power of the average office computer. 

A built-in disk drive that would 
drive up the price 
of a less-senior 
machine. 

And built- 
in electronics 
for adding 
accessories like 
a printer, a 
modem, an 
AppleMouse or 



He can even run away from home. 



So while your children's shoe sizes 
and appetites continue to grow at an 
in us optimal carrying cm t% (he alarming rate, there's 

one thing you know 
can keep up with them. 
Their Apple He. 

To learn more 
about it, visit any 
authorized Apple dealer. 
Or talk to your own 
computer experts . _0_ 
As soon 
an extra disk drive when the time comes, as they get home from school. 




* The FI'C is concerned ahoul price- fixing. So this is only a Suggested Retail Price. You can pay more if you really want to. © 19th A/file Computer Inc. Apple and the Apple logo are 
registered trademarks of Apple Computer Inc. Stiekvhear Shapes is a trademark of Optimum Resource For an authorized typle dealer nearest yon call (800) 538-9696* In Canada, call 

(800) 268-7796 or (800) 268-7637. 



CONTENTS 





286 



FEATURES 



Introduction 96 

Ciarcias Circuit Cellar: Understanding Linear Power Supplies 

by Steve Garcia 98 

Proper design brings simplicity and reliability. 

The Visual Mind and the Macintosh by Bill Benzon 113 

MacPaint provides a tool for thinking. 

A Glimpse into Future Television by ]oseph S. Nadan 135 

How will high-definition television open the window on the world for users 
of personal computers? 

Microsoft Macintosh BASIC Version 2.0 by Gregg Williams 155 

This new version offers greater support of the Macintosh's distinctive features. 

The Apple Story Part 2: More History and the Apple III 

conducted by Gregg Williams and Rob Moore 167 

The interview with Steve Wozniak continues. 

Uninterruptible Power Supplies by VJilliam Rynone 183 

These devices can save you from losing data in the dark. 

An Introduction to Fiber Optics, 

Part 2: Connections and Networks by Richard S. Shuford 197 

Optical fibers are becoming practical for use in applications such as local networks. 

Algorithms for a Variable-Precision Calculator 

by Paul A. Nilson , 211 

There's help for those who need to perform decimal computations 
on large numbers. 

Audio-Frequency Analyzer by Wince Banes 223 

You can build IBM PC accessories to analyze your stereo. 

Font Design for Personal Workstations by Charles Bigelow 255 

Improved on-screen and printer fonts can help to make computers more 
acceptable as tools for a literate public. 

Expert Systems— Myth or Reality? by Bruce D'Ambrosio 275 

Artificial intelligence is considered by some to be one of the most important 
technologies on the horizon. 



REVIEWS 



Introduction 286 

Reviewer's Notebook by Rich Malloy 289 

The HP 110 Portable Computer by Mark Haas 290 

Hewlett-Packard's 80C86-based lap-size machine. 

Gifford'S MP/M 8-16 by Charles H. Strom 305 

A multiuser S-100-based operating system. 



BYTE is published monthly by McGraw-Hill Inc. Founder: James H. McCraw (1860-1948). Executive, editorial, circulation, and advertising offices: 70 
Main St.. Peterborough. NH 034 58. phone (603) 924-9281. Office hours: Mon-Thur 8:30 AM - 4:30 PM. Friday 8:30 AM - 1.00 PM. Eastern Time Ad- 
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and fulfillment questions to BYTE Subscriptions. POB 596, Martinsville. Nl 08836. Second-class postage paid at Peterborough. NH 03458 and additional 
mailing offices. USPS Publication No 528890 (ISSN 0360-52801. Postage paid at Winnipeg. Manitoba. Registration number 932 1. Subscriptions are S21 
for one year. S38 for two years, and S55 for three years in the USA and its possessions In Canada and Mexico. S23 for one year. S42 for two years. 
$61 for three years. S69 for one year air delivery to Europe 17.100 yen for one year surface delivery to lapan. S3 7 surface delivery elsewhere. Air delivery 
to selected areas at additional rates upon request. Single copy price is S3.50 in the USA and its possessions. $3.95 in Canada and Mexico. S4.50 in 
Europe, and S5 elsewhere Foreign subscriptions and sales should be remitted in United States funds drawn on a US. bank. Please allow six to eight 
weeks for delivery of first issue. Printed in the United States of America. 



2 BYTE • JANUARY 1985 



COVER ILLUSTRATION BY ROBERT T1NNEY 



VOLUME 10, NUMBER I, 1985 



Lotus's Symphony by Dick Pountain 317 

Another large, multipurpose spreadsheet program from the makers of 1-2-3. 

MagicPrint by Alan R. Miller 329 

Enhanced print programs for CP/M and MS-DOS systems. 

The Hewlett-Packard ThinkJet Printer by Mark Haas 337 

Ink-jet technology for HP, IBM, and Apple computers. 

The TI Omni 800/Model 855 Printer by Mark Haas 345 

Multiple fonts via ROM cartridges. 

Review Feedback 353 

Readers respond to previous reviews. 



KERNEL 

Introduction 361 

Computing at Chaos Manor: The Fast Lane by }erry Pournelle 363 

This month's whirlwind tour of the computing scene includes a look at 
Orchid's PCturbo 186. the Ml-286 from Macrotech. and AshtonTate's dBASE III. 

Chaos Manor Mail conducted by ]erry Pournelle 393 

jerry's readers write, and he replies. 

BYTE UK.: The Amstrad CPC 464 by Dick Pountain 401 

This "home" computer has potential for business applications as well. 

Circuit Cellar Feedback conducted by Steve Garcia 413 

Steve answers project-related queries from readers. 

BYTE West Coasts Light Touches by ]ohn Markoff and Phillip Robinson. . .415 
The Mac goes to college, and mice and laser disks are in the news. 

Mathematical Recreations: The Fundamental Counting Principle 

by Michael W. Ecker 425 

Dr. Ecker explores ways of counting without enumerating. 

BYTE Japan: The New and the Old by William M. Raike 429 

Our Tokyo correspondent focuses on denser chips and software piracy 
in the East. 



editorial: autonomous weapons 
and Human Responsibility 6 

MiCROBYTES 9 

Letters 14 

Fixes and Updates 33 

What's New 39, 440 

Ask BYTE 48 

Clubs & Newsletters 59 



Book Reviews 65 

Event Queue 83 

Books Received 435 

Unclassified Ads 493 

BYTE's Ongoing Monitor Box, 
BOMB Results 494 

Reader Service 495 




Address all editorial correspondence to the Editor. BYTE. POB 372. Hancock. NH 03449. Unacceptable manuscript will be returned if accompanied 
by sufficient first-class postage. Not responsible for lost manuscripts or photos. Opinions expressed by the authors are not necessarily those of BYTE. 
Copyright © 1985 by McGraw-Hill Inc. All rights reserved. Irademark registered in the United States Patent and Irademark Office. Where necessary, 
permission is granted by the copyright owner for libraries and others registered with the Copyright Clearance Center (CCC) to photocopy any article 
herein for the flat fee of $1.50 per copy of the article or any part thereof. Correspondence and payment should be sent directly to the CCC. 29 Congress 
St. Salem. MA 01970. Specify ISSN 0360-5280/83. Sl.50. Copying done for other than personal or internal reference use without the permis- 
sion of McCraw-Hill Inc. is prohibited. Requests forspecial permission or bulk orders should be addressed to the publisher. BYTE is available 
in microform from University Microfilms International. 300 North Zeeb Rd„ Dept. PR. Ann Arbor. Ml 48106 or 18 Bedford Row. Dept. PR. 
London WC1R4EI England. 
Subscription questions or problems should be addressed to: BYTE Subscriber Service. POB 328, Hancock, NH 03449 



SECTION ART BY GEOFFREY MOSS 



JANUARY 1985 -BYTE 3 



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BYTE 



EDITOR IN CHIEF PUBLISHER 

Philip Lemmons Gene W. Simpson 

MANAGING EDITOR ASSISTANT PUBLISHER 

Gene Smarte Michele P. Verville 

CONSULTING EDITORS PUBLISHER'S ASSISTANT 

Steve Ciarcia Doris R. Gamble 

Jerry Pournelle 

senior technical editors advertising sales 

G. Michael Vose. Themes |. Peter Huestis. Safes Manager 

Gregg Williams Sandra Foster. Administrative Assistant 

TECHNICAL EDITORS ADVERTISING 

Thomas R. Clune Lisa Wozmak. Supervisor 

Ion R. Edwards Robert D. Hannings. Senior Account Manager 

Glenn Hartwig. Reviews Marion Carlson 

Richard Kraiewski Karen Cilley 

Ken Sheldon Lyda Clark 

Richard S. Shuford Denise Proctor 

Jane Morrill Tazelaar advertising/production 

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WEST COAST EDITORS * 

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Phillip Robinson. Senior Technical Editor. Palo Alto Andrew Iackson. Subscriptions Manager 

Donna Osgood. Associate Editor. San Francisco Cathy A. R. Drew. Assistant Manager 

Brenda McLaughlin. Editorial Assistant. San Francisco Laurie Seamans. Assistant Manager 

NEW YORK EDITOR SUSAN BOYD 

Richard Malloy. Senior Technical Editor Phil Dechert 

managing editor. user news mary emerson 

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user news editors agnes e, perry 

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Mark Welch. Mi'crobytes James Bingham. Single-Copy Sales Manager 

• Linda Turner. Assistant Manager 

CONTRIBUTING EDITORS CAROL AHO 

Dennis Allison, at large Claudette Carswell 

Mark Dahmke. video, operating systems Edson Ware 

Mark Haas, at large - • 

Rik Jadrnicek. CAD. graphics, spreadsheets MARKETING COMMUNICATIONS 

Mark Klein, communications Horace T. Howland. Director 

Alan Miller, languages and engineering vicki Reynolds. Marketing Associate 

John C. Nash, scientific computing Priscilla Arnold. Marketing Assistant 

Dick Pountain. U.K. Stephanie Warnesky. Graphic Arts Supervisor 

William M. Raike. \apan Sharon Price. Graphic Arts Designer 

Perry Saidman. computers and law Douc Webster. Director of Public Relations 

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Bruce Webster, software Patricia Akerley. Research Manager 

* Cynthia Damato Sands. Reader Service Coordinator 

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CROMEMCO COMPUTERS: 
DESIGNED TO MAKE UNIX SYSTEM V 

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Inquiry 90 



JANUARY 1985 -BYTE 



EDITORIAL 



Autonomous Weapons and 
Human Responsibility 

The human desire to avoid responsibility 
for difficult decisions probably goes back 
to the dawn of time. In their brief period 
on this earth, computers have taken the 
blame for millions of human mistakes, 
Who hasn't heard a computer blamed for 
an error in billing or delivery? One typical 
case of blaming the computer occurred 
in a school system in which a computer 
handled scheduling of classes. On the first 
day of school, the most vocal complaints 
came from- students whose lunch hours 
had been assigned at 8:30, 9:30, 10:30, 
2:30, and 3:30. That's right— someone had 
forgotten to instruct the computer that 
lunch has to occur in the middle of the 
day. The school's new computer took the 
blame. Those who knew little about com- 
puters hated them more over this incident. 
Those in positions of authority found a 
versatile new scapegoat. 

Anecdotes like this are amusing when 
little hangs in the balance. In the presiden- 
tial debates in the fall, however, one of the 
candidates suggested that military deci- 
sions affecting the fate of the earth might 
be irrevocably delegated to computers if 
the other candidate's programs were 
enacted. The candidate making that claim 
either understood nothing of computers 
or else he was acting as a demagogue, 
casting himself as the hero to save the 
earth from the tyranny of computers. In 
either case, the candidate did his coun- 
try a disservice. 

Computers, of course, do as people tell 
them. The hard part is for people to 
foresee all circumstances and write in- 
structions to handle all circumstances op- 
timally. Lack of foresight and poor plan- 
ning occur in many fields with or without 
computers. But computers make wonder- 
ful scapegoats. When foresight and plan- 
ning fail, computers take the blame. Con- 
sequently their image as cold, dehuman- 
izing villains is perpetuated. Some fictional 
and cinematic depictions of computers 
also endow them with a villainy that ex- 
ceeds the capabilities of digital 
electronics. 



lb be sure, computers are cold and in- 
different. But let's consider a few cases in 
which the inhuman properties of com- 
puters enable them to help people. Com- 
puter conferencing enables people to ex- 
change text messages with others who 
share their interests. One advantage of 
computer conferencing is clear: people 
needn't be in the same place at the same 
time in order to exchange comments. But 
computer conferencing also prevents loud 
and aggressive people from dominating 
a group as they can in face-to-face con- 
versation. As Starre Roxanne Hiltz and 
Murray Tliroff point out in their book The 
Network Nation: Human Communication via 
Computer (Reading, MA: Addison-Wesley. 
1978), ". . . persons who happen to be 'fast 
on the draw' in a face-to-face verbal situa- 
tion, and who may not be particularly in- 
telligent or correct, tend to dominate the 
discussion and decision-making process 
in small groups." In computer conferenc- 
ing, "one participant making a statement 
in no way interferes with the ability of 
another person to be making a statement 
that overlaps in time." Computer con- 
ferencing for the BYTE staff has led to 
much better discussions with much 
broader and more balanced participation 
than occurs in face-to-face staff meetings. 
In fact, it has been a joy to see some shy 
people blossom in our computer- 
mediated meetings. Who would have sup- 
posed computers would emancipate the 
shy? 

Some of the benefits that computers can 
bestow on humans are more obvious. In 
giving instructions to slow learners, com- 
puters persist when even the most saint- 
ly human instructors would lose patience. 
In providing simulations of difficult or 
dangerous situations, computers reduce 
the risks bome by people who must some- 
times face the real hazards. If we use our 
electronic resources reasonably, bomb 
disposal will soon become the exclusive 
domain of robots. We can make com- 
puters serve human needs. 

People who understand computers 
understand how these machines can 
serve people. But some people who 
understand computers well are letting us 



fall victim once again to the myth of com- 
puters as villains. The phrase that magical- 
ly shifts blame from humans to computers 
is "autonomous weapons." The issue 
skirted is the same one dealt with so poor- 
ly in the presidential debates. 

We can build unmanned tanks that 
detect certain kinds of objects and then 
destroy them. We can build and program 
computers to monitor motion and radia- 
tion and, upon detection of patterns that 
we have specified, to hurl devastation on 
targets that we have chosen. But using the 
phrase "autonomous weapons" confers 
on such devices a higher status than that 
of the glorified booby traps that they are. 
A concealed pit of sharpened stakes is just 
as autonomous a weapon as an un- 
manned tank. A terrorist's time bomb is 
just as autonomous a weapon as an or- 
bital launching pad or beam weapon. But 
we have no doubt that the man who digs 
the pit and sharpens the stakes bears 
responsibility for killing the man who falls 
in, or that the man who builds and plants 
the time bomb murders its victims, even 
if the victims are not those intended. 

Humans will build the coming genera- 
tion of "autonomous" weapons. Humans 
will program them, and humans will either 
make, delegate, or blunder all decisions 
about their control. Humans will bear all 
the responsibility for the good or ill these 
weapons do. 

This is not the place to argue the merits 
of such weapons or the likelihood of 
events that might justify the manufacture, 
deployment, or use of such weapons. But 
as one of the world's most widely read 
computer magazines, BYTE is the place to 
say that computers should never be the 
scapegoats for difficult human decisions 
affecting the fate of the earth. Computers 
follow sequences of human instructions. 
People decide. If we forget this, we may 
someday find ourselves speechless when 
we hear a leader explain a missing conti- 
nent by saying, 'The autonomous weapon 
was in a loop." 

We must insist that individuals who 
decide to deploy autonomous weapons 
bear responsibility for everything these 
weapons do. 

— Phil Lemmons, Editor in Chief 



BYTE • JANUARY 1985 



thing 



to 



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word pw^sfifriq software, | Get your hands 
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Inquiry 3 1 1 



JANUARY 1985 -BYTE 7 



Wordstar Wordprocessing and SuperCalc 3 Integrated Spreadsheet now included Free with all Seequa computers. 



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programs available. It comes complete with two of 
the best programs around, Perfect Writer™ and 
Perfect Calc.™ It's portable. And you can plug it in 
and start computing the moment you unwrap it. 
So if you've been inter- 
ested in an IBM personal com- 
puter, now you know where you 
can get one for $1595. Wherever 
they sell Chameleons. 



The Chame leon by 

SEEQ UA 

COMPUTER 

CORPORATION 

8305 Telegraph Road 
Odenton, MD 21113 

Chameleon shown with optional second disk drive. 

To learn more about Seequa or for the location of the Seequa deaJer 

nearest you, caJI (800) 638-6066 or (301 ) 672-3600. 

IBM is a registered trademark of International Business Machines Corporation, 



8 BYTE • JANUARY 1985 



Inquiry 313 



MICROBYTES 



Staff-written highlights of late developments in the microcomputer industry. 



Optical Disks Move Toward Reality 

Information Storage Inc., Colorado Springs, CO, expects to provide samples of its 525 WC 
optical-disk drive (write-once, read-often) in April, with full production later this year. The 
drive uses removable 100-megabyte 5 l A -inch disk cartridges. IS1 hopes to eventually sell the 
optical-disk drive to computer makers for about $600 and the disks for about $40 each. Ini- 
tial prices will be much higher. 

Compact Discs as Read-Only Memory for PCs 

At the fall COMDEX show in Las Vegas, several companies announced products using a 
standard compact disc (CD) as a read-only-memory device for computers. Each CD ROM 
can store up to 550 megabytes of data (about 275,000 pages of text) using the same 
4.72-inch disc format used in CD digital audio recordings. Philips Subsystems and 
Peripherals Inc., Hitachi America Ltd., Sony, and Denon America inc. all announced or 
showed CD ROM drives at COMDEX. Earlier, 3M announced that it will produce discs for 
use in CD ROM drives. Sony and Denon both expect to sell drives to computer makers for 
less than $300; with a controller, a CD ROM should retail for substantially less than $1000. 

New Chips Will Find Uses in Image Processing 

NEC Electronics announced the /*PD7281D, which it says is the first non-von Neumann 
single-chip image processor. The 7281 executes as many as 5 million instructions per sec- 
ond. Linking multiple 7281s further increases processing speeds. The chip can also be used 
for signal processing and mathematical calculations. NEC plans to produce samples of the 
chip late this year. 

NCR announced the Geometric Arithmetic Parallel Processor (GAPP), developed jointly 
with Martin Marietta Aerospace. The GAPP includes a 6 by 12 array of 1-bit processor 
elements, each having 128 bits of RAM. Many GAPP chips can be cascaded for use in 
image processing. NCR suggests that robot vision, image compression and enhancement, 
digital signal processing, and arithmetic array processing are possible applications. NCR is 
selling samples of the NCR45CG72 GAPP for $545. 

Portable Computers Feature 80 by 25 Displays 

Mitsubishi's TVedia notebook computer includes an 80-line by 25-character LCD, 64K bytes 
of RAM, a Z80A processor, a microcassette drive, a 300-bps modem, serial and parallel 
ports, a bar-code-reader port, and a ROM cartridge slot. A 64K-byte ROM includes a 
spreadsheet, database, graphics, word processing, and communications software. Internal 
nicad batteries allow use of the machine for up to 8 hours. The $1200 TVedia weighs 6.6 
pounds and measures WA by 8/2 by 3/2 inches. 

Quadram announced DataVue, a 14-pound portable computer with an infrared keyboard 
link. The $2195 system includes 128K bytes of RAM, one 5 '/4-inch disk drive, an 8088 pro- 
cessor, parallel and serial ports, a pivoting 80 by 25 LCD, an AC adapter, and batteries that 
will last about I x h hours. It will be available in March. 

Display Technology 

Sony announced a new multicolor display technology called Currentron. The monitor alters 
the shade and color displayed by changing the beam current. Resulting colors include red, 
orange, yellow, and yellowish-green. Two versions will be available as engineering samples: 
one displays 900 by 200 pixels, and the other, 1100 by 864 dots. Monitors using the Curren- 
tron technology should be sharper but less expensive than full-color monitors. 



{continued) 
JANUARY 1985 -BYTE 9 



MICROBYTES 



COMDEX: New 2400 bps Modems 

Several companies introduced 2400-bps modems at the COMDEX show in Las Vegas. Most 
of the modems are compatible with the Bell 212A standard at 1200 bps, the Bell 103 stan- 
dard at 300 bps, and the CCITT V.22bis standard at 2400 bps. Most also include auto-dial 
capabilities, some phone-number memory, and claim some degree of compatibility with 
Hayes "AT" modem commands. Some of the modems are stand-alone units; others are IBM 
PC expansion cards. T\vo use front-panel LCDs instead of the usual LEDs: Penril DataComm's 
$895 Datalinx Model 224 and Novation's $795 Professional 2400. Telenetics, Multi-Tech 
Systems, and Cermetek announced $795 modems; U.S. Robotics chose an $895 list price. 
Neither NEC America nor Microcom had set pricing for their 2400-bps modems. 

Team Technology, Taiwan, introduced a line of low-cost modems, available through Chen 
Manufacturing, Alhambra, CA. The SmarTEAM 2400 features 2400-, 1200-, 600-, and 
0-300-bps capabilities for $450; no availability date was set. The $159 SmarTEAM 103/212A 
is a 1200- and 0-300-bps modem. Team's ModemPhone 300 is a $37 300-bps modem. 

Users May Find Surprises in Apple Insurance 

Apple has endorsed a computer insurance policy offered by Emett & Chandler Inc., but 
neither Apple's letter nor the enclosed brochure explained that only one computer could 
be covered under a single policy. Since the application didn't require purchasers to list what 
non-Apple equipment they had— only its dollar value— some owners may not realize their 
non-Apple computers aren't covered. 

NANOBYTES 



Volition Systems, Del Mar, CA, is now shipping its $295 Modula-2 compiler for the 
Macintosh. . . . Living Videotext, Mountain View, CA, announced a $245 version of 

Thinktenk for the 512K-byte Macintosh Advanced Micro Devices introduced the 

Am29300 32-bit bipolar microprocessor family. Included are a 32-bit parallel multiplier, a 
floating-point processor, a microprogram sequencer, and an ALU. . . . Digital Research 
Japan will adapt CP/M, CP/M-86, Concurrent DOS, and other system software to run on 
NEC's recently announced V series of 16-bit CMOS microprocessors. . . . Sinclair Research 
is developing a wafer-scale 512K-byte memory device. . . . TTGT Corp., Hampton, NH, an- 
nounced NH-Ada, a $225 subset Ada compiler for the IBM PC. . . . AT&T has published the 
"System V Interface Definition," which defines a minimum set of system calls and library 
routines that should be included in all operating systems based on its UNIX System V. . . . 
Microsoft is shipping Microsoft Networks 1.0 and MS-DOS 3.1, both of which add network 
capabilities to MS-DOS. . . . The FCC has authorized use of the TV vertical blanking interval 
for data transmission, which could mean software delivery by TV. The FCC had earlier 
cleared the way for broadcast of software over radio. . . . Versatron Research, Healdsburg, 
CA, introduced the $225 Footmouse, used to control cursor keys. . . . Lotus Development 
formally announced Jazz, its long-expected Macintosh product. The $595 program includes 
word-processing, spreadsheet, database, communications, and graphics functions but re- 
quires a 512K-byte Mac. Lotus also announced spelling-checker and text-outlining add-on 
products for Symphony. . . . Tbmcat Computer, Los Angeles, CA, announced the Tomcat 
3200-AT, which includes an 80286 processor, IBM PC AT-compatible expansion slots, 640K 
bytes of memory, one 1.2-megabyte floppy disk, a 20-megabyte hard disk, serial and 
parallel ports, and a color graphics card for $4529. . . . Maxell is ready to produce 514-inch 
floppy disks with a capacity of 6.5 megabytes for use in drives made by its parent com- 
pany, Hitachi. Maxell showed two metal floppy disks: a 10-megabyte 514-inch disk and a 
5-megabyte 3!/2-inch disk. Maxell also showed a 5!4-inch optical disk that stores 250 
megabytes per side. . . . Ttanstec Technology, Dublin, Ireland, announced its Hydra PC, 
featuring 800- by 512-pixel graphics in four colors or, optionally, 16- or 4-color graphics with 
a resolution of 1024 by 1024 pixels. With a 1.2-megabyte floppy disk, a 10-megabyte hard 
disk, and 512K bytes of memory, the Hydra PC will cost $4900. 



10 BYTE • JANUARY 1985 



Squeeze More Out Of Every 
On-Line Minute. 




Presenting the software 
package that makes your 
computer more productive 
and cost-efficient. 



CompuServe's new Vidtex™ is compatible 
with many personal computers sold today 
(including Apple,® Commodore® and 
Tandy/Radio Shack® brands). And it offers 
the following features*-and more-to let 
you communicate more economically 
with most time-sharing services (including 
CompuServe's Information Service). 

Auto-Logon. Lets you log on to a host 
simply and quickly by utilizing prompts 
and responses defined by you. Also allows 
quicktransmission of predefined responses 
to host application programs after 
logging on. 



Function Keys. Let you consolidate 
long commands into single keystrokes. 
Definitions can be saved to and loaded 
from disk file, allowing multiple definitions 
for multiple applications. 

Error-Free Uploading and Down- 
loading. CompuServe *B* Protocol con- 
tained in Vidtex lets you transfer from 
your computer to CompuServe and from 
CompuServe to your computer anywhere 
in the country. Also provides error-free 
downloading from CompuServe's exten- 
sive software libraries. 

Full Printer Support. Printer buffer 
automatically buffers characters until 
printer can process; automatically stops 
on-line transmission when full; and 
automatically resumes transmission 
when capacity is re-established. Also, lets 
you print contents of textual video screen 
or RAM buffer at any time. 



'Some versions of Ihe Vidtex software do not implement all features listed 

Vidtex is a trademark of CompuServe, Incorporated Apple is a trademark of Apple Computer, Inc. Commodore is a trademark of 
Commodore Business Machines. Radio Shack is a trademark of Tandy Corp. 



Capture Buffer. Saves selected 

parts of a session. Contents can be 
written to a disk file; displayed both on and 
off line; loaded from disk; and transmitted 
to the host. 

On-line Graphics. Integral graphics 
protocol displays stock charts, weather 
maps and more. 

If you are already a CompuServe sub- 
scriber, you can order Vidtex on line by 
using the GO ORDER command. Other- 
wise, check with your nearest computer 
dealer; or to order direct, call or write: 

Inquiry 68 

CompuServe 

P.O. Box 20212, 5000 Arlington Centre Blvd. 
Columbus, Ohio 43220 

1-800-848-8199 

In Ohio, call 614-457-0802 
An H&R Block Company 



Give people the took they need, 
and there is no limit to what they achieve. 




A nnouncing the first major 
breakthrough in word processing 
technology since WordStar. 

Now, state- of the- art 
comes easy 



Introducing WordStar 2000, a totally new 
word processing program from the makers 
of WordStar. 

WordStar 2000 removes all limits from 
word processing. From what you can create. 
From what you can achieve. 

Because WordStar 2000 lets you do 
everything. 

Easily. 

From windows, to undo, 

to spelling correction, WordStar 2000 

does it all. And more. 

WordStar 2000 gives you the works. 

"Windows" allows you to work on different 
documents— simultaneously. "Undo" lets you 
replace text you mistakenly removed. A built-in 
spelling corrector checks and corrects mis- 
spellings from over 97% of the most commonly 
used words. 

WordStar 2000 also has a "typewriter 
mode" to fill in forms or envelopes easily Plus 
"format sheets" which give you ready-made 



headings, tabs and margins at the touch of one 
key. It can even create and update footnotes. 

Finally, a truly integrated 
word processing system. 

WordStar 2000 goes well beyond words. 

It comes with a built-in five function calculator. 
A built-in mail merge enables you to mass pro- 
duce form letters. Get our special Plus package 
and you also get a built-in mail list data base that 
allows you to create, update and sort your own 
mailing lists. Also a built-in indexer. Not to 
mention built-in telecommunications capabilities. 

All integrated together, so you never have 
to leave the program. 

The only word processing program 

that interacts with you on your level, 

whatever your level. 

Before we created WordStar 2000, we studied 
the way people worked, and thought. We also 
drew from our experience with over 1,250,000 
WordStar owners. 



12 BYTE • JANUARY 1985 







As a result, the keys you 
press are the keys you'd expect to press ("c" for 
copy, "p" for print, etc.). You may also use your 
computer's function keys. Menus have been 
uniquely designed for easy access to all functions. 
And MicroPro's exclusive "tutor-in-your- 
computer w " makes learning fast and fun. 

WordStar 2000 is the easy word processing 
program you'll never outgrow. Of course, the 
original WordStar and WordStar for PCjr will con- 
tinue to provide substantial and proven word 
processing capability for those with more modest 
budgets. 

See your local MicroPro dealer today or call 
(800) 227-6703 [in CA (800) 632-7979] for the 
dealer nearest you. 

So you can remove all limits from what you 
can achieve. 



WORDSTAR 




Current WordStar owners can upgrade to WordStar 2000 Quickly and 
easily through their dealer, or by calling MicroPro Customer Update 
(800) 227-5609, 9am-3pm RS.T. 



Now there are no limits? MicroPro. 



Inquiry 235 



JANUARY 1985 -BYTE 13 



LETTERS 



QXDraw 



In reference to the letter "A Call for QX-10 
Support" in the August 1984 issue (page 
23)— there is at least one inexpensive pro- 
gram that is semi-educational for the 
Epson QX-10. 

The program I am talking about is 
QXDraw. It is available through your local 
Epson dealer or directly from American 
Small Business Computers. 

QXDraw is a graphics design tool that 
uses the graphics capabilities of the Epson 
QX-10. It allows someone unfamiliar with 
computers to design and draw figures, 
charts, schematics, or blueprints in no 
time. QXDraw has the capability to store, 
retrieve, and print figures drawn on the 
screen. In addition, it can fully manipulate 
figures and text by changing size, angles, 
and dimensions. 

Paula Mibb 

American Small Business Computers 

Pryor, OK 



Benchmarking 
UNIX Systems 



I have been using the UNIX operating 
system on various machines for several 
years. I am happy to see it gaining 
popularity in the microcomputer world. I 
enjoy reading the articles in your 
magazine on the C programming language 
and on anything dealing with UNIX, and 
I hope to see more in the future. 

I found the article "Benchmarking UNIX 
Systems" by David F. Hinnant (August 
1984. page 132) interesting and infor- 
mative. However. I would like to bring to 
your attention a few errors 1 found in that 
article. 

In the first benchmark (listing 1). the 
parent process should issue a wait system 
call after closing the pipe to wait for the 
child process to complete for two reasons. 
First, if the parent process terminates 
without waiting for the child process to 
complete, the reported elapsed (real) time 
may be too small, since the child process 
may continue reading from the pipe for 
a while after the parent has terminated. 
Second, unless the parent process issues 



the wait system call, the user and system 
times reported will be those of only the 
parent process, rather than the sums of 
both processes. 

In the results of the multitasking UNIX 
benchmark (table 3 and figure 1). the in- 
dicated number of concurrent processes 
is misleading. This number is actually the 
number of shell processes concurrently 
running tstsh. Each of these shells may 
have up to three child processes running 
concurrently (when executing the pipleline 
containing grep, tee, and wc). The user 
performing the benchmark has three ad- 
ditional processes: the shell running 
multi.sh. the time utility, and the shell in- 
terpreting commands from the user's ter- 
minal. In addition to this, there are at least 
three background processes: the swapper, 
init (the system initializer), and update. 
Thus, it is not surprising that some micro- 
computer implementations of UNIX were 
not able to concurrently run tst.sh more 
than three times. This would have resulted 
in a total of 12 to 18 processes, depend- 
ing on how many active child processes 
each tstsh had. Note that the limiting fac- 
tor here was probably the size of the 
system's process table and not an arbitrary 
limit of processes per user, as Mr. Hinnant 
suggests. 

Gilbert Detillieux 
Winnipeg, Manitoba, Canada 

Mr. Detillieux s letter brought to my at- 
tention a typographical error I had not 
caught. When developing the benchmark 
programs, I used two sources for each 
benchmark: one with comments and one 
without. This was because I usually had 
to enter (or have someone else enter) the 
benchmark sources by hand, and an un- 
commented source listing is much easier 
to read. Unfortunately, the line 

wait((int *)0); 

must have been inadvertently deleted 
from the commented version of the 
sources that I furnished to BYTE in 
machine-readable form. That line should 
appear immediately after the line 

printf("Error in parent closing \ rT); 

/ regret the error and thank Mr. Detillieux 
for bringing it to my attention. 



The second point Mr. Detillieux raises 
deserves some discussion. Upon reflec- 
tion, perhaps a better label for columns 
I through 6 would be "Number of Back- 
ground Submissions." However, I still con- 
tend that the inability of some of the 
microcomputer systems to complete the 
benchmarks is the per-user process limit. 
One would expect the process table size 
to be at least as large as the per-user pro- 
cess limit because even on single-user 
systems there is commonly more than 
one user. Consider the "roof-owned 
programs like update, cron, swapper, and 
init. Also, UNIX UUCP communications 
programs typically run under their own 
user ID. You would expect the implemen- 
tation to take this into account and to 
provide enough process table slots for all 
possible normal background processes 
as well as enough for every "real" user. 
David Hinnant 
Raleigh. NC 

On FORTH 



1 believe the FORTH standards committee 
has a death wish because it continues to 
create new dialects with each "standard" 
it creates. I am concerned that readers will 
be turned off by FORTH when they read 
TORTH-83: Evolution Continues" by C. 
Kevin McCabe (August 1984. page 137). 
A careful reader will realize that FORTH-83 
is more revolution than evolution from 
FORTH-79. 

If the FORTH standards committee used 
new names, new dialects would not have 
to be created. For example, the FORTH-83 
DO LOOP and DO +LOOP are very dif- 

{continued) 



LETTERS POLICY: lb be considered for pub- 
lication, a letter must be typed double-spaced on 
one side of the paper and must include your name 
and address. Comments and ideas should be ex- 
pressed as clearly and concisely as possible. 
Listings and tables may be printed along with 
a letter if they are short and legible. 

Because BYTE receives hundreds of letters each 
month, not all of them can be published. \£tters 
will not be returned to authors. Generally, it takes 
four months from the time BYTE receives a let- 
ter until it is published. 



14 BYTE • JANUARY 1985 



WHO SAYS YOU CANT TAKE IT WITH YOU"? 




When weatlntertec intro- 
duced our new HeadStart™ com- 
puter we said "it's the fastest, 
smallest, most powerful business 
computer in its class." 

What more could we say? 

How about "it's also portable" 

Every HeadStart computer 
comes with its own easy-carrying 
handle. You can choose between 
a full size keyboard or a special 
compact version that snaps easily 
on the front of the screen. Either 
way, you get all the great features 
that make HeadStart unique. A 
big twelve inch screen, eight and 
sixteen bit processors, upgrad- 
able to one megabyte and it's 
networkable up to 255 users. 

We named our new business 
computer "HeadStart" because 



that's exactly what itil give you. 
And because it's also portable, 
you can take it anywhere. 

Well, almost 

For more information call us 
at (803) 798-9100 or write: 
Intertec, Dept "HeadStart;' 2300 
Broad River Road, Columbia, SC 
29210. 




intertec 



HeadStart Standard Features: 

Size: 15.75"wide, 12.75"deep, 11.30" high. 
Ufeight: 25 lbs. 

Processors: Z80A {8 bit) and 8086 (16 bit). 
Memory: 128Kto 1MB depending on model. All models 
are expandable to 1MB. 

Disk Storage: 500K to 1MB (unformatted) on a 3^" 
Micro-Disk. RAM disk feature emulates second system 
drive. Optional ?>W or 5^" external drives. 
Display: 12"(diagonal) P31 phosphor, non-glare screen, 
25 lines x 80 or 132 columns. 
Keyboard: Detachable with 104 total keys. A port- 
able version snaps onto the front screen for easy 
transportability. 

Disk Operating Software: XP/M 80 for 8 bit 
"MS DOS for 16 bit IAN DOS for multi-user 8 or 16 
bit operation. 

'Concurrent CP/M 86 optional. 
Interfaces: One RS 449/RS 232 compatible serial port. 
One Centronics compatible parallel printer port 
External data bus. Coaxial communications interface. 
External disk I/O interface. Optional network print 
spooling interface. 

Networking: Up to 255 HeadStarts may be connected 
via a coaxial, multi-user network into one of 2 optional 
data storage systems. 

Optional Data Storage Systems: Two models are avail- 
able. A 10MB, 5tf" system is expandable to 20MB. A 
50MB, 8" system {25MB fixed, 25MB removable) is 
expandable to 545MB in 165MB increments. 

*CP/M 80and Concurrent CP/M 86are regislered trademark; of Digital Research. 
"MS DOS is a registered trademark of Microsoft. 



Inquiry 181 



JANUARY 1985 'BYTE 15 



A COMPUTER 
PROGRAM 

DELIVERED VIA 
SATELLITE! 




The Computer Chronicles, a half- 
hour weekly television series brings 
you an in-depth look at the latest 
developments in the computer world. 

Correspondent Stewart Chefeit and 
Gary Kildall, creator of CP/M provide 
interviews with industry leaders plus 
news and information from Silicon 
Valley and around the world. 



The Computer Chronicles, every 
week on a public television sta- 
tion near you. 



(Check local listings for time and channel.) 

Produced by KCSM, San Mateo, CA and WITF, Harrisburg, PA with funding from McGraw-Hill's BYTE and 

POPULAR 

computing magazines. 



M 



\ • RESOLUTION • REVOLUTION I 



S100 GRAPHICS -8 COLOR- 1024 by 1024 Resolution- 1 BOARD 






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The heart of the board is the 7220 
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allowing vector and arc drawing 
speeds of 1 .3 million pixels per se- 
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C language driver source for draw- 
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• 3 million pixel display memory 
with 1024 by 1024, 1200 by 872, or 
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SOFTWARE 

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Contact us for applications software currently available 

ILLUMINATED TECHNOLOGIES INC 

3005 N. May • Oklahoma City, Oklahoma 73107 
(405)943-8086 



DEALERS 



LETTERS 



ferent from the FORTH-78 DO LOOP and 
DO + LOOP. I would like to use both ver- 
sions of FORTH and I would be able to 
if the FORTH-83 commands were D083, 
LOOP83, and +LOOP83. More impor- 
tant, I would use the new keywords only 
when their new properties are relevant 
and I would continue to use the proven 
FORTH-78 keywords as before. In this way 
evolution can take place with a minimum 
of risk. (Note my use of FORTH-78; the 
FORTH-79 standard is incomplete and 
thus useless to me.) 

As an experienced FORTH programmer, 
I find the changes from FORTH-78 listed 
in table 3 (on page 4 1 2) to be marginal and 
mostly unnecessary. For example, having 
/ and /MOD leave floored quotients is a 
plus, but the FORTH-78 names create a 
dialect. The plus is overwhelmed by the 
dialect minus. If the standards committee 
had used the names /83 and /MOD83. 
you would be able to use all of the 
keywords without any dialect. Further- 
more, implementations of the new key- 
words have not yet been fully evaluated; 
their practical consequences are not 
known. 

I think the new definitions in FORTH-83 
are not significant improvements over the 
old ones-additions to FORTH-78 would 
have made more sense. 

I suggest that the FORTH standards 

committee address new areas such as 

graphics, mathematics, and databases in 

lieu of massaging yesterday to death. 

Nicholas L. Pappas, Ph.D. 

Oakland, CA 



Alternatives to In-Search 



As an information broker and consultant 
with I0 years of experience in searching 
various on-line information-retrieval 
systems, including Dialog. I would like to 
comment on the July BYTE West Coast. 
"Trends in lelecommuni cations" by John 
Markoff (page 341). especially the section 
subtitled "In-Search" (page 342). 

In-Search purports to make it easier for 
both the novice and the experienced user 
of Dialog to interact with the system, but 
does it? On examination of the package 
it appeared to me that the introduction 
of this intermediary to the Dialog system 
would at most save the user only seconds 
of on-line connect time The $399 that ln- 
Search costs could be better spent on 
some other options available; for exam- 
ple, the Online leaching and Practice 

[continued) 



16 BYTE • JANUARY 1985 



Inquiry 410 



Inquiry 262 — ► 



I7JTTTI7 



WHILE BALANCING THE BOOKS. 



Go ahead. Slip into something comfortable. Ware the 
most comfortable, most sophisticated microcomputer ac 
counting software in the world. Open Systems. Account- 
ing software so rich in features, it can handle the complex 
problems of today's small business with unprecedented ease. 
Software so flexible, it runs on all popular microcomputers. 
And can grow right along with your business needs. 

No other accounting software line is so complete. With a 
choice of General Ledger, Accounts Receivable; Accounts 
Payable, Inventory, Payroll, Job Cost, Sales Order, Purchase 
Order and Fixed Assets as well as a 



Report Writer that links your accounting data to popular 
spreadsheets, word processors and graphics software. 
Assuring you the luxury of a perfect software fit. 

The fact is, Open Systems meets the needs of todays 
small business so completely, it's become one of the best 
selling lines of accounting software on the market. More 
than 300,000 accounting products are providing compre- 
hensive accounting solutions for businesses throughout 
the world. Now that's comforting. Call Open Systems 
right now. And get your mind off the books. 

For the dealer nearest you call 1-800-328-2276 




OPEN SYSTEMS • 430 OAK GROVE 



UC( 



Inquiry 29 




It's as Simple as Saying 
"On" and "Off" 

Plug in the new MICRO-EAR™ Voice 
Command System, and experience the 
incredible thrill of talking with your 
personal computer. Become virtually 
keyboard-independent, because your 
computer will now understand and obey 
your vocal commands. 
Just Think of the Applications 
Speak a single word or phrase and you: 
invoke functions . . . load and run 
programs . . . enter data . . . perform 
practically any keyboard operation. 
You Select the Vocabulary — 
and Change It at Will 
Input up to 256 words or short phrases 
you select, define, and train to your 
voice. MICRO-EAR achieves 95-98% 
recognition accuracy . . . and retains its 
training even when turned off! 



TALK 

to your 
computer 

FREE Voice-Activated Software 

You get demonstration software for 
the IBM™ PC and Apple™ II computers 

• voice-activated programs for a type- 
writer, a calculator, and voice-command 
video games • high quality microphone 

• plus communications software for the 
IBM PC and compatibles. 

Software for the IBM PC includes 
EAR-DOS™ ,for concurrent 
voice/keyboard input capability while 
running applications software. 
And because it plugs into a standard 
RS-232 interface port, you can use 
MICROEAR with just about any 
personal computer. MICRO-EAR Voice 
Command System — suggested price 
$579.00. 

Act Now — 

Call or write today for more information. 



arc tec J systems 

9104 Red Branch Rd. . Columbia, MD 21045 . (301) 730-1237 

Micro«Ear and EAR-DOS are trademarks of Arctec Systems, Inc. Apple is the trademark of Apple Computer, Inc. 
IBM is the trademark of International Business Machines Corporation. 




1 



PC FORTH' 

IBM PC & XT, 

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Apple II, 

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MSDOS computers. 



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hotline, updates, and newsletters. 



Laboratory Microsystems Incorporated 

Post Office Box 10430, Marina del Rey, CA 90295 
Phone credit card orders to (213) 306-7412 



LETTERS 



(ONTAP) files. These are subsections of 
several files available for $I 5 per connect 
hour, plus less than $I0 per connect hour 
for telecommunications charges. Another 
option, popular with personal computer 
users, is a subscription to Knowledge 
Index, a subset of the complete Dialog 
files, available after 6 p.m. on weekdays 
and on weekends for $24 per hour, all 
inclusive. 

Therefore, for the price of the In-Search 
package, you can have about 1 5 hours of 
search time. Since a typical search should 
take less than 10 minutes, this translates 
into a lot of searches. As well, to use the 
In-Search package you have to learn more 
key functions and commands, all of which 
are no less complicated than the few 
Dialog commands you have to learn to use 
the database. With or without the In- 
Search package you still must learn and 
understand the concepts of Boolean logic 
and search building. 

One of the beauties of Dialog is that it 
is available throughout the world for a 
good portion of each week. Once you 
have learned some simple commands and 
concepts, made more mnemonic and user 
friendly in Knowledge Index, you can 
search the system wherever you happen 
to be and with whatever equipment is 
available. How unfortunate then, to intro- 
duce the In-Search crutch if you cannot 
operate Dialog without it. 

In addition, there are other telecommu- 
nications software packages that are 
cheaper and are not tied to a particular 
information-retrieval system but that, 
nevertheless, allow downloading and edit- 
ing of results. 

In conclusion, I believe that this package 
is indeed an example of patronizing the 
naive user and never giving him a chance 
to grow up. Currently In-Search and similar 
tools are being reviewed by several pub- 
lications. It is evident from reading these 
reviews that the reviewers have been 
unable to intensively test and evaluate the 
products. I would suggest that balanced 
reviews can only be carried out by infor- 
mation professionals who know what to 
look for. 

Mary M. Nash 
Ottawa, Ontario, Canada 



BASIC09 



Wendell Brown's desire for a well-struc- 
tured BASIC that runs on the Apple II duly 
1984 Letters, page 16) would probably be 

[continued) 



18 BYTE • JANUARY 1985 



Inquiry 197 



And you thought there was only 
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—AST's Preview! brings high resolu- 
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monochrome screen. And there's 
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Preview! provides all the features 
and functions you'd expect, like 
bit-map addressing the maximum 
supported 720 horizontal pixels 
by 348 vertical lines for two pages of 
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port and Hercules™ bit-mapped 
graphics card compatibility. 

It works with all kinds of soft- 
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New generation integrated business 
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Then there's the nonstandard fea- 
tures AST is famous for— consistent 
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sive documentation, service, support 
and extra value. We include our 



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So you can settle for the com- 
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best— Preview! only from AST. For 
more information and dealer loca- 
tions call our Customer Information 
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Or write, AST Research, Inc., 2121 
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• 64K Screen Memory 

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Preview! and Super Rtk trademarks of AST Research, 
Inc. IBM trademark of International Business Ma- 
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Hercules Computer Technology. Lotus 1-2-3 and 
Symphony trademarks of Lotus Development Corp. 
Fmmavork trademark of Ashton-Tate. \Nord trade- 
mark of Microsoft. Inc. MctaWlNDOW trademark 
of Metagraphis. 



R€S€MCH INC. 

Inquiry 3 for Dealers. Inquiry 4 for End-Users. 









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registered trademark, and DATA GENERAL/One is a trademark of Data General Corp. © 1984 Data General Corporation, Westboro, MA 



Inquiry 376 



JANUARY 1985 -BYTE 21 



LETTERS 



satisifed by BASIC09. which runs under 
the 0S9 operating system and therefore 
requires a 6809 card. The card and soft- 
ware are available from: Stellation Two, 
POB 2342, Santa Barbara. CA 93120. 

BASIC09 features IF. . THEN . . .(ELSE) 
. . .ENDIF, REPEAT. . .UNTIL, WHILE. . . 
DO. . .ENDWHILE, LOOP. . .ENDLOOR 
EXITIF. . THEN. . .ENDEXIT, and FOR 
, . TO. . .(STEP). . .NEXT control struc- 
tures. IF. . THEN . . . ELSE statements can 
be nested. The language compiles to an 
intermediate code, which is then inter- 
preted, and. unlike CBASIC. the compiler/ 
decompiler is interactive and flags most 
errors immediately, 

Stellation Two provides excellent sup- 
port and has a reasonable update policy. 

F. KUECHMANN 

Vancouver, WA 

Modula-2: 

Two Dissenting Views 



David B. Moffat's "UCSD Pascal vs. 
Modula-2: A Dissenting View" (August 
1984, page 428) was a pleasure to read— a 
sort of the-emperor-isn't-wearing-any- 
clothes type of critique. I agree with Mr. 
Moffat's objections to separate input/out- 
put statements for every variable type and 
to the case sensitivity of the language. The 
language has one other feature that in my 
opinion is a nuisance— the required use of 
IMPORT statements to specify the 
libraries in which modules exist. Not only 
do you have to know the names, purposes, 
and acceptable arguments of procedures 
that are usually considered "standard." but 
you also have to know where those 
modules are located in order to be able 
to call them into a program. This is the sort 
of bookkeeping task that higher-level lan- 
guages were invented to avoid. 

As an application programmer 1 fail to 
see how Modula-2 is an advance in meet- 
ing my programming needs. 1 am far hap- 
pier with llirbo Pascal, which lets me set 
up libraries (though not precompiled) that 
are easily called into programs with an 
INCLUDE compiler command. 

TUrbo Pascal is case-insensitive and pro- 
vides convenient low-level capabilities for 
bit manipulation and direct access to 
memory and MS-DOS interrupts. 

Perhaps systems programmers, for 
whom Modula-2 was developed, -can ap- 
preciate the virtues of that language— but 
1 do not think that Modula-2 is a superior 
applications language. Every time 1 read 
one of Jerry Pournelle's glowing comments 
about Modula-2, 1 react with the question: 



But has he tried programming in that lan- 
guage? 

John Figueras 
Victor: NY 

After reading the articles concerning 
Modula-2 in the August 1984 BYTE, 1 feel 
compelled to comment. On the whole, I 
thought the articles were well written and 
gave a good overview of the language. 
However, I believe that 1 detected a cer- 
tain amount of chauvinism on the part of 
those committed to Modula-2, and it is 
this point 1 would like to address. 

Engineers have a tendency to fall in love 
with certain designs, and software engi- 
neers are no exception. We put so much 
time and energy into the designs we work 
with that it is as if we become married to 
them and can no longer look at them with 
objectivity. 1 know I have been guilty of 
this on many occasions, and I am sure that 
others can recognize this capacity in 
themselves. However, as software engi- 
neers we have an obligation to be objec- 
tive when considering designs and to ad- 
dress any legitimate concerns that are 
raised. 

Currently we are confronted with debate 
between the proponents of both Modula- 
2 and Ada. Being in the Ada camp, I would 
like to have the Modula-2 devotees ad- 
dress my legitimate concerns regarding 
this language. All too often the debate 
degenerates to nit-picking about this or 
that feature of Ada being clumsy or inef- 
ficient or not theoretically pure enough. 
I can play this game as well as the next 
engineer, but 1 won't because I feel that 
this only results in the chauvinism 1 speak 
of. My single largest concern is one 1 feel 
is carefully avoided in debates of this 
nature, and it desperately needs to be ad- 
dressed in an objective manner by anyone 
advocating the use of a new language. 

Ada, as a language, has one great ad- 
vantage over all others. It is rigidly stan- 
dardized and the standard can be effec- 
tively enforced. While it may have many 
serious drawbacks, which opponents are 
quick to point out, lack of standardization 
is not one of them. Even a poor standard, 
enforced by the entire might of the 
Department of Defense, is infinitely 
superior to no standard at all. My ques- 
tion to the Modula-2 people is how do 
they propose to ensure that a software 
commitment on one machine using one 
compiler can be salvaged when migrating 
to another machine with a different com- 
piler? An ANSI standard alone, should one 
be produced, is not always enough. 

1 own a company that has committed 



itself to software development in Ada. We 
believe that our success will hinge on our 
ability to generate software that is reliable, 
reusable, and above all else, transportable. 
Reliability is dependent only on our 
abilities as software engineers and the 
quality of the tools we select. Reusability 
is provided in both Modula-2 and Ada 
through their ability to generate libraries 
of general-purpose utility routines. How- 
ever, only Ada provides a language refer- 
ence manual so precise and detailed that 
it has spawned a new generation of "lan- 
guage lawyers." a trademarked name that 
guarantees the DOD the ability to enforce 
the standards laid down in this manual, 
and a validation procedure that will test 
every Ada compiler against the standard 
before it can bear the name. What does 
Modula-2 offer me in this respect as a 
businessman to justify a software commit- 
ment to this language? 

Ada has some flaws: complexity, lack of 
certain theoretical advantages, the 
massive size of its associated compilers, 
and others. But because we have an ef- 
fective standard to work with, I feel that 
we can produce software at a lower cost 
to our clients. The logic is simple: if we stay 
within the standard, and if our clients have 
a validated Ada compiler, any software 
written on our system should run on their 
system. We spend less time making patch- 
work fixes and adjustments, and we can 
bring in software tools developed on other 
projects without fear of needing to modify 
the tools. 

Modula-2 is a good language. It incor- 
porates some of the best developments 
in the field of theoretical computer 
science to come along in recent years. 
However, 1 think that it will have some 
serious problems in the future if the ques- 
tion of portability and standardization is 
not addressed quickly. 

Marin D. Condic President 

Modular Systems Research 

Kalamazoo, Ml 

Caltechs 
Computer Network 



The article "A Computer on Every Desk" 
by Donna Osgood (June 1984. page 162) 
was interesting but failed to mention the 
educational computing activities at the 
California Institute of Technology (Caltech). 
I feel our program has several unique 
features. A fully functioning campus-wide 
network links all our computers. The net- 
work was completed this summer by a 
team of Caltech students that installed 



22 BYTE • JANUARY 1985 



LETTERS 



outlets in the dormitories. The following 
description of our program is excerpted 
from the June 1984 edition of Caltech News. 

Caitech has received major grants from 
IBM and from Hewlett-Packard to support 
its educational computing project. 

From IBM. Caltech will receive several 
hundred IBM Personal Computer worksta- 
tions, a hostprocessor. several graphics sub- 
systems, and technical support, all to be 
used in the development of educational 
software. 

From Hewlett-Packard. Caltech will be re- 
cipient of 22 color desktop computers and 
support equipment for an introductory com- 
puting course, an introductory solid-state 
electronics course, and a solid-state elec- 
tronics laboratory. In the first course, fresh- 
men will use the Hewlett-Packard computers 
to learn programming, and in the last two, 
undergraduates will use the computers to 
design electronic devices. The equipment 
is worth $528,694. 

Along with the IBM equipment will come 
a cash grant of $150,000 to purchase 
adapter cards to tie the IBM workstations 
to Caltech's campus-wide high-speed com- 
puter network. IBM has also assigned a tech- 
nical support person to the project during 
the three years that the company is 
involved. . . . 

When it is fully implemented over the next 
three years. . , . (the) Caltech educational 
computing project will include more than 
800 workstations. Linked by the campus 
computer network, they will be grouped in 
clusters of up to 10 or 20 machines in 
classroom areas, laboratories, the com- 
puting center, and libraries. 

Faculty and teaching assistants will have 
individual workstations to prepare course- 
ware Students will have network outlets in 
their dormitories, enabling them to com- 
municate with the campus system, using 
their personal computers. All the individual 
units will be tied to campus mainframe 
computers. , . . 

The Caltech project is aimed primarily at 
developing courseware for ail the disciplines 
at the Institute Educators will emphasize 
creation of specialized graphics software 
that will enable students to "see" abstract 
concepts in visual terms. . , 

Besides IBM and Hewlett-Packard, other 
manufacturers contributing to the project in- 
clude Data General, Digital Equipment Cor- 
poration. Evans & Sutherland, and Tektronix. 
Howard Rumsey Jr., Ph.D. 
California Institute of Technology 
Pasadena, CA 

Scout 



l would like to tell BYTE readers about an 
IBM PC XT product that has saved me a 
great deal of time, money, and frustration 

[continued) 



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EasyLink: 6277-1271 




Inquiry 39 



JANUARY 1985 -BYTE 23 



LETTERS 



over the past four months. Scout, a Com- 
puter Insights product, provides a set of 
functions that greatly enhance those pro- 
vided by DOS 2.X for using subdirectories. 
Scout allows you to define "imaginary 
drives." These drives model DOS I.X disk 
directories and allow programs that do not 
understand DOS 2.X paths to access files 
in subdirectories. This makes many older 
programs usable and will save you money 



by eliminating the need to buy new DOS 
2.X versions. The "imaginary drives" can 
be defined as read-only and provide pro- 
tection of valuable data. Scout can be 
used to prevent catastrophes such as your 
accidentally formatting your hard disk. 
Although these capabilities are useful, 
Scout's greatest asset is its ability to search 
subdirectories for data, profile, help, over- 
lay, etc., files in a manner similar to. but 






What do you get when you cross 
1200 baud, free on-line time, 
and extra features at a price Hayes 
can't match? 



Data Rate? 

The MultiModem 
gives you a choice — 
either 1200 or 300 bits 
per second. So you can 
go on-line with the 
information utilities. 
Check out bulletin 
boards. Dial into corpo- 
rate mainframes. Swap 
files with friends. 

On-L/'ne Time? 

With the Multi- 
Modem you get 
CompuServe's 
DemoPak, a free two- 
hour demonstration of 
their service, and up to 
seven more free hours 
if you subscribe. You 
also get a $50 credit 
towards NewsNet's 
business newsletter 
service. 

Features & Price? 

Of course, the 
MultiModem gives you 
automatic dial, answer, 
and disconnect. Gives 
you the Hayes- 
compatibility you need 
to support popular 
communications soft- 
ware programs like 
Crosstalk, Data Cap- 
ture, our own MultiCom 
PC, and dozens of 
others. Gives you a 
two-year warranty, 
tops in the industry. 



Inquiry 248 



Trademarks— MultiModem. MultiCom 
PC: Multi-Tech Systems. Inc. —Compu- 
Serve: CompuServe Information Sewices. 
anH&R Block company— NewsNet: 
NewsNet. Inc.— Crosstalk: Microstul. 
Inc.— Data Capture: Southeastern Soft- 
ware— Smartmodem: Hayes Microcom- 
puter Products, Inc. 



MultiModem. 



But Better? 

Yes. The Multi- 
Modem gives you fea- 
tures the Hayes 
Smartmodem 1200™ 
can't match. Features 
like dial-tone and busy- 
signal detection for 
more accurate dialing 
and redialing. Like a 
battery-backed mem- 
ory for six phone num- 
bers. All at a retail price 
of just $549— com- 
pared to $699 for the 
Smartmodem. 

What do you get? 
The new MultiModem, 
from Multi-Tech Sys- 
tems. Isn't this the 
answer you've been 
looking for? 



For the name of 
your local distributor, 
write Multi-Tech Sys- 
tems, Inc., 82 Second 
Avenue S.E., New 
Brighton, MN 55112. 
Or call us at 
(612)631-3550. 







MultiTechflb 

Systems ^Qr 
The right answer every time. 



more flexible than, the DOS 2.X PATH 
command. This saves a great deal of disk 
space because it lets you maintain only 
one copy of files used by programs run 
in many different subdirectories. 

I have yet to find a bug in Scout. I recom- 
mend this product to anyone who uses 
DOS 2.X, especially if you think subdirec- 
tories are a good idea and ought to be 
more useful than they currently are. 

If you're interested, you can obtain 
Scout from Computer Insights, POB 
H0097, Pittsburgh, PA 15232. 

Paul Crumley 
MonroeviUe, PA 



"Good bye, Teacher 
Explained 



Stephan L. Chorover recently referred to 
me in "Cautions on Computers in Educa- 
tion" (June 1984, page 223) as 

. , ,a behavioristically inclined psychologist 
who was one of the leading developers of 
an earlier system of automated instruction 
inspired by the work of B. F. Skinner. The 
so-called "Keller Plan" is one of the old 
theories that has died along with many 
other well-intended measures for increas- 
ing educational productivity through auto- 
mation. 

In the interest of veracity it should be 
noted that personalized instruction, to 
which Mr. Chorover refers, is not a theory, 
but a teaching method; the method is alive 
and well and is a frequently used alter- 
native to the group-instruction-by-lecture 
method; personalized instruction has 
nothing whatever to do with automation 
(as Mr. Chorover would know if he had 
read the paper "Good-bye, Teacher. . ." 
to which he makes a reference); and it was 
inspired by, but not modeled after, B. F. 
Skinner's work on individualized instruc- 
tion, for which we were all grateful. I am 
not just "behavioristically inclined," I am 
a behaviorist and have been one for more 
than 50 years. 

Fred S. Keller 
Chapel Hill, NC 



One Reader s 

"Perfect" Microcomputer 



In regard to Richard Knop's concept of the 
perfect microcomputer (July 1984 Letters, 
page 26): The Olivetti M-20 computer uses 
the Z8000 microprocessor and meets 

[continued) 




Introducing the Hercules Graphics Card 
for the technical user. 



OK. We confess. The 
Hercules Graphics Card in 
the picture above isn't a 
special version for the tech- 
nical user. 

In fact, it's exactly 
the same as the standard 
Hercules Graphics Card 
running programs like 1-2-3™ 
and Symphony™ in more 
than 100,000 IBM® PCs. 

We just wanted to make 
the point that the Hercules 
Graphics Card is not only 
big with business users— it's 
also the most popular high 
resolution graphics card for 
the technical user. 

Why? We run more 
software than anyone else. 

The Hercules Graphics 
Card is supported by more 
technical software than any 
other hi-res graphics card. 

There a re word proc- 
essors that 
can produce 
publication 
quality documents with 
mathematical formulas. 

There are programs 
that enable your PC to 
emulate a graphics terminal 





and run mainframe graphics 
software. 

There are toolkits of 
graphics utilities that can be 
linked to popular program- 
ming^languages. 

There are CAD pro- 
grams that can provide 
features normally associated 
with $50,000 systems. 

And we supply free 
software with 
each card to do 
hi-res graphics 
with the PC's 
BASIC. No one else does. 

Hardware that set the 
high performance standard. 

When we introduced the 
Hercules Graphics Card in 
August, 1982, it set the 
standard for high resolution 
graphics on the PC. 

But we didn't stop there. 
In the past two years, we've 
continually refined the 
original design. 

Today's Graphics Card 
gives you two graphics 
pages, each with a resolu- 
tion of 720h x 348v, and a 
parallel printer port- 
standard. 




A 2K static RAM buffer 
elegantly eliminates scrolling 
flicker. And our exclusive 
safety switch helps prevent 
damage to your monitor. 

Convinced? Good. Now, 
how about a little color? 

Should you want IBM 
compatible 
color graphics 
for your sys- 
tem, then the 
new Hercules Color Card is 
the smart way to go. 

It gives you a parallel 
printer port and a size small 
enough to fit in one of the 
XT's or Portable's short slots. 

And both Hercules 
cards are compatible with 
the new AT™ and backed by 
our two year warranty. 

Call 800 255-5550 Ext. 
408 for the name of the 
Hercules dealer nearest you 
and we'll rush you a free info 
kit. See why the company 
that made the first graphics 
card for the IBM PC still 
makes the best. 

Hercules. 

We're strong on graphics. 



Address: Hercules, 2550 Ninth St., Berkeley, C A 94710 Ph: 415 540-6000 Telex: 754063 Trademarks/Owners: Hercules/Hercules Computer Technology, 1-2-3, 
Symphony/Lotus Development; IBM, AT/International Business Machines 



Inquiry 160 



JANUARY 1985 -BYTE 25 



Achieve laboratory automa- 
tion at low cost— connect a 
DAISI™ (Data Acquisition and In- 
strument Systems Interface) to 
your Apple® //or He Computer. 

DAISI peripheral devices... 

■ Interface with Apple // and 
Apple lie Computers and their 
lookalikes 

■ Work with all popular language 
systems 

■ Come with cable, instructional 
diskette and comprehensive 
manual 



DAISI and Apple work together as 
a single system to measure, 
monitor, time, analyze, control and 
record a wide variety of research 
and testing functions. 

DAISI peripherals plug easily into 
any Apple expansion slot, ready 
to be used in chromatography, 
environmental data collection, 
evoked response, gas analysis, 
spectroscopy, signal processing, 
solar heating, mechanical mea- 
surement, structural testing, and 
many moref unctional applications. 

The AI13 analog-to-digital con- 
verter reads instruments and sen- 
sors and has its own external unit 
for easy cable access. 



DISCOVER NEW 
HORIZONS IN 

AND KEEP YOUR COSTS DOWN TO EARTH 



Here's a rundown on the 

DAISI Peripherals: 

AI13 12-Bit Analog 

Input Interface..... .......$550 

■ 16 input channels 

■ 20 microseconds conversion time 

DI09 Digital Interface 

with Timers. ..$330 

■ timing and interrupt capability 

■ direct connection to BCD digits, 
switches, relays 

AO03 8-Bit Analog 

Output Interface ....... $195-3437 

■ up to 8 independent channels 

■ range and offset adjustable 
AI02 8-Bit Analog 

Input Interface............. $299 

■ 16 input channels 

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Plus the SC14 system for front- 
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Using AMPRIS is as easy as in- 
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LETTERS 



most of Mr. Knop's other requirements. 

I had come'to the conclusion that since 
the IBM does not use the Zilog 8000 or 
the Motorola MC68000, computers with 
these microprocessors must not exist; one 
certainly cannot find articles in BYTE in- 
dicating that there are software programs 
that are compatible with the 8000. 

It is frustrating, to say the least, to always 
have to contact Olivetti to learn of pro- 
grams I can use with the Z8000. 

C. L. Norris 
West Palm Beach, FL 

Icons versus Commands 



In the 1 960s it was batch processing, and 
I felt so modern sitting at a card punch. 
Around 1970, a number of batch systems 
introduced timesharing "options," and I 
signed up for a terminal days in advance. 
(For a number of years I clung to my card 
decks as a backup; then they were phased 
out.) In the mid-1970s, minicomputers 
were the rage, and operating systems 
came out that were designed from the 
start to be conversational; henceforth I 
never wanted to return to the data-entry 
kind of system. Around 1980. microcom- 
puters became powerful enough to be 
useful, and the cathode-ray tube has 
become a fact of life. 

Now the issue is icons versus com- 
mands, a trend that BYTE apparently has 
not caught on to. 

I assert that icons are an advance over 
command-driven systems comparable to 
the advance from cards to the cathode- 
ray tube. It is not simply a matter of add- 
ing a new capability to an old design: after 
being introduced to icons (you guessed 
it: I now own a Macintosh). I am still 
curious to see what wonderful software is 
available on other systems, but I find that 
I have lost the patience to plow through 
a manual and gobble up the keywords, the 
syntax, the options, and the modes. To- 
day I want it in dynamic pictures or not 
at all, and I don't want to have set up 
statements underneath, like punched 
cards in a drawer. 

Francisco Jose Oyarzun 
Los Angeles, CA 

More Mac Feedback 



Two letters in BYTE have caused me to 
take word processor in hand. The first let- 
ter was from Robert Lurie ("More Mac 
Reactions" May 1984, page 16) concern- 

[continued) 



26 BYTE • JANUARY 1985 



Inquiry 175 



With Macalendar, 
You Would've Been on Time 






.* 



m 





!**4 




itf X\3 






alp 




o'ffcm 


/ V 




§j5^ -~ " ■■* 


fc^-^- — ^^ .. 






"^V^r-^ 











xld., 



For detailed reminders or notes, 
take advantage of Macalendar's 
notepad. Simply enter memoranda for 
the appropriate day, and the information 
will be waiting for you when you call it 
up. Plan weeks - even years! - ahead. 
And never again miss another appoint- 
ment, birthday, class, whatever. 

Run out of room on your notepad? 
Just "turn the page" and fill unlimited 
pages with all your information. 
Macalendar lets you document phone 



calls, assemble "to-do" lists, plan out a 
daily schedule, etc. 

Now, finally, losing yourself in your 
work doesn't have to mean losing track 
of time . . . thanks to Macalendar. * 

Macalendar, $89; Lisa Desktop Calendar, $295 



I! 



idex 



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We know how easy it is to 
become so totally immersed in your 
work that you forget all about such 
things as 10 o'clock appointments, 
luncheon dates, or even (shudder) 
Board Meetings. That's why we 
designed Macalendar to help you 
plan, organize and implement your 
busy schedule. 

Macalendar is a powerful time 
management tool for the Macintosh® 
which uniquely combines a calendar 
with an alarm and a notepad - all 
designed to keep you on schedule and 
up-to-date. Best of all, Macalendar 
runs concurrently with all other 
programs, so it's always there when you 
need it. 

Once you've entered important 
times and dates into Macalendar, you 
can go on to work on other applications. 
Macalendar will automatically interrupt 
your program with a chime to remind 
you of your appointment. There's no 
separate disk to insert; Macalendar is 
an ever-present, integral part of your 
Macintosh. 

^Expanded version of Macalendar, the Desktop Calendar,® is available for the Lisa. Macintosh is a trademark of Apple Computer, Inc. Lisa is a registered trademark of Apple Computer, Inc. 
Inquiry 365 JANUARY 1985 • BYTE 27 




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Jerry Pournelle, 
Byte, July 1984 






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LETTERS 



ing Apple's not putting the floating-point 
software in the Mac's ROM. He mentioned 
that Apple programmers had exhausted 
their ROM space, so they moved the soft- 
ware to RAM. How can you exhaust ROM 
space unless you have reached the cen- 
tral processor's memory-addressing limits? 
The answer is: you cannot. In this case, 
they hadn't run out of ROM space— the 
fact that a 512K-byte RAM Mac is possi- 
ble refutes that remark. You have to freeze 
the ROM at a point sometime, however, 
and possibly the company forgot to add 
the floating-point software before it froze 
the final version of the ROM at 64K bytes, 
so they put it in RAM. 1 have to agree with 
him, though; if the floating-point will run 
25 percent slower out of RAM than ROM, 
then Apple's programmers did make a 
design mistake. It may be too late to do 
anything about it. though, because too 
many Macs have been distributed to 
change the situation. 

The second letter 1 want to comment on 
was from David Nibbelin in the June 1984 
issue ("American as Apple Pie." page 14). 
1 have seen patriotism before, but this is 
ridiculous. I cannot understand why he Is 
so angry that the Mac uses a Sony disk 
drive. If Mr. Nibbelin hasn't noticed, the 
computer revolution is not just happen- 
ing in the United States but all over the 
world, and if advanced computers are to 
be built, technology must be used from 
wherever it is found. If he is really against 
non-American technology, then he will 
also boycott the Radio Shack Model 100. 
the AT&T PC. and almost any computer 
that uses 256K-byte RAM chips (a great 
deal of which are made in Japan). A per- 
son interested in the computer industry 
cannot shut out a nation like japan, which 
has so much to offer us and the industry. 
To restate and add to a quote by Mr. Nib- 
belin: 1 hope the rest of the computer- 
buying public will recognize this un- 
American approach and express their 
reaction at the computer-store purchase 
counter, showing that they are not swayed 
by where a product is from— rather, by 
what substance it is made of. 

David Zimmerman 
Elizabeth, Nl 

1 am a software engineer at a major 
defense corporation. Most of my work is 
done on Digital Equipment Corporation 
(DEC) super-minicomputers, although 1 
also work with military processors and a 
number of different desktop computers 
such as the IBM PC and the DEC Pro 350. 
1 also own an Apple Macintosh, the cute 

(continued) 



30 BYTE • JANUARY 1985 



Inquiry 244 



Indo Page Edit Font Style Size Misc 



/M 


u 


o 


V 


4? 


rv; 




>* 


1 


x 


^ 


'TV 


T 





IMSI Presents PC Paintbrush" 



With PC Paintbrush, you'll now be 
able to do things that you once only 
dreamed about. 

Because, like your dreams, you'll be 
working with a palette of up to 256 
vibrant colors and shades, depend- 
ing on your color card. 

And, as you'll notice, you'll also have 
drawing tools, drop-down menus, and 
a range of brush widths and shapes. 
Plus your choice of mouse or joystick. 

In addition to freeform drawing, you'll 
be able to draw precise triangles, 
rectangles, boxes, circles and ellipses. 

You'll be able to cut, paste, and move 
things around. Even enhance graphs, 
text, and images from other programs 
like Lotus 1 -2-3, Microsoft Word, 
and SuperCalc 3. 

But don't stop with painting. 
PC Paintbrush also gives you an 
electronic type shop to work with. 
Several 1onts, from Olde English to 
Computer. Each in seven styles 
(boldface, italics, underline, etc.) and 
seven sizes. 



All of which makes it great for 
designing everything from fliers and 
report covers to greeting cards and 
birthday banners. (For a wall-sized 
work of art, just print sideways.) 

The possibilities are endless. But the 
best way to see for yourself is to see 
for yourself. Get a demonstration at 
your nearest computer store. 

Then, draw your own conclusions. 




I software publishers Inquiry 374 
INTERNATIONAL MICROCOMPUTER SOFTWARE, INC. 
633 Fifth Avenue • San Rafael. CA 94901 • 415/454-7101 



RUNS ON: IBM PC/compatibles, 
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All require DOS 2.0 and 
up and 1 drive. 

MICE: Summagraphics, Mouse 

Systems, Microsoft. 

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Plotters: HP 7475A and 
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PC Paintbrush is a registered trademark of ZSOFT CORP. 



LETTERS 



little machine everyone is so curious 
about— the one without any documenta- 
tion or software. 

1 must admit. Jerry Pournelle hit the nail 
on the head when he said that many of 
us who no longer consider ourselves "the 
rest of us" have been attracted to this lit- 
tle imp. Certainly the Macintosh is the 
closest thing to a Xerox Star workstation 
that one might hope to have on one's desk 



at home. Oh sure, it could have been 
cheaper, and it could use more memory. 
And it obviously could use some more 
software. But all these criticisms aside, one 
must admit that it is without a doubt one 
of the most innovative personal com- 
puters ever introduced. It also has great 
mass appeal because it's the first personal 
computer that's both fun and easy to use. 
Personally, I don't feel the least bit in- 




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suited using a computer that represents 
information with pictures. Rather, I am in- 
trigued by these uncommon techniques. 
The concepts alone merit one's attention 
whether they are the way of the future or 
not. Witness however, DEC'S latest prod- 
uct announcement, the VAXstation 100 
workstation, with its bit-mapped graphics, 
multiple windows, pop-up menus, use of 
icons, and even a mouse. 

The Macintosh presents a whole new set 
of concepts to the personal computer user 
in its man-machine interface. It is a com- 
puter that people want to try. It is a desk- 
top productivity tool that anyone can use. 
1 won't argue that without application soft- 
ware there is not much you can do with 
it. But software will come. There is always 
a learning curve associated with doing 
something completely new, so it may take 
a little longer to develop Macintosh soft- 
ware than if you were simply porting soft- 
ware to yet another IBM semicompatible. 

I believe, however, that Apple may have 
one problem with this wonderful ma- 
chine—Apple's image. Apple's designers 
have always enjoyed the image as the 
wonder boys of the personal computer in- 
dustry, and this is true now more than 
ever. However, this image will make it dif- • 
ficult for Apple and others to convince the 
corporate powers of many large and con- 
servative companies that the Apple 
Macintosh is the desktop computer their 
employees really need. After all. the 
"three-letter" machines they now have on 
their desks have been quite an improve- 
ment over nothing at all. 

If 1 can find any fault with Apple. 1 must 
say that I don't believe they are giving the 
"basement programmer" enough support. 
Surely they are in need of application soft- 
ware for this new product. Yet by relying 
only on the proven vendors, I feel they are 
ignoring the history of the personal com- 
puter software industry. Many of the soft- 
ware vendors Apple now considers a 
good risk started in their basements with 
just a computer and a unique idea. Also, 
it seems that most small software com- 
panies are good for only one or two really 
innovative products. 

1 don't fault Apple in its goal of secur- 
ing a solid base of established software 
products for the Macintosh. This is critical 
to the Mac's success. However, Apple and 
the rest of the personal computer industry 
must not forget the yet-unknown software 
designers, as these people, unpressured 
to produce new products, will continue to 
be key innovators in the industry. 

T. M. Nicholson 
St Louis, MO ■ 

•*— Inquiry 206 



FIXES AND UPDATES 



FEEDBACK 



Solution Doesn't Wash 



T. I. Higgins felt that he could improve 
upon Martin lanzen's solution to the dif- 
ficulties that pop up when disabling/en- 
abling interrupts during critical sections of 
code on the early versions of the IBM PC 
with defective 8088 firmware. (See "Bug 
in Early 8088 Arises Later, Reader and 
Author Explain Fix." July 1984 BYTE, page 
38.) According to Mr. Janzen. who devised 



the fix. Mr. Higgins's touch-up will not 
work. 

In the original discussion. Messrs. 
Roskos and Janzen concluded that pushf/ 
cli/popf would work for most applications 
and. when using a stack switch, that the 
code needed to be analyzed before cli/sti 
could be added to the program. 

Mr. Higgins, however, saw another op- 



Listing A: Mr. 


Higgins's solution for the disabling /enabling problem in early 8088 


microprocessors i 


ises the sequence lahf/sahf. 




dev strategy: 


; switch to local stack 






lahf 


save flags in register AH 




cli 


disable interrupts 




mov spsave.sp 


save DOS's stack pointer 




mov sssave.ss 


. . . and stack segment regs 




mov bx.cs 


set up a local stack in 




mov ss.bx 


. . . this code segment 




mov sp, offset stkbot 


bottom of local stack 




sahf 


restore flags to previous status 




; switch back to DOS's stack 






lahf 


save flags in AH 




cli 


disable interrupts 




mov ss.sssav 


, restore DOS's stack segment 




mov sp.spsav 


, . . . and stack pointer 




sahf 


; restore flags to previous status 




ret 





tion for the stack switch: why not use 
lahf/sahf? If another register, perhaps BX, 
were available, you could save and restore 
the flags without analyzing the code and 
inserting cli/sti instructions. Mr. Higgins's 
suggestion is shown here in listing A. 

Mr. Janzen reports that, unfortunately 
the lahf and sahf instructions cannot sur- 
round critical sections of code, temporari- 
ly disable interrupts, and then restore the 
interrupt flag to its previous value. 

"The lahf and sahf instructions ... do 
not do this. They appear to have been in- 
cluded in the 8086 instruction set to make 
it easier to convert existing 8080 pro- 
grams." 

Writes Mr. Janzen: "These instructions 
transfer the lower 8 bits of the 8086 flags 
register to and from an AH register. The- 
interrupt flag is one of the upper 8 bits 
and is not affected by the lahf and sahf 
instructions. Therefore, the sequence of in- 
structions [suggested by| Mr. Higgins will 
leave interrupts disabled, rather than 
restoring the flag." 

The pushf/cli sequence suggested by Mr. 
Roskos is endorsed by Mr. Janzen when 
it is used for surrounding any critical sec- 
tions that do not move the stack. If you 
have a block of code that you know is a 
part of a routine that runs with interrupts 
enabled. Mr. Janzen recommends you use 
cli/sti. If you don't know which way to go, 
he suggests saving and restoring the en- 
tire flags register with the program in 
listing B. 



Listing B: Save and restore the entire flags register with this program. 


cnt/calsection: 

pushf 
pop ax 
cli 


;push flags register onto stack 
;save flags in an unused register 
;disable interrupts 


• 


; switch to local stack as before 


push ax 
popf 


;put the old flags on stack 

; restore contents of flags register 







Carroll Tbuch Technology 
Relocates 

Ann Marett, marketing communications 
manager for Carroll Touch Technology, 
wrote to say that her company has re- 
located since it was mentioned in a 
System Review in the July 1984 BYTE. (See 
"The Sage II and Sage IV Computers," by 
Allen Munro. page 23 5.) 

The correct address for Carroll Touch 
Technology is POB 1309. Round Rock. TX 
78680. The telephone number is (512) 
244-3 500. 

{continued) 



JANUARY 1985 -BYTE 33 




MINORITY 

HI-TECH 

INDUSTRIES 



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FIXES AND UPDATES 



BYTE'S BUGS 



Patch Now Quilt 



A trio of program lines were inadvertent- 
ly omitted from listing I, the type- 
justification patch, in the September 1984 
Fixes and Updates (page 3 3). (See "Patch 



Justifies Model 1 00 'type.") Add the lines 
in listing C to the program. 

Our thanks to Frederick Crane of Iowa 
City Iowa, for catching this bug. 



Listing C: A patch to the Model 100 type- justification program. 

302 FOR Q = VTOR-L + 1:IF LEN(PR$)> =R-L + 1 THEN 314 

314 IF RIGHT$(PR$,1)=" "THENPR$ = LEFT$(PR$,LEN(PR$)- 1:GOTO302 

315 IF LEN(PR$)>R-L + 1THENPR$ = RIGHT$(PR$,LEN(PR$)-1):GOT0315 



Bugs in Real-Time Graphics 



Marcus Newton found a few bugs in listing 

1 in his "Real-Time 3-D Graphics for Micro- 
computers" (September 1984. page 251). 

Make the following changes on page 

2 56: delete the comma after POP DS and 
change MOV AX,' to MOV AX/ ' (note 
that there are two spaces between the 



single quotation marks). 

On page 272. change MOV AL,' to MOV 
AL,' ' (one space between the single 
quotation marks). Substitute CMPAL,'.' for 

cmral;. 

On page 2 70, replace the lines around 
the label PER70 with listing D. 



Listing 


D: Apply this patch around the label PER70 in Marcus Newton's program in 


the September 198^ 


\ BYTE. 






ADD 


H,AX 


;H = ZX*X + ZY*Y + ZZ*Z 




MOV 


AX.H 






CALL 


INORM 


;BX STILL = SORT Q 




CMP 


AX.CCLIP 






JLE 


PER90 


;POINT NOT IN FRONT OF CAMERA 


PER70: 


TEST 


P.0FH 






JZ 


PER80 


;TRUE PERSPECTIVE 


PER75: 


MOV 


BX.H 




PER80: 


MOV, 


AX.I 






CALL 


INORM 






MOV 


I.AX 


;l = NORM*l/BX 




MOV 


AX.J 






CALL 


INORM 




■ 


MOV 


J.AX 


;J = NORM*J/BX 




CALL 


PLOT 


;PLOT PIXEL OR DRAW VECTOR 



Bang Is Dud 



Symbolic Changes 



Pat McHargue wrote to tell us that an error 
mars Dick Pountain's listing in the August 
1984 BYTE U.K. (See "Microcomputer 
Design," page 361.) The process bang, as 
defined in listing 1 on page 364, is incor- 
rect. At present, it does not print 
"WHAM!" on the screen; rather it outputs 
"HM." The correct definition is presented 
here in listing E. 



Listing E: Corrections to the process bang. 

PROC bang (CHAN send) = 
DEF bang.word = "WHAM! ": 
SEQ i = [1 FOR bang.word[BYTE 0]] 
send ! bang.word[BYTE i]: 



Dr. Michael W. Ecker found a bug in the 
sample animation program that accom- 
panies Bill Sudbrink's review of the Sanyo 
MBC 5 50 microcomputer (August 1984. 
page 270). 

In listing 1 (page 282), change the 
greater-than symbol (>) in line 1 50 to a 
less-than symbol ( < ). otherwise the down- 
arrow key will not function as intended. 



Book Gets Wrong Name 

In the August Fixes and Updates section, 
we inadvertently misstated the name of 
one of Scot Kamins's books (on page 40). 
The correct name is Apple BackpackM 



34 BYTE • JANUARY 1985 



What's the best recommendation 

you can make when you're asked 

about business graphics? 




The Business 
Professional Plotter 
fromHewlett-Packard 
-The 6-Pen HP 7475A 

Today, business professionals are 
more aware of the vital importance 
of business graphics to their success. 
Tomorrow, they may ask for your recom- 
mendation. Here's some important information 
that will help. Tell them . . . 

Make a first impression that lasts 

Truly impressive graphic presentations can create a first 
impression of quality and professionalism that lasts and 
lasts. The way you present your information can be equally 
as important as the information you're presenting. And that's 
where the HP 7475A Business Professional Plotter lets your pro- 
fessionalism shine through. 

Standards unsurpassed in the plotter business 

The technical standards of the HP 7475 A have no equal for produc- 
ing quality graphics. With a resolution of one-thousandth-of-an- 
inch, curved lines are smooth, not jagged, and straight lines are 
consistently straight. Its exceptional repeatability (the ability of a 
pen to return precise!}/ to a given point) assures that intersecting 
lines and circular shapes will meet exactly. 

Compatible with almost any personal computer 
in your office and supported on today's most 
popular graphics software packages 

The HP 7475A quickly "makes friends" with most of the personal 
computers you may already have in your office, including IBM®, 
Apple™, and Compaq™— as well as a host of HP computers. You 
even have a choice of many off-the-shelf software packages, such 
as Lotus 1-2-3™ and Symphony™, that give you "first-day" produc- 
tivity with the HP 7475A. 

Your Choice: 2 media sizes 

While most professional business applications will be satisfied 
with standard Wi x 11" paper or transparencies, the HP 7475 A 
adds the capability of plotting on larger 11 x 17" media, too. 

The cost? Surprisingly affordable 

The HP 7475 A Business Professional Plotter is an amazingly afford- 
able $1895. When you consider the high cost of having your graphics 
prepared by an outside service, you'll find the return on your invest- 
ment is almost immediate. 

1-2-3 and Symphony are trademarks of Lotus Development Corporation 
Inquiry 389 



Another choice: 
HP's low- cost, 
high performance 
Personal Computer 
Plotter 

For the "business on a budget," you 
may also want a look at our 2-pen 
Personal Computer Plotter, the HP 
7470A. Its low-cost (only $1095) is as 
remarkable as the quality of its plots. With 
many of the same features as the HP 7475A, 
the HP 7470A plots on media up to 8I/2 x 11." It 
stores and caps two-pens, and you can easily change 
the pens for multi-color plotting. 



Send for your FREE ' 
Package" today! 



Better Presentations 



For a FREE sample plot, overhead transparency, and more details, 
mail the coupon below. We'll also enclose a list of graphics software 
packages you can use right "off-the-shelf!' 



For the name of your nearest 
Hewlett-Packard dealer, call 
toll-free 800-FOR-HPPG 



HEWLETT 
PACKARD 



YES! I want to make the most informed business graphics 
recommendation I can. Please send me your FREE "Better 
Presentation Package," so I can learn more about the HP 7475A 
Business Professional Plotter and the HP 7470A Personal 
Computer Plotter. I understand I will receive this valuable 
package without cost or obligation. 



Name. 



. Title . 



Company- 
Address _ 



City, State & Zip_ 
Phone Number ( 
My computer is _ 



Send to: Hewlett-Packard, 16399 W. Bernardo Drive, 
San Diego, CA 92127-1899 
Attn: Marketing Communications 



11404BT1 



JANUARY 1985 -BYTE 35 




w+ 



AND NOW FOR SOMETHING 
INCOMPLETELY DIFFERENT! 



Incomplete, yes. 
But it's not just because 
we're always bringing 
out new stories in the 
Infocom interactive fic- 
tion collection. Nor is it 
simply due to the fact 
that with all the writing 
and re-writing, honing 
and perfecting that we 
put into every one of 
our stories, our work is 
seemingly never done. 

The real reason is: an 
Infocom work of fiction 
can never be complete until you 
become a part of it. 

You see, as hard as we work at 
perfecting our stories, we always 
leave out one essential element- 
the main character. And that's 
where you enter in. 

Once you've got Infocom's 
interactive fiction in your 
computer, you experience 
something almn to waking up 
inside a novel. You find yourself 
at the center of an exciting plot 
that continually challenges you 




In CUTTHROATS:- the plot 
involves a motley band of 
hardbitten salts who get wind 
of a shipwreck laden with 
sunken treasure near the 
remote island where you live. 
In exchange for your diving 
skills, they offer you a piece 
of the action. Your challenge: 
survive them, the perils of 
the deep, and escape with 
the treasure and your life. 
Good luck! 



THE HITCHHIKER'S 
GUIDE TO THE GALAXY™ 
by Douglas Adams is the 
most mind-boggling story 
we've ever published. In the 
person of Arthur Dent, you'll 
chortle as your planet is 
demolished. You'll yelp with 
laughter as your life is 
threatened by a galaxy of 
horrors. Your sides will 
positively split as you search 
the universe for. . . well, 
you'll find out. Maybe. 



In SUSPECT:* our newest 
mystery thriller, you're a 
reporter who gets the scoop 
on the society event of the 
year— the murder of a 
Maryland Blue Blood at a 
fancy costume ball. Great! 
Except you're the prime 
suspect. And if you can't 
find the real killer, your 
next by-line could be in the 
obituaries. 



with surprising twists, unique 
characters (many of whom 
possess extraordinarily developed 
personalities), and original, logical, 
often hilarious puzzles. Communi- 
cation is carried on in the same 
way as it is in a novel-in prose. 
And interaction is easy— you type 
in full English sentences. 

But there is this key differ- 
ence between our tales and 
conventional novels: Infocom's 
interactive fiction is active, not 
passive. The course of events is 
shaped by the actions you choose 
to take. And you enjoy enormous 
freedom in your choice of actions - 



you have hundreds, even 
thousands of alternatives 
at every step. In fact, an 
Infocom interactive story 
is roughly the length of 
a short novel in content, 
but because you're 
actively engaged in the 
plot, your adventure 
can last for weeks and 
months. 

In other words, only 
you can complete the 
works of Infocom, Inc. 
Because they're stories 
that grow out of your imagination. 

Find out what it's like to get 
inside a story. Get one from 
Infocom. Because with Infocom's 
interactive fiction, there's room 
for you on every disk. 

inFocom 

Infocom, Inc., 55 Wheeler Street, Cambridge, MA 02138 

For your: Apple II, Atari, Commodore 64, CP/M8", DECmate, 
DEC Rainbow, DEC RT-11, IBM PC" and PCjr, KAYPRO II, 
MS-DOS 2.0; NEC APC, NEC PC-8000, Osborne, Tandy 2000, 
TI Professional, TI 99/4A, TRS-80 Models I and III. 
•Use the IBM PC versionforyour Compaq, and the MS-DOS 2.0 
version for your Wang or Mindset. 

CUTTHROATS and SUSPECT are trademarks of Infocom, Inc. 
THE HITCHHIKER'S GUIDE TO THE GALAXY is a trademark 
of Douglas Adams. 



Inquiry 169 



JANUARY 1985 -BYTE 37 



Is Your PC 

Buried By 

Floppy Disk 

Back-Up? 



* 
$ 




Dig Out 
With Model 70 PC 
Cartridge Tape System 

Digi-Data's Model 70 PC cartridge tape system lets you back-up your 
PC's Winchester drive without getting buried in floppies. One cartridge 
holds 16.5 Mbytes of data, more than you can put on 51 floppy disks! 
And you can back-up your 10 Mbyte PC XT® drive in less than 15 min- 
utes of unattended operation . That is a small fraction of the time it 
would take with the PC's floppy, with you standing there changing 
disks. 

Our file-oriented structure makes it possible for you to back-up 
only what has to be changed on your disk. That saves still more time 
and storage capacity. 

70 PC comes ready to run on your IBM PC XT and most compati- 
bles like Compaq, Columbia Data Products and Eagle. Complete with 
controller board, driver software and cables. 

Digi-Data's products also include V2 inch and 1 A inch start/stop 
and streaming drives and systems. 




DIGI-DATA 
! CORPORATION 

. First In Value 

8580 Dorsey Run Road 

Jessup, MD 20794 

(301) 498-0200 Telex 87580 

In Europe contact: 

DIGI-DATA LTD 
Unit 4 

Kings Grove 
Maidenhead, Berkshire 
England SL 6 4DP 
Tel. 0628-29555-6 
Telex 847720 



3 PC XT is a registered trademark 
of IBM Corporation 



Inquiry 105 



WHAT'S NEW 



Texas Instruments Adds Briefcase Portable 




The briefcase-size Pro- 
Lite portable computer 
is compatible with Texas In- 
struments' Professional Com- 
puter. Pro-Lite includes one 
720K-byte 3 l /2-inch floppy- 
disk drive, an 80C88 micro- 
processor, an 80-column by 
25-line liquid-crystal display, 
and 256K bytes of memory, 
expandable to 768K. 

TWo internal expansion 
slots can be used for a 
300-bps modem, an external 
color monitor interface, an 
RS-232C interface, or a 
"solid-state software" ROM 
card. A second 3 /2-inch disk 
drive and an eight-hour bat- 
tery pack are available as 
external expansion options 
and attach to the rear of the 
Pro-Lite. An optional inter- 



face cable allows the Pro- 
Lite to be linked to any MS- 
DOS computer to transfer 
files; the Pro-Lite can 
emulate an external disk 
drive to simplify file 
transfers. 

Without the battery pack, 
the Pro-Lite weighs 10.5 
pounds with one disk drive 
or 13.5 pounds with both 
drives. The Pro-Lite will be 
available this month through 
national account direct sales 
and value-added resellers 
for $2995; TI will make it 
available through retail chan- 
nels at a later date. Contact 
Texas Instruments Inc., Data 
Systems Group, POB 
809063. Dallas, TX 75380- 
9063. (800) 527-3 500. 
Inquiry 540. 



Rolm Unveils Computer/Telephone Systems 



Rolm has introduced two 
new systems combining 
personal computers with 
Rolm telephone systems. 
Cedar is a complete IBM 
PC-compatible computer 
and multiline digital 
telephone, and Juniper is a 
telephone attachment for 
the IBM PC. Both systems 
can only be used by com- 
panies that have Rolm's CBX 
private branch exchange 
(PBX). Both can emulate 
DEC or IBM terminals to ac- 
cess mainframes. 

Cedar includes a multiline 
digital telephone, a speaker- 
phone, an IBM-compatible 
personal computer, and 
communications hardware 
and software allowing com- 
munications over internal 
phone lines at up to 19.200 
bps. Cedar and Juniper can 
also access modems at- 




tached to the CBX system to 
communicate with the out- 
side world. The system in- 
cludes 512K bytes of 
memory, two 5!4-inch disk 
drives, a 9-inch monitor, and 
MS-DOS 2.11. 
Juniper consists of an 



adapter board for the IBM 
PC, software, and a multiline 
digital telephone with a two- 
way speakerphone. It re- 
quires an IBM PC with 256K 
bytes of memory. 

Cedar is priced at $4995, 
and Juniper is $1495. In 



quantities of 100, the prices 
are $424 5 and $1360, re- 
spectively. Contact Rolm 
Corp.. 4900 Old Ironsides 
Dr.. Santa Clara. CA 95054, 
(408) 986-1000. 
Inquiry 541. 

(continued) 



JANUARY 1985 'BYTE 39 



WHAT'S NEW 



Okidata Introduces $268 Color Printer 



Okimate 20 from Okidata 
combines thermal- 
transfer and dot-matrix tech- 
nologies in a $268 full-color 
printer. Its 24-pin square-dot 
print head can produce a 
resolution of up to 144 by 
144 dots per inch. Okidata 
says the Okimate 20 can 
print more than 100 dif- 
ferent shades by mixing the 
four ribbon colors. The 
thermal-transfer technology 
doesn't require special ther- 
mal paper— it can print on 
plain paper, letterhead, or 
overhead transparencies. 

The Okimate 20 also in- 
cludes either a parallel or 
serial "Plug 'N Print" inter- 
face, which means the 
printer can be used with 
most personal computers. It 
can print 80 characters per 
second (cps) in draft mode, 
or 40 cps in letter-quality 
mode. 

For more information, con- 
tact Okidata, 532 Fellowship 
Rd. Mt. Laurel, N) 08054. 
(609) 235-2600. 
Inquiry 542. 




Video for the Mac 

Mentaur Technologies 
has introduced a solid- 
state, compressed-circuitry 
video-output device for the 
Macintosh. The Mentaur 
Composite Video Adaptor 
provides a composite video 
signal of the Macintosh 
screen through a built-in, 
standard BNC connector. 
This lets the operator use 
the Macintosh with large- 
screen video projectors and 
monitors for business or 
educational applications. 

The Mentaur CVA installs 
with no soldering, wire 
splicing, or mounting 
hardware. Illustrated 
instructions are included. 
This device eliminates the 
need for hard-wire modifi- 
cations and interface units. 

Documentation includes 
projector and monitor 
manufacturer information. 
The Mentaur CVA lists for 
$199.9 5. Contact Mentaur 
Technologies, POB 1467. San 
Marcos. TX 78666, (512) 
396-1565. 
Inquiry 543. 



PC-Compatible Seequa Cobra Features 16-bit Expansion Bus 



The Seequa Cobra is an 
IBM PC-compatible 
computer with an extended 
PC ATcompatible 16-bit ex- 



pansion bus. The Cobra 
uses an 8086 processor with 
a clock speed of 8 MHz. 
switchable to the standard 




IBM PC rate of 4.77 MHz. 
Seequa says another func- 
tion of the 16-bit hardware 
bus is to produce a flicker- 
free image for the Cobra's 
color-graphics display. 

In addition to the 8086. 
the Cobra features a Z80 
processor. 2 56K bytes of 
memory, one 5 % -inch floppy 
disk, a 10-megabyte hard 
disk, a clock/calendar, and 
parallel and serial ports. 
Seequa bundles WordStar. 
SuperCalc, and a number of 
other programs with the 
Cobra. 

Seequa plans to release 
the Cobra in March for 
$4995 without a monitor. 
Contact Seequa Computer 
Corp.. 8305 Telegraph Rd.. 
Odenton. MD 21113. (301) 
672-3600. 
Inquiry 544. 



Juki Announces $299 
Daisy-Wheel Printer 

The Juki 6000 is a 
portable letter-quality 
printer that uses standard 
daisy-wheel print elements 
and ribbons. The printer 
weighs about 13 pounds 
and measures 16 by 914 by 
5/2 inches. It prints at a 
speed of 10 characters per 
second on paper up to 9 
inches wide. 

The Juki 6000 is available 
with either serial or parallel 
interfaces and can print at 
10, 12, or 15 characters per 
inch using any Diablo-type 
daisy wheel. 

List price of the Juki 6000 
is $299. Contact luki 
Industries of America. 299 
Market St.. Saddle Brook, Nl 
07662, (201) 368-3666. 
Inquiry 545. 

[continued) 



40 BYTE • JANUARY 1985 



Available for the IBM PC, AT, XT, jr.* and true compatibles 

GOT YOUR 
SIDEKICK YET? 



The Super Organizer 

Whenever you're using your 
computer . . . from start to finish of 
your session Sidekick™ will be there 
. . . ready to serve. And it's as lightning- 
feist and compact as only Borland knows 
how to make it. 

There's a notepad that has a full- 
screen editor that can time and date 
stamp your notes, and then save them to 
disk. You can even pull information into 
the notepad directly from the screen of 
your "underlying" software. 

Suppose you're working in Lotus and 
the phone suddenly rings. Give your Sidekick 
a call and it pops right up over Lotus with 
the notepad you need. Or an appointment 
calendar ... one you can never misplace. 

What if you need to do a quick calcula- 
tion? A keystroke instantly brings up the cal- 
culator. And the results of your calculations 
can even be transferred to your "underlying" 
software. 

Need to make a phone call? Up pops your 
personal phone directory. Type in the name you 
want ... and Sidekick jumps right to the phone 
number. Another keystroke, and the phone is 
automatically dialed for you.* * 

There's lots more, too. You can move the Sidekick 
windows anywhere on the screen you like. And you can have 
as many on screen at a time as you need. There's even an 
on-line help window for each of Sidekick's features. 

We designed it because we needed it. If you've 

ever been writing a report and needed 
to do a quick calculation, 



"IF YOU USE A PC, 

GET SIDEKICK. YOU'LL SOON 

BECOME DEPENDENT ON IT. " 




8N& • • * 







running undem t _, chpe nvmpo. Ws 



you 



underneath. 

d^thats^ ^ 



can see 
screen. 



On 



the upp er 



that's 



Sickener. 



or jot down a note, 

then you need Sidekick, too. 

" 'Only with Hayes Smartmodem and compatibles. 

WHETHER YOU'RE RUNNING 

LOTUS, WORDSTAR, dBASE OR WHATEVER 

JUST A KEYSTROKE 

AND A SIDEKICK WINDOW 

OPENS . . . 

• A CALCUIATOR 

• A NOTEPAD 

• AN APPOINTMENT CALENDAR 




/ 



• AN AUTO DIALER 

• A PHONE DIRECTORY 

• AN ASCII TABLE 



YOU CAN ORDER YOUR COPY OF SIDEKICK™ TODAY! 

For VISA and MasterCard orders call Toll Free 1-800-255-8008 in California 1-800-742-1133 

(lines open 24 hours, 7 days a week) Dealer Distributor Inquiries Welcome 408-438-8400 inquiry 42 



SIDEKICK™ $49.95 

No n -copy protected 

Version: $79.95 

(Plus $5.00 shipping and handling.) 



Please be sure your computer is an IBM PC, AT, XT, jr., or 
true compatible! 

NAME 




Check D 
VISA □ 

Card # _ 



Money Order □ 
MasterCard □ 



ADDRESS 



CITY/STATE/ZIP 
TELEPHONE 



Expiration Date 






'PCjr, runs non<opy protected version onfy. 



California residents add 6% sales tax. Outside U.S.A. add $15.00. (If outside of 
U.S.A. payment must be by bank draft payable in the U.S. and in U.S. dollars.) 
Sorry, no C.O.D. or Purchase Orders. S1S 



») BORIADD 

■> INTERNATIONAL 

Borland International 
41 1 3 Scotts Valley Drive 
Scotts Valley, California 95066 
TELEX: 172373 



WHAT'S NEW 



Device for Macintosh Uses Removable 5-Megabyte Cartridges 



Iomega has introduced a 
5-megabyte version of its 
Bernoulli Box for the Apple 
Macintosh. The Bernoulli 
Box uses removable car- 



tridges that contain 
floppy-disk-like media with 
an average access time of 
50 milliseconds. 
Iomega also makes 10- 




and 20-megabyte versions of 
the Bernoulli Box for the 
IBM PC and compatibles; 
the Mac Bernoulli Box is not 
compatible with the IBM 
version. Mac Bernoulli Box 
cartridges can be exchanged 
with any other Macintosh, 
however, allowing transfer of 
large quantities of data on a 
single disk. The 5-megabyte 
cartridges are physically 
smaller than the 10- and 
20-megabyte cartridges. 
The Mac Bernoulli Box 
costs $1895; cartridges are 
$65 each. For further infor- 
mation, contact Iomega 
Corp., 4646 South 1 500 W, 
Ogden, UT 84404. (801) 
399-2171. 
Inquiry 546. 



Thesys Offers 5-Megabyte RAM Expansion System for $3495 



Fastf ile stores u p to 5 
megabytes of data in a 
stand-alone device with an 
access time of less than 2 50 
nanoseconds. Fastfile uses 
256K-byte RAMs and fea- 
tures an uninterruptible 
power supply to prevent 
loss of data. Also included 
are an expansion card for 
the IBM PC and software for 



print spooling and disk 
caching. While Fastfile will 
speed up ordinary PC ap- 
plications, the company 
stresses that it can also be 
used to improve the perfor- 
mance of a local-area net- 
work. 

Fastfile will be available 
for the IBM PC in January, 
according to the manufac- 



turer. It measures 5.3 by 9.7 
by 12.4 inches. Fastfile will 
cost $1795 with 1.5 mega- 
bytes. $2795 with 3 mega- 
bytes, and $3495 with 5 
megabytes. Contact Thesys 
Memory Products Corp., 
7345 East Acoma Dr.. 
Scottsdale, AZ 85260, (602) 
991-73 56. 
Inquiry 547. 



HyperDrive 
Internal Hard Disk 
for the Macintosh 

General Computer Com- 
pany has introduced 
HyperDrive, a hardware ex- 
pansion for Apple's Macin- 
tosh computer combining a 
512K-byte memory upgrade 
and an internal 10-megabyte 
hard-disk drive. The com- 
pany connects the Hyper- 
Drive's logic board directly 
to the Macintosh's main cir- 
cuit board and fits the disk 
drive inside the computer. 
Users can boot from either 
the floppy or the hard disk. 
Both Macintosh serial ports 
remain free for modems, 
printers, or network use. 
Software is included to par- 
tition the hard disk into 
many virtual disks, which are 
automatically resized to ac- 
commodate the user's files. 

Hyperdrive will be avail- 
able this month for $2795; 
for Macintoshes already 
equipped with 512 K bytes of 
RAM. the price is $2195. For 
more information, contact 
General Computer Corp., 
21 5 First St., Cambridge, MA 
02142, (800) 422-0101; in 
Massachusetts. (617) 
492-5 500. 
Inquiry 548. 



Whitechapel Workstation Displays 1024 by 800 Pixels 



Whitechapel Computer 
Works' graphics work- 
station has a resolution of 
1024 by 800 using the Na- 
tional Semiconductor 32016 
processor. The MG-1 in- 
cludes 512K bytes of mem- 
ory, a 10-, 22-, or 
4 5-megabyte hard disk, an 
800K-byte 5 14 -inch floppy- 
disk drive, a high-resolution 
display, a mouse, and the 
Genix operating system. 
Main memory can be ex- 
panded to 4 megabytes. 

Its UNIX-based operating 
system and optional 
Ethernet link are designed 
to enhance the system's 
usefulness in computer- 



aided design and engineer- 
ing and scientific 
applications. 

The MG-1 is about $6975 
with a 10- megabyte hard 



disk, $82 50 with a 22-mega- 
byte hard disk, and $9500 
with a 45- megabyte hard 
disk. Contact Whitechapel 
Computer Works Ltd., 75 



Whitechapel Rd., London EI 
1DU, England, tel; 
01-377-8680; from the U.S.. 
011-44-1-377-8680. 
Inquiry 549. 



Gifford MC-186 Expands to Multiuser MS DOS System 



Gifford Computer Sys- 
tems' MC-186 uses both 
80186 and Z80H processors 
to support up to eight users. 
The MC-186 uses Multiuser 
Concurrent DOS, based on 
Digital Research's Concurrent 
DOS, which enables each 
user to run four applications 
concurrently. The MC-186 
can be attached to an ARC- 



NET-compatible DR Net net- 
work to link with up to 255 
other MC-DOS computers. 

The MC-186 includes one 
megabyte of RAM, a 23-, 
44-, or 62-megabyte hard 
disk, a 1.2-megabyte floppy- 
disk drive, 10 serial ports, 
and a single parallel port. 
Other features are a clock/ 
calendar, a diagnostic 



EPROM. and an optional 
network controller board. 
With a 44-megabyte hard 
disk, the system costs 
$13,700. 

Contact Gifford Computer 
Systems, 2446 Verna Court. 
San Leandro, CA 94 577, 
(415) 895-0798. 
Inquiry 550. 

[continued) 



42 BYTE • JANUARY 1985 



NEW PRODUCT NEWS 
FROM TELETEK 



Systemaster II. Responding to 
market demand for speed and in- 
creased Versatility, Teletek is proud 
to announce the availability of the 
next generation in 8-bit technology 
— the new Systemaster II! The 
Systemaster II will offer two CPU 
options, either a Z80B running 
at 6 MHz or a Z80H running at 
8 MHz, 128K of parity checked 
RAM, two RS232 serial ports with 
on-board drivers (no paddle 
boards required), two parallel 
ports, or optional SCSI or IEEE-488 
port. The WD floppy disk control- 
ler will s/mu/taneous/y handle 
8" and 5Va" drives. A Zilog Z-80 
DMA controller will provide in- 
stant communications over the bus 
between master 
and slave. Add 
to the DMA 
capability a true 
dedicated inter- 
rupt controller 
for both on- 
board and 
bus functions, 
and the re- 
sult is un- 
precedented 
performance. 

Systemaster II will run under 
CP/M 3.0 or TurboDOS 1.3, and 
fully utilize the bank switching 
features of these operating systems 



SBC 86/87. As the name indi- 
cates, Teletek's new 16-bit slave 
board has an Intel 8086 CPU with 
an 8087 math co-processor op- 
tion. This new board will provide 
either 128K or 512K of parity 
checked RAM. Two serial ports 
are provided with individually 
programmable baud rates. One 
Centronics-compatible parallel 
port is provided. When teamed up 
with Systemaster II under TurboDOS 
1 .3, this 5MHz or 8MHz multi- 
user, multi-processing, combina- 
tion cannot be beat in speed or 
feature flexibility! 



- Ji 
TELETEK 77/Vfrs ffljf 

nwsbcMW 

symmfERii 



Teletek Z-150 MB. Teletek is 
the first to offer a RAM expansion 
board designed specifically for the 
Z-150/Z-160 from Zenith. The 
Teletek Z-150 MB is expandable 
from 64K to 384K. Bring your 
Z-1 50 up to its full potential by 
adding 320K of parity checked 
RAM (or your IBM PC, Columbia, 
Compaq, Corona, Eagle, or Seequa 
to their full potential). The Teletek 
Z-150 MB optionally provides 
a game port for use when your 
portable goes home or a clock/ 
calendar with battery backup! 

Evaluate the Systemaster II, SBC 
86/87 or Teletek Z-1 50 MB for 
30 days under Teletek's Eval- 
uation Program. A 

money-back guarantee 
is provided if not com- 
pletely satisfied! All 
Teletek products carry 
a 3-year warranty. 

(Specifications subject to 

change without 
notice.) 




RETEK 



4600 Pell Drive 
Sacramento, CA 95838 
(916)920-4600 
Telex #4991834 
Answer back — Teletek 

Inquiry 349 



WHAT'S NEW 



Networking Operating System for IBM PC 



Waterloo Port is a net- 
working operating sys- 
tem for IBM personal com- 
puters and compatibles. Ac- 
cording to the manufacturer, 
Port users can run such ap- 
plications as Lotus 1-2-3, 
WordStar. MultiMate, dBASE 
II, and Advanced BASIC 
using PC-DOS 2.1 as a 
"guest operating system" 
under Port. Port also in- 
cludes a built-in Text Editor 
and Text Formatter. Port 
allows several tasks to ex- 
ecute concurrently: they can 
be displayed as separate on- 
screen windows or can be 
hidden from view until 
selected. 

Port uses icons and "of- 
fices" for each application 
function; selections can be 
made using the keyboard or 




an optional mouse. With 
Port, network users can 
share printers and other pe- 
ripherals. Diskless work- 
stations can download soft- 



ware, including the operat- 
ing system, through the 
network. 

Waterloo Port also allows 
users to access mainframe 



computers through the net- 
work. Port includes its own 
development system and 
programming language to 
develop network-based soft- 
ware. Processes can pass 
messages to each other 
through the network, en- 
abling real-time multiuser 
applications to be devel- 
oped. 

Software and hardware to 
convert an IBM PC into a 
Waterloo Port software 
server is $1540. Workstations 
can be added to the net- 
work with a $920 software/ 
hardware package. For more 
information, contact Water- 
loo Microsystems Inc.. 175 
Columbia St. W. Waterloo, 
Ontario N2L 5Z5. Canada, 
(519) 884-3141. 
Inquiry 551. 



MicroPro Enhances WordStar 



MicroPro's WordStar 
2000 adds a number 
of features to its popular 
WordStar word-processing 
program. Some of the en- 
hancements are an Undo 
command to restore deleted 
text, use of windows to view 
up to three documents si- 
multaneously, user-definable 
function keys, a "keystroke 
glossary" for frequently 
typed text or command se- 
quences, footnoting, spelling 



correction, proportional 
spacing, and on-screen bold- 
facing, underlining, center- 
ing, and pagination. 

WordStar 2000 also in- 
cludes some spreadsheet 
and database features. It 
can perform calculations 
within a document, sort lists 
of text or numbers, and 
merge data into letters for 
customized mailings. 

A separate version, called 
WordStar 2000 Plus, adds 



telecommunications, a mail- 
ing list database program, 
and indexing and table of 
contents capabilities. 

WordStar 2000 requires an 
IBM PC or compatible with 
PC-DOS 2.0 or later, 2 56K 
bytes of memory, and two 
double-sided disk drives; a 
hard disk is recommended. 
WordStar 2000 Plus requires 
a Hayes Smartmodem or 
compatible modem to use 
the telecommunications 



features. 

WordStar 2000 is $495; 
WordStar 2000 Plus is $595. 
Current WordStar owners 
can upgrade to WordStar 
2000 for $2 50 or WordStar 
2000 Plus for $3 50. For 
more information, contact 
MicroPro International Corp.. 
33 San Pablo Ave., San 
Rafael, CA 94903. (415) 
499-1200. 
Inquiry 552. 

{continued on page 440} 



Page I line 12 Col I 
IMIIHC REKIi 



A I»i5 m wrgifis 
A I*eit« text 
Wxt locate 



A m« enMncetents 
A Kt3 iltsiug 



% mu$ MM km Ctrl m ml tfess C, 

f_l» — *_2 3 $T 5— 6- 

is i list of silts f i$uNS fop the first six maNs of 
presented in ascend ins order; 



Jane $71,5. _ 
January $75,W8 



Total: $337,384 




44 BYTE • JANUARY 1985 






Brighten up your dumb terminal 
add a UDS 212 A/D 



A little outside intelligence can turn your dumb terminal into a data 
communications genius. And the intelligence you need is built into UDS' new 
212 A/D, a smart 300/1200 bps modem with an integral automatic calling unit. 

With the 212 A/D you can dial from keyboard or, with a single 
keystroke, from memory. Five 30-digit numbers in memory 
are battery backed for 3-5 year retention after shutdown. 
Built-in test functions allow fast, reliable verification 
of system operation. 

Before you invest in more microcomputers, check 
the advantages of add-on intelligence. Call 
800/633-2252, ext. 353. Universal Data Systems, |0| Universal Data Systems 
5000 Bradford Drive, Huntsville, AL 35805. 
Telephone 205/837-8100; TWX 810-726-2100. ® " OTO « ot * '~ c - 

information Systems Group Inquiry 357 

UDS modems are offered nationally by leading distributors. Call the nearest UDS office for distributor listings in your area. 

DISTRICT OFFICES: Atlanta, GA, 404/998-2715 • Aurora, CO, 303/368-9000 • Bellevue, WA, 206/455-4429 • Blue Bell, PA, 215/643-2336 • Boston, MA, 617/875-8868 
Columbus, OH, 614/895-3025 • East Brunswick, NJ, 201/238-1515 • Glenview, IL, 312/998-8180 • Houston, TX, 713/988-5506 • Huntsville, AL, 205/837-8100 
Mesa, AZ, 602/820-6611 • Minnetonka, MN, 612/938-9230 • Mountain View, CA, 415/969-3323 • RichardsonJX, 214/680-0002 • Silver Spring, MD, 301/942-8558 
Tampa, FL, 813/684-0615 • Thousand Oaks, CA, 805/496-3777 • Tustin, CA, 714/669-8001 • Willowdale, Ont, Can, 416/495-0008 • Ypsilanti, Ml, 313/483-2682 

Created by Dayner/Hall, Inc., Winter Park. Florida 





aw****** 9 

rt deluded' 



REMEMBER WHEN THEY SAID, 
"ALL INFORMATION SHALT BE 80 
COLUMNS BY 25 ROWS?" 
NEITHER DO WE! 

ALL INFORMATION ISN'T CREATED EQUAL . . . 
AT LEAST NOT IN SHAPE OR SIZE. 

Whoever said information is always 80 columns by 25 rows? Check the directory on your PC sometime. Long and skinny. 

Got any ideas on what to do with the other half of the screen? 

Or suppose your information needs to be contained in screens bigger than your monitor, as is the case with the average 

spreadsheet. How would you handle it? Sure, you can spend the hours and miles of code to work it out . . . but why 

bother? We've already done it for you I 

But, let's get a little more interesting. Suppose you were writing a program that used a combination of differing shapes of 

information? You might need to combine various help screens, menus, forms and vast "plains" of information. All kinds of 

windows on-screen at once. 

Now. it's easy to do! 

And how about putting some time into thinking up new shapes of information? The boys who put together those first 

spreadsheets sure made a couple of dollars doing that! 

With VSI— THE WINDOW MACHINE you can design and test new ideas effortlessly. Then, when you're ready, VSI— THE 

WINDOW MACHINE letsyou build your ideas into your code. Very, very easily! 

WHO IS VSI -THE WINDOW MACHINE MADE FOR? 

We built it for you. Whether you're a Sunday programmer or a round-the-clock professional, we've built a tool for everybody 
who writes code. 

If you program in Pascal, C, Basic, Cobol, Fortran or even PM , there's a version of VSI— THE WINDOW MACHINE for you. 
We've even recently completed an interface for Turbo Pascal™ so that true, full-featured windowing can now be utilized 
with this fine compiler. (Turbo's own "windowing" procedure is extremely limited.) 

WHAT ABOUT TOPVIEW™ . . . AND THE ELUSIVE MICROSOFT WINDOWS™ . . . 
WHERE DO WE FIT IN? 

VSI— THE WINDOW MACHINE is a racy, compact engine (about 12K) that allows you to put windows into your programs 
instead of putting your programs into somebody else's windows. So your end-user doesn't have to buy other soflware in 
order to run your code. 

And we haven't tied ourselves (or your programs) to big-memory machines, graphics cards or the "IBM only" syndrome. 
We also run on the compatibles and some of the not-so-compatibles. 

HERE'S THE BIG SURPRISE . . . VSI-THE WINDOW MACHINE WILL FIT 
RIGHT INTO TOPVIEW, TOO! 

Your code will never become obsolete. VSI— THE WINDOW MACHINE can add virtual screens and all of the rest of its 
power to IBM's Topview. You can rest assured that the software you develop now will have the broadest possible market 
today and tomorrow. 

Turbo Pascal Is a registered trademark of Borland International • IBM and TopVieware registered trademarks of International Business 
Machines » Microsoft Windows is a registered trademark of Microsoft Corporation 




■ WHAT DOES THE VSI IN OUR NAME STAND FOR? VIRTUAL SCREEN INTERFACE! 

Windowing is only half of the picture. Behind each window there's a much bigger picture. And that picture is what we call 
the Virtual Screen. VSI defines virtual screens rather than just windows. Each window relates to its own private virtual screen. 
The window then displays on your monitor whatever portion of its virtual screen you wish to exhibit at any given point in 
your program. Each screen can be up to 128 x 255 (either columns x rows or rows x columns). And you can have up to 
255 of them at a time!!! 

■ VSI -THE WINDOW MACHINE INCLUDES: 

• Multi-mode Exerciser (Great for rapid design of screens. You can type in commands and watch them happen or you 
can make a whole file of commands and then stand back and watch the magic. You can even design using just 
cursor keys and menu selections.) 

• Zoom Windows (Windows that grow open as you watch them.) 

• Choice of Borders (including flashing borders) 

• Support For All Color and Monochrome Video Attributes (no graphics card required) 

• Built-in Diagnostics 

• Your choice of Language Interfaces (Lattice C, Turbo Pascal, Microsoft/IBM Pascal, Microsoft Basic Compiler, Microsoft 
Fortran, Digital Research PL1 , Realia Cobol) 

• Multiple Virtual Screens (up to 255) 

• And much, much more! 

YOU CAN ORDER YOUR WINDOW MACHINE TODAY!! 

(and save hundreds of hours of coding from now on!) inquiry 1 7 

FOR VISA, MASTERCARD AND AMERICAN EXPRESS ORDERS, CALL TOLL FREE: 
1 "800"227"3800 GXt. 986 (Lines are open 24 hrs. a day, 7 days a week.) 



For dealer inquiries . . . call our 800 number 
Language Interface: 

— Lattice C 

— Digital Research PL1 

— Microsoft Basic Compiler 
Computer (please check the list) 



$59.95 per copy 

Shipping, handling and tax included 



— Microsoft Fortran 

— Microsoft/IBM Pascal 



—Turbo Pascal 
—Realia Cobol 



AMBER SYSTEMS, Inc. 

1171 S. Saratoga-Sunnyvale Road 

San Jose, CA 95129 



(VSI-THE WINDOW MACHINE-IBM PC. XT, AT, PC 3270, IBM Compatibles, and Wang, T! Professional, HP 150 and Tandy 2000.) 

Name 

Title : Company 

Address 

City 



State . 



-Zip. 



Work Phone ( 
Check 

Card# 



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_ Money Order 



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_ American Express 



MAIL TO: Amber Systems, Inc., 1171 S. Saratoga-Sunnyvale Road, San Jose, CA 95129 

30 Day Money Back Guarantee! 

' 'California residents: tax included. Orders outside the U.S.: please add $5 for shipping and handling, (rf outside of U.S., payment must either 
be by credit card or bank draft payable in the U.S. in U.S. dollars.) Sorry, no C.O.D. or Purchase Orders. 



ASK BYTE 



Conducted by Steve Garcia 
80-Column in Slot 3 

Dear Steve. 

Your August 1984 Ask BYTE column 
stated that an 80-column card cannot be 
used in slot 3 of the Apple He when an- 
other card is installed in the auxiliary slot. 
While this is generally the rule, there is an 
exception. 

Videx's UltraTerm is the only 80-column 
card that will work in slot 3— even if there 
is another card in the auxiliary slot. With 
compatible software, such as Word Juggler 
He and Multiplan 1.07, the UltraTerm's 
128-column by 32-line display can be used 
in conjunction with the extra memory of 
the Apple extended 80-column card. For 
programs that exclusively use the Apple 
80-column card (PFS series for the He), an 
optional switch plate is available to toggle 
between the UltraTerm and the Apple text 
card's display. 

For a list of spreadsheets, word pro- 
cessors, and databases that utilize the ex- 
panded display features of the UltraTerm 
on the Apple He, BYTE readers should call 
Videx at (503) 758-0521. 

William Leineweber 

Videx 

Corvallis. OR 

High Resolution Confusion 

Dear Steve. 

As a new subscriber to BYTE. 1 was 
delighted to find your Ask BYTE column 
as a help for the perplexed (me). 

I'm hoping you can offer some 
desperately needed information on a 
most confusing subject, namely, how are 
high-resolution graphics created? Are they 
the product of hardware, software, or 
both? 

In looking through BYTE ads. I've seen 
monitors, processors, software, and 
printers all described as possessing high 
resolution. For example. Quadram's 
QuadScreen monitor features "bit- 
mapped graphics (that) allow dot- 
addressable resolution of 960 horizontal 
by 512 vertical (pixels)." Wang recently 
introduced a desktop scanner for its Pro- 
fessional Computer that digitizes images 
at a resolution of 200 dots per inch (1728 
by 2200 pixels for the maximum 1 1- by 



1 4-inch image). Yet the Wang Professional 
Computer monitor has an advertised res- 
olution of only 800 by 300 pixels. Many 
microcomputers have add-on graphics 
boards and image processors offering 
enhanced resolution; e.g.. the PC Com- 
ponents Bi-Graphix board for the IBM PC 
offers 720- by 700-pixel resolution with 
"software support for higher resolution." 
Similarly printers are rated at dots per 
inch with varied high-density settings for 
high-resolution graphics. 

lust how does one go about creating 
high-resolution (say, 150 to 200 dots per 
inch horizontally and vertically) graphics 
hard copy? Must one have a high-resolu- 
tion graphics-board-equipped computer 
with graphics-support software outputting 
through a high-resolution monitor to a 
high-resolution printer? Help! 

Betsy McCloskey 
Los Angeles, CA 

Producing a high-resolution graphics 
display with a microcomputer depends 
primarily on features built into the hard- 
ware, but software is required to drive 
the hardware to achieve the desired dis- 
play characteristics. This is usually in 
ROM when it is included as a standard 
feature of a personal computer. 

First, a microcomputer that can pro- 
duce graphics has a video-display con- 
troller with graphics capability and 
enough screen memory to produce a bit- 
mapped image with the desired resolu- 
tion built into it. The controllers used 
these days are usually one-chip inte- 
grated circuits that can produce either 
graphics or text displays. Motorola ap- 
plication note AN-834 (Motorola Semi- 
conductor Products Inc., POB 20912, 
Phoenix, AZ 85036} shows how the 
MC6845 can be used to produce a 256- 
by 2 56-pixel or 512- by 512-pixel graph- 
ics display. This chip is also used in the 
IBM PC to produce 320 by 200 color 
graphics or 640 by 200 monochrome 
graphics. The actual bit map produced 
depends on the memory allocated and 
the software (or firmware) driving the 
display. 

You can also see how another chip, the 
Texas Instruments TMS9918A, can be 
used to produce graphics with sprites in 



my article "High-Resolution Sprite- 
Oriented Color Graphics" in the August 
1982 issue on page 57. 

To display the high-resolution graphics 
requires a high-resolution monitor. The 
QuadScreen monitor you mentioned is 
a high-resolution monitor with its own 
graphics video-driver card, which is made 
to replace the display driver card in the 
IBM PC. This system can produce a 960- 
by 512-pixel display, but the usual IBM 
PC commercial software requires special 
interface routines to use this resolution, 
and the PCs BASICA is still limited to 640 
by 200 by its own structure. More con- 
ventional 12- or 13 -inch color (RGB) or 
monochrome monitors with 15- to 
20-MHz video bandwidths are available 
that can make full use of the standard- 
or second-source video cards for the IBM 
PC and compatible computers, as well as 
many other computers with graphics 
built in. 

Creating high-resolution graphics on 
paper with a printer or plotter is a dif- 
ferent story. This doesn't even require 
graphics capability in the computer. All 
you have to do is set up an array of points 
to be plotted and send the points to a 
printer with dot-graphics capability. The 
programming is a little complicated 
because you must first define the dot 
array you want printed and then sort it 
into a form the printer can use. This 
usually means that you must arrange the 
data to be plotted in a top-down, line- 
by-line array. Since the print head has 
seven or eight print wires in a vertical col- 
umn that can be used in graphics mode, 
the graphics lines are taken seven or 
eight at a time and read as columns of 
dots. These are coded into I -byte char- 
acters and sent to the printer one at a 
time. For example, if a given position on 
the line needs only the top dot printed, 
the character sent (in BASIC) would be 
CHR$(I). Similarly, if all eight dots are to 
be printed, the character would be 
CHR$(255). The coding system estab- 
lishes a correspondence between the 
wire positions and bit positions in the 
data byte, so that wire 1 has the same 
value as bit 1, wire 2 with bit 2, etc. This 
allows easy calculation of the character 

[continued) 



48 BYTE • JANUARY 1985 



COPYRIGHT © 1985 STEVEN A. GARCIA. ALL RIGHTS RESERVED. 



A BUREAUCRAT'S 
GUIDE TO WORD PROCESSING 



Now, if it were you or I and we 
wanted a word processing program 
for our IBM-type PC, we'd probably 
stop off at our local computer 
store and simply diddle with a few. 

You and I, however, are not 
the U.S. Department of Agriculture. 

(Nor any of its permutations 
of subsystems like the Economic 
Research Service, National Re- 
sources Economics Division, Data 
Services Center, etc., etc.) 

So when the USDA told 
ERS to tell NRED and DSC to look 
into a truckload of w.p. programs 
for all their PCs, the last thing they 
wanted was simple diddling. Their 
dedicated Wangs and Lexitrons 
were far too few to handle their 
needs, their IBM® PCs weren't 

THISI ARE THE PACKAGES 
THE COMMITTEE EVALUATED: 




compatible with them anyway, and 
nobody really, quantifiably, knew 
from word processing with a per- 
sonal computer. 

Definitely not a diddling-mode 
condition. 

As they put it in The Exchan ge, 
an internally distributed publication 
of the Department of Agriculture: 
'A needs assessment showed that, 
in the long-term, a word processing 
system is needed that can increase 
word processing capability and 
also be compatible with ERS' Long 
Range Information Management 
goals" 

Well, "Needs assessment" led 
swiftly to "procurement action" 
which galloped into an "objective 
review' of the eight top-rated PC 
programs on the market (as com- 
piled by The Ratings Book pub- 
lished by Software Digest ), along 
with WordStar® and Display Write 2, 
because they had some around. 

Thus armed with the names, 
the final evaluators (a team of secre- 
taries from NRED who would be the 
primary users of the PC software) 
became armed with each of the 
programs, along with checklists to 
record such things as ease of use, 
advanced features, and similarity to 
their existing dedicated equipment. 

Since NRED has some hard 
disk base systems, any packages 
that were copy-protected could 

THESE WERE THE FINALISTS: 




MultiMate 

Professional 
Word Processor 



not be transferred to the hard disks, 
and were eliminated on that basis 
alone. OfficeWriter™ and SAMNA 
WORD™ II were the first to go. 

Next, IBM's Diplay Write 2: 
because its "not compatible with 
other software used in ERS (like 
Lotus™ 1-2-37 dBase Ilf etc.)," and 
it's "full of confusing menu options 
and cryptic error messages!' Au 
revoir IBM. 

Then, three more, for a variety 
of reasons. Which left: 

Volkswriter® Deluxe™ 

MultiMate™ 

Leading Edge™ 

Volkswriter® Deluxe? "Too 
complicated and confusing" Not 
"easy to leam or use!' 

MultiMate? Not bad. It actually 
tied the winner in a few categories. 

The winner being the one that 
won 82% of the votes in the Ease 
of Use/Ease of Learning categories. 
The one about which they said, 
"The ability to store deleted text and 
automatic document backup fea- 
tures were both highly desirable!' 
The one they thought they'd quickly 
"be able to use ... for their day-to- 
day word processing tasks!' 

The whole process took some 
three months of work by people 
in DSC to support the NRED in 
its work with the ERS and DSC 
to make the world a better place 
for the USDA. 

But the results were well 
worth the wait. Because at last 
they've solved their word- a 
processing problems . . . /\ 



"With Leading Edge!" 



I IABIKC (OCI 



THIS WAS THE WINNER: 
LEADING EDGE™ 
LEADING EDGE WORD PROCESSING 




LEADING EDGE PRODUCTS. INC. 
LEADING EDGE SOFTWAkE DIVISION. 21 HIGHLAND CIRCLE. NEEDHAM.MA 02194-0009 TEL. 800-343-3436. (617) 449-4655 

HELP HOTLINE 800-523-HELP 

IBM is a registered trademark of International Business Machines. WordStar is a registered trademark of MicroPro IntemationalCorporation. OfficeWriter is a trademark ofOfftce Solutions (nc 

S AMN A WORD H is a trademark of SAMNA Corporation. Lotus and 1-2-3 are trademarks of Lot usDevelopment Corporation. dBa sell is a registered trademark of As hton-Tate. Volkswriter is a 

registered trademark and Deluxe is a trademark or Lifetree Software Inc. MultiMate is a trademark of MultiMate International Corporation. Leading Edge is a trademark of Leading Edge Products, Inc. 



Inquiry 199 



JANUARY 1985 • BYTE %9 



Inquiry 70 



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ASK BYTE 



value to produce a given pattern: simply 
add the values of the wires to be printed. 
Since the wires are in the binary se- 
quence I, 2, 4, 8, 16, 32, 64, and 128. 
the arithmetic is easy. 

Printers with 150 to 200 dots per inch 
in both directions are available, but most 
of the low-cost graphics printers are in 
the 72- to 120-dot-per-inch range— -Steve 

No Need to Modify SA400S 

Dear Steve, 

In regard to your response to Claudio 
Pugliese's letter in the June 1984 issue 
(page 70) concerning Shugart SA-400s for 
Apples, I think there is a better solution 
than the one you proposed, which was to 
modify the SA-400s. I use the Suntronics 
(12621 Crenshaw Blvd., Hawthorne. CA 
902 50) AFDC-1 floppy-disk controller to 
connect two SA-400 drives to slot 6 of my 
Apple II + . Interfacing is as simple as plug- 
ging in the drives; at $55.95 you can't beat 
it. Furthermore, the drives sound like they 
did on the Radio Shack instead of the way 
the Apple drives sound when they seek 
track zero. The only disadvantage is that 
the AFDC-1 doesn't support half-tracking. 
I've never had a problem reading, writing, 
or copying regular Apple ll+-created 
disks. 

Jim Means 
Lompoc, CA 

SA400~Apple Interface 

Dear Steve, 

Regarding an Apple II interface to a 
Shugart SA-400 disk drive, I have been 
selling the plans for one such interface for 
the past two years. It's a highly simplified 
circuit, consisting of five common TTL 
chips. The SA-400 PCB requires only two 
cuts, a resistor substitution, and a chip 
replacement. 

For interested readers. I will supply the 
schematic for this interface, a parts list, 
complete instructions, and diagrams for 
$16 U.S. or $20 Canadian. Please send it 
to |. Cygman, 1 58 Leslie St.. DDO, Mon- 
treal, Quebec H9A 1X3, Canada. Money 
orders only, please. Or call (514) 683-9392 
for information. 

J. Cygman 
Montreal, Quebec, Canada 

PCjr Screen Modes 

Dear Steve, 

I have an expanded IBM PCjr, and I have 
not been able to use screen modes 5 and 
6. The BASIC manual states that you can 



use these modes (and others) only if you 
have 128K bytes and Cartridge BASIC. I 
have these, and I still get an illegal func- 
tion call when I attempt to use these 
modes. I have also experienced the same 
problem on another PCjr with the same 
specifications. Can you offer an explana- 
tion or a remedy for the problem? 

Chris Newbold 
Lexington, MA 

Before screen mode 5 or 6 can be used 
on the PCjr, it is necessary to allocate 
some memory for it. The CLEAR com- 
mand does this, among other things. The 
simplest way to use it is as follows: 

10 CLEAR , , ,32768 
20 SCREEN 5 

or 

10 CLEAR , , ,32768 
20 SCREEN 6 
—Steve 

Sons of 8086 

Dear Steve. 

I have been reading a lot of articles and 
ads in BYTE featuring computers based on 
the Intel 80186 microprocessor. Now In- 
tel has introduced a new processor, the 
80286. An ad in BYTE says "the 80286 is 
capable of supporting up to 16 megabytes 
of physical memory and up to 1 gigabyte 
of virtual memory when utilized in virtual 
address mode." What are the differences 
between the 8086. 80186, and the 80286, 
and how are the 80286's large memory 
capabilities accomplished? 

TImothy Russell 
Bellevue, NE 

The 8086 is the first processor in the 
Intel 1 6-bit line. The 80186 and 80286 are 
enhancements on the 8086 and will run 
most or maybe all 8086 software. 

The 80186 is a more integrated system 
than the 8086 in that it includes, on the 
chip, most of the "glue" parts that are 
added externally in 8086 applications, 
such as timers, interrupt controller, and 
DMA controller. It also includes a few 
new instructions like PUSHA and POPA. 
which push and pop all registers at once, 
and INS and OUTS for strings. Instruc- 
tion execution times are the same as the 
8086, and clock speeds up to 8 MHz are 
available. Addressing capability is the 
same as the 8086. 

. The 80286 represents evolution of the 
8086 family in a different direction. This 
processor is designed for multiuser sys- 

[continued) 



50 BYTE • JANUARY 1985 



maxell 

FLOPPY DISK 




Gold. 



The floppy disk that 
lets PC AT speed ahead, 

makes PC/XT 
Xtraordinary 

and helps IBM.PC 

capitalize 
on its powers. 



For your Big Blue, only the Gold 
Standard will do. Maxell. The floppy disk 
chosen by many disk drive manufac- 
turers to test their new equipment. 
Each Gold Standard is backed by a 
lifetime warranty. And each 
is a perfect match for your IBM. 
In fact, there's a Gold Standard 
for virtually any computer made. 
Even if it's the new IBM PC AT! 



maxell 

IT'S WORTH IT 




PC AT. PC/XT and PC are trademarks of IBM Corp. 



Maxell Corporation of America, 60 Oxford Drive, Moonachie, NJ. 07074 
Inquiry 220 



JANUARY 1985 -BYTE 51 



Inquiry 24 7 



A 




Fill your IBM XT or Portable's half-size expansion slot 

with the only 1200 baud internal modem designed for it: ' 

The Ven-Tel Half Card: Under $500 from MTI. 

The Half Card™ includes the most popular communications software, 
Crosstalk XVI from Microstuf . 

This same modem also works in the IBM PC, the Compaq, and the 
Panasonic Senior Partner. 

MTI is an authorized distributor for Ven-Tel. And we honor Visa and 
MasterCard. Whether you buy, lease or rent, MTI is the one source 
for all the computer and data communications equipment, applica- 
tions expertise and service you'll ever need. At great prices. Call us. 



mti 

systems 



\^ 



A DUCOMMUN SUBSIDIARY 

Computer & Data Communications Equipment 
Sales / Leasing / Service / Systems Integration 

DEC, Intel, Texas Instruments, Hewlett-Packard, Dataproducts, Diablo, 
LearSiegler, Esprit, C.Itoh, Racal-Vadic, MICOM, Ven-Tel, Develcon, PCI, 
U.S.Design, Digital Eng., Cipher, MicroPro, Microsoft, Polygon & Select. 

New York: New Jersey: Ohio: California: 

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Powerful in circuit emulation, priced 
well within your grasp, Thai's NICE. ™ 

NICE may be only 3" square and W thick, but it hands you full speed, 
real-time emulation— over 50 emulation functions, software breakpoints \ 
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Just plug NICE directly into the target MP socket and any RS23.2 terminal 
for system development, troubleshooting, debugging or testing . . .^tt home, 
in the lab or in the field. 

And NICE hands you all this performance, portability and versatility for only 
$498*. . . the best emulator price /performance ratio on the market, hands down. 

Call in your order today using 
your VISA or Mastercard num- 
ber: (800) NICOLET outside ^VN« 
CA, or (415) 490-8300 in CA. 
Or send your 
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order 
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' Payment h>' cht 
order. VISA or M; 



^ISslicolet 




ASK BYTE 



terns and has direct addressing for up to 
16 megabytes of memory. This is accom- 
plished with a 24-line address bus. This 
chip also has an enhanced instruction set 
and protection features to prevent ac- 
tions by one user from interfering with 
another or to prevent unauthorized ac- 
cess to specific files (memory areas). Up 
to 16,383 memory areas can be defined 
with lengths between IK and 64 K bytes. 
Calls and jumps within and across pro- 
tection boundaries and between tasks in 
multitask applications are included in the 
instruction set. 

The virtual-memory addressing range 
is up to 1 gigabyte for each user. This is 
accomplished by providing most of the 
required capacity on hard disks and 
transferring blocks in and out of physical 
memory under control of the processor's 
memory-management program. This is 
transparent to the user, so that it appears 
to be the same as "real" memory al- 
though each user gets only as much 
physical memory as is needed. 

Virtual memory can be done in a 
limited fashion with the 8086 and other 
processors, but the 80286 s architecture 
and instruction-set enhancements are 
optimized for this application.— Steve 

Hardware-OS Interfacing 

Dear Steve, 

I am an engineer who specializes in 
digital hardware. I intend to build a home 
computer. My problem is that I do not 
know how to interface my hardware to an 
operating system. Can you help? 

Richard Goodrich 
Richardson, TX 

Interfacing between the operating 
system and the hardware was discussed 
briefly in my article "Build the Circuit 
Cellar MPX-1 6 Computer System, Part 3" 
in the January 1983 BYTE (page 54 j. As 
mentioned in that article, the CP/M-86 
manuals from Digital Research give the 
details of writing the BIOS, which is 
basically a set of device drivers that pro- 
vides the interface between the operat- 
ing system and your specific hardware. 

The IBM PC Technical Reference 
Manual gives a good example of a BIOS 
for 80881 80 86-based systems in Appen- 
dix A. This contains many of the inter- 
rupt-service routines used by the PC for 
I/O to the keyboard, printer, serial ports, 
disk drives, and screen as well as the 
bootstrap loader. 

A few books on operating systems are 

{continued} 



52 BYTE • JANUARY 1985 



Inquiry 259 



Need RGB color and ^ 
TTL monochrome y, "*"" 
support from a 
single board? 




r INIlLUGENr B-450 
Mono/Color Display Card 




Color Graphics Mode: 640 dots x 200 lines TTL Monochrome Mode: 640 dots x 350 lines Interlace Mode: 640 dots x 400 lines 



Look no further, the INTELLIGENT 
B-450 has it all. Designed to work 
with the IBM PC, PC XT, and PC AT, 
the INTELLIGENT B-450 is also suitable 
for IBM PC look-alikes. In addition to a 
parallel printer port, the B-450 has fourteen 
different screen modes which cover everything 
from medium-resolution monochrome text to 
high-resolution color graphics with interlace. 



Everyone from the ordinary user to the CAD/CAM 
specialist will find the B-450 is just right. 

Sound good? With a suggested retail price 
of only $294, it's nothing less than great! 

IBM and IBM PC are registered trademarks of International Business Machines Corporation. 



INrELUGENr 
DATASYS1EM 



Intelligent Data System, Inc. 

14932 Gwenchris Ct., Raramount, CA 90723 
Toll Free Tel: (800)325-2455 Calif. Tel: (213)633-5504 Telex: 509098 



Inquiry 174 



JANUARY 1985 -BYTE 53 




e'C 

for the 
Macintosh 



mmercial software development system 

Full Version 7 C Compiler • Fast and Compact 
'Code » Linker (overlay) • Resource Editor • No 
Royalties • Source Editor • Compatible with AZTEC 
'C for PC DOS, CP / M-86, CP / M-80, APPLE / / , TRS- 
80, COMMODORE 64 • 68000 Macro Assembler • 
Extensive Run Time Support • Utilities • Shell Envi- 
ronment • Requires 128K MACINTOSH • Compati- 
ble with LISA MACWORKS and 512 MACINTOSH • 
Full access to MACINTOSH TOOLBOX (ROM & OS) 



personal software development system 



ke, grep, diff, Z editor) 



U 



., PC DOS, MS DOS, 
M-80, APPLE //, VAX, 
PDP11 







TO ORDER OR FOR INFORMATION 

CALL OR WRITE: CALL: 

MANX SOFTWARE SYSTEMS ftfin QOi CXAACi 

Box 55 ^ 

Shrewsbury, NJ 07701 £ 

TX 4995812 

NJ RESIDENTS ADD 6% SALES TAX 

TRS-80 iS A TRADEMARK OF TANDY CORP, MACINTOSH fS A TRADEMARK OF APPLE, 
CP. M-86 & CP'M-80 ARE TRADEMARKS OF DIGITAL RESEARCH, PC DOS IS A TRADEMARK OF IBM 



CALL: 

800-221-0440 
201-780-4004 (NJ) 



ASK BYTE 



available. Three you might check out are 
Microcomputer Operating Systems by 
Mark Dahmke, Operating Systems by 
Harold Lor in and Harvey Deitel (both 
from McGraw-Hill), and The Design of 
Operating Systems for Small Computer 
Systems by Stephen H. Kaisler (John 
Wiley & Sons).— Steve 

Tape-Drive Controllers 

Dear Steve, 

I plan to buy an IBM PC or an MPX-16. 
I want to have two floppy-disk drives and 
two IBM 9-track tape drives. I want to be 
able to format the tapes, not just use them 
as streaming backup. I do not care 
whether a mainframe can read my tapes 
or vice versa. 

Where can I get a controller for these 
drives, or can it be done by software? I 
know a manufacturer who makes a nice 
system, but I am thinking of used drives 
for $500 each. 

Roger Cain 
Ottawa, Ontario, Canada 

You definitely need a controller to hook 
9-track drives onto a PC. Luckily, several 
manufacturers make such controllers and 
the software to go with them. I have not 
used these products, so 1 can't tell you 
how well they perform. These controllers 
are in the $500 to $1000 price range. 
Contact the manufacturers directly to get 
current information. 

Ibex Computer Corp. 
20741 Marilla St. 
Chatsworth, CA 91311 
(818) 709-8100 

Innovative Data Technology 
4060 Morena Blvd. 
San Diego, CA 92117 
(619) 270-3990 

Good luck with your project —Steve m 



IN ASK BYTE, Steve Garcia answers questions 
on any area of microcomputing. The most rep- 
resentative questions received each month will be 
answered and published. Do you have a nag- 
ging problem? Send your inquiry to 

Ask BYTE 

do Steve Garcia 

POB 582 

Glastonbury, CT 06033 
Due to the high volume of inquiries, personal 
replies cannot be given. All letters and photo- 
graphs become the property of Steve Garcia and 
cannot be returned. Be sure to include "Ask 
BYTE" in the address. 

The As/e BYTE staff includes manager Harv 
Weiner and researchers Bill Curlew, Larry 
Bregoli, Dick Sawyer, and )eannette Dojan. 



54 BYTE- JANUARY 1985 



Inquiry 215 




C COMPILERS FOR 
PC DOS MS DOS CP/M-86 CP/M-80 APPLE //, A/e, lie 
COMMODORE 64 RADIO SHACK and MACINTOSH 

AZTEC C86 

Optimized "C" compiler for PC DOS, MS DOS & CP/M-86 

PC DOS, UNIX I/O, math, screen, graphics libraries 

8086 assembler, linker & librarian, overlays 

/PRO-library source, debug, ROM, MASM & RMAC, 8087, large model 



SIO 



NEW C COMPILERS 

AZTEC C68K for MACINTOSH 
VAX cross compilers 

C TOOLS & AIDS 

Z editor (like Vi), C TUTOR compiler, PHACT database, 

C GRAFX, UNI-TOOLS I, QUICK C, BABY BLUE for PC 

to CP/M cross, QUADLINK for PC to APPLE cross 





AZTEC C II 

Optimized "C" compiler for CP/M, TRSDOS & LDOS 
assembler, linker & librarian, overlays, utilities 

UNIX I/O, math & compact libraries 
/PRO-library source, ROM, M80 & RMAC 



AZTEC C65 

"C" compiler for APPLE DOS 3.3, ProDOS or COMMODORE 64 

VED editor, SHELL, UNIX & math libraries 

/PRO-library source, ROM, overlays 



CROSS COMPILERS 

Compile & link on HOST— test on TARGET machine 
HOSTS: UNIX, PC DOS, CP/M-86, CP/M-80, VENIX, PCIX, APPLE 
TARGETS: PC DOS, CP/M-86, CP/M-80, APPLE, RADIO SHACK, 

COMMODORE 64, other hosts and targets available 








PRICES 








AZTEC C86 C COMPILER 




AZTEC CMC COMPILER 




AZTEC C CROSS COMPILERS 


TARGETS 


PC DOS MSDOS 


249 


CP/M 


199 


PDP-11 HOST 


2000 


PC DOS 


CP/M-86 


249 


CII/PRO 


349 


PC DOS HOST 


750 


CP/M-86 


BOTH 


399 


/PRO. UPGRADE 


150 


CP/M-86 HOST 


750 


CP/M-80 


C86/PRO 


499 


TRS 80 MODEL 3 


149 


CP/M-80 HOST 


750 


APPLE 


/PRO UPGRADE 


250 


TRS 80 MODEL 4 


199 


APPLE HOST 


750 


RADIO SHACK 


Z (VI EDITOR) 


125 


TRS 80 PRO (3 & 4) 


299 


VAX HOST 


CALL 


COMMODORE 64 


C TUTOR COMPILER 


99 






MACINTOSH 


CALL 


MACINTOSH 


PHACT DATABASE 


299 


AZTEC C65 C COMPILER 










C GRAFX 


99 


APPLE DOS 3.3 


199 








SUPERDRAW 


299 


PRODOS 


CALL 








UNI-TOOLS 1 


99 


E EDITOR 


99 








QUICK C 


125 






TRS 80 RADIO SHACKTRSDOS 


s a trademark of TANDY. 



MANX SOFTWARE SYSTEMS 
Box 55 
Shrewsbury, NJ 07701 
TELEX: 4995812 




APPLE DOS MACINTOSH is a trademark of APPLE. 



TO ORDER OR FOR INFORMATION: 

CALL: 800-221-0440 (outside NJ) 
201-780-4004 (N J) 



Australia: Blue Sky Industries — 2A Blakesley St. — Chatswood NSW 2067 — Australia 61-2419-5579 

England: TAMSYS LTD — Pilgrim House — 2-6 William St. — Windsor, Berkshire SL4 1 BA — England — Telephone Windsor 56747 

Shipping: per compiler next day USA $20, 2 days USA $6, 2 days worldwide $75, Canada $10, airmail outside USA & Canada $20 

UNIX is a trademark of Bell Labs. CP/M, CP/M-80 and CP/M-86 are trademarks of DRI. PC DOS is a trademark of IBM. MS DOS is a trademark of MICROSOFT. 

N.J. residents add 6% sales tax. 



Inquiry 216 



JANUARY 1985 -BYTE 55 



Three 






of today's 
most 

mlar 






•it • 



X 



computer 
accessories. 



J 



EXTRA- STRENGTH 



enira pain relief... 
contains no aspirin 





J&& 



^^^ ,.W HOT 



■.fror^**^* 




Tylenol * is a registered trademark of McNEILAB, INC- Visine* and 
Ben-Gay® are registered trademarks of Lemming Division, Pfizer Inc. 



Do you ever get the feeling 
that computers are treated with 
more respect than people? 

Everyone talks about 
technology. 

But what about the people 
who have to use it? 

Quite clearly, they're having 
problems. 

Industry publications like 
PC Magazine have written about 
those problems. 

And now, more than twenty 
states are currently preparing 
special computer legislation 
to force some changes. 

You are not a machine. 

Computers are designed by 
engineers. 

They usually know a lot 
about technology but very little 
about people. 

Which is why so many com- 
puters often are technically im- 
pressive yet strangely unnatural 
to use. 



Computer-induced 
problems (%) 



Eyestrain 

Back pain 

Headaches 

Shoulder 

Hand/wrist 

Neck pain 

(Source: "Ergonomic 

Principles in Office 

Automation" Pub. 

1983byE.LS.AB, 

Sweden.) 



55% 
43% 
30% 
25% 
18% 
15% 



The result 
has been a whole 
range of com- 
puter-induced 
problems rang- 
ing from stress 
and fatigue to 
blurred vision. 
In Sweden, 
they have an 
attitude the 
world is just catching up with. 
It's this: 

That the machine is the 
servant of man. 

Not the other way around. 
That excellent ergonomic 
design isn't a privilege. 
It's a right. 

That ergonomics isn't just a 
noble gesture. 

It's good business. 
Because computers are only as 
fast and as accurate as the people 
who operate them. 

If they suffer, so does business. 
This attitude has made Ericsson 
No. 1 in Europe twice over: 

First, as the giant of European 
telecommunications. 

Then again as Europe's biggest 
workstation company by far. 



(You couldn't ask for a 
better marriage of technology for 
the future.) 

Here is one example of how 
Ericsson got there. 

It's the first of a range of 
computers being introduced in 
the U.S.A. 

The Ericsson PC. 
It's Ergo-Intelligent.™ 

Ericsson has spent $300 
million finding ways to make 
people and computers work better 
together. 

Here are some of the results. 

Ergo-Screen.™ 

Aspirin gets rid of a headache. 

Ergonomics gets rid of 
the cause. 

The Ericsson PC has a non- 
glare screen with restful amber 
characters on a specially devel- 
oped, low-fatigue background 
color. 

Even the shape of the charac- 
ters was specially developed to 
allow easier recognition of difficult 
letters like O and Q. 

On the monochrome monitor, 
the resolution is double that of 
IBM's, so clarity is remarkable. 

You can even have text and 
graphics on the same screen. 

Ergo- Arm.™ 

Thousands of 
people get neck 
and back pain from 
inadequate screen height 
and angle adjustment. 
The Ericsson Ergo- 
Arm lets you 
move your 
screen exactly 
where you want it. 

Ergo-Touch.™ 

Ericsson keys are full-size, and 
the layout is economically planned 
for greater speed and accuracy. 

Yet the keyboard is 20% more 
compact and less than half the 
weight of IBM's. 

Even the cord is adjustable to 
suit left- or right-handers. 

Ergo-Color.™ 

Even the color of the case is 
economically selected to be restful 
on the eye over many hours. 





Ergo-Space.™ 

The system unit is 
one-third smaller than 
IBM's. 

It even fits under your 
desk in a special verti- 
cal rack. 

So your desktop is 
your own again. 

IBM Compatible. 

Many companies claim to be 
compatible. 

Some are. Some are stretching 
the truth. 

The Ericsson PC boasts the 
highest compatibility rating 
there is. 

It's operationally compatible. 

You can take advantage of 
thousands of PC-compatible pro- 
grams already available. 

In fact, with the best-selling 
software, program and data disks 
are interchangeable with those 
of the IBM PC. 

Service. Not excuses. 

Ericsson wouldn't give you 
anything less than on-site or carry- 
in service. The choice is yours. 

3 Free Offers. 

Ericsson will send you reveal- 
ing literature on ergonomics. 

Also a detailed brochure on 
the Ericsson PC. 

And arrange a hands-on test 
if you ask for it. 

Call toll-free 1-800-FOR-ERGO. 




ERICSSON ^ 



IBM is a trademark of International Business Machines Corp. 



Inquiry 128 



Master Piece 
The 100% 
compatible 
accessory 




Master Piece is the most versatile 
accessory ever made for IBM Per- 
sonal Computers. Master Piece 
combines the four most popular 
IBM® accessories into one elegant 
accessory offering the most con- 
venience and best value available. 

A SWIVEL BASE 

The Master Piece has a swivel so 
you can adjust the viewing angle o 
your monitor with just the touch of 
a finger. Since the Master Piece 
swivels with your monitor, its 
switches and static control are in 
front of you at all times. 

FIVE SWITCHED OUTLETS 

Stop searching for outlets to plug 
in your peripherals. Master Piece's 
five outlets put your entire system 
at your fingertips. Power up with 
the "Master" switch, then use the 
individual switches to control your 
peripherals. Touch the "Master" 
switch to shut down and you'll 
never accidentally leave your pe- 
ripherals running overnight. 

SURGE SUPPRESSION 
CIRCUITRY 

Power surges, spikes and line nois< 
are responsible for 70-90% of all 
PC malfunctions. They can wipe ou 
memory in your PC, taking hours oi 
hard work with them. They can zap 
your delicate chips, sending your 
PC in for costly repairs. Master 
Piece clips surges and spikes at a 
safe level. You end up with an IBM 
that's more accurate and reliable. 

STATIC PROTECTION 

Even you are a threat to your IBM. 
During the day you build up static 
charges — as much a threat to your 
PC as surges and spikes. Master 
Piece offers an elegant alternative 
to expensive and unsightly static 
mats, lust touch its nameplate be- 
fore you begin work and static 
charges are grounded. 

If you bought these accessories 
separately, you could spend more 
than $200. Master Piece's recom- 
mended retail price is under $150. 
Available now from IBM dealers 
everywhere. 

Inquiry 194 



^ KENSINGTON" 
^ MICROWARE 

251 Park Avenue South 

New York, NY 10010 

(212) 475-5200 Telex: 467383 KML NY 



Trademarks Master Piece/Kensington Microware Ltd 
IBM/ International Business Machines 
© 1984 Kensington Microware Ltd. 



CLUBS & NEWSLETTERS 



• C-PRO IN VIRGINIA 

The bulletin board of the 
CompuPro Users Group is 
up and running at (703) 
491-1852. operable via 
modem at 300 or 1200 bps. 
A remote CP/M system is 
also available. Members of 
the group produce a news- 
letter regularly that contains 
software reviews, hardware 
help, and tips. Annual 
membership is $20. Call 
Don Kelley at (703) 690- 
3312. or write Toni Bennett. 
C-PRO Users Group. 14057 
Jefferson Davis Highway, 
POB 1474, Woodbridge, VA 
22193. 

• ADAM ON THE HUDSON 

Members of the Metropoli- 
tan Adam Users Group from 
the New York-New Jersey 
area meet in New York City 
at 7 p.m. on the second and 
fourth Thursdays of every 
month. Information and ex- 
periences with the hardware, 
software, and related litera- 
ture are shared. At present, 
no dues have been set; a 
newsletter is in the early 
stages of production. Con- 
tact Russell Williams, 414 
West 149th St., New York, 
NY 10031. (212) 208-0645. 

• BUGS ON THE WEST 
COAST— The Basis Users 
Group Sacramento (BUGS) 
meets at 7 p.m. on the first 
Sunday of every month at 
the Shoreline Software 
Center in Sacramento, Cali- 
fornia. A magnetic news- 
letter allows members to ex- 
change technical notes for a 
$5 fee. A membership is 
$20. Contact Ms. Leslie 
Carroll, BUGS, 12 5 Faro 
Ave.. Davis, CA 95616. 

• THE MAC IN L.A. 

The Los Angeles Macintosh 



Group promotes the ex- 
change of information, 
offers help to all levels of 
users, and provides a forum 
for people to hear about 
new products from company 
representatives. Details are 
available from Eric Ander- 
son, 12021 Wilshire Blvd., 
#405. West Los Angeles, CA 
90025. (213) 392-5697. 

• LOGO NEWS OFFERS 

PEN PALS— The National Logo 
Exchange (NLX) is a news- 
letter for teachers that 
covers techniques and philo- 
sophies from successful 
Logo teaching programs. 
The subscription is $25 in 
the U.S., Canada, and 
Mexico for the eight-month 
school year. The newsletter 
also provides a Logo Class 
Penpal Network, which 
enables both students and 
teachers to exchange ideas 
and projects during the 
school year. To receive an 
application, send a legal- 
sized, self-addressed, 
stamped envelope to the 
Logo Class Penpal Network 
at the address below. For 
details about the newsletter, 
contact the National logo 
Exchange, POB 5341. Char- 
lottesville, VA 22905. 

• PHOENIX SENDS 

TELEGRAM-The National 
Phoenix User Group News- 
letter, CBTelegram. contains 
technical support, news from 
Goal Systems, details about 
the formation of regional 



groups, and notes about 
past conferences. Efforts 
have been made to raise 
funds at national events to 
provide members with bi- 
annual meetings. The Na- 
tional Phoenix User Group 
is funded and operated by 
users. Goal Systems pro- 
vides free advertisements, 
the cost of producing the 
newsletter, and support for 
user groups associated with 
the Phoenix. Send inquiries 
to the National Phoenix 
User Group, POB 14623, 
Cleveland, OH 44114. 

• DEC DRIVE 

The Association of DEC Pro- 
fessionals (ADP) welcomes 
interested DEC programmers 
and system managers as 
new members for 1985. For 
information, send your title, 
model, and operating sys- 
tem for your DEC system 
along with a self-addressed, 
stamped envelope to ADP, 
POB 81045, Atlanta, GA 
30366. 

• ROBOTIC CONSUMER 

A monthly newsletter de- 
signed for manufacturing 
managers, Robotics Forum: 
Management Issues in Manufac- 
turing, addresses issues on 
manufacturing and industrial 
robots. Nontechnical, user- 
oriented articles, covering 
such topics as fiscal justifica- 
tion and the myth of turnkey 
systems, assist managers in 
making informed decisions. 
The annual subscription fee 



CLUBS & NEWSLETTERS is a forum for letting BYTE readers know what 
is happening in the microcomputing community. Emphasis is given to elec- 
tronic bulletin-board services, club-sponsored classes, community-help projects, 
field trips, and other activities outside of routine meetings. Of course, we will 
continue to list new clubs, their addresses and contact persons, and other in- 
formation of interest. To list events on schedule, we must receive your infor- 
mation at least four months in advance. Send information to BYTE, Clubs 
& Newsletters, POB 372. Hancock, NH 03449. 



is $125. For information, 
contact the editor. Jay 
Goldstein, Robotics Forum: 
Management Issues in Manufac- 
turing, POB 123. Lorane, OR 
97451, (503) 683-4445. 

• SLUG IN PULLMAN 

The Sanyo Lovers' Users 
Group (SLUG) is an MS-DOS 
group designed to provide 
technical support for users 
of the Sanyo MBC series in 
the Moscow, Idaho/Pullman, 
Washington area. Members 
can benefit from regular 
meetings and access to a 
public-domain software 
library. Contact Michael 
Russell, POB 2084 CS, 
Pullman, WA 99163. (509) 
878-1714. 

• NEWS FOR MEDICAL 

SCIENTISTS-The New York 
University Medical Center 
Personal Computer Users 
Group maintains a public- 
domain software library that 
specializes in programs of 
interest to medical scientists. 
Information on how to ac- 
cess the group's bulletin- 
board service and library 
can be obtained by contact- 
ing Dr. James Mihalcik, 
Department of Anesthe- 
siology, University Hospital, 
5 50 First Ave., New York, NY 
10016. 

• A PAL IN HAL 

The Houston Area League 
of PC Users (HALrPC) is a 
group for users of the IBM 
PC and its compatibles. 
Benefits include a public- 
domain software library, a 
monthly newsletter that in- 
cludes software reviews, and 
more than a dozen special- 
interest groups. Members of 
the club are in the process 
of setting up a bulletin- 

{continued) 



JANUARY 1985 'BYTE 59 



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CLUBS & NEWSLETTERS 



board service. Meetings are 
held at 7:30 p.m. on the first 
TUesday of every month at 
the Radisson Inn in 
Houston. Texas. The annual 
dues are $25. For details, 
write the Houston Area 
League of PC Users. POB 
610001. Houston, TX 77208. 

• OSBORNE IN BOULDER 
The Boulder Osborne Users 
Group (BUG), affiliated with 
the Denver Osborne Group 
(DOG), offers support to 
owners of the Osborne 
through monthly meetings 
and DOG's monthly news- 
letter. People interested in 
portable computers or the 
CP/M disk operating system 
are welcome. Meetings are 
held at 7 p.m. on the sec- 
ond Wednesday of every 
month in Room 224 of the 
University of Colorado's 
Business School Building in 
Boulder. Contact Bruce 
Keith. Boulder Osborne 
Users Group. 715 South 
45th St.. Boulder. CO 80303. 

• PROS ORGANIZE 

The Association of Com- 
puter Professionals (ACP) is 
a nonprofit, educational 
organization designed for 
the mutual benefit of pro- 
grammers, software devel- 
opers, hardware designers, 
consultants, and other pro- 
fessionals in the microcom- 
puter field. The newsletter. 
ACP NEWS$, contains an ex- 
change of information to 
promote members' effec- 
tiveness and career interests. 
Contact Sy Bos worth. ACP, 
Suite 460. 230 Park Ave.. 
New York. NY 10169. (212) 
599-3019. 

• ILLINOIS USERS HELP 
The Champaign County 
Computer Club (CCCC) 
meets at 7:30 p.m. on the 
first Wednesday of every 
month to support new or 
experienced users with com- 
puters ranging from Apple 
to Zenith. Members benefit 
from special-interest groups, 
computer classes, a con- 



stantly updated public- 
domain software library of 
DOS and CP/M disks, and a 
monthly newsletter. The $12 
annual dues also include ac- 
cess to a 24-hour bulletin- 
board service at (217) 
3 59-9577. Contact Jim 
Mullen. 1004 Kinch. Urbana. 
1L 61801. (217) 344-2178. 

• SPECIAL SIG 

The Gila Valley Apple 
Growers Association 
operates a free voice help 
line for users of the Apple- 
writer He at (602) 428-4073. 
For information, write to the 
Gila Valley Apple Growers 
Association. POB 809. 
Thatcher. AZ 85552. 

• A ROOM WITH 

TERMINALS-The Stanford/ 
Palo Alto Users Group for 
the IBM PC meets at 7 p.m. 
on the last Wednesday of 
each month in Polya Hall, 
the computer science 
auditorium of Stanford Uni- 
versity. Members can see 
demonstrations on the ter- 
minals at each desk. The 
club maintains a public- 
domain software library, pro- 
duces a monthly newsletter, 
and opens its membership 
to the community. The an- 
nual fee is $2 5. Write to the 
Stanford/Palo Alto Users 
Group for the IBM PC POB 
3738. Stanford, CA 94305. 
(415) 326-7006. 

• 3000 FILES ON LINE 
New releases, communica- 
tions, and utilities for Apple. 
Osborne. IBM PC Compu- 
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are available on a nonprofit 
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SiMMS (Silicon Multiple 
Message System) Network 
Headquarters runs on a 
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To register, send a six-digit 
password and $25 to SiMMS 
Headquarters. Silicon Valley 
Interchange RCP/M Registra- 
tion, POB 532. Cupertino. 
CA 95015. ■ 



C Copyright 1984 C0Mr\rn3JS*NC Afl Rights ResevoJ 



60 BYTE • JANUARY 1985 



Inquiry 80 



PERSONALITY 
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Inquiry 356 
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Getting UNIX Software 
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JANUARY 1985 • BYTE 61 





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Inquiry 344 



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Inquiry 221 



BOOK REVIEWS 



THE SECOND SELF: 
COMPUTERS AND THE 
HUMAN SPIRIT 
Sherry lUrkle 
Simon & Schuster 
New York: 1984 
362 pages. $17.95 

INFORMATION SYSTEMS 

SECURITY 

Royal P. Fisher 

Prentice-Hall 

Englewood Cliffs. NJ: 1984 

240 pages. $24.95 

MICROPROCESSORS: 
HARDWARE. SOFTWARE. 
AND DESIGN 
APPLICATIONS 
Wunnava V. Subbarao 
Reston Publishing 
Reston. VA: 1984 
500 pages. $29.95 



THE SECOND SELF 
Reviewed by 
Anthony Townsend 

The press has focused 
lately on the novelty of 
computers, telling us what they are. and will be. capable 
of doing. We are told that we will see them with increas- 
ing frequency in everyday life, and that they will become 
a greater presence in our work and play. Rare, though, is 
the article or study of how computers are changing our 
definition of society. While sociological studies obvious- 
ly take longer to research and compile than feature ar- 
ticles, they are no less important to the public's under- 
standing of computers as a social force. 

In The Second Self: Computers and the Human Spirit. Sherry 
lUrkle, a sociologist and psychologist at the Massachusetts 
Institute of Technology, attempts to chronicle the impact 
of computers on humanity. Using six years of data and 
observations, she portrays the computer as an unprece- 
dented influence on civilization, a tool that can simulate 
the process of the human mind. 




Tjrkle begins by discuss- 
ing the relationships that 
children form with micro- 
processor-controlled toys. 
Her discussions of how 
children interact with even 
the most rudimentary elec- 
tronic toys show insight into 
how the computer is now 
commonplace, as television 
was to a previous genera- 
tion. 

Using children as an initial 
study group. TUrkle ex- 
plored their concepts of 
whether or not machines 
are alive. What is it about 
computers and electronic 
toys that gives them that 
added dimension of life? 
This theme is carried 
through the book as the 
author explores what it 
means for a person to 
"think" and whether a 
machine can be expected 
to perform the same pro- 
cess or merely mimic it. 

TUrkle chronicles the ex- 
periences of children at a 
private school where they 
have almost unlimited ac- 
cess to computers. As part of a research project, the 
children learned to use computers as a method of express- 
ing themselves. Using these children as case studies. TUrkle 
begins to develop her theory of how people interact with 
computers, classifying how children and adolescents use 
the computer. A distinction is made between "soft" and 
"hard" masters, a description dependent on whether the 
child uses the computer as an artistic tool or as a tech- 
nological shortcut to play and fantasy. 

In the second part of the book. TUrkle focuses on how 
people who interact daily with computers view them. She 
writes about personal computer owners, hackers, and peo- 
ple involved in artificial-intelligence research. Although all 
three groups have diverse reasons for their attachment 
to computers. lUrkle draws parallels among all three. She 

[continued) 



ILLUSTRATED BY JAMES STEINBERG 



JANUARY 1985 -BYTE 65 




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BOOK REVIEWS 



postulates that computers in general have the capacity 
to make human beings think about themselves in a dif- 
ferent light. This implies a more introspective process 
where the faculty of thought becomes the vehicle for com- 
paring human reason to the analytical process of a think- 
ing machine. If a machine can think (and Tlirkle does not 
imply that this is likely or probable— simply possible), then 
it is logical that the human race may no longer be at the 
top of the evolutionary ladder. Humans could boast the 
dubious distinction of spawning their own successors. 
In the book's final section, "Into a New Age," the author 
ties together the research and hypotheses of the previous 
sections. She looks at what it may mean to think of a 
human being as a machine, and how this affects the human 
soul, psyche, and spirit in a culture where machines are 
quite often taken for granted. This idea dates from the 
Industrial Revolution, but The Second Self delves into the 
rationale of such an assumption. The advent of psycho- 
analysis is compared to research in artificial intelligence. 
Tlirkle implies that today's computers and tomorrow's ar- 
tificial intelligence will beget a new science of the mind. 

Study in Style 

Tlirkle employs a literary style quite different from the style 
of other sociological volumes. Quotations from her 
research subjects are used extensively and case studies 
are predominant. She calls her research methods ethno- 
graphic, or employing descriptive anthropology. In this 
context, the word means that her research consisted of 
exploring the culture she was studying by being present 
in those groups germane to her work. She uses this par- 
ticular technique effectively, conveying a real sense of what 
computers mean to those people involved in their use. 

New Interpretations 

The second part of the title, Computers and the Human Spirit, 
perhaps tells the most about what Sherry Tlirkle is trying 
to accomplish. Using a unique blend of sociological 
research and psychological insight, she makes you think 
about what it means to think. Is the human thought pro- 
cess merely a multilevel collection of chemical processors 
and instructions? Can something as complex as emotion 
be reduced to a set series of equations, however complex? 
TUrkle demonstrates that even the abstract activity of think- 
ing about how we think sets us a step beyond a strictly 
logical perception of consciousness. She hints that com- 
puters may have been created prior to a clear understand- 
ing of the possible implications. 

Tlirkle frequently refers to Douglas R. Hofstadter's Godel 
Escher. Bach: An Eternal Golden Braid (Random House, 1980) 
in formulating her hypotheses on how computers in- 
fluence and interact with humans. Hofstadter's explana- 
tions of esoteric logic have met with wide acceptance 
among artificial-intelligence experimenters as a kind of 
symbol that even the most logical proof can be clouded 
in illogical ramifications. Using the culture of computers 
and the people involved with them as vignettes of a larger 



66 BYTE • JANUARY 1985 



Inquiry I77 



Inquiry 14 



BOOK REVIEWS 



picture. TUrkle attempts to reconcile the image of the com- 
puter as bound by rules with a freewheeling image of the 
mind that knows no boundaries. She uses paradox, as 
Hofstadter does, to stimulate the reader to think that just 
because an item can be taken for granted does not mean 
that item is without deeper meaning. 

A New Discipline 

The Second Self: Computers and the Human Spirit is a book with- 
out boundaries. Combining her expertise as sociologist 
and psychologist. TUrkle has created an excursion into 
thought, a fundamental function of the human race. 
Authors who use such abstract and undefined parameters 
in writing usually end up with readers as lost as they were 
at the start. But TUrkle's skill makes it otherwise. Although 
dealing with subjects as hard to quantify as computers 
and the human spirit, she does not allow herself to lose 
sight of the fact that without rational, progressive thought, 
nebulous concepts become just so much babble. 

Because TUrkle is a professor in the Science. Ikchnology. 
and Society Program at MIX this work may well be the 
vanguard of a growing branch of science. This young 
discipline is vital for perspective as computers become 
more a part of the fabric of human culture. A better 
understanding of what it means to be human is only one 
result of further research into this area. Sociologists, 
psychologists, and philosophers can benefit from examina- 
tion of the principles put forth by TUrkle. 

The Second Self is not a book to be read lightly. It requires 
you to think and respond to its concepts, to postulate what 
it is that your mind does and how that process is changed 
by. and is similar to. the electronic parts of machine in- 
telligence. I recommend TUrkle's book to anyone who 
wants a better understanding of themselves and the 
culture in which they live. 

Anthony Townsend (Box 7603. Charlottesville. VA 22906) is an 
independent microcomputer consultant and software evaluator. 



INFORMATION SYSTEMS SECURITY 
Reviewed by Annette Hinshaw 



Royal Fisher in Information Systems Security outlines pro- 
cedures for managers to discover potential danger 
spots (exposures) in information systems, develop 
numerical values for each exposure, and decide which 
security actions are most cost-beneficial. Examples, work- 
sheets, and charts support straightforward, easy-to-under- 
stand explanations of data-security principles. While Fisher 
uses a mainframe environment as the matrix for his discus- 
sion, his techniques can be profitably used by anyone who 
has information to secure. 

Fisher sets out to show managers that data security is 
a basic business concern, and one that belongs to man- 
agement as a whole rather than just to managers of data 

[continued) 



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$2.00 EACH 10 FOR $18.00 




5 STATION 
INTERLOCKING 

MADE BY ALPS. 
3 - 2PDT AND !££** 
2 - 6PDT lSV?tW 

SWITCHES ON FULLY 
INTERLOCKING ASSEMBLY. 
3VT BETWEEN 
MOUNTING CENTERS. 
S2.50 EACH 

5 STATION 
NON-INTERLOCKING 

SAME AS ABOVE. EXCEPT 

EACH SWITCH OPERATES 

INDEPENDENTLY. 

S2.50 EACH 



When You Want The Best, Call. 



nbs 



inc. 



National Business Software and Supplies 



$ + SENSE 


SARGONHI ! TRIVl/ 


$110 




$35 CALL 




MULTIMATE 


$285 


FLIGHT SIMULATOR 


S 35 


PFSFILE 


89 


MULTIPLAN 


125 


PFS REPORT 


79 


DESK ORGANIZER 


CALL 


PFS WRITE 


89 


BANKSTREET WRITER 


CALL 


SYMPHONY 


CALL 


CROSSTALK 


CALL 


LOTUS 1*2-3 


CALL 


PRO KEY 


59 


TURBO GIFT PACK 


72 


PRO KEY 3.0 


82 


WORDSTAR ■ 


229 


NORTON UTILITIES 


55 


SIDEKICK 


35 


R BASE 4000 


268 



TEAC MODEL #55-B DRIVES FOR IBM PC S 1 39 

Ribbons and Printwheels 

EPSON-OKIDATA-NEC-DIABLO, ETC. 

call for prices 

(602)967-5681 visa Mon-Fri 
P.O. Box 3163 8AM-5PM 

Tempe.AZ 85281 Mas,er0ard 



No cash refunds— all sales final. 20% restocking fee. Add S5 for credit card purchases. 
AZ residents add 6%. Prices subject to change, product subject to availability. Allow 
two weeks for personal/company checks to clear. All items are new with manufacturers 
warranty. Software not warranted for suitability of purpose. Shipping and handling 
add $5 per order. Minimum order $50. 



Inquiry 249 



JANUARY 1985 -BYTE 67 



EH" 



100% FLAWLESS 
COPIES . . . 

...FAST! 



No need to tie up your valuable computer to duplicate 
diskettes . . . when VICTORY can provide you with a 
duplicator that will do the job flawlessly, and much 
faster. One button operation automatically formats, 
duplicates and verifies up to 8 diskette copies at the 
same time. 

VICTORY can supply you with literally dozens of 
standardized formats to match the protocol of virtually 
any current computer. In addi- 
tion, built-in utilities enable 
you to read or devise any for- 
mat you may require. If that's 
not enough, VICTORY can 
help you with unusual or 
unique formatting, serializing 
or copy-protecting problems. 

VICTORY duplicators are 
designed to be reliable. Each 
of the copy drives has a 
separate controller to increase 
copying throughput and 
ensure maximum uptime. 
VICTORY Duplicators use 
industry proven drives com- 
bined with 100% digital tech- 
nology . . . there are no 
analog circuits to slowly drift 
out of tolerance. 

Let us help free you from 
your disk-duplicating bottle- 
neck at a surprisingly 
attractive price. Write or call: 
VICTORY ENTERPRISES 
TECHNOLOGY, INC., 8910 
Research Blvd., Suite B2, 
Austin, Texas 78758— 
(512)450-0801. 






Victory Enterprises 
Technology, Inc. 



BOOK REVIEWS 



processing. The author broadens the field of concern. In 
addition to data theft or modification by intruders, 
managers should also consider data corruption by error 
a breach of information security. Fisher also emphasizes 
a need for tested plans to recover vital data that could 
be lost in disasters such as fire and flood. 

Computer security is only one of the information- 
security issues the author addresses. A businessperson 
whose vital data is mostly on paper can utilize the systems 
proposed in this book as readily as someone working in 
a large data-processing center. 

Fisher defines data security as "the protection of data 
from unauthorized disclosure, modification and/or destruction 
whether accidental or intentional." He develops this defini- 
tion into a classification system for types of exposures. 
This classification is the first of many practical tools sug- 
gested by the author for analyzing potential data-security 
problems. 

The Procedure 

The first step in developing an effective information- 
security system is to draw a flowchart of the data life cy- 
cle. In a payroll application, for example, data is generated 
from workers' time cards, which are physically moved, 
checked, and entered into the data system. The data com- 
pletes the cycle when the workers receive their paychecks. 
Every data-transfer point from time card to paycheck is 
a potential source of disclosure of privileged information, 
error, or fraud. 

With a complete flowchart, a manager can divide infor- 
mation security into manageable chunks called control 
points, which can then be handled as separate entities. 
Fisher's systems are not precise because they do not at- 
tempt to map real-world interactions between the 
modules. However, the complexity of such interactions can 
easily obscure system analysis. What Fisher's procedures 
lose in precision they make up for in manageability. The 
author points out this and other limits in his procedures, 
which are meant to guide decisions rather than dictate 
action. 

Building information security begins with an analysis of 
the risks at each control point in the data life cycle, the 
author says. Considering each type of security exposure 
(accidental or intentional data disclosure, change, or loss), 
the analyst identifies the specific exposures for each data- 
transfer area. He completes a worksheet for each control 
point and summarizes the risks on another form that maps 
the data-security system and highlights the greatest risks 
to information security. Fisher has designed formats for 
these worksheets. 

In a brief chapter. "Limiting Risk." the author reviews 
a few commonsense. inexpensive ways to improve data 
security. Fisher shows that careful data-handling pro- 
cedures in the hands of cooperative employees can 
eliminate as many potential risks as can elaborate, expen- 
sive security designs. Fisher places this chapter between 

[continued) 



68 BYTE • JANUARY 1985 



Inquiry 363 



You don't need a computer 
to talk to another computer. 



DISPLAY (VP3012D). High 
performance, 1 2" diagonal, 
non-glare, green phosphorous 
screen. 



RESIDENT MENUS. User-friendly 

terminal set-up and 

phone directory maintenance. 



DIRECT CONNECT MODEM 

Built-in, 1200 or 300 baud, 
originate/answer/auto answer. 



AUTO DIAL. Tone or pulse dialing 
of up to 26 stored phone numbers, 
voice or data base calls, 



AUTO LOG-ON. Enters information 
automatically after auto dialing, 




VIDEO OUTPUT. Selectable 80 
or 40 characters x 24 lines 
on standard monitor. 



TV OUTPUT. Displays 
40 characters x 24 lines 
on Ch. 3/Ch. 4 of standard TV set. 



MEMORY BACKUP. Minimum 
48-hour storage of directory, log- 
on and other parameters without 
plug-in power. No batteries 
required. 



FUNCTION KEYS. User 
programmable or 
downloadable 
from host computer. 



APT VP580 1 , 1 200 baud modem 

APT VP4801 , 300 baud modem 



The RCA APT ( All-Purpose Terminal). 
Now with built-in 1 200 baud modem for greatly 
expanded data communications capabilities. 



For business, professional and personal 
data communications, you'll find more user- 
friendly features and greater communications 
capabilities in the RCA APT than in other termi- 
nals selling for up to three times the price. 

The new APT terminals are ideally suited 
to multi-data base time sharing by telephone 
line, and dedicated, direct computer-connected 
applications. They feature menu-controlled 
operation and a programmable ''personality" to 
match specific communications requirements 
for your data bases. 

A single keypress can dial a stored 
number, send the log-on sequence to the host 
computer, and return terminal control to the 
user. Password protection prevents unauthor- 



OTHER FEATURES 

RS232C port for direct computer connections at 
data rates to 9600 baud, or for connecting high 
speed modems and other accessories. Parallel 
printer port for hard copy. Numeric keypad can dial 
phone numbers not in terminal directory. Built-in 
speaker with adjustable volume control for audio 
monitoring off phone line. Automatic screen blank- 
ing to reduce possibility off burn. Briefcase size: 1 7" 
x 7 ' x 2". Weight: under 4 lbs. 



ized access to designated numbers. APT 
can also be used as an autodialer for voice 
communications. 

The APT VP5801 terminal with 1 200 baud 
modem lists for $798. The APT VP4801 termi- 
nal with 300 baud modem lists for $498. The 
data display monitor alone (VP3012D) is 
$199 list. 

Quite simply, matching features with price, 
there are no other professional quality terminals 
available today that can do as much at such 
low cost. 

For more information — or to order — call 
800-722-0094. In Penna., call 717-295-6922. 
Or write for fully descriptive brochure to RCA 
Data Communications Products, New Holland 
Avenue, Lancaster, PA 1 7604. OEM and dealer 
pricing available. 

The RCA APT Expansive. Not expensive. 



Inquiry 299 



ItC/l 

Data Communications 
Products 



JANUARY 1985 -BYTE 69 



High performance to cost ratio... 

Programming Chips? 



Projects develop profitably with devekjpnrat hardware /software from GTE3L 



MODEL 7228 - $599 

This model has all the features 
of Model 7128, plus Intelligent 
Programming Algorithims. It 
supports the newest devices 
available through 51 2 Kbits; pro- 
grams 6x as fast as standard 
algorithims. Programs the 2764 in 
one minute! Supports Intel 2764A 
& 27128A chips. Supports 
Tektronics, Intel, Motorola and 
other formats. 




MODEL 7956 

(with RS232 option) .... $1099. 
MODEL 7956 (stand alone) $ 979. 

GTEK's outstanding Gang Pro- 
grammer with intelligent 
algorithm can copy 8 EPROMS at 
a time! This unit is used in a pro- 
duction environment when pro- 
gramming a large number of chips 
is required. It will program all 
popular chips on the market 
through the 27512 EPROMS. It 
also supports the Intel 2764 A & 
271 28 A chips. It will also program 
single chip processors. 

EPROM 

PROGRAMMERS 

— These features are standard from GTEK— 
Compatible with all RS232 aerial interiacB parts • Auto sefedt baud rate • With or without hand- 
shaking • Bidinrtoal XaVXrf • CIStfTTR suppntad • Read pin conpatibte ROMS' No per- 
sonality modules • Intel, Motoula, MCS86 Hex frrmats • Spat facility for 16 bit data paths • 
Read, program, formatted list anvnands* In tenupt driven — program and verify real time white 
sendingdata • Program single byte, block, orwlmfc EPROM • Intelligent diagnostics dtran bad 
and/or eraaabfe EPROM • Verify erasure and ampere commands • Busy light • Compile with 
Tbrtool zht) insertion farce sncket ard integral 1 20 VAC power (240 VAC/50Hz available) • 



&PAL 



MODEL 7324 - $1199 
This unit has a built-in compiler. 
The Model 7324 programs all 
MML National and TI 20 and 24 
pin PALs, Has non-volatile 
memory. It operates stand alone 
or via RS232. 



MODEL 7128 -$429 
This model has the highest 
performance-to-price-ratio of any 
unit. This is GTEK's most popular 
unit! It supports the newest 
devices available through 
256Kbits. 

MODEL 7316 Pal Programmer $ 599 

Programs Series 20 PALs. Built-in PALA3M compiler. 

DEVICES SUPPORTED 




NMOS 



by GTEK's EPROM Programmes 
NMOS CMOS EEPROM 



2758 2764A 


2508 


68764 


27C16 


2716 27128 


2516 


8755 


27C16H 


2732 27128A 


2532 


5133 


27C32H 


2732A 27256 


2564 


5143 


27C64 


2764 27512 


68766 




27C256 



MPirs 



5213 12816A 8748 8741H 

5213H I2817A 8748H 8744 

52B13 8749H 8751 

X2816 8741 68705 

48016 8742H 

UTILITY PACKAGES 

GTEK's PGX Utility Packages will allow you to specify a range of addresses to 
send to the programmer, verify erasure and/or set the EPROM type. The PGX Utili- 
ty Package includes GHEX, a utility used to generate an Intel HEX file. 

PALX Utility Package — for use with GTEK's Pal Programmers — allows 
transfer of PALASM® source file or ASCII HEX object code file. 

Both utility packages are available for CPM,® MSDOS,® PCDOS,® ISIS® and 
TRSDOS® operating systems. Call for pricing. 

AVOCET CROSS ASSEMBLERS 

These assemblers are available to handle the 8748. 8751, Z8, 6502, 68X and other 
microprocessors. They are available for CPM and MSDOS computers. When order- 
ing, please specify processor and computer types. 

ACCESSORIES 



Model 7128-L1. L2, L2A 

(OEM Quantity) $259. 

Model 7128-24 $329. 

Cross Assemblers $200. 

PGX Utilities Call for pricing 

PALX Call for pricing 

Gtek 



XASM (for MSDOS) $250. 

U/V Eraser DE-4 $ 80. 

RS232 Cables $ 30. 

8751 Adapter $174. 

8755 Adapter $135. 

48 Family Adapter $ 98. 

68705 Programmer $299. 



Development Hardware/Software 
P.O. Box 289. Waveland, MS 39576 
601/467-8048 

,INC. 



BOOK REVIEWS 



GTEK. PALASM. CPM. MSDOS. PCDOS. ISIS, and TRSDOS 
are all registered trademarks. 



"Identifying Exposures" and "Risk Analysis." I can't help 
but wonder if the chapter is meant to reassure those 
managers who are shocked at the number of exposures 
in their systems and concerned about the cost of 
correction. 

The goals of risk assessment are to rank security ex- 
posures and assign numbers (costs per possible loss, 
estimated number of events) to identified data-security 
exposures. Fisher presents two methods for evaluating a 
potential loss, neither of which requires special math skills. 
He outlines the advantages and limits of each. The results 
of risk analysis are mapped on a grid that distributes ex- 
posures by type and potential loss. 

The author's insistence that problems can be reduced 
to numbers and compared more or less objectively is one 
of the strongest points in his system for handling infor- 
mation security. Every action he recommends is rooted 
in realities. He never lets managers lose sight of the fact 
that breaches of data security are potentially losses, but 
he emphasizes that correction of such breaches should 
not cost more than the potential losses. He provides rules 
of thumb for getting numbers, evaluating the validity of 
the numbers, and making decisions based on the numbers 
throughout his process. 

Fisher does not discuss specific hardware or software 
control systems. Rather, he divides controls into preven- 
tive, detective, and corrective types and discusses the 
philosophy of control. However, his approach is not at all 
abstract; he provides concrete examples on each point. 
His examples are so successful that many people may read 
this part of the book and not realize they have absorbed 
principles instead of facts. 

In an extensive table. Fisher analyzes data-security 
features available in IBM products. The reader can extract 
a checklist of possible security controls from this table. 
Appendix C is an effective checklist that defines applica- 
tion controls. 

The book addresses the making of cost-effective deci- 
sions for installing controls. The major factors in the pro- 
cess, the author says, include estimated potential loss from 
an exposure, estimated cost of proposed controls to pre- 
vent the loss, and estimated probability of the success 
of those controls. Fisher provides formulas for using these 
factors to determine "return on investment" for proposed 
controls. Filling out the selection worksheet for all the ex- 
posures in a system gives managers numbers for deciding 
to install or redesign controls or to accept a given risk as 
too costly to correct. 

In two chapters. Fisher explains a highly detailed analysis 
and selection process that should cover even the largest 
computer system. For readers who need just a fast assess- 
ment of their security system, the author outlines an ab- 
breviated approach. He assumes that the reader under- 
stands the concepts of previous chapters. This version uses 
a worksheet for each control point and for each likety ex- 
posure type at that control point. An analyst fills out the 

[continued) 



70 BYTE • JANUARY 1985 



Inquiry 153 



When all else 

fails. 



Most diskettes are pretty good. 

And some of the time that's good enough. 

But next time you throw away one that won't 
format or you lose the cash flow analysis you Ve 
been working on for weeks, make a mental note to 
try a box of Dysan diskettes. 

They're better. 

So much better, in fact, that major computer 
manufacturers put their names on our diskettes 
and sell them as their own. 

Without fear of failure. 

You see, we make our diskettes better with 
advanced manufacturing processes that our 
competitors have yet to figure out. 

And we test them. 

Almost to the point of absurdity. 

Dysan diskettes are inspected almost a hundred 
times as they come down the line. They're tested 
to performance levels way beyond industry 
standards. And each one is certified to be 100 
percent error free. 

Then our corporate quality assurance fanatics 
come along and check them all over again. For all 



Dysan is ;i registered trademark of Dysan Corporation. © 1984, Dysan Corporation. 
PFS^is :i registered trademark of Software Publishing Corporation. 



the same things. Plus some things only they 
understand. 

When we're done, you get exactly what you 
wanted in the first place. Diskettes that will record 
and retain all your data all the time. 

We don't expect you to keep all that in your 
mental note, but we would like you to remember 
your last diskette failure. 

And when your computer products dealer 
offers you another box of pretty good diskettes, 
tell him you're ready for something better. 

Dysan. 

Call toll free for the name of the Dysan dealer 
nearest you. (800) 551-9000. 

Dysan Corporation, 5201 Patrick Henry 
Drive, P.O. Box 58053, Santa Clara, CA 95050, 
(408)988-3472. 

Dysan 9 

Somebody has to be better 
than everybody else. 

Inquiry 122 



1 



Flexible Diskette 



Micros. Mice. 



When you can't stop by your local Micro Mart Store, call us direct. 
ORDERS ONLY 

1-800-241-8149 



Dot Matrix 
EPSON FX80/100._ 
EPSON RX80/100._ 
EPSON LQ1500.. 



MAYN ARD Complete line.. 

Graphic Cards 



At Micro Mart, we've got our 
finger on the pulse of the microcomputer 
industry. And, from our retail stores to 
our telemarketing divisions, we're in 
touch with the very latest developments, 
the newest products and the cutting edge 
of expert advice. 

When you need the right product at 
the right price, remember the sales, 
service and support our local store 
experts and national distribution center 
can give you. 

So if you can't drop by your local 
Micro Mart Store, let us point you in the 
right direction. Ask for your best price 
and expert advice. 



AT&T Personal Computer. Innovative 
hardware for a wide range of business 
applications. 







128 K expandable to 640K, 2-360K, 
DS/DD Disk Drives, Monochrome 

Display, IBM Compatible Special 

introductory price. 



LEADING EDGEColor PC, 256K, 2-360K 

DS/DD Disk Drives, Amdek Color 600. $1995 

MINDSET Personal Computer, 256K, 2-360K 
DS/DD Disk Drives, W/Mindset Mouse. $1795 

Networking/Protocol 
Conversion 

SNA & BIS YNC 3780, 525 1 , 3274, 3278._ 



PC TURBO 186 by ORCHID, 80186 coprocessor 

board $829 

IRMA/IRM ALINE Replaces 3278's 



w/PC's.. 



_$899/$1099 



IRMAGRAPH Upgrades IRMA to 3278 graphics 

capability. 

IRMAPRINT Enhances IRMA graphics.. 



PCnet By ORCHID, complete line._Start @ $299 
BLUE LYNX 5251 Mod 12 & 5276Emulators by 

TECHLAND 

SANTACLARA PC Terminal. 

Printers & Plotters 

Thousands in stock. 

HOUSTON INSTRUMENTS Plotters and 

Digitizers. 



EPSON J X 80, color printer.. 
OKIDATA 92 & 93, ML84, 
(200cps.),w/opt. IBM 
PROMS, Pacemark 2410, 
(350 cps) . 

TOSHIBA P-1351 & 1340. $1295/$799 

DATAPRODUCTS 

PRISM 8050 Color, 

132col.,200 

cps. $1295 

STARMICRONICS 

Complete line._ 



STB Graphics Plus II, color & mono, w/par. port 

& software. $369 

HERCULES Mono & color graphics cards support 

Lotus . 

PLANTRONICS ColorPlus + , HiRes color bd., 
par. port w/software.. 



TEXAS INSTRUMENTS 

855. $729 

NEC Pinwriters,P2&P3, 180 

cps 

DIABLO C-SeriesC-150. Color 
ink jet, IBM color compatible._$985 
Letter Quality 

NEC Spinwr iters 2050, 3550, 8850. 

DIABLO 630/630ECS. $1395/$1795 

C-ITOH Starwriter; (40 cps), Printmaster, 

(55 cps). $950/$1299 

We carry a full range of form handling options, 

Floppy Disk Drives 

TANDON TM 100-2, DD/DS, 360K. 

1/2 HEIGHT DISK DRIVES From SHUG ART, 

TEAC. PC, XT & AT compatible. $119 

Hard Discs 

M icro Mart carries all the major brands. 
If you don't see it — ask for it. 
PEACHTREE PERIPHERALS 
P-10, 20& 50, auto boot, int. & 

ext. start @ $845 

SYSGEN70c£20Meg 
w/streamer tape..$2395/$2795 
SYSGEN Image &Quickj lie, 
streamer tape back-up for 

your IBM XT & AT. 

BERNOULLI 
TECHNOLOGY Hard Disc 

Subsystems $2895 

MAYN ARD Complete 
line of hard disc 
subsystems.. 



TECMAR Graphics Master, HiRes color & mono 

supports Lotus. $459 

QUADRAM QUADCOLOR I & II, color cards._ 
PARADISE SYSTEM Multi-display or Modular 
Graphics Cards, color & mono, par. 
port. Starting @ $299 

Software 

Accounting 

SORCIM/IUS Complete line including windows.. 

BPI ACCOUNTING Complete line. 

Spreadsheets & Integrated Packages 

ASHTON-TATEFrantework. _$345 

LOTUS Symphony andLotus._ 



MICROSOFr MultiPlan, w/templates._ 

MDBS Knowledge Man. 

1 k SORCIM SuperCalc 3, Vers. 2.0 _ 
SPI Open Access.. 



Enhancements & Utilities 
SOFrCRAFr Fancy Font.. 



FOX & GELLER Complete line 
of enhancements for dBase II, 
III ScRbase 4000. 

NORTON Utilities. $65 

ROSESOFT ProKey 

3.0. $89 



EMERALD Hard disc 
drives w/back-up 

Chips 

INTEL 8087 High speed 
coproc. 



_$35/64K 



64KRAMCHIPS._ 

256K RAMCHIPS. 

Multifunction Boards 

We have a complete line of multifunction 

bds . compatible with the Portable, AT, XT, & Jr 

SIX PAK 64-384K, multifunc. 

MEGAPLUS 64-5 12K, max. 8 func 

I/O PLUS Ser.,Clk.,Splr., Ramdisk, opt. 2nd 

Ser., Par. & Game 



QUADRAM QUADBOARD, 64-384K 
multifunc. 



TECMAR CAPTAIN, 64-384K, multif unc._$249 

TALLTREE J-RAMII, 0-5 12K, w/software 

TALLTREE ./-/MM/AY, 0-5 12K, 

w/software. $129 

MICROLOG BABY BLUE II, 64-256K, Z80 
coproc. , + software. 



ORCHID PC Blossom, 64-384K, w/opt. PCnet 
Piggy-Back. $259 



Atlanta, New Orleans, Nashville, Miami, Tampa, Orlando 



72 BYTE • JANUARY 1985 




Advice. Price. 



CENTRAL POINT SOFrWARE 

Copy II PC. 

ATI Training.. 



_$35 
_$55 

SOFrSTYLE Set FX rinter 

control packages.. 



SIDEWAYS Inverts printout.. 
BORLAND Sidekick. 



_$45 
.$39 



LIVING VIDEO TEXT Think Tank 

Compi ers & Language Tools 
LATTICE C-Compilers.. 



_$299 



MICROSOFT Complete line 

WORDTECH The dBase compiler. 

DIGITAL RESEARCH Complete line. 

BORLAND Turbo Pascal, Turbo Toolbox 

and more. $39/each 

Graphics & CAD 
Zsoft PC Paint Brush, mouse driven graphics._$95 
DECISION RESOURCES 

ChartMaster/ 'Sign-Master pkgs . 

AUTODESKAutoCAD. Complete line. Start @ 

$745 
ENERTRONICS Ener graphics, graphics & CAD 

package. 

MICROPRO ChartStar. 



Microsoft Mouse. Bus or serial 
mechanical mouse, comes with Mouse 
Menu software. Works with WORD and 
other popular software $159 




P C M o u s e, from Mouse Systems. Serial 
optical 3-button mouse with Pop-Up™ 
Menus and PC Paint software. 
Preconf igured for all the most popular 
software. $159 



MICROSOFT Chart. 

DIGITAL RESEARCH Presentation Master 

Communications 

MICROSTUF CROSSTALK XVI $99 

HAYES SMARTCOMII. 

Word Processors 
MULTIMATE w/Spelling checker & tutorial.$259 

SAMNA HI, wd. processor. 

MICROSOFT Word, w/orw/out mouse. 

LIFETREE Vol kswr iter Deluxe 

MICROPRO WordStar Pro Pack & 
Series2000. 



_$245 



SSI WordPerfect 

WORDMARC Wordmarc. 



Office & Project Planning 

Call for our Tax and Tax Planning packages. 

HARVARD Harvard Project Manager. $249 

IUS Easy SalesPro. 

MICROSOFT Prayed.. 



Data Base Managers 

MICRORIM 4000 or 6000, Report Writer & Clout 
options. 



GMS SYSTEMS Power-base. 

WARNER SOFTWARE The desk organizer.. 
ASHTON-JATEdBaselI& III.. 
MICROSTUF Infoscope._ 

Modems 

HAYES Smartmodem300, 1200, & 



1200B.. 



_$199/$469/$329 



RIXON 1 200-4800 BAUD sync. & async. models.. 
ANCHOR AUTOMATION Signalman Mark 
XII $259 

VEN-TEL 1200BAUDHalf CardforthelBM 
Portable &XT._ 



Service & Repairs 

*On-Site — We have hundreds of service 

locations nationally. 
*Depot — Our National Service Center is 

one of the fastest in the US. 
*We have — A wide variety of services 
available. Just call us. 



POPCOM Popcorn, int. and ext. w/ voice & data 
comm . 

Miscellaneous 
Hardware 
& Accessories 

DYSAN Diskettes, PC, XT & 

AT compatible. 

MICRO MART Diskettes 

DS/DD, 7 yr. war $19/10 

KEYTRONICS 5150&5151. 

Keyboards . 

LQ SHEET FEEDERS Sheet feeders.. 
CURTIS Accessories. 



©Copyright Micro Mart 1984. 
Technology Corporate Campus 
3159 Campus Drive 
Norcross, Georgia 30071 



For information or the store location nearest you, call 

(404) 449-8089 



HAYES Mach II & Mach ///joysticks.. 

PENCEPT Penpad, software avail. 

TOUCHSTONE TECHNOLOGY 

Touchstone I. Ten key pad w/ cursor 

control 

QUADRAMM/C/?OZvlZ£tf, print buffer, 

8-128K. 

TRIPPELITE Back up power supply 
200-1000 watts, and ISOBAR surge 
protectors, 4 & 8 plug. 

Mo itors& CRT's 

PGS MAX 12, amber, 720h x 350v._ 



_$775 



PGS SR-12, 690h x 480v, w/dual scan cd. 
PGS HX-12, 690 Dot RGB.. 



QUADRAM QUADCHROME, 690 Dot 
RGB 

AMDEKCOLOR300,500,600, 700, 710, 725, 
new complete line of HiRes RGB 's w/new low 

prices. 

AMDEK 300A /300G, composite 
monitors. 



_$139/$129 



AMDEK 3 10 A, amber w/3 yr. war. 

WYSE Terminals, 100, 75, 50, entire line in stock 



YOT^ERSONALBLUECHIP CARD 



1234 567 890 123 



Micro Mart has financing options 
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_$439 




America's PC Specialist. 




\ftM is a registered trademark of International Business Machines Corporation. AT&T, Leading Edge, Mindset, Microsoft, Mouse Systems and their products, respectively, are trademarks 
^of AT&T Information Systems, Leading Edge Products Inc., Mindset Corporation, Microsoft Corporation and Mouse Systems Corporation. All Prices arc subject to change without notice. 

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Inquiry 230 



JANUARY 1985 'BYTE 73 



Inquiry 158 



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BOOK REVIEWS 



sheets and evaluates the degree of control for that ex- 
posure on a 0-4 scale. A summary sheet uses these 
grades to map strong and weak points in the system and 
to average a grade for security control in the system as 
a whole. 

Almost half of Information Systems Security is appendix. The 
author reprints questionnaires and guidelines on 
information-system security from IBM and other com- 
panies. The appendixes demonstrate that Fisher's ideas 
are not original. His contribution is that he gives managers 
practical methods for assessing risk, evaluating controls, 
and making decisions on new controls for data security. 
The appendixes are valuable in light of Fisher's methodical 
approach to dealing with security systems. Once a 
manager absorbs Fisher's methods, these appendixes 
become intermediate readings for further study. 

Information Systems Security is not exciting or original, but 
it is competent and readable for managers who are not 
computer people. Fisher presents a "can-do" framework 
for a comprehensive introduction to the principles of 
developing information security. Managers will still have 
to determine specific control solutions for their informa- 
tion systems, but they can do so from solid points of 
departure and with methods they can translate into ef- 
fective data-security decisions. 

Annette Hinshaw (POB 58063 5. TUlsa, OK 74 1 58) is a freelance 
technical writer. 



MICROPROCESSORS: 

HARDWARE, SOFTWARE, AND DESIGN APPLICATIONS 

Reviewed by Alan Finger 

Given the importance of microprocessor courses in 
today's engineering curriculum, it is natural that many 
textbooks have been written on the subject. Microprocessors: 
Hardware, Software, and Design Applications is one example. Its 
intent is to introduce junior and senior engineering 
students to the fundamentals of modern microprocessors 
and the microcomputer systems and software built around 
them. Wunnava Subbarao is an associate professor at 
Florida International University and has based this text 
on his courses there. He examines five well-known micro- 
processors and illustrates their applications with student 
projects. This practical approach is well suited to 
motivating students as well as giving them a hint as to 
what awaits them in the Real World. 

Subbarao begins with an introduction to the general 
concepts of microprocessors. Other chapters are split into 
two sections on each device: Intel's 8085, Motorola's 6800, 
MOS Ikchnology's 6502, Zilog's Z80. and RCA's 1802. The 
first section on each chip describes the processor and, 
except for the Z80, a commercial single-board "training" 
microcomputer using the device. In the second section, 
the author details several practical applications developed 

{continued) 



74 BYTE • JANUARY 1985 



Inquiry 83 





What C did for Programming 
Mark Williams has done for C Programming 

'rogramming System 



The C Programming System 
from Mark Williams 

MWC86 gets your C programs run- 
ning faster and uses less memory space 
than any other compiler on the market. 
Then csd, Mark Williams' revolutionary 
C Source Debugger, helps you debug 
faster. That's The C Programming Sys- 
tem from Mark Williams Company. 



"Of all the compilers reviewed, MWC86 
would be my first choice for product 
development. It compiles quickly, pro- 
duces superior error messages, and 
generates quick, compact object code. 
The library is small and fast and close- 
ly follows the industry standard for 
C libraries." 



MWC86 



MWC86 is the most highly optimized 
C compiler available anywhere for the 
DOS and 8086environment.The bench- 
marks prove it! They show MWC86 is 
unmatched in speed and code density. 

MWC86 supports large and small 
models of compilation, the 8087 math 
coprocessor and DOS 2.0 pathnames. 
The compiler features common code 
elimination, peephole optimization and 
register variables. It includes the most 
complete libraries. Unlike its competi- 
tion, MWC86 supports the full C lan- 
guage including recent extensions such 
as the Berkeley structure rules, voids, 
enumerated data types, UNIX* I/O calls 
and structure assignments. 

Quality is why Intel, DEC and Wang 
chose to distribute MWC86. These in- 
dustry leaders looked and compared 
and found Mark Williams to be best. 

User Friendly 

MWC86 is the easiest to use of all 
compilers. One command runs all 
phases from pre-processor to assembler 
and linker. MWC86 eliminates the need 
to search for error messages in the back 
of a manual. All error messages appear 
on the screen in English. 

A recent review of MWC86 in 
PC Ubrld, June, 1984, summed it up: 



•Unix is a Trademark of Bell Laboratories. 



1 



csd C Source Debugger 

Mark Williams was not content to 
write the best C compiler on the mar- 
ket. To advance the state of the art in 
software development, Mark Williams 
wrote csd. 

csd C Source Debugger serves as a 
microscope on the program. Any C 
expression can be entered and evalu- 
ated. With csd a programmer can set 
tracepoints on variables and expressions 
with full history capability and can 
single step a program to find bugs. The 
debugger does not affect either code 
size or execution time, csd features 
online help instructions; the ability to 
walk through the stack; the debugging 
of graphics programs without disturb- 



SIEVE 

Time in Seconds 
D Large Model 
■ Small Model 
Size in Bytes 
CD Urge Mode! 
D Small Model 

L29 



ing the program under test; and evalu- 
ation, source, program and history 
windows. 

i csd eases the most difficult part of 
development — debugging. Because 
csd debugs in C, not assembler, a pro- 
grammer no longer has to rely on old- 
fashioned assembler tools, but can 
work as if using a C interpreter — in 
real time. 

The C Programming System 
from Mark Williams now supports 
the following libraries: 

Library 

Windows for C 

Halo 

PHACT 

The Greenleaf Functions 




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Company 

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The C Programming System 
from Mark Williams 

The C Programming System from 
Mark Williams delivers not only the 
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why it does for C programming what C 
did for programming. The Mark Wil- 
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programmer the MWC86 C compiler 
and the csd C Source Debugger for 
only $495. Order today by calling 
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Technical support for The Mark Wil- 
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developed it. 



Mark Williams Company 

1430 W. Wrightwood Ave. 
Chicago, IL 60614 




Inquiry 217 



JANUARY 1985 -BYTE 75 



Inquiry 101 for Dealers. Inquiry 102 for End-Users. 



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Powerful Single Board Computer 
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One 64K bank of memory is devoted to CP/M and rls 
disk cache blocks, while the other MK b.ink is. devoted 
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Internal Floppy Disk Controller 
MSC-ICO handles ShugarUANSl standard (loppy disk 









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High Speed CRT Controller 
MSC-ICO containsan80 x 24 linememoiy rrvjppedCRT 
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A standard Centronics parallel port allows MSC-ICO to 
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Parallel Keyboard Port 
MSC-ICO connects to any ASCII parallel keyboard of 
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This port allows you to access printers, rel.iys. LED's. 
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Clock Calendar 
The battery backed up clock calendar piovides time and 
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External Bui 
MSC-ICOs 50 pin bus connector provides expansion lor 
a hard disk controller. RAM disk, graphics or a 46000 
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tfieseoptions. 

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With MSC-ICO's low cost and q tality worksmanship. 
why spend time, energy and money to design, debug 
and test your own system Whether you require single 
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needs Order your evaluation unit today! 




Inquiry 31 for Dealers. Inquiry 32 for End-Users. 
76 BYTE • JANUARY 1985 



BOOK REVIEWS 



by students. Although I might quibble with the timeliness 
of the author's choices of processors and examples, which 
seem to be governed by what was on hand, they are cer- 
tainly adequate for an introduction. 

Two Points of View 

To review this book, I approached it from two perspec- 
tives. First I put myself in the position of an engineering 
student with a limited knowledge of the subject matter. 
I would have had courses in digital design and probably 
an introduction to programming by way of one or two 
high-level languages. A good textbook should lead me, 
step by step, through the concepts involved in the design 
of microcomputer systems and software with appropriate 
problems to verify my understanding of the material. 

I also examined the book as an expert, checking the 
quality and accuracy of the text and illustrations. Unfor- 
tunately, from both viewpoints, Microprocessors fails. 

An Introduction? 

For students, the trouble starts right in chapter I . The 
author plunges into a discussion of the internal contents 
of a "typical" microprocessor and then goes on to a 
description of address, data, and control buses, and in- 
struction formats. Only after all this are we treated to one 
diagram and a half page of text as an overview of micro- 
computer-system organization. 

The remainder of the book continues similarly. The 
chapters discussing the 8085 and its cousin, the Z80, are 
illogically separated by the very different 6800 and 6502, 
which are somewhat related to each other. Subbarao 
makes only a vague attempt to relate any processor to 
the others. Instruction sets are presented as poor 
reproductions of the manufacturer's summary sheets— 
usually pasted to the wall by an experienced programmer 
as a memory jogger. 

The book creates an overall impression of topics strewn 
haphazardly. What organization there is is counter- 
productive because it lacks purpose. General system con- 
cepts such as system clocks, bus cycles, design rules, and 
assembly-language programming procedures are ignored 
in favor of more specialized information on such topics 
as commercial interconnection schemes (S-I00 bus and 
Multibus) and rarely used components. It seems to this 
reviewer that the author paraphrased manufacturers' data 
sheets and student reports. 

The material is oriented toward hardware; software 
design concepts are not discussed. The software portions 
of the design examples are presented in a "pseudoassem- 
bly language" used to hand-assemble code, something I 
haven't seen in 10 years. The explanations relate only to 
the hardware "bit-twiddling" aspects of the programs. 

Adding to the Confusion 

If a student does absorb information from this book, much 
of it will be wrong. Although it hardly seems necessary, 

{continued) 



POWdhr cpm sonwAB 

inual fcW 



NEVADA 



FORTRAN. 

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I $29-95 



Nevada FORTRAN is based upon 

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debugging. Package includes a diskette, 214-page manual and 5 

sample programs. Included also is an 8080 assembler. Requires 48K 

RAM. 



NEVADA 

BASIC. 

DISKETTE & MANUAL 

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With the built-in, full-screen 

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Requires48KRAM. 



NEVADA 

PILOT. 

DISKETTE & MANUAL 

I $29.95 



Nevada PILOT, written by Prof. 
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useful sample programs. 

WHY WAIT70RDER YOURS TODAY! 

Satisfaction guaranteed — or your money back. If for any reason 
you're not completely satisfied, just return the package— in good 
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we'll refund your money. 

Checks must be in U.S. Dollars 

and drawn on a U.S. Bank. 

California deliveries add 6% or 

6.5% sales tax. 

SHIPPING AND HANDLING FEES: Add $4.00 for the first package or 
manual and $2.00 each additional. OVERSEAS: Add $15.00 for the 
first package or manual and $5.00 each additional. COD's: Add 
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3917 Noriega Street 
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NEVADA 



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NEVADA 

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DISKETTE & MANUAL 

1 $29.95 



Advanced features include: 

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+ 63 -64; TRACE debugging; Arrays up to 8 dimensions; 64K strings; 

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ALSO AVAILABLE: 

• EXTRA MANUALS $14.95 

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• BIG PRINT-Diskette $19.95 

The CP/M Operating System, an 8080, 8085, or Z-80 (8-Bit) micropro- 
cessor, and 32K RAM are required, unless otherwise sjated above. 

WHEN YOU ORDER, PLEASE SPECIFY ONE OF THE 
FOLLOWING DISKETTE FORMATS: 

D 8" SSSD (Standard CP/M IBM 3740) □ 

5 1 /4 M Diskettes for: □ 

D Access/Actrix □ 

D Apple CP/M D 

D DEC VT 180 D 

D DEC Rainbow D 

D Epson QX-10 D 

Heath Hard Sector (Z-89) □ 

Heath Soft Sector 

(Z-90, Z-100) □ 

IBM-PC (Requires Z-80, □ 

Baby Blue II Card) □ 



Kaypro Double Density (NCR) 
MicropolisModll 
NEC PC 8001 

North Star Double Density 
North Star Single Density 
Osborne Single Density 
Sanyo 1000, 1050 
Superbrain DD DOS 3.X 

(512 byte sec) 
Televideo 

TRS-80 Model 1 (Base O Mapper) 
Xerox 820 Single Density 



CP/M is a registered trademark ol Digital Research, i nc. Microsoft is a registered trademark of Microsoft 
Corp. TRS-80 is a registered trademark of Tandy Corp. Apple I) is a trademark of Apple Computer. Inc. 
Osborne is a registered trademark of Osborne Computer Corp. Xerox 820 is a trademark of Xerox Corp. 
Kayprots a trademark ol Nonlinear Sys. Heath/Zenith isa trademark of Heath Corp. IBM is a registered 
trademark of International Business Machines, Corp. Nevada BASIC. Nevada COBOL, Nevada FOR- 
TRAN. Nevada PILOT. Nevada EDIT. Nevada PASCAL, and Ellis Computing are trademarks of Ellis Com- 
puting, Inc. <H 1984 Ellis Computing, Inc. 



JANUARY 1985 -BYTE 77 



64K S100 STATIC RAM 

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BOOK REVIEWS 



a number of pages on single-chip microcomputers are 
thrown in at the end of several chapters. In one such case. 
Intel's 8048 is incorrectly described as a modified version 
of the 8085. They do not even belong to the same family 
Another error exists in the description of how the 8085 
responds to its interrupt input INTR. According to the 
author's description, the 8085 resp onds t o INTR by issu- 
ing an interrupt-acknowledge signal INTA to a requester, 
which, in turn, places the vector address on the data bus. 
In reality, the 8085 will accept the next complete instruc- 
tion, usually a l-byte restart (RST) or 3-byte CALL from 
the requester. Trying to bring up an interrupt-driven system 
with information like this would certainly prove interesting. 
Much of the misinformation is more subtle. Subbarao 
uses microcomputer jargon, usually with little or no ex- 
planation. He uses much of it incorrectly. The term "bus." 
for example, has two meanings. It can be used in reference 
to a collection of related signals connecting different com- 
ponents within a microcomputer system. It can also refer 
to any of a number of industry-standard arrangements for 
interconnecting function boards in a larger system. The 
second type generally contains several of the first type 
along with other signals. In several instances, the author 
discusses them as if they were the same. The IEEE-488 
(GPIB) bus somehow finds its way into one of these discus- 
sions, even though it is actually a data-communications 
standard generally used to connect a computer to in- 
struments (and occasionally intelligent peripherals such 
as disk systems and plotters). I would presume its inclu- 
sion is due to the presence of the word "bus." The author 
uses another term. "I/O |input/output| bound." to refer to 
something "bound for input or output" as opposed to its 
normal usage as a reference to a program with its speed 
limited by I/O operations. 

Good Problems 

If the book has one saving grace, it is the abundance of 
examples and problems, many of which are accompanied 
by answers that provide better information than the body 
text. After reading the chapters on the 1802 processor, 
with which I am not very familiar. I was still in the dark 
about many aspects of its operation. I then worked 
through some of the problems with an RCA data book 
at hand and felt much more comfortable about the pos- 
sibility of dealing with one of these rather arcane devices. 
Perhaps this is what this book is all about: providing prob- 
lems to be solved using other sources of information. 
Subbarao wisely suggests that readers consult the ap- 
propriate manufacturer's literature. This book will not pro- 
vide the student with enough information to use a micro- 
processor or write software for it. Although the idea 
behind Microprocessors is a good one. the book is too flawed 
with organizational and conceptual errors for me to 
recommend it to anyone. ■ 

Alan Finger is a vice president at Comprehensive Computer Con- 
sultants (270 Littleton Rd.. Building 14. VJestford, MA 01886). 



78 BYTE • JANUARY 1985 



Genicom would like to get personal with you. 
On a professional level, of course. 



Personal computers have become a valuable asset in busi- 
ness. The problem is that most personal computer systems 
are originally sold with "personal printers". . . printers built for 
home use, not for heavier business work. 

These "personal printers" are too slow for many busi- 
ness needs. They can tie-up your computer for extended 
periods of time. ..time you could be using to do other work. 

Another problem is durability. In business, you need a 
printer that can produce high volume output over a long 
duty cycle. The common "personal printer" will often just 
quit under such continuous operation. 

That's why Genicom has created the 3014, 3024, 
3304 and 3404... professional printers built for personal 
computers. 

Price/performance matched for small business sys- 
tems, the Genicom 3000 PC printers are designed to in- 
crease productivity and maximize the value of your personal 
computer. 

The 3000 PC printers provide 160-400 cps draft, 80-200 
cps memo, and 32-100 cps NLQ printing... performance for 
both high productivity and high quality printing. 

The 3014/3024 models print 
132 columns. The 3304 and 3404 



Inquiry 147 



GENICOM 

The New Printer Company. 

For the solution to your printing needs call 

TOLL FREE 1-800-437-7468 

In Virginia, call 1-703-949-1170. 

Epson MX with GRAFTRAX-PLUS is a trademark of Epson America. Inc. 
Okidata Microline B4 Step 2 is a trademark of Okidata Corporation 



models give you a full 136 column width, and offer color 
printing as well. 

Each printer is easy to use, lightweight, functionally 
styled and attractive. And you can choose options from 
pedestals and paper racks to document inserters, sheet 
feeders and 8K character buffer expansion, plus more. 

Genicom 3000 PC printers feature switch selectable 
hardware, dual connectors and dual parallel or serial inter- 
faces. Plus the 3014 and 3024 emulate popular protocols for 
both Epson MX with GRAFTRAX-PLUS™ and Okidata Micro- 
line 84 Step 2™, while the 3304 and 3404 emulate popular 
protocols for Epson MX with GRAFTRAX-PLUS™ So your 
current system is most likely already capable of working 
with these Genicom printers without modification. 

Most important, the Genicom 3000 PC printers are 
quality-built, highly durable printers designed for rapid, con- 
tinuous duty cycle printing. So take some personal advice. 
Get a Genicom professional printer for your personal com- 
puter today. 

Genicom Corporation, One General Electric Drive, Dept. 
C421 , Waynesboro, VA 22980. In 
Virginia, call 1-703-949-1170. 



Great Ideas 

look even better 

on a Princeton monitor 



Your Great Ideas deserve the best image you can give them. But, 
just as a music system's performance depends on the speakers, your 
computer system \s limited by the quality of your monitor. 

Monitor performance can be measured. That's something you 
should know about. 

In other words, your Great Ideas should be seen, not blurred. 




W. Shakespeare composing Great Ideas on a Princeton Monitor 



80 B YTE • JANUARY 1985 



Things you should know about monitors 



Resolution The quality of 
a color monitor's image is 
directly related to its resolution. 
The greater the number of dots 
available within a given area for 
displaying an image the greater 
the resolution. 



Dot pitch The image on an 
RGB color monitor is made up of 
a series of tiny dots. Dot pitch 
measures the distance between 
those dots. Anything finer than 
.38mm \s considered high 
resolution. 



Price All Princeton monitors 
set the price/performance stand- 
ard in their class. The SR-12 
at $799 compares favorably 
with monitors costing hundreds 
more. The HX-12 is in a class by 
itself at $695. 



f) The PRINCETON SR-12 

monitor features an extra- 
ordinary 640x480 (non-inter- 
laced) resolution. The result is 
an extremely high quality, flick- 
erless image with text that ap- 
proaches monochrome quality. 
When used in conjunction with 
the PRINCETON Scan-Doubler 
card, the SR-12 runs from a 
standard IBM or equivalent color 
card, maintaining complete com- 
patibility with all IBM software. 



W The PRINCETON HX-12 

RGB color monitor, with a dot 
pitch of .31 mm, offers the finest 
resolution in its class. The HX-12 
delivers 16 crisp, sharp colors 
including clean whites without 
color bleed — a not-so-easy 
accomplishment in an RGB 
monitor. 



The PRINCETON MAX- 12, 

with easy-on-the-eyes amber 
phosphor, sets the standard for 
monochrome monitors at $249. 
The MAX-12's dynamic focusing 
circuitry ensures sharpness not 
only in the center but also in 
the edges and corners. And it 
runs off the IBM PC mono- 
card — no special card is 
required. 






All three monitors feature a non-glare screen and an IBM 
compatible cable. A PCjr adapter cable is also available for the HX-12. 
And to see your Great Ideas from the best possible angle, you can put 
your Princeton monitor on the Princeton Undergraduate Tilt and 
Swivel Base for only $39.95. Or, while supplies last, get the 
Undergraduate FREE with the purchase of a MAX- 12 monitor 

Image The ultimate test of any monitor is how the image looks 
to your own eyes. Compare the Princeton monitors side-by-side with 
the competition at Computerland, Entre or your local independent 
dealer. 

Do it soon. You and your Great Ideas deserve the best. 

Inquiry 28! 



For more information call 

toll-free: 

800-221-1490 Ext. 804 

PRI NCETON 

GRAPHIC SYSTEMS 

AN INTELLIGENT BYBTEMS COMPANY 



1 70 Wall Street 
Princeton NJ 08540 
TLX821402 PGS Prin 

Technologically tuned for excellence 

JANUARY 1985 'BYTE 81 



YOUR PC CAN BE YOUR 
NEXT SMART TERMINAL. 

SrmarTerm software can make 
your personal computer a lot 
more intelligent than it really is. 

Our terminal emulators have the 
features that do the job: Full 
keyboard emulation. Multiple 
setups. TTY mode. "Smart" 
softkeys. Printer support. 
Help screens. And a friendly 
user manual. 

Built-in text and binary file 
transfer is powerful and simple 
to use, and does not require 




A WORLD 
OF CHANGE, 
THE SMART 
GET SMARTERM 



any special host software. 
SrmarTerm also features 
automatic file transfer and two 
different "error-free" protocols, 
including XMODEM. 

There's a SmarTerm emulator 
that matches your needs: 
SmarTerm 100 for emulation 
of DEC VT100, VT102 and 
VT52. This program now 
features 132-column display 
mode support, using either 
horizontal scrolling or special 
132-column video display 
boards. SmarTerm 125 
includes all the features of 
SmarTerm 100, plus 
VT125 ReGIS graphic 
support. SmarTerm 400 
for emulation of Data 
General Dasher D100, 
D200 and D400. 

More than 15,000 cus- 
tomers have discovered 
just how smart their PCs 
can be with SmarTerm. 
We think you'll agree. 
Try it for 30 days with 
full refund privilege. 



S0KW 



smarts 



r ~®ivm 



flffl"S»P 



Call today for more information. 

Available through your local 
software dealer, or 
Persoft, Inc., 
2740 Ski Lane, 
Madison, Wl 53713. 
Phone (608) 273-6000. 
TELEX 759491. 



SMARTERM is a trademark of Persofl. Inc. • OEC. VT and 
ReGIS are trademarks of Digital Equipment Corp. ■ Dasher is a 
trademark of Data General Corp. • IBM is a registered 
trademark of International Business Machines Corp. 




82 BYTE • JANUARY 1985 



persofr 



Inquiry 377 



EVENT QUEUE 



]anuary 1985 

• DEVELOPMENT SEMI- 
NARS— Professional Devel- 
opment Seminars, various 
sites throughout the U.S. 
The Institute for Advanced 
Technology presents semi- 
nars in a variety of areas, 
including data communi- 
cations, database manage- 
ment, software engineering. 
CAD/CAM. personal com- 
puters, office automation, 
and personnel management. 
A catalog is available. Con- 
tact Institute for Advanced 
Technology. 6003 Executive 
Blvd.. Rockville. MD 20852. 
(800) 638-6590; in Maryland. 
(301) 468-8576. 
]anuary-February 

• NETWORK TROUBLE- 
SHOOTING-A Trouble- 
shooting Guide to Support- 
ing and Maintaining the 
Data Communications Net- 
work, various sites through- 
out the U.S. This seminar 
outlines a systematic ap- 
proach to network mainte- 
nance methods and proce- 
dures, presents specific 
troubleshooting techniques, 
and explains software tools. 
For more information, con- 
tact Data : Iech Institute. 
Lakeview Plaza. POB 2429. 
Clifton. N] 07015. (201) 

4 78-5400. January-February 

• PROCESSING FUNDA- 
MENTALS— Fundamentals of 
Data Processing for Adminis- 
trative Assistants and 
Secretaries and Fundamen- 
tals of Information Process- 
ing for Nontechnical Ex- 
ecutives, various sites 
throughout the U.S. Two-day 
seminars. Contact New York 
University. School of Con- 
tinuing Education, Seminar 
Center. 575 Madison Ave.. 
New York. NY 10022. (212) 
580-5200. January-March 



• TECH, MANAGEMENT 
SEMINARS-Technical and 
Management Seminars for 
Professionals, various sites 
throughout the U.S. Major 
topic areas include network- 
ing, system performance and 
data management, and real- 
time applications design. A 
catalog is available. Contact 
Digital Equipment Corp.. 
Educational Services. 
Seminar Programs BUO/E58. 
12 Crosby Dr.. Bedford. MA 
01730. (617) 276-4949. 
}anuary-March 

• INTENSIVE SEMINARS 

Intensive Seminars for Pro- 
fessional Development, vari- 
ous locations in the Boston 
metropolitan area. Syracuse. 
NY. and Saddle Brook. NJ. 
Computer, management, and 
manufacturing seminars are 
offered. A catalog is 
available. Contact Kathy 
Shaw. Office of Continuing 
Education. Worcester Poly- 
technic Institute. Higgins 
House. Worcester. MA 
01609. (617) 793-5517. 
\anuary-\une 

• SME CONFERENCES. 
EXPOS— Conferences and 
Expositions from the Society 
of Manufacturing Engineers, 
various sites throughout the 
U.S. For a calendar, contact 
the Society of Manufacturing 
Engineers. Public Relations 
Department. One SME Dr.. 
POB 930. Dearborn. MI 
48121. (313) 271-0777. 
January-November 

• BUSINESS COMMUNICA- 
TIONS— The Second Annual 
Business Telecommunica- 



tions Exposition: BizTelCom 
Northeast. Aspen Hotel- 
Manor, Parsippany. NJ. 
Seminars and product dis- 
plays. Preregistration is com- 
plimentary; $10 at the door. 
Contact Michael C. J. 
Houston. T E. G. Inc.. The 
Exposition Group. 83 
Barnegat Blvd.. Barnegat. NJ 
08005. (609) 698-7020. 
\anuary 16-18 

• MEASUREMENT SCIENCE 

Measurement Science Con- 
ference. Marriott Hotel. 
Santa Clara. CA. 'Iechnical 
sessions will explore such 
topics as laser and optical- 
fiber metrology, time and 
frequency measurements, 
and the effects of data net- 
works on calibration. Ex- 
hibits and formal addresses 
highlight this event. Registra- 
tion details are available 
from Darlene Diven. Mea- 
surement Science Con- 
ference. POB 61344. Sunny- 
vale. CA 94088-1344. (408) 
756-0270. January 17-18 

• C WORKSHOP 

C Programming Workshop. 
Raleigh. NC. Contact 
Suzanne B. Battista. Plum 
Hall Inc.. I Spruce Ave.. Car- 
diff. NJ 08232. (609) 
927-3770. January 21-25 

• IN-FLIGHT COMPUTING 
EXPLORED-Meeting of the 
Radio 'Iechnical Commission 
for Aeronautics. Washington. 
DC. An industry committee 
will look into the possible 
effects that battery-operated 
portable computers may 
have on an airplane's naviga- 
tional equipment. The com- 



IF YOU WANT your organizations public activities listed in BYTE's Event 
Queue, we need to know about them at least four months in advance. Send 
information about computer conferences, seminars, workshops, and courses 
to BYTE, Event Queue. POB 372. Hancock. NH 03449. 



mittee. called SC-156. meets 
at 9:30 a.m. Contact the 
Radio Technical Commission 
for Aeronautics. Suite 500. 
1425 K St. NW. Washington. 
DC 20005. \anuary 22-23 

• MICROS, COMMUNICA- 
TIONS, AND BUSINESS 

Microspeak '85. San Fran- 
cisco. CA. This conference 
will focus on ways to set up 
a cost-effective microcom- 
puter communications sys- 
tem. The fee is $695. Con- 
tact Stephen J. Schneider- 
man. Micro Communica- 
tions. 500 Howard St.. San 
Francisco. CA 94105. (415) 
397-1881. January 22-24 

• SEMICONDUCTOR 
EQUIPMENT. CONFERENCE 

Advanced Semiconductor 
Equipment Exposition and 
Technical Conference. Con- 
vention Center, San jose, 
CA. Admission to the show 
is free with preregistration. 
Contact Joyce Estill. ASEE 
'85 Show Manager. Cartlidge 
& Associates Inc.. 1101 
South Winchester Blvd. 
#M2 59. San Jose. CA 95128. 
(408) 554-6644. 
January 22-24 

• TECH CONFERENCE. 
TUTORIALS-USENIX Asso- 
ciation Technical Conference 
and Tutorials, Fairmont 
Hotel Dallas. TX. Contact 
USENIX Conference Office. 
POB 385, Sunset Beach. CA 
90742, (213) 592-1381. 
January 23-2 5 

• COURSEWARE TIPS 

Selecting and Evaluating In- 
structional Courseware. 
Princeton. NJ. This seminar 
shows teachers how to iden- 
tify sources and the effec- 
tiveness of educational 

[continued) 



JANUARY 1985 -BYTE 83 



'There's no magic to using 
your personal computer for 
data acquisition." 




Fred Molinari, President 



There's no trick to it. 

Just take your choice of our new 
single board plug-ins and bring com- 
plete analog and digital I/O capabilities 
to your personal 
computer. 

Whether you're 
working in laboratory 
research or indus- 
trial process con- 
trol, our single 
boards can give you 
measurement and 
control capabilities 
without having to 
spend big bucks. 

And who 
knows that better 
than the leading sup- 
plier of low cost 
data acquisition 
boards, systems, 
and software? 

Our boards 

include A/D with programmable gain, D/A, digital I/O, 
clock and direct memory access capabilities. With power 
and performance to match your PC, our analog interfaces 
provide 12 or 16-bit A/D resolution and direct connection 
for high or low level signal inputs. 

And these boards just plug into the PC's backplane. 
No messy external boxes or cables. User input connec- 
tions are simple with our compatible line of screw 




terminal panels. 



DATA ACQUISITION FOR PC'S 


mm 


/ 


IBM PC" 


X 


X 


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X 


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APPLE II" 


X 






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Tl PROFESSIONAL™ 


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DEC RAINBOW" 


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COMPAQ'" Portable 


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Data Translation is the leading supplier of 
personal computer hardware and software 
for data acquisition and control. 



Comprehensive 
user manuals with 
many programming 
examples get you 
up and running fast. 

So why look 
any further? No other 
analog I/O systems 
can offer PC users 
such quality, power 
and performance for 
such a reason- 
able price. 

After all, 
making data 
acquisition easy 
is what we're 
all about. 

And that's 
no illusion. 

Call 
(617) 481-3700, 



DATATRANSLATION 



m 



World Headquarters: Data Translation Inc.. 100 Locke Dr.. Marlboro. MA 01752 (617) 481-3700 Tlx951-646. 
European Headquarters: Data Translation. Ltd.. 430 Bath Rd.. Slough. Berkshire SLI 6BB England (06286) 
3412 Tlx 849-862. 
In Canada: (416) 625-1907. 

IBM PC is a registered trademark of IBM. Apple II is a registered trademark of Apple Computer Corp. Tl Profes- 
sional is a registered trademark of Texas Instruments. Inc. DEC Rainbow is a registered trademark of Digital 
Equipment Corp. COMPAQ is a registered trademark of COMPAQ Computer Corp. 



EVENT QUEUE 



courseware, how to evaluate 
courseware, and how to 
select and use courseware 
directories, clearinghouses, 
databases, and published re- 
views. Hands-on experience 
is provided. The fee is $12 5. 
Contact Educational Testing 
Service. Princeton. NJ 08541. 
(609) 734-1108. January 24 

• INFO ON TELECOMM 

Finding Telecommunications 
Information, AMFAC Hotel. 
Burlingame. CA. This semi- 
nar explains how to find and 
stay up-to-date with informa- 
tion on the telecommunica- 
tions industry. For seminar 
details, contact Christopher 
Sterling at (202) 676-8243. 
For registration details, con- 
tact Phillips Publishing Inc.. 
Suite 1200 N. 7315 Wiscon- 
sin Ave., Bethesda. MD 
20814. (301) 986-0666. 
January 28-29 

• FAULT-TOLERANT 

DESIGN— Introduction to 
Fault-Tolerant Microcom- 
puter Systems. Sheraton 
Mockingbird Hotel. Dallas. 
TX. This course introduces 
attendees to various topics 
in fault-tolerant computing, 
including fault classification, 
detection, diagnosis, and 
recovery; error correction 
and detection; micropro- 
cessor testing; and redun- 
dancy techniques. The fee is 
$650. Contact William C. 
Dries. University of Wis- 
consin-Extension. Depart- 
ment of Engineering & Ap- 
plied Science. 432 North 
Lake St.. Madison. Wl 
53706. (800) 362-3020; in 
Wisconsin, (608) 262-2061. 
]anuary 28-30 

• INSTRUCTIONAL COM- 
PUTING CONFERENCE 

The 1985 Florida Instruc- 
tional Computing Con- 
ference. Sheraton Twin 
Towers Convention Center 
and Howard Johnson's 
Florida Center Hotel, 
Orlando. FL. This fifth an- 
nual conference will feature 
more than 100 sessions on 



instructional and administra- 
tive computing as well as 
general conference sessions. 
More than 130 companies 
will exhibit. Contact the 
Florida Department of Edu- 
cation, Educational Tech- 
nology Section, Knott 
Building, Tallahassee, FL 
32301, (904) 487-3104. 
January 28-31 

• ADVANCED C TOPICS 

Advanced C Topics Seminar, 

Raleigh. NC. Contact 

Suzanne B. Battista. Plum 

Hall Inc.. 1 Spruce Ave., 

Cardiff. NJ 08232, (609) 

927-3770. 

January 28-February 1 

• GERMAN TRADE SHOW 
Micro-Computer '85, Hall #4. 
Fairgrounds. Frankfurt, West 
Germany. More than 200 
exhibitors of hardware, soft- 
ware, accessories, and ser- 
vices will display their 
wares. Other features in- 
clude seminars, workshops, 
and discussions. Contact Mr. 
Philippe Hans. German 
American Chamber of Com- 
merce. 21st Floor. 666 Fifth 
Ave.. New York. NY 10103. 
(212) 974-8856. 

January 29-February 3 



February 1985 

• COMPUTER COURSES 

Courses from Integrated 
Computer Systems, various 
sites throughout the U.S. 
Among the courses to be 
offered are '"Digital Image 
Processing" and "Modern 
Pattern Recognition Sys- 
tems." Course fees are $945. 
Contact Ruth Dordick. Inte- 
grated Computer Systems, 
6305 Arizona Place, POB 
45405. Los Angeles. CA 
90045. (800) 421-8166; in 
California. (800) 3 52-82 51 or 
(213) 417-8888; in Canada. 
(800) 228-6788. 
February-March 

• LANGUAGE COURSES 

Courses from The Micro- 



84 BYTE • JANUARY 1985 



Inquiry 103 



EVENT QUEUE 



Engine Company, Johannes- 
burg, Republic of South 
Africa. Courses in UNIX. C, 
and Pascal are offered Con- 
tact Laurie Butgereit. The 
MicroEngine Co. (Pty) Ltd., 
POB 78992. Sandton, 2146. 
Republic of South Africa, 
(ON) 789-1736. 
February-March 

• SPECIAL EDUCATORS 

Computers & Reading/Learn- 
ing Difficulties. Third Annual 
Western States Conference. 
Los Angeles. CA. Sixty pre- 
sentations and hands-on 
workshops will explore the 
use of computers in reading, 
language arts, and learning 
difficulties. Educational 
materials will be exhibited. 
Workshop fees are $55. and 
conference fees are $5 5 and 
$95. Contact Educational 
Computer Conferences, 1070 
Crows Nest Way Richmond, 
CA 94803. (415) 222-1249. 
February 1-2 

• AUTOMATED FACTORY 

EXPLORED— Automated 
Manufacturing. Don CeSar 
Hotel, St. Petersburg, FL. 
Contact Eleanor Bernet. 
Frost & Sullivan Inc.. 106 
Fulton St.. New York, NY 
10038. (212) 233-1080. 
February 4-5 

• TECHNOLOGY AND THE 
OFFICE-The 1985 Office 
Automation Conference, 
Georgia World Congress 
Center. Atlanta. GA. The 
theme for the sixth annual 
Office Automation Con- 
ference is 'Today's Partner- 
ship: People and Tech- 
nology." More than 45 
technical sessions are 
planned. Full-conference 
preregistration fees are 
$100. which includes admis- 
sion to the exhibit area. Stu- 
dent, one-day, and exhibit- 
only rates are $10. $40, and 
$30. respectively. Full- 
conference registration at 
the door is $125. Contact 
OAC '85. American Federa- 
tion of Information Process- 
ing Societies Inc.. 1899 



Preston White Dr., Reston, 
VA 22091, (703) 620-8952. 
February 4-6 

• PROLOG INSTRUCTIONS 

Prolog Workshop, New York 
City. A hands-on program in 
Prolog, running under UNIX. 
Subjects covered include the 
fundamentals of logic pro- 
gramming with Prolog, arti- 
ficial intelligence representa- 
tion techniques, and expert 
system design. Participants 
should be familiar with a 
high-level language. Contact 
Keith Eisenstark, Structured 
Methods Inc., 7 West 18th 
St.. New York. NY 10011, 
(212) 741-7720. 
February 4-7 

• SIMULATION AND 

MODELING— Simulation and 
Modeling with SIMSCRIPr 
11.5. Westpark Hotel, Arling- 
ton, VA. This course serves 
as an introduction to the 
concepts of simulation and 
model building using SIM- 
SCRIPr 11.5, a programming 
language tailored for simu- 
lation analysts, model 
builders, engineers, and 
computer scientists. The fee 
is $850. Contact Ed Russell, 
CACI, 12011 San Vicente 
Blvd.. Los Angeles, CA 
90049. (213) 476-6511; on 
the eastern seaboard, call 
Carl Joeckel, (215) 628-3701. 
February 4-8 

• MANUFACTURING EXPO 

Florida Computer Manufac- 
turing Expo, Centroplex 
Expo Center. Orlando. FL. 
Hardware, software, periph- 
erals, and accessories will 
be displayed. A seminar 
program is planned. Contact 
Great Southern Computer 
Shows. POB 655. Jackson- 
ville. FL 32201. (904) 
3 56-1044. February 5-8 

• STRIDE TO FAIRE 

Stride Faire '85, MGM Grand 
Hotel/Casino. Reno, NV. This 
is the second annual tech- 
nical trade fair sponsored by 
Stride Micro, formerly 

{continued) 



i 






m 



^^^^.rzr.r-,, 




Print 

o spreadsheets 

ptexi 

• graphics 

in any order! 

QShuffleBuffer 

• Has Random Access Printing ... an intelli- 
gent processor which stores phrases, pas- 
sages, entire letters, spreadsheets, graphics 
and commands, then prints the information 
in whatever order you want, as many times as 
you want. 

• Has FIFO printing (first-in, first-out) ... acts as a 
reservoir, accepts data at computer speed, 
prints on its own, freeing the computer for 
further tasks. 

• Has BYPASS Printing . . . permits interruption of 
long-term buffer operations for straight-thru 
short-term printing. 

PLUS 

Data compression . . . expands memory stor- 
age to 4 times. Infinite copy capability. Sim- 
ple erase feature to clear buffer. Compatible 
with virtually any serial or parallel computer, 
serial or parallel printer (letter quality or dot 
matrix) as well as plotters and modems. 

WRAP it all up with SHUFFLE/BUFFER! 

Call or write for the dealer nearest you: 



«s 



Interactive Structures Inc. 
146 Montgomery Avenue 
Bala Cynwyd, PA 19004 
Telephone: (215) 667-1713 




Inquiry 176 



JANUARY 1985 -BYTE 85 



Inquiry 62 



COMPETITIVE EDGE 

P.O. BOX 556 • PLYMOUTH, MI 48170 • (313) 451-0665 

LOMAS DATA PRODUCTS INC. 

Thunder™ 186, 256K,2-5"DRS, CCP/M-86 $1995. 

Thunder™ 186, 256K, 2-5", 10MB HD, CCP/M-86 3295. 

Thunder™ 186, 512K, 2-5", 10MB HD, MCCP/M-86 3895. 

ABOVE THUNDER SYSTEMS INCLUDE 8080 EMULATOR 

LDP S-100-PC $2395. LDP S-100-PCTM 5495. 

CompuPro® and/or Macrotech Components 

MT286/Z80H, 256K, 4 SERIAL, 2-8" DRS CCP/M™ 5095. 

MT286/Z80H, 512K, 9 SERIAL, 1-8", 40MB HD, CCPM 7895. 

286/287, 8080 EM, 9 SERIAL, 1-8", 40MB HD, CCPM 8095. 

TELETEK COMPONENTS CE INTEGRATED 

Master/Slave Systems Single & Multi-User 

Systemaster® II, 8MHZ Z80, Single Turbo 2-8" 2695. 

Sysmas II, 8MHHZ Z80, Multi Turbo™ 10MB 1-8" 

Two 6MHZ, 128K Slaves 5595. 

Systemaster® , SBC-2™ Dual Slave, 1-8" 10MB TD 4595. 

CIRCUIT BOARDS 

CompuPro® 

RAM 22™ . . . $995.RAM23™-64K . . . 308.RAM 23™-128K .539. 
DISK1 A™ 459. 286/287 1229. DISK 3™ 525. 

,TM 



Jan. Only Special 286/287 CPU 1M 1229. 

LOMAS DATA PRODUCTS 

286 .... 1116. Hi-Speed DRAM 5 12K 876. 8086-1 .... 520. 

LDP 72 . . 220. Thunder™ 186 CCP/M . . 1 195. CCPM™ . . 280. 

TELFTFK 
Systemaster® II . . . .899. Systemaster® . . . .557. HDCTC™ . . . .525. 
SBC-1™6MHZ 128K. . . .736.SBC-1-4-64K. . . .525 .SBC-2™. . . .837. 

SBC 8086 8MHZ 1035. SBC86/87 1 195. CP/M® 135. 

Many Terminals, Printers & Software Packages Available 

ALL PRICES SUBJECT TO CHANGE ON STOCK ON HAND 
ALL PRICES ABOVE CASH PREPAID PRICES 

Turbodos is a trademark of Software 2000 Inc. 286/287 CPU, RAM 22, RAM 23, Disk la. Disk 

3 are either trademarks or registered trademarks of CompuPro® a Godbout Company. CP/M, 

CCP/M are either trademarks or registered trademarks of Digital Research Inc. 

Thunder 186, Color Magic, LDP 72, are trademarks of LDP Inc. Systemaster, Systemaster II, 

SBC-1, SBC-2 HDCrC are either trademarks or registered trademaeks of Teletek Enterprises 

Inc. 



Introducing USER-PORTABILITY with the 

Uirtual/Uolume/Manager™ 1 

The user's common link to: 

(MS T -DOS,PC Tfl DOs) 



UNIX n Xenix' 



V VM T "1 — fuCSD p-System 

. / \ 







® 



( CP/M® 2.2,5.0,86,68k) 



VVM, the Virtual/Volume/Manager, is a screen-oriented directory 
maintenance utility and working environment. Even if you don't 
need to be USER-PORTABLE, you'll still love its features: 

• use as a utility or visual shell 

• spreadsheet-like file cursor 

• full set of single-key directory commands 

includes file viewing or directory changes 

• multi-column or single column extended info 

• simple macro commands 

• full color support with user-defined schemes 

• Microsoft®mouse support for PC-DOS version 

Available 
NOW for: 



Coming 
SOON for: 



PC-DOS, MS-DOS, 

CP/M 86, UCSD p-System 

CP/M 2.2, 3.0. 68K 

UNIX. Xenix. UNIX work-alikes 



$44.95 



For 



MicroTASK, Inc. (919) 851-9045 hc/visa 

Suite 345, 6040-A Six Forks Road, Raleigh, NC 27609 

* Add $5.00 shipping inside USA, $ 1 5.00 outside USA ( payment by bank 
draft payable in the U.S. ). North Carolina residents add 4.52! sales tax. 
Payment by MC/VlSA/check/money order only. Dealers and OEM's call. 

Trademarks: VVM. Virtual/Volume/Manager, MicroTASK - MicroTASK, Inc.; 

MS,Xenix - Microsoft Corporation; UNIX - Bell Laboratories; 

PC- DOS - International Business Machines Corporation. 
Registered CP/M - Digital Research, Inc.; Microsoft - Microsoft Corporation; 

Trademarks: UCSD p-System - The Regents of the University of California. 



EVENT QUEUE 



known as Sage Computer. 
Contact Laura Smith, Stride 
Micro, 4905 Energy Way, 
Reno. NV 89502. (702) 
322-6868. February 8-10 

• SOFTWARE MANAGE- 
MENT CONTROL-Con- 

figuration Management of 
Software Programs. San 
Diego. CA. Intended to show 
those working in software 
management how to control 
development, maintenance, 
and operational costs. 
Familiarity with MIL-STD 
480. 483. and 490 is helpful, 
but there is no prerequisite 
for this course. The cost 
is $730. Contact Stod 
Cortelyou. Continuing Engi- 
neering Education. George 
Washington University. Wash- 
ington. DC 20052. (800) 
424-9773; in the District of 
Columbia. (202) 676-8520. 
February 11-13 

• NETWORK COM- 
PONENTS EXPLAINED 

Data Communications Net- 
work Components, Atlanta. 
GA. This course provides a 
thorough overview of the 
use. operation, applications, 
and acquisition procedures 
of 25 major communications 
components. The fee is 
$795. Contact Elaine Had- 
den Nicholas, Department of 
Continuing Education, 
Georgia Institute of Tech- 
nology. Atlanta, GA 30332- 
0385. (404) 894-2547. 
February 12-14 

• INTERACTIVE 
INSTRUCTION-The Third 
Conference on Interactive In- 
struction Delivery. Sheraton 
Towers Hotel. Orlando, FL. 
Contact the Society for Ap- 
plied Learning Technology, 
50 Culpeper St.. Warrenton, 
VA 22186. (703) 347-0055. 
February 13-15 

• COMPUTERS FILL 
EDUCATORS' TALL ORDER 

The Fifth Annual Conference 
of the Texas Computer Edu- 
cation Association, Hyatt 
Regency Hotel, Austin. TX. 



The theme for this con- 
ference is "New Directions 
for Education Using Modern 
Day Technology." Contact 
TCEA Conference. POB 
2573. Austin. TX 78768. 
February 13-16 

• PC SYMPOSIUM 

The 1984 UNM Personal 
Computer Symposium. Uni- 
versity of New Mexico. Albu- 
querque. The second annual 
Personal Computer Sym- 
posium will feature exhibits, 
seminars, and demonstra- 
tions of personal computer 
systems of interest to 
businesspeople, educators, 
and professionals. Contact 
the lau Beta Pi Honor Soci- 
ety, c/o Dr. Randy TVuman, 
Department of Mechanical 
Engineering. University of 
New Mexico, Albuquerque, 
NM 87131, (505) 277-6296. 
February 15-16 

• COCO CONVOCATION 

Rainbowfest, Irvine Marriott, 
Irvine, CA. A show for users 
of the Radio Shack TRS-80 
Color Computer. More than 
50 exhibitors are expected. 
Contact Falsoft Inc.. POB 
385. Prospect. KY 40059, 
(502) 228-4492. 
February 15-17 

• SOFTWARE UPDATE 

The Second Annual Interna- 
tional Software Update, 
Waiohai Resort Hotel, Kauai. 
HI. An international lineup 
of speakers will focus on 
domestic and international 
marketing concerns and 
future trends in microcom- 
puter software. Attendance 
is limited. Contact Raging 
Bear Productions Inc., Suite 
175. 21 lamal Vista Dr.. 
Corte Madera. CA 94925. 
(800) 732-2300; in California. 
(415) 924-1194. February 16-20 

• MICROS FOR 
EDUCATORS— Association of 
Teacher Educators National 
Conference. Riviera Conven- 
tion and Resort Hotel. Las 
Vegas. NV. Exhibits and 

(continued) 



86 BYTE • JANUARY 1985 



Inquiry 232 



^c^ 





THE PROFESSIONAL'S CHOICE 



WORD PROCESSING/ 
EDITORS 

Easywriter II System 

Fancy Font 

FinalWord 

Microsoft Word 

Microsoft Word/Mouse 

Multimate 

PeachText 5000 

PFS: Write 

Samna Word III 

Volkswriter Deluxe 

The Word Plus (Oasis) 

Word Perfect (SSI) 

WordPlus-PC with The Boss 

WordStar 

WordStar Professional 

IWS/MM/SS/Sl] 
WordStarOptionsPak 

(MM/SS/SI) 
XYWrite 11+ 



219 
159 
189 
239 
299 
269 
199 
95 
SCall 
169 
109 
:;249 
319 
219 

$279 

$189 
$229 



SPREADSHEETS/ 
INTEGRATED PACKAGES 

Aura 5 $329 

Electric Desk #229 

Framework $369 

Integrated 7 $339 

Jack 2 $329 

Lotus 1-2-3 1309 

Multiplan {135 

Open Access J299 

Smart System 1579 

SuperCalc3 5219 

Symphony |429 

TKI Solver 1269 

VisiCalcIV SI 59 



COMMUNICATIONS/ 




PRODUCTIVITY TOOLS 




Crosstalk 


$119 


Memory Shift 


$ 79 


Move It 


$109 


Prokey 3.0 


$ 95 


Relay 


$ 99 


SmartcomH 


$109 



DATABASE SYSTEMS 

Alpha Data Base 

Manager II £179 

Condor 111 1299 

dBase II $279 

dBase III |369 

DBplus I 89 

Friday Si 79 

lnfoStar+ $289 

Knowledgeman $299 

PFS: File/PFS: Report $169 

Powerbase $239 

QuickCode $159 

R:base 4000 $269 

TIM IV $249 

Versaform $249 

LANGUAGES/UTILITIES 

Concurrent w/Windows $219 
Digital Research 

C Compiler $219 

DR Fortran 77 $219 

Lattice V $299 

Microsoft C Compiler $309 

MS Basic Compiler $249 

MS Fortran $239 

Norton Utilities $ 59 

PROJECT MANAGEMENT 

Harvard Project 

Manager $239 

Microsoft Project $169 

Scitor Project 5000 $299 

VisiSchedule $199 

ACCOUNTING MODULES 

BPI Accounting $369 

IUS EasyBusiness System {319 

MBA Accounting [369 

Open Systems Accounting 1429 

Peachpak4 (GL/AP/AR) {239 

Peachfrec Accounting 1299 

Real World Accounting J469 
Star Accounting Partner 

(GL/AP/AR/PAY) $249 

Star Accounting Partner II $699 



GRAPHICS/STATISTICS 

Abstat $279 

BPS Business Graphics $229 

Chartmaster $259 

DR Draw $199 

Energraphics w/Plotter 1319 

Execuvision 1279 

Fast Graphs 1219 

Graphwriter Combo $399 

MS Chart $169 

PC Draw $279 

PFS: Graph | 95 

Signmaster $199 

Statpak-NWA $329 

Statpac-Walonick $299 

PROFESSIONAL 
DEVELOPMENT 

Management Edge $169 
Think Tank $129 

HOME/PERSONAL FINANCE 

Dollars and Sense $119 

Financier II $119 

Home Accountant Plus $ 99 
Sundex-CPA $109 

HARDWARE/ 
PERIPHERALS* 

AST Six Pack Plus (64k) 
Quadboard (Ok) 
Hayes 1200B with 

Smartcom 
Hayes Smartmodem 1200 
Keytronic 5151 DLX 
IRMA 

Hercules Graphics Board 
Epson FX-100 Printer 
Comrex II Printer 
C Itoh Prowriter 
Okidata 93A 
Toshiba P1351 Printer 
64K Memory 

"Call for shipping. 



$269 
SCall 

$399 
$489 
$209 
$995 
$349 
SCall 
SCall 
SCall 
$689 
SCall 
$ 55 



LOWEST PRICE GUARANTEE!! 

We will match current nationally 
advertised prices on most products. 
Call and compare. 



FREE! 

Diskette Library Case 

. . . with your order. This attractive 
case protects, indexes and stores 
10 diskettes for quick retrieval. 
Normally a $10 value, it is now 
available FREE to Softline customers 



TERMS; 

Checks— allow 14daystoclear. Credit processing— add 3%. COD orders— cash, M.O. or certified 
check— add $3.00. Shipping and handling UPS surface— add $3.-00 per item (UPS Blue $6.00 
per item). NY State Residents— add applicable sales tax. All prices subject to change. 




1-7-^ Symphony 



dBase III 

'369 




MultiMate 

'269 



R:base 
4000 

269 



Volkswriter 
DLX 

'169 



WordStar 
Professional 

'279 






AST 6 Pak 
Plus 

'269 


Smartmodem 
1200B 


'399 






Quad Board 
Expanded 64K 

'279 


Smartmodem 
1200 

'489 



To Order call 

1-800-221-1260 

In New York State call (718) 438-6057 

k. ..a 

For technical support 

and information call 

(718) 438-6057 



flS B5li 



VISA 




:line corporation 
P.O. Box 729, Brooklyn, 
'TELEX; 421047 ATLN Ul 



RGET MARKET 




Now last minute presentations 

can be made from 
your personal computer. 

In color. In house. In minutes. 



Introducing Polaroid Palette. 



Whether your presentation is in 30 
minutes or 30 days, the new Polaroid 
Palette Computer Image Recorder will 
make it easier. Priced at under $1800* it 
lets you make Polaroid instant 35mm 
slides or prints from personal 
computer-generated data. Right at your 
desk. So now you can create a presen- 
tation in minutes. Without sending out 
for processing, paying premiums for 
rush service or risking the security of 
your confidential information. 

Works with the graphics 

packages of the IBM PC orXi; 

DEC Rainbow, Apple He and 11+ 

as well as other pes. 

The Polaroid Palette is designed to 
work with many graphics software 
packages. In fact, when using such 
popular programs as Graphwriter, 
Chart-Master, Sign-Master, DR Draw 
and DR Graph, Palette can virtually 
double both the horizontal and vertical 
resolution of your monitor. Plus, a 

Inquiry 279 



"backfill" feature reduces raster lines 
for a smoother, more finished appear- 
ance. The result— presentation quality 
slides. On-the-spot. 

Color 35mm slides, even from a 
black and white CRT 
Think of it as an artists palette. Be- 
cause Palette "paints" your graphs, 
charts and text. You're choosing from 
up to 72 colors. If you don't want red, 
press a few keys— it's green. And if 
you're not the artistic-type, Polaroid 
has developed a menu of color sets: 
combinations of colors that have been 
specially coordinated to complement 
your presentations. And all of this is 
yours, even if you have a black and 
white monitor. 

Lets you make last minute 

changes or add 

up-to-the-minute information. 

The Polaroid Palette is the fast, con- 
venient, low-cost way to prepare slides 
for your presentation. And perhaps 



even more important, Palette allows 
you to keep confidential information 
confidential. You won't have to send 
your work out to anyone again. 

So why wait until the last minute to 
find out about Polaroid Palette? Call 
this toll-free number or return this 
coupon. Because with Palette you'll 
make your deadlines, in no time. 

r 1 

For a demonstration, call toll-free, or mail the 
coupon to Polaroid Corp., E.I. Marketing, Dept. 
604, 575 Technology Sq., Cambridge, MA 02139. 

CALL 1-800-225-1618 

□ Send information. □ Have representative call. 
Title 



B-l/85 

Name 



Company 

Address , 

Citv State _ 



-Zip- 



Telephone. 



> 



PC makeand model- 



= Polaroid 



l_. 



•Suggested list price. Polaroid* 
JANUARY 1985 -BYTE 89 



Inquiry 138 



FRIENDLY SERVICE AT A FRIENDLY PRICE 

Friendly Computer Center, Inc. 

1381 Coney Island Avenue, Brooklyn. New York 1 1230 



EPSON 



RX80 219 

RX 80 ft 279 

FX80.. 

JX 80 color 599 

Titan 2 Board for OX-10 



RX100 

FX 

LQ 1500 1095 




APPLE HE' Entry System 

NEW APPLE DUODISK 
DRIVE W/EXTENDED 60 
COLUMN CARD IN 
STOCK-MACINTOSH CALL 
NEWAPPLE 11C $895 

DISK DRIVES-FOR IBM 

Teac '/, ht. DS/DD 149 

Rana 2000 IBM 149 



ADD ON BOARDS 

FDR IBM 

AST Six Pack Plus 249.00 

Quadram Expanded Quadboard 

w/64K 259.00 

Hercules Graphics Board , 319.00 
Hercules Color Card w/Parallel 

Port 179.00 

Koala Speed Key System . 149.00 
Mouse Systems House w/Mouse 
w/P C Paint and Menue . . 159.00 
Hayden Saragon III Chess. 34.90 
Microsoft Flight Simulator 1137.90 
Hayden Saragon III lor Mac 39.90 

De Base III 389.00 

Framework 419.00 

SYMPHONY CALL 



MODEMS 



Hayes 1200B IBM 


. 379.00 


Hayes 1200 RS232 


. 459.00 


Hayes 300 RS232 


. 195.00 


Micromoden HE w/ 




Software 


235.00 


New Hayes 2400 


. . CAM 


Racal-Vadic 1200 EXT-RS- 




232 


42900 


Raca:-Vadic Internal w/George 


Software 


419.00 


CompuServe Starter Kit . 


. 28.95 


The Source Starter Kit . 


. 28.95 


Grappler Bufferd Plus 16K 




w/cable 


149.00 


FLOPPY DISCS 




Verbatim Datalife w/Free Head 


Cleaner and Storage Case 




S.S/DDbox ol 10 


. . 22.95 


DS/DD. box of 10 


. 29.95 



MONOCHROME PRO 
PACKAGE $2249 

• IBM* PC 64K 

• 2-320K DS/DD DRIVES 

• MONOCHROME DIS- 
PLAY CARD 

• MONOCHROME 
MONITOR 

LEADING EDGE PC _ CALL 



MONITORS 

Princeton HX-12 Graphics . 459.00 
New Amdek Color 300.... 269.00 
New Amdek Color 700-Ultra Hires 

RGB 499.00 

Amdek 310A 175.00 

Com rex 5650 Hires 12" 

Green 89.00 

Gorilla 12" Green 89.00 



PRINTERS 

Juki-6100 369.00 

Juki-6300 CALL 

Juki-Tractor 6100 99.00 

New Toshiba 1340 7B9D0 

Toshiba 1351 1295.00 



FOR MAIL ORDERS: Send Money Order. Certified Check. Mastercard. VISA gladly accepted Add estimated price tor 
shipping, handling and insurance WE WILL SHIP ORDERS AT THE AOVERTISED PRICES GUARANTEED UNTIL JAN. 31. 1985 

sgisiered trademark ol International Business Machines. 



(800)258-5805 m HI 252-9737 

Friendly Computer Center, Inc. 



138lConeylslandAvi 



Brooklyn. New York 11230 





■K? 




44- 








A Software Implementation 
within Your Product Hardware 

If you manufacture a computer system or a computer based product, 
allow it to EMULATE COMMUNICATE by installing one or more of 
Systems Strategies "C" Language based communication packages. 

• 3270 SNA SDLC Emulation 

• 3270 BSC Emulation 

• 2780 3780 HASP Emulation 

• X.25 Levels 1 , 2, 3 Communication 

You can purchase these "C" Language packages with source code 
and license to distribute in your hardware product. Each package is 
available either "Port it Yourself" with instruction manual and training or 
ported to your hardware by Systems Strategies' communications staff. 

Systems Strategies/ Advanced Technology Division 
Specialists in Data Communications Software 

> — ^-^ Systems Strategies Inc. 
/ /V\ 225 West 34th Street 
\ ^W/ New York, New York 10001 
(212) 279-8400 



EVENT QUEUE 



demonstrations of micro- 
computers, microcomputer 
products, and communica- 
tions equipment will be 
featured. Contact Peter C. 
West, Learning Center, Col- 
lege of Education, Gabel 
Hall 8, Northern Illinois 
University, DeKalb. 1L 601 1 5. 
(815) 753-1241. 
February 18-19 

• MANAGE YOUR 
COMPUTER-Managing 
Computer Resources, Winter- 
green Learning Institute. 
Wintergreen, VA. Focuses on 
networking, system design, 
performance evaluation, and 
operational difficulties en- 
countered by managers and 
executives. Rates include 
lodging and ski-lift tickets 
and vary from $570 to $769 
depending on accommoda- 
tions. Contact Dr. M. D. 
Corcoran. Wintergreen 
Learning Institute. POB 7. 
Wintergreen. VA 22958. 
(800) 32 5-2200; in Virginia. 
(804) 325-1107. 

February 18-22 

• DIGITAL USERS MEET 

DECUS Canada Spring Sym- 
posium. LHotel. Toronto, 
Ontario, Canada. This sym- 
posium covers a variety of 
topics of interest to Digital 
computer users. Contact 
Jeanne McNeish, DECUS, 
100 Herzbug Rd., POB 
13000. Kanata. Ontario K2K 
2A6, Canada. (613) 592-5111. 
ext. 2782. February 19-22 

• COMMUNICATIONS FOR 

EXECS-lnfo/Central, O'Hare 
Exposition Center, Chicago, 
1L. This show and con- 
ference on computers and 
communications is tailored 
to the needs of executives 
and data-processing mana- 
gers. Mainframes, microcom- 
puters, telecommunications 
systems, and micrographics 
are a few of the areas to be 
addressed. Contact the 
Show Manager, Info/Central, 
999 Summer St.. Stamford. 
CT 06905. (203) 964-8287. 
February 20-22 



• COMPUTERS IN 
EDUCATION-The Role of 
the Computer in Education 
5, Arlington Park Hilton. 
Arlington Heights. IL A 
range of topics of interest to 
educators will be presented. 
Contact Rick Nelson. The 
Role of the Computer in 
Education 5, Micro-Ideas. 
2701 Central Rd., Glenview. 
IL 60025. (312) 998-5065. 
February 20-22 

• BUSINESS GRAPHICS 

Computer Business Graph- 
ics. Bonaventure Intercon- 
tinental Hotel, Fort Lauder- 
dale, FL. Contact Carol 
Every, Frost & Sullivan Inc., 
106 Fulton St.. New York. 
NY 10038. (212) 233-1080. 
February 20-23 

• MAC IN SPOTLIGHT 

MacWorld Exposition. 
Brooks Hall. San Francisco. 
CA. A hands-on festival of 
Macintosh hardware, soft- 
ware, and peripherals. Con- 
tact World Expositions. 
Mitch Hall Associates. POB 
860. Westwood. MA 02090. 
(617) 329-7466. 
February 21-23 

• COMPUTER FA1RE 

The Fourth Annual IEEE 
Computer Faire. Huntsville. 
AL Sponsored by the In- 
stitute of Electrical and Elec- 
tronics Engineers Inc. For 
complete information, con- 
tact r Ierry Mizell. POB 5188. 
Huntsville. AL 3 5805. (205) 
532-2036. February 22-23 

• FARM AUTOMATION 

Agri-Mation. Palmer House 
Hotel, Chicago, IL. This con- 
ference and exposition will 
focus on the role of automa- 
tion in agriculture. Contact 
the Society of Manufacturing 
Engineers. One SME Dr., 
POB 930. Dearborn, MI 
48121, (313) 271-1500. 
February 25-28 

• COMPUTING IN 

ANESTHESIA— Computing 
in Anesthesia '85, The Third 
International Seminar, 



90 B YTE • JANUARY 1985 



EVENT QUEUE 



Mira mar-Sheraton, Santa 
Monica. CA. Medical and 
computer specialists will 
describe their research and 
use of computers in data ac- 
quisition and display, com- 
puterized monitoring, in- 
struction, education, data- 
base management, and 
knowledge-based systems. 
The registration fee is $300. 
Contact Program Chairman. 
Computing in Anesthesia 
'85. Anesthesiology Educa- 
tional Foundation. Federal 
Building. POB 24230. Los 
Angeles. CA 90024. (213) 
825-7561. 
February 25-March 1 

• SHORT COURSE FOR 

ENGINEERS— Dynamics on 
Microcomputers. University 
of Michigan-Dearborn. For 
information, contact R. E. 
Little. University of 
Michigan. 4901 Evergreen 
Rd.. Dearborn. Ml 48128. 
(313) 593-5241. 
February 25-March 1 

• HIGH-TECH IN FOCUS 

High-Tech '85 Exhibit and 
Seminar. Thunderbird Motel. 
Bloomington. MN. More 
than 100 manufacturers will 
exhibit computer terminals, 
peripherals, data-communi- 
cations equipment, and 
digital test instruments. Ad- 
mission is free. Contact John 
Bastys or Barb Mueller. 
Countryman Associates Co.. 
1821 University Ave.. St. 
Paul. MN 55104. (612) 
645-9151. February 26-27 

• AUTOMATION FOR 
ELECTRON ICS-Automated 
Design and Engineering for 
Electronics. Anaheim Hilton 
and Towers. Anaheim. CA. 
This conference and exposi- 
tion covers the use of auto- 
mation in the design of elec- 
tronic circuitry. For further 
details, contact Michael In- 
dovina. Cahners Exposition 
Group. Cahners Plaza. 13 50 
East Touhy Ave.. POB 5060. 
Des Plaines. 1L 60018. (312) 
299-9311. 

February 26-28 



• MICRO-AIDED MANAGE- 
M ENT— Microcomputer- 
aided Maintenance Manage- 
ment System. Ramada Inn, 
Airport. Milwaukee. Wl. This 
course is designed to show 
how computers can help im- 
prove the maintenance func- 
tions of any organization. 
The fee is $60. Contact Unik 
Associates. 12 54 5 West 
Burleigh. Brookfield. Wl 
53005. (414) 782-5030. 
February 27 



March 1985 

• FOSE SOFTWARE SHOW 

Federal Office Systems Ex- 
position (FOSE) Software 
'85. Convention Center. 
Washington. DC. Four days 
of workshops, symposia, and 
exhibits of software. Contact 
Rosalind Boesch. National 
Trade Productions Inc.. Suite 
400, 2111 Eisenhower Ave.. 
Alexandria. VA 22314. (800) 
638-8510; in Virginia. (703) 
683-8500. March 4-7 

• MINI/MICRO 

Mini/Micro Southeast-85, 
Georgia World Conference 
Center. Atlanta. A con- 
ference and exposition. Con- 
tact Electronic Conventions 
Management. 8110 Airport 
Blvd.. Los Angeles. CA 
9004 5. (213) 772-2965. 
March 5-7 

• COMPUTER. COMMUNI- 
CATIONS SECURITY 

SECUR1COM '85: The Third 
World Congress on Com- 
puter and Communications 
Security and Protection. 
Palais des Festivals et des 
Congres. Cannes. France. 
Topic areas include elec- 
tronic banking security, 
security implications of new 
media, security within micro- 
computers and distributed 
systems. Contact SEDEP. Ex- 
positions Department. 8. 
Rue de la Michodiere. 
75002. Paris. France; tel: 
742 41 00; Tfelex: 2 50303 

[continued) 




And then 
there 



were none 



The list of already extinct animals 
grows . . . the great auk, the Texas gray 
wolf, the Badlands bighorn, the sea mink, 
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Inquiry 258 



JANUARY 1 985 • BYTE 91 



Inquiry 1 1 



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EVENT QUEUE 



PUBLIC X PARIS. 
March 6-8 

• INDUSTRIAL AUTO- 

MATION-AUTOTECH Hong 
Kong '85, Hong Kong. An 
international conference on 
industrial automation held 
in conjunction with the First 
Exhibition on Automation 
Technology. The theme is 
'"Micros in Affordable Auto- 
mation—Creating New In- 
dustrial Opportunities for 
All." Contact Hong Kong 
Productivity Centre, 1 2th 
Floor, World Commerce Cen- 
tre. Harbour City 1 1 Canton 
Rd.. r teimshatsui, Kowloon. 
Hong Kong; tel: 3-723 5656. 
March 7-8 

• SUGl CONFERENCE 

The Tenth Annual SAS Users 
Group International (SUGl) 
Conference. Reno. NV. 
Topics include capacity plan- 
ning and evaluation, systems 
software, education, graph- 
ics, information systems, and 
microcomputers. Contact 
SAS Institute Inc.. SAS Cir- 
cle. POB 8000. Cary, NC 
275H. (919) 467-8000. 
March 10-13 

• CONFERENCE ON 

SCIENCE-ACM Computer 
Science Conference, Marriott 
Hotel, New Orleans, LA. This 
conference, sponsored by 
the Association for Com- 
puting Machinery and a 
number of college and uni- 
versity computer science 
departments, features an 
employment register, where- 
by job seekers can meet 
prospective employers. Con- 
tact ACM Computer Science 
Employment Register, 
Department of Computer 
Science. University of Pitts- 
burgh, POB 13 526. Pitts- 
burgh. PA 15234. 
March 11-14 

• DESIGN SHOW 

The 1985 National Design 
Engineering Show. McCor- 
mick Place. Chicago. IL. 
More than 600 CAD/CAM 
system and electronic com- 



ponent companies will ex- 
hibit products. Contact the 
Show Manager, National 
Design Engineering Show. 
999 Summer St.. Stamford. 
CT 06905. (203) 964-0000. 
March 11-14 

• SCSI SEMINARS 
Small Computer Systems 
Interface (SCSI) Forum. 
Houston, TX. Seminars and 
exhibits of SCSI controllers 
and related peripherals. 
Contact Mr. J. Molina. SCSI 
Forum Ltd., POB 2625. 
Pomona, CA 91768-2625. 
March 12 

• EDUCATIONAL CON- 
FERENCE-The 1985 Micro- 
computers in Education 
Conference, Arizona State 
University, Tempe. The 
theme is "Tomorrow's 
Technology." Emphasis will 
be placed on integrating 
computer technology and 
languages into the educa- 
tional environment. Contact 
Donna Craighead. Payne 

B4 7. Arizona State Universi- 
ty, College of Education. 
Tempe. AZ 85287. (602) 
965-7363. March 13-15 

• SIMULATION IN SUN- 
SHINE— The Eighteenth An- 
nual Simulation Symposium. 
Tampa, FL. A forum for in- 
terchange of ideas, tech- 
niques, and applications 
among those working in this 
field. Contact Alexander 
Kran. IBM Corp.. East Fish- 
kill Facility. Hopewell junc- 
tion. NY 12533. 

March 13-15 

• COMPUTERS AND TELE- 
COMMUNICATIONS 

COMTEL '85: International 
Computer and Telecommuni- 
cations Conference. In- 
fomart, Dallas. TX. Contact 
COMTEL '85. Suite 600. 
13740 Midway Rd.. Dallas. 
TX 75244. (214) 458-7011. 
March 18-20 

• TECHNOLOGY AND 
EDUCATION-The First An- 

{continued) 



92 BYTE • JANUARY 1985 



Inquiry 274 




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Inquiry 27 



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JANUARY 1985 'BYTE 93 



Inquiry 257 



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EVENT QUEUE 



nual Conference on Tech- 
nologies in Education, 
University of Arizona. TUc- 
son. This conference will 
focus on the effective im- 
plementation of research in 
educational technology. Con- 
tact Steve Louie, NACC1S, 
Suite 125. 2200 East River 
Rd.. TUcson. AZ 85718. (602) 
323-6144. March 18-20 

• ROBOTICS TECHNOLOGY 
UPDATE— The Second An- 
nual Robotic End Effectors: 
Design and Applications 
Seminar. Holiday Inn 
Livonia West. Livonia. Ml. 
This seminar explores 
robotic end effector tech- 
niques, sensors for tooling, 
compliant devices, inter- 
changeable end-of-arm tool- 
ing devices, multihand tools, 
and magnets for tooling. 
More than 25 companies 
will exhibit. Contact John 
McEachran. Special Pro- 
grams Department. Society 
of Manufacturing Engineers. 
One SME Dr.. POB 930, 
Dearborn. Ml 48121. (313) 
271-1500. ext. 382. 

March 19-20 

• Al FOR ROBOTS 

Aircon 2: The Second 
Annual International Con- 
ference on Artificial In- 
telligence for Robots. Stouf- 
fers Concourse in Crystal 
City. Arlington. VA. This con- 
ference is designed to pro- 
mote a dialogue between 
experts and users of arti- 
ficial-intelligence systems. 
The theme is "Toward In- 
telligent Robots: The Droids 
Are Coming." Contact Cindy 
Mega. 11T Research Institute. 
10 West 3 5th St., Chicago, 1L 
60616. (312) 567-4024. 
March 21-22 

• ELEMENTARY 

COMPUTING-University of 
Delaware Second National 
Conference: Computers and 
Young Children. University 
of Delaware, Newark. The 
emphasis is on programs for 
children 4 to 8 years old. 
Contact Dr. Richard B. 



Fischer. Division of Continu- 
ing Education. University of 
Delaware. Newark, DE 
19716. (302) 451-8838. 
March 21-22 

• ELECTRONIC TRANS- 
FERS-The 1985 EFT Expo. 
Fairmont Hotel. San Fran- 
cisco, CA. The annual con- 
vention and exposition of 
the Electronic Funds Trans- 
fer Association. Contact the 
EFT Association. Suite 800. 
1029 Vermont Ave. NW. 
Washington. DC 20005. (202) 
783-3 55 5. March 24-27 

• DATABASE SYMPOSIUM 
The Fourth Annual ACM 
S1GACT/S1GMOD Symposium 
on Principles of Database 
Systems. Portland. OR. This 
conference covers develop- 
ments in the theoretical and 
practical aspects of database 
systems. Topics include the 
application of artificial- 
intelligence techniques to 
database systems, data 
models, and data structures 
for physical database im- 
plementation. Contact David 
Maier. Department of Com- 
puter Science, Oregon Grad 
Center, 19600 Northwest 
Walker Rd.. Beaverton. OR 
97006. March 25-27 

• OPTICAL STORAGE 
TECHNIQUES-The Third 
Annual Conference on Op- 
tical Storage of Documents 
and Images. Shoreham 
Hotel. Washington. DC For 
information, contact 
Technology Opportunity 
Conference. POB 14817, San 
Francisco. CA 94114-0817, 
(415) 626-1133. March 25-27 

• WEST COAST FAIRE 

The Tenth Annual West 
Coast Faire. Moscone 
Center. San Francisco. CA. 
This is one of the largest 
computer shows. Contact 
Computer Faire Inc.. Suite 
201. 181 Wells Ave.. Newton 
Falls. MA 02159, (800) 
826-2680; in Massachusetts. ' 
(617) 965-8350. 
March 30-April 2 ■ 



94 BYTE • JANUARY 1985 



Inquiry 58 



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JANUARY 1985 • BYTE 95 




>J~. ■.— ••■• 



EHE 



Garcia s Circuit Cellar. 
Understanding Linear Power Supplies 

by Steve Ciarcia 98 

The Visual Mind and the Macintosh 

by Bill Benzon 113 

A Glimpse into Future Television 

by )oseph S. Nadan 135 

Microsoft Macintosh 
BASIC Version 2.0 

by Gregg Williams 155 

The Apple Story. Part 2: 
More History and the Apple III 

conducted by Gregg Williams and 

Rob Moore 167 

Uninterruptible Power Supplies 

by William Rynone 183 

An Introduction to Fiber Optics. 
Part 2: Connections and Networks 

by Richard S. Shuford 197 

Algorithms for a 
Variable-Precision Calculator 

by Paul A. Wilson 211 

Audio Frequency Analyzer 

by Vince Banes 223 

Font Design 

for Personal Workstations 

by Charles Bigelow 255 

Expert Systems-Myth or Reality? 

by Bruce D'Ambrosio 275 



Features 



THE JANUARY ISSUE OF BYTE begins what we hope is another banner year 
for microcomputer enthusiasts. Artist Robert Tinney has restarted the per- 
sonal computing hourglass, depicting the inevitable flow of new products and 
technology that will appear in 1985. 

This month we offer an exceptional number and variety of feature articles. 
As in past lanuary issues, we do not have a theme section; we take this op- 
portunity to publish twice the number of features. We'll return to our normal 
theme format in February with a section dedicated to computing in the 
sciences. 

To start this month, Steve Ciarcia focuses on an analog topic: power sup- 
plies and their attendant problems. If you've wanted a robust 12- to 13.2-V, 
1 5-A power supply made from readily available components, check out Ciar- 
cia's Circuit Cellar. 

The pictures-versus-words user-interface debate is likely to continue for some 
time, but Bill Benzon provides a strong argument for the Macintosh as a tool 
for the visual brain in "The Visual Mind and the Macintosh." 

Speaking of the Macintosh, Gregg Williams, senior technical editor, describes 
the content and structure of Microsoft's latest version of BASIC for the Mac 
in "Microsoft Macintosh BASIC Version 2.0." And along with Rob Moore, Gregg 
continues part 2 of "The Apple Story," which began in the December supple- 
ment. BYTE Guide to Apple PCs. Also continued from December is part 2 of 
"An Introduction to Fiber Optics" by Richard Shuford, BYTE's special-projects 
editor. Richard discusses connections and networks of optical-fiber waveguides. 

If you've ever tried "computing in the dark," you'll find William Rynone's 
"Uninterruptible Power Supplies" enlightening. While not intended to be com- 
prehensive, his article provides a comparison among some commercial units, 
a do-it-yourself project, and some shopping tips. 

New developments in VLSI enable Joseph Nadan to give "A Glimpse into 
Future Television" and describe how this technology is evolving in parallel 
with personal computers to bring television into the "information age." 

If you do decimal computations on large numbers, read "Algorithms for a 
Variable-Precision Calculator" by Paul Nilson. He uses a pseudocode to ex- 
plain the logic in his arithmetic algorithms. 

If you have an IBM PC and are interested in charting the frequency response 
of your lease-breaker stereo system, read Vince Banes's "Audio-Frequency 
Analyzer" construction article. 

A difficult-to-read display based on coarse-resolution dot-matrix letters may 
be a thing of the past, as described in "Font Design for Personal Worksta- 
tions" by Charles Bigelow. 

In Bruce D'Ambrosio's "Expert Systems— Myth or Reality?" he touches on 
some of the capabilities and limitations of expert systems and the directions 
in which researchers are heading. 

We've quite a variety of topics in lanuary, and we look forward to a variety 
of editorial topics and themes in the remainder of 1985. 



— Gene Smarte, Managing Editor 



JANUARY 1985 'BYTE 97 




98 BYTE • IANUARY 1985 



PHOTOGRAPHED BY PAUL AVIS 



CIARCIAS CIRCUIT CELLAR 

UNDERSTANDING 

LINEAR POWER 

SUPPLIES 



by Steve Ciarcia 



Proper design brings 
simplicity and reliability 




Sometimes it is the more 
trivial aspects of elec- 
tronics that create the 
greatest problems. With 
all the concern about 
16-bit versus 32-bit pro- 
cessors and multitasking 
operating systems, who would think that a 
simple linear power supply could cause the 
demise of a company? Even with a board 
of directors full of venture capitalists, it's 
often too late when they look beyond their 
spreadsheet projections and ask whether 
the product they are financing actually 
works. 

While looking over someone's shoulder 
is not my favorite consulting activity, I 
recently was involved in such a situation. 
One of the founders of a venture-capital- 
funded company was getting very nervous 
because his engineering department was 
seriously overdue on two products. Since 
his responsibility was sales, and about 
$800,000 in pending orders was riding on 
cost-effective delivery of these products, it 
was no wonder that he was concerned. One 
of the products was way over budget, and 
the other seemed to have a "heat problem." 
My job was to determine if there was a 
problem and help rectify it if possible. 

The first product was a speech synthesizer 
that attached to a parallel printer port. Its 
problem was "engineering buzzword injec- 



tion phenomenon." Inexperienced engi- 
neers try to impress management by de- 
signing microprocessors into products that 
don't need them. 

The synthesizer chip required parallel 
data and a strobe. It signified that it needed 
more data with a single ready line. Instead 
of merely attaching the chip directly to the 
printer port and pretending it was a printer 
(attaching printer busy to the ready line), 
the engineer had added a mask-pro- 
grammed microprocessor, external charac- 
ter-buffer memory ("In case the program- 
mer wanted it," he said.), external program 
memory (in case the mask-programmed 
chips didn't arrive in time and they had to 
use EPROMs |erasable programmable read- 
only memoriesl), and a parallel port for the 
synthesizer chip. Direct connection to the 
printer port (without the microprocessor) af- 
forded a 75 percent cost reduction. 

The second product, which I'll call E, was 
a stand-alone speech-and-music synthesizer 
board that communicated serially with the 
host computer. To make a long story short. 
I was called in to look at E after 5000 sets of 

[continued] 

Steve Ciarcia (pronounced "see-ARE-see-ah") is an elec- 
tronics engineer and computer consultant with experience 
in process control digital design, nuclear instrumenta- 
tion, and product development. He is the author of 
several books about electronics. You can write to him 
at POB 582. Glastonbury. CT 06033. 



COPYRIGHT © 1985 STEVEN A. CIARCIA. ALL RIGHTS RESERVED. 



JANUARY 1985 -BYTE 99 



components and printed-circuit 
boards had been purchased but 
nothing had been shipped. It was now 
four months overdue. 

I agreed on the basic design 
method. Because of the data in serial 
format and multiple peripheral chips, 
this device did require a micropro- 
cessor. Unfortunately, it suffered from 
another common ailment among in- 
experienced designers: ,l three- 
terminal-regulator narcosis." This oc- 
curs when you read the manufac- 
turer's spec sheets on a three-terminal 
regulator and use the information 
without understanding it or the other 
elements in the power supply. 

My first experience with the E prod- 
uct almost burned my nose. I leaned 
over an operating prototype to make 
a closer inspection and sensed in- 
tense heat rising from the power- 
supply section. According to the 
designer, everything was within the 
manufacturer's specifications. The 
board needed + 12 and + 5 volts (V) 
at 0.5 ampere (A), which was 
regulated down from an 18-V (plus 10 
percent ripple) rectifier output. The 
90° Celsius (C) case temperature was 
"warm," but the engineer hotly con- 
tested that everything was okay. When 
further queried about added heat 
once the unit was enclosed, he 
assured me that it still wouldn't ex- 
ceed the manufacturer's specified 



limit of 1 50°C (apparently he didn't 
know the difference between junction 
and case temperature). 

I come from the school of design 
that says, "If you can't touch it. you've 
got big problems." Eventually, my 
greatest fears were realized. E boards 
were installed in ABS (acrylonitrile- 
butadiene-styrene) thermoformed 
plastic cases and allowed to burn in 
(aptly named) overnight. When in- 
spected in the morning, the tops of 
many cases had melted and de- 
formed. In addition, many of the 
regulators had failed and were now in- 
operable. At this point, the bad 
design could not be hidden from the 
venture capitalists. Even marketing 
concurred, "We can't ship an incen- 
diary device to every kid with a 
computer!" 

Linear Power Supplies 

Virtually all electronic equipment 
operates on a DC power supply. This 
DC voltage can come from a battery 
or can be converted from an energy 
source such as the AC power line. The 
two commonly used conversion 
methods are switching and linear. 

The advent of easy-to-use three- 
terminal regulators has given de- 
signers a false sense of security. 
Because of the wide operating limits 
and built-in protection of many of 
these monolithic regulators, brute 



force and a rule-of -thumb design tech- 
nique can still result in functional 
power supplies. It takes resourceful 
and knowledgeable designers who 
understand the interrelationships of 
power-supply components to pro- 
duce efficient and cost-effective prod- 
ucts. In the case of E. larger heatsinks 
or lower input voltages would have of- 
fered some after-the-fact relief. Some 
better understanding of linear power 
supplies and a bit of initial computa- 
tion would have resulted in a ship- 
pable design in the first place, 
however. 

My Circuit Cellar projects range 
from the esoteric to the instructive. I 
do. however, presume that the 
builders of these projects have a cer- 
tain level of basic understanding and 
that many hours of construction won't 
go up in smoke because of a poorly 
designed power supply. This recent 
experience has made me hesitate to 
be quite so presumptuous, and I will 
now add linear power supplies to my 
periodic tutorial subject list (with 
speech synthesis, home control, etc.). 

This month I'll go back to basics and 
analyze the construction of linear 
power supplies. I'll describe trans- 
former selection, input-filter design, 
regulator selection and connection, 
heatsinking. and layout. I will par- 
ticularly emphasize the filter, heatsink- 
ing. and layout. Most articles seem to 



CONFIGURATION 



AVERAGE 
V DC 



PEAK 
INVERSE 
VOLTAGE 
PER DIODE 



FUNDAMENTAL 

OUTPUT 

RIPPLE 

FREQUENCY 

60Hz 



OUTPUT 
WAVEFORM 



Vrms 

I 



£R L 



SINGLE-PHASE 
HALF WAVE 



1.41Vrms 



r V 0(PEAK)=0- 45V RMS 



OVDC-' V-( *» 



-N- 



Vrms 

_L_ 



SINGLE -PHASE 
CENTER-TAP 
FULL WAVE 



^V 0{PEAK , = 0.90V RMS 



AAA 




SINGLE -PHASE 
BRIDGE 
FULL WAVE 



F V 0(PEAK1=°-90V RMS 



AAA 



Figure I : Three single-phase transformer-rectifier configurations. 



100 BYTE • JANUARY 1985 



overlook these items while they 
discuss various regulator configura- 
tions. If. after building a supply from 
such a slanted article, the end product 
is in thermal shutdown most of the 
time because of naive filter design, 
you are better off reading comic 
books. I believe that the construction 
of power supplies isn't difficult, but 
perhaps no one has ever described 
how to do it. Hopefully, the process 
will become easy after reading this 
article. 

Starting with the Basics 

Generally speaking, a basic single- 
phase linear power supply consists of 
little more than a transformer, rec- 
tifier, and filter. Where it is necessary 
to accurately maintain the output 
potential, a voltage-regulator circuit is 
added. More precisely, the four com- 
ponents function as follows: 

1. A transformer isolates the supply 
from the power line and reduces the 
input voltage (120 or 220 V AC) into 
usable low-voltage AC. 

2. A rectifier converts the AC to a DC 
waveform and satisfies the charg- 
ing-current demands of the filter 
capacitor. 

3. A filter capacitor maintains a suffi- 
cient voltage level between charging 
cycles to satisfy the minimum voltage 
requirements of either the load direct- 
ly or a voltage regulator attached to 
the load. 

4. A regulator maintains a specific out- 
put voltage over various combina- 
tions of input voltage and load. 

The three basic forms of single- 
phase transformer-filter circuits are 
half-wave, full-wave bridge, and full- 
wave center-tap. The terms "half- 
wave" and "full-wave" refer to the AC- 
input waveform. In a half-wave circuit, 
only half of the 360-degree input 
voltage is applied to the load. In a full- 
wave circuit, the full -360 degrees is 
usable. Figure I shows their configura- 
tions and relationships. 

The first consideration to be made 
in the transformer choice is the type 
of circuit configuration: full-wave 
center-tap or full-wave bridge. The 
half-wave rectifier is generally used 
only for low-current or high-frequency 
applications since it requires twice the 
filter capacitance to maintain the 
same ripple as a full-wave rectifier. 

Both the center-tap and bridge con- 
figurations have their own merits. The 



center-tap circuit dissipates less 
power, requires less space, and is 
potentially more economical than the 
bridge because it uses only two (as 
opposed to four) rectifier diodes. 
Using only two diodes, it has a lower 
impedance than a bridge circuit. How- 
ever, for the same DC output voltage, 
the diodes must have twice the PIV 
(peak inverse voltage) rating. And 
since diodes are inexpensive, there is 
less real economy in using center-tap 
transformers. Their selection often 
results more from finding available 
transformers with the proper second- 
ary voltages for a particular appli- 
cation. 

A 120V AC RMS (root mean square) 
sine wave is applied to the primary 
winding of the transformer. A similar 
lower-voltage waveform is produced 
at the secondary windings. This AC 
output voltage is then applied to a 
full-wave bridge rectifier of the form 
described in figure I. 

Since we are dealing with actual 



components and not theoretical ex- 
amples, it is important to note that dif- 
ferent output voltages will be pro- 
duced from bridge and center-tap cir- 
cuits, even though they may start with 
the same secondary potential. If you 
observe a full-wave rectifier output on 
an oscilloscope, you will note a period 
of nonconduction at every zero cross- 
ing. Real diodes have an intrinsic 
voltage drop across them and dis- 
sipate power. For most low-current ap- 
plications, this threshold voltage is 
about 0.6 V. At 5 A or more it is closer 
to 1.1 V. 

Depending upon the configuration, 
one or two diode drops may be be- 
tween the transformer and the filter 
capacitor. (Figure 2 shows the current 
flow through a bridge rectifier.) The 
voltage regulator requires a certain 
minimum DC input level to maintain 
a constant output voltage. Should the 
applied voltage drop below this point, 
output stability can be severely de- 

{contimed) 




Figure 2: The current flow through a full-wave bridge. Ttoo diodes are conducting 
current at any one time. They present a voltage drop of 1 V each. 



TRANSFORMER 



RECTIFIER CAPACITOR FILTER 



120VAC. 
INPUT 




1 

T 



! ^r 



DC OUTPUT 
'TO 
REGULATOR 



AA 



AA 



; aaa 



Figure 3: The block diagram of a filtered power supply. 



IANUARY 1985 • BYTE 101 



graded. Where efficient low-dissipa- 
tion designs are involved, these diode 
drops can be significant. In full-wave 
bridge designs, two diodes are in 
series at all times. The 2.2-V loss 
through the bridge is an important 
consideration that should be reflected 
in the calculations. 

To smooth the rectifier output and 
help maintain a minimum input level 
to the voltage regulator, a filter 
capacitor is used (see figure 3). When 
the diodes are conducting, the 
capacitor stores enough energy to 
maintain the minimum voltage until 
the next charging cycle. With a 60-Hz 
transformer and a full-wave rectifier, 
the charging cycle has a frequency of 
120 Hz. The capacitor must charge up 
in 8.3 milliseconds (ms) and maintain 
a sufficient level until the next charg- 
ing cycle. 8.3 ms later. 

The peak-to-peak magnitude of this 
periodic charge/discharge cycle is 
called the ripple voltage (V„ >pl J. The 
highest level of voltage including the 
ripple is called peak voltage (V peak ). 
Shown in figure 4. the ripple voltage 
should never be more than 10 percent 
of the steady-state voltage (V c ); V c 
should never be less than the mini- 
mum input required by the regulator. 
Selecting the values of these com- 
ponents requires some calculation. 

Learning by Doing 

The best way to understand the inter- 
relationships of the components in a 
linear power supply is to design one. 
For purposes of this discussion, let us 
design a whopping 12- to 13.2V 15-A 
supply using LM338K regulators. 

This choice is not arbitrary. Most ar- 
ticles on linear power supplies pre- 
sent low-current circuits that are 
relatively idiot-proof. At such low cur- 
rents, simple rule-of-thumb practice is ' 
acceptable. It is only at high power 
levels that design knowledge, layout 



principles, and proper component 
selection are mandatory. Somewhere 
in between the 5 -watt (W) bench sup- 
ply you build from an article for hob- 
byists and the 198-W supply we will 
discuss is a gray area where experi- 
menters who rely on luck and rule of 
thumb will be out of one or both. 

I am presenting such a big supply 
for another reason. For quite some 
time I've been receiving letters regard- 
ing uninterruptible power supplies. 
While I can't guarantee that I can 
design one that is more cost-effective 
than a commercial unit, I intend to in- 
vestigate the options. To aid in this 
task. I need a high-current DC supply 
for the initial experiments. Rather than 
dragging in car batteries (a "12V" car 
battery actually produces 13.2 V) and 
chargers. I thought I'd build a high- 
current supply that demonstrates 
something for this project and can be 
put to good use later. 

198 Watts! 

You might think that specifying the 
transformer's secondary voltage 
would be the first consideration when 
building a power supply. Yes and no. 
While it is important, the choice of 
components in a power supply is in- 
terrelated. Too great an emphasis on 
one component over another can 
greatly influence cost and perfor- 
mance. The approximate secondary 
voltage can be determined by certain 
logical rules, but the exact require- 
ments are deduced only by a 
thorough analysis that begins at the 
final power-supply output voltage and 
proceeds backward. In practice, the 
advantages gained in laborious trans- 
former calculations are of benefit only 
to those designers capable of speci- 
fying custom-wound transformers. 
The majority of designers will have to 
rely upon readily acquired trans- 
formers with standard output volt- 




VOLTS 



VpeAK V C 

J 



VpEAK _ V RIPPLE + V C 



Figure 4: The components of peak voltage. V pCa *. are the steady-state voltage. V c , 
and the ripple voltage. V ripp/e . 



ages. For greatest efficiency, the stan- 
dard voltage should be as close to the 
calculated value as possible. 

Given an understanding of the basic 
filter components at this stage, we can 
proceed to the case at hand: a 1 3.2 V 
15-A supply. The regulator, which I'll 
discuss later, uses the LM3 38K chip. 
These units are variable-voltage out- 
put devices, in contrast to fixed- 
voltage output devices such as the 
LM340T-5 (5 V) or 7812 (12 V). For 
them to properly operate over a 
temperature from to 70°C the in- 
put voltage to the LM338K must be 
3 V greater than the output set point. 
(Fixed-voltage output regulators by 
contrast can suffice with a 2- to 2.5V 
difference.) To be on the safe side. 1 
always plan a minimum of 3.5 V. If this 
I/O (input/output) differential is less 
than 3 V, regulation becomes un- 
stable. For a 13. 2-V output, therefore, 
V c has to be at least 16.7 V. For a 5V 
output, V c should be 8.5 V minimum. 
(Too much input voltage creates a dif- 
ferent problem. Any V ou ,-V Irt dif- 
ference greater than 3 V simply 
generates heat and should also be 
avoided.) 

Whatever the magnitude of W peak 
and V r i PP i e , V c must not drop below 
16.7 V or the regulator may not work. 
If this supply, which operates at 1 1 5 V 
AC input, is to still function at 105 V 
AC, we must make sure that V c is 
16.7 V at 105 V AC The 8.5 percent 
voltage rise to 115V AC, however, will 
make V c 18.2 V (and 20.5 V at 130 V 
AC). Going much above these values, 
while still satisfying the input criteria, 
will increase power dissipation sub- 
stantially. 

Thus far. we have calculated or 
assumed the following at 2 5°C and 
115V AC input: 

V c = regulator input voltage at 

115 V AC = 18.2 V 
V rippie = 10 percent of V c max- 
imum = 1.8 V 
y peak = V c + Vrfcp,. = 20 V 
\ out = output current = 1 5 A 
V rcc r = voltage drop across diode 
bridge = 2.2 V (two diodes) 

Choosing the Transformer 

We have determined the voltage 
drops across the various components 
and the minimum regulator input 
voltage. These values can be used to 
calculate the required RMS secondary 
output voltage as follows: 



102 B YTE • JANUARY 1985 



v c + v ripple + v r 



V2 



.2 + 



+ 2.2 



1.414 
= 15.70 VAC 

In practice, 15-A 15.70-V trans- 
formers aren't available off the shelf, 
but many 1 5- and 18-V units are avail- 
able. While 16 V is the proper trans- 
former secondary-winding selection, 
15- and 18-V 10-A transformers will 
work fine if you can live with 10 A 
rather than 1 5 A. (One of these is part 
number F-62U from Tfiad-Utrad. 1124 
East Franklin St., POB 1147. Hunting- 
ton, IN 46750.) The 15-V unit will not 
give complete operation to 105 V AC 
however, and the 18-V transformer will 
increase power dissipation in the 
regulator by 12.5 percent. (I don't 
recommend using 2 5.2-V center-tap 
transformers.) 

I don't like presenting an optimized 
design and then apologizing for not 
taking my own advice. The calcula- 
tions might seem a bit rigged when 
you find that I just happened to use 
a 16-V 1 5-A transformer to complete 
this project. I have to confess that I 
had it custom wound to meet the ap- 
plication. While I don't expect the 
average experimenter to resort to 
such expensive tactics, when I build 
a piece of test equipment. 1 want 
reliable and consistent operation. The 
final transformer secondary winding 
is 16 V AC at 1 5 A, and the secondary 
resistance is 0.04 ohm. (A 2-A 18-V 
center-tap transformer such as the 
Radio Shack 273-1 5 1 5A by contrast is 
about 0.6 ohm.) With the additional 
wiring and connections between the 
transformer and the bridge, the 
source resistance is about 0.1 ohm. 

Using a 16-V transformer, the true, 
as opposed to calculated, voltage 
levels are 

V, ec = 16 V AC 

V recr = 2.2 V 

V P eak = (V, ec x 1.414)- V recf = 20.4 V 

V c = 18.6 V 

V r , pp i. = 1.8 V 

R s = transformer secondary 
resistance and resistance of 
connecting wires = 0.1 ohm 

Sizing the Filter Capacitor 

When the supply is turned on, a 120- 
Hz rectifier output is applied to the 



capacitor. The capacitor is large 
enough so that it can supply the full 
load current with only a negligible 
drop. If the capacitor is very near 
peak when the next charging cycle oc- 
curs, as would be the case with light 
loads and large capacitors, the diodes 
conduct for a very short time. The 
exact time during which the capacitor 
supplies current is fixed by the per- 
missible peak-to-peak ripple voltage. 
This time: 



T c , 



= ((9/180) (8.33) ms 



where = |90 + arcsinlVc/V,..*)) 
degrees. 

For ripple voltages equivalent to 10 
percent of V peak , the filter-capacitor 
conduction time is 7.14 ms rather than 
8.33 ms. For simplicity, however, it is 
often assumed that the capacitor 
must carry current for the full half 
cycle and 8.33 ms is used in the 
calculations. The capacitor value is 
chosen as follows: 

C = (T c /V ripp , e ) I 

where C = capacitance in farads (F) 
= ?, I = continuous output current = 
1 5 A, T c = charging time of capacitor 
= 8.33 ms. and V ri>p/e = allowable rip- 
ple voltage = 1.8 V. Plugging in the 
values: 



C = 



15) (0.00833) 
(1.8) 

= 0.069417 F 



or 



= 69,000 microfarads 
(MF) 

In the nearest commercial value. C 
= 75.000 /xF at 2 5 V. Generally avail- 
able commercial electrolytic capaci- 
tors have a tolerance of + 50 percent 
and -10 percent. I chose to use a 
General Electric 86F543 75,000-/*F 
2 5-V [V peak is 20 V) unit, but any 
capacitor of similar size will work. The 
ripple-current rating on capacitors of 
this size is also adequate. 

Choosing the Bridge 
Rectifier 

The four considerations when choos- 
ing a bridge rectifier are surge current, 
continuous current, PIV rating, and 
power dissipation. These parameters 
are generally ignored in rule-of-thumb 
designs because the 3- and 10-A 
diode bridges (which are generally 
available, coincidentally) have ratings 



When I build a 

piece of test 

equipment, I want 

reliable and 

consistent operation. 



that protect against bad designs. With 
15-A power supplies, however, we 
should take nothing for granted. 
These specifications are not inconse- 
quential and must be considered. 

When a power supply is first turned 
on, the filter is totally discharged and 
for an instant appears as a dead short 
to the diode bridge. In this condition, 
the only thing that limits the current 
flowing through the bridge is the 
resistance in the secondary windings 
and the connecting wires. This sudden 
inrush is called surge current and is 
computed as follows: 

» Deak 



1 surge n 

- 20.4/OT 
= 204 A 

The time constant of the capacitor is 
t = (Rs) (C) 

- (0.1) (0.075000) 
= 7.5 ms 

Generally speaking, power surges 
will not damage the bridge if the 
surge is less than its surge-current 
rating and if the time constant, r, is 
less than 8.33 ms, which it is. A readily 
available bridge rectifier that fits the 
bill is the Motorola MDA990-2, which 
is rated at 30 A continuous and 300 
A surge. Its PIV rating is 100 V, which 
is significantly in excess of our 22.6-V 
secondary peak. 

One final consideration on the 
bridge is power dissipation. Since 
diodes exhibit voltage drops when 
current flows through them, they 
dissipate power just as the regulators 
do. The rule of thumb says that if \ out 
is 1 5 A and V recr is 2.2 V, power dis- 
sipation (PD) is 33 W. Such a high 
value would suggest the need for a 
heatsink. 

A possibility exists, however, that 

[continued] 



JANUARY 1985 'BYTE 103 



30V>Vin>14.5V 



IN 



7812 



0.22^F 



OUT 



-O V 0UT =12V 











10^F 
16V 





-O GND 



Figure 5: A typical + 12-V fixed-voltage output regulator. 






Dl 
1N4002 






+o 



35V| N 



-o- 



LM338K 



'C3 
"0.1/i.F 



ADJ 



>120Jl : r 






D2 
1N4002 



-C2 
10/xF 



t O V OUT 

1.2-32V 



■CI 
'lO^F 
50V 



■<> O GND 



Figure 6: A typical variable-voltage three-terminal regulator. 



v, n O — 

32<V| N >7.5 



IN 



LM338K 



out £iS 



ADJ 



2N2905 



LM338K 



OUT 



0.1ft 



ADJ 



IN 



LM338K 




OUT 0.1 SI 
wv — 






<HZ> 



4.5V TO 25V 
15AMPS 



20pF 



C^ 



-# •■ 



150 



5K 




Figure 7: A 15-A mwlt/pk regulator. 



the true (as opposed to the rule-of- 
thumb) PD could be significantly dif- 
ferent and may or may not need ex- 
traordinary measures for heat 
removal. At the very least, you might 
like to know how to calculate real 
dissipation. 

First, theonlytime the diode in the 
bridge conducts for a full cycle is im- 
mediately after turn-on. After that, it 
conducts only during that period 
when the input voltage is greater than 
V c . In our supply V c is 18.6 V and V peak 
is 20.4 V. 

You'll remember that I previously 
said that the capacitor supplied 
power for 7.14 ms of every 8.33-ms 
charging cycle. The diode, therefore, 
conducts for the remaining 1.19 ms. 
(The time depends on the amplitude 
of the ripple.) During this time, the 
transformer and diodes must charge 
the capacitor from 18.6 to 20.4 V 
while they also supply power to the 
load. The required current is 



I. = 



(C) (Vnpp/,) 

T c 

(0.075 F) (1.8 V) 

(1.19 ms) 
113.4 A 



To this you add the output current 
of 15 A: I p = 128.4 A peak. This trans- 
lates to a peak power dissipation of 

PD = \ p x V recr 

= 128.4 x 2.2 

= 282.5 W peak! 

However, this occurs for each pair of 
diodes for only 1.19 out of 16.6 ms, 
and the average power becomes 

- (282.5) x (1.19/16.6) 

PD = 20.2 5 W average 

TWenty watts isn't much. Simply 
mounting the bridge to the metal 
power-supply enclosure should pro- 
vide enough cooling. To know for 
sure, however, look up the bridge's 
rated junction temperature, keep the 
PD value in mind, and calculate the 
cooling requirements when we get to 
heatsinking. 

Voltage Regulators 

Once the filter section --Js-eenfiguFed; — 
our next consideration is the voltage 
regulator. All linear regulators per- 
form the same task: convert a given 
DC input voltage into a specific, 



104 B YTE • JANUARY 1985 



stable, DC output voltage and main- 
tain it over wide variations of input 
voltage and output load. 

Entire books have been written on 
regulation circuits, and 1 think the sub- 
ject material is adequate. The best 
sources are, in fact, the data manuals 
from the regulator-chip manufac- 
turers. These manuals specify the I/O 
voltages and other specifications im- 
portant to the power-supply designer. 
(Rather than go into the history and 
successive milestones in regulator 
evolution, I'm going to presume that 
you know a lot about this and want 
me to quickly get back to building a 
real supply.) 

Three-terminal regulators come as 
fixed- or variable-voltage output 
devices (fixed-voltage output regula- 
tors can be configured to provide vari- 
able-voltage outputs). A typical + 1 2-V 
fixed-voltage output regulator is 
shown in figure "5. The regulator has 
three terminals: in, out, and ground 
reference. In a 7812 regulator, V out - 
V,„ should be 2.5 V; therefore, V c 
should be 1 4. 5 V for proper opera- 
tion. The maximum input, disregard- 
ing power dissipation as a limiting fac- 
tor, is 30 V. 

If you want a 1 3. 2-V supply you 
would substitute a variable-voltage 
three-terminal regulator such as the 
LM3 38K shown in figure 6. Here, the 



three terminals become in, out, and 
voltage adjust. A potentiometer in the 
adjust line sets a reference level to the 
chip that determines its output 
voltage. This circuit also contains 
diodes to protect the regulator. 

While manufacturers would like you 
to think otherwise, three-terminal 
regulators are not indestructible and 
can fail. One source of failure is the 
discharge of external capacitors 
through the regulator. For example, if 
the regulator output is shorted, C2 
will discharge through the voltage- 
adjust pin. A diode, D2, diverts the 
current around the regulator protect- 
ing it. If the input is shorted. CI can 
discharge through the output of the 
regulator, possibly destroying it. 
Diode DI shunts the current around 
the regulator, protecting it. While such 
protection is merely insurance on 
hefty devices such as the LM338K, it 
is a necessity on lower-current 
regulators. 

The LM338K can be adjusted for 
outputs from 1.2 to 32 V at 5 A. and 
devices can be paralleled to provide 
increased output current. Figure 7 
outlines a circuit composed of three 
LM338KS configured as a I5-A 
regulator that will satisfy the regula- 
tion requirements of the supply we 
are building. With a V c input of 18.6 V 
at 1 1 5-V AC input, the supply is adjust- 



Three-terminal 
regulators have been 
known to fail. 



able from about 4.5 to 15.6 V. Figure 
8 is the final schematic of the unit. 

Layout Is Important 

Three-terminal regulators employ 
wideband transistors to optimize 
response. Unfortunately, stray capac- 
itance and line inductance caused by 
poor layout can introduce oscillations 
and unstable operation into these cir- 
cuits. Keeping lead lengths short, as 
shown in photo 1 , and adding exter- 
nal bypass capacitors will limit the 
problems caused by the regulator. 
Builder-introduced problems are an- 
other matter entirely. 

Figure 9 illustrates a typical three- 
terminal-regulator supply layout, in- 
cluding the areas that can cause prob- 
lems. All wires and connections within 
a power supply have resistance. In the 
case of high-current supplies such as 
ours, small resistances can introduce 
major errors. For example, a 0.1 -ohm 
resistance at 1 5 A drops 1.5 V. Heavy 
wire should be used, and it is impor- 

[contmued] 




■ 75.000/iF 
'30VDC 



0.1 SI 



NOTES: LM338S "ARE MOUNTED ON A COMMON HEATSINK 

FAN IS CONTROLLED BY 130°F THERMOSTATIC 
SWITCH ATTACHED TO HEATSINK 

OPAMP SHOULD BE LOW-OFFSET TYPE LM308 
OR EQUIVALENT ONLY. 

MOST PARTS ARE AVAILABLE FROM 

JDR MICRODEVICES. 1224 SOUTH BASCOM AVE. 
SAN JOSE. CA 95128. (800) 538-5000 OR 

JOHN J. MESHNA. JR. INC.. 19 ALLERTON ST.. 
LYNN. MA 01904. (617) 595-2275 



o.m 



-VAr 



^ioo a 

* COMMON HEATSINK 




t — ° r 1 O +v OUT 




. 100 M F 
•25VDC 




15-AMP 
CIRCUIT 
BREAKER 



— Ognd 



Figure 8: A 12- to 13. 2-V 15-A power supply that uses readily available components. 



JANUARY 1985 'BYTE 105 



tant to separate the charging-current 
and the output-current paths. 

As demonstrated in figure 9, im- 
proper placement of the input capac- 
itor can induce unwanted ripple on 
the output voltage. This occurs when 
the charging current to the filter 
capacitor influences the common 
ground or voltage-adjustment line of 
the regulator. As previously men- 
tioned, the peak currents in the filter 
circuit are in excess of 100 A. The 
voltage drop across R2' will cause the 
output to fluctuate as if the voltage 
trim were being adjusted. 

The output-current loop is also 
susceptible to layout. In a three- 
terminal fixed-voltage output regula- 
tor, the output voltage is referenced 
between the output pin and the com- 
mon line of the chip. Because the load 



current flows through R2', R3', and 
R4' before reaching R loadl there may 
not be the correct voltage across the 
load due to accumulated voltage 
drops in the wiring. Also, while points 
B and C are both ground, they are at 
different voltages depending upon 
the resistance of and the current flow- 
ing through R3'. Similarly, resistance 
R4' in the output lines continually 
reduces the output voltage as the cur- 
rent increases. This serves to negate 
the purpose of the regulator. 

Figure 10 is a diagram of the proper 
layout. In the layout, all high-current 
paths should use heavy wire to 
minimize resistance, and the input- 
filter and output-load circuits are ef- 
fectively separated. Most important, 
the wires from the transformer go 
directly to the bridge and then to the 




IN OUT 

COMMON 



R4' A 

-wv 



VoUT(REG) 



>R2* 



rh 




c R3' 
> wv- 



Figure 9: Sources of layout-induced errors in a typical three-terminal-regulator 
power supply. 



Photo I : Short leads in the regulator sections limit noise pickup and add to overall 
stability. In my prototype, 1 connected the op amp and other discrete components 
directly to the regulators on the bottom side of the heatsink. 





lS 











filter capacitor. Power to the rest of 
the circuit should come directly from 
the terminals of the capacitor and not 
from any point between the bridge 
and the capacitor. The result is two 
sets of wires (input from the bridge 
and output to the regulator) con- 
nected to the capacitor— but it is ab- 
solutely necessary. Mixing current 
paths is the most common problem 
in experimenter-built supplies. 

The last layout consideration is the 
concept of a single-point ground. One 
point in the power supply must be 
designated as the ground, and the 
ground connections of the other cir- 
cuit sections are connected to it. In 
practical terms, this is often just a 
metal strip or busbar called a ground 
bus. There should be virtually no 
measurable voltage between any two 
points on this bus. Don't be afraid to 
use thick wire! 

Heatsinking 

The final consideration is heatsinking. 
Generally speaking, linear power sup- 
plies, while easy to build, are grossly 
inefficient. A 4 5 percent-efficient 
design is good (the usual range is 40 
to 55 percent). Before you start think- 
ing of this as both a 5- and 1 5-V 1 5-A 
supply, remember the old saying, 
"what goes in. comes out." With a 
16-V rm , 15-A input, we are putting in 
16 x 1.414 x 15 = 339 Wand taking 
out 5 V x 15 A = 75 W. The other 
264 W is dissipated in heat. Power is 
simply V ouf -V ( „ times the current. If 
you are going to want a 5-V supply, 
you should not start with a V c of 
18.6 V but rather something like 9 V. 
(The best transformer/filter for a 5-V 
supply is an 1 8-V center-tap configura- 
tion.) In the 13.2-V supply we are 
building, the maximum power dissipa- 
tion is 

PD ma , = ( (V e + Mn PP J2) - V ou , ) x (I ouf ) 

= ((18.6+ 1.8/2) - 13.2) x 15 

= 94.5 W 

For linear supplies of this 
magnitude, 95 W is relatively cool. 
Nonetheless, it must be dissipated 
properly through a device called a 
heatsink, as shown in photo 2. 

Basically, the entire process of 
calculating factors such as dissipation, 
temperature rise, and junction tem- 
peratures is to determine a quan- 
titative value of absorbable power for 
a given set of physical conditions. For 



106 B YTE • JANUARY 1985 



a predetermined rise in heatsink 
temperature, you will be able to cal- 
culate the maximum power dissipa- 
tion of the circuit to maintain that limit 
or, vice versa, to calculate the junction 
and heatsink temperatures given the 
input power. 

Heatsink ratings and heat transfer 
through component mountings are 
stated in terms of thermal resistance: 
°C/W. For a particular application, it 
is necessary to determine the thermal 
resistance that a cooler must have to 
maintain a junction temperature that 
sustains adequate semiconductor per- 
formance. The basic relationship is 



PD = 



AT 



where PD = power dissipated in the 
semiconductor, AT = difference in 
temperature between ambient and 
the heatsink. and LR e = the sum of 
the thermal resistances of the heat 
flow path across which AT exists. In 
elaboration: 



PD = 



T a 



R* + R„ + R. 



where T,- = the maximum junction 
temperature as stated by the semi- 
conductor manufacturer (°C). T Q = 
ambient temperature (°C). R yc = ther- 
mal resistance from junction to case 
of semiconductor (°C/W), R„ = ther- 
mal resistance through the interface 
between the semiconductor case and 
the heatsink (°C/W). and R 5a = ther- 
mal resistance from heatsink to am- 
bient air (°C/W). 

The best way to understand this is 
to look at an example. First, we have 
a 7805T in a TO-220 case that is dis- 
sipating 5 W, and we select the proper 
heatsink. Given: 

PD = 5 W 

Rj C = 4°C/W (from the manufacturer) 

T y = 12 5°C maximum for TO-220 

package 
T a = 50°C ambient 
R cs = 1°C/W insulator with heatsink 

grease 

We use the equation for PD to solve 
for R 5fl : 



Rsa = 



125-50 
5 



(4 + 



R 5a = 10°C/W 



Thermalloy part number 6299B has a 
50° rise in temperature for a 1 2-W in- 



put. Therefore: 

R sa = 50/12 = 4.16°C/W 

The 6299B is more than adequate for 
the task and will, in fact, heat up only 
4.16 x 5 = 20.8°C over ambient in 
this example. 

Getting back to the supply we are 
building, the minimum power dissipa- 
tion is at maximum output voltage 
and vice versa. If the supply will be 
used in the range of 12 to 14 V, the 
heatsinking must accommodate the 
worst-case conditions. When the out- 
put is set for 12 V, the power dis- 
sipated in the regulator section will be 
112.5 W (at 15 A). Each of the three 
regulators will be dissipating 112.5/3 



or 37.5 W. The minimum R SI 
follows. Given:- 



is as 



PD = 37.5 W 
R ye = 1.0°C/W 
T y = 125°C 
T Q = 40°C 

R C5 = 0.28°C/W (anodized washer 
and heatsink grease) 

The R, a minimum is thus 

125 - 40 



Rsa = 



37.5 



(I + 0.28) 



= 0.99°C/W 



A 3-inch piece of Thermalloy part 
number 6560 has a 0.70°C/W R Sfl 

[continued) 



TRANSFORMER RECTIFIER 



REGULATOR 




I LOAD IS HIGH-CURRENT PATH 
l RE6 IS LOW-CURRENT PATH 
l )N IS HIGH-CURRENT PATH 



SINGLE POINT - 
GROUND FOR ALL 
CIRCUIT 
CONNECTIONS 



Figure 1 0: The proper power-supply layout. 




Photo 2: Any high-current linear power supply needs large heatsinks to carry away 
the heat dissipated in the regulators. When more than one regulator is to be mounted 
on the same heatsink, special insulated mounting kits must be used. 



JANUARY 1985 



J Y T E 107 



Inquiry 241 



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108 BYTE • JANUARY 1985 




Photo 3: The completed power supply has little extra Internal space, you'll 
notice that the filter capacitor has two sets of connecting wires to conform to the 
layout guidelines I've described. ^Jhile the heatsink is sized properly for ambient 
air installations, I have added a fan to compensate for the insulating effect of the 
enclosure. To limit noise, the fan is controlled by a 130°F thermostat attached to 
the heatsink. The thermostat turns on the fan only when necessary. 



value. It would operate satisfactorily 
for an individual LM338K. A 7-inch 
piece of the same material would 
have an effective R sa of 0.42°C/W. 

To accommodate the full 12 5 W, 
forced-air cooling is recommended. 
From the data I have at hand, it ap- 
pears that R sa is reduced approxi- 
mately by half with 600-cubic-feet-per- 
minute forced convection. With a fan 
on the heatsink, 112.5 W should be 
adequately dissipated while maintain- 
ing a low ambient temperature within 
the supply case. Photo 3 shows the 
complete supply with fan. I added a 
130°F thermostatic switch on the 
heatsink to turn on the fan only when 
needed. 

In Conclusion 

The product failure described in the 
beginning was not a result of mis- 
understanding three-terminal-regula- 
tor specifications but instead ig- 
norance of the supporting circuitry. I 
could have discussed a lot more, but 
much of it relates to experience, and 
it might sound as if I were a propo- 
nent of rule-of-thumb design. Instead, 
I would hope that you no longer take 
linear power supplies for granted. 
Even in today's VLSI (very-large-scale 
integration) world we continue to de- 
pend on tried-and-true. even if some- 
what ancient designs. Linear power 



supplies have a definite place in our 
world of electronics. 

1 don't expect venture capitalists to 
get excited about power-supply 
design, but the next time the words 
"meltdown" and "incendiary" are 
mentioned, I know a few who will be 
listening more closely. 

Circuit Cellar Feedback 

This month's feedback begins on 
page 413. 

Next Month 

Steve will be building a low-cost serial 
EPROM programmer. ■ 

This article is dedicated to Kram Nurtam and 
the E product. May that great heatsink in the 
sky cool any thoughts he might have of 
designing another linear power supply. 

Editor's Note: Steve often refers to previous 
Circuit Cellar articles. Most of these past ar- 
ticles are available in reprint books from 
BYTE Books. McGraw-Hill Book Company, 
POB 400, Hightstown. Nj 082 50. 

Garcia s Grcuit Cellar. Volume I covers articles 
that appeared in BYTE from September 1977 
through November 1978. Volume II covers 
December 1978 through lune 1980. Volume 
III covers July 1980 through December 1981. 
Volume IV covers January 1982 through June 
1983. 



To receive a complete list of Ciarcia's Cir- 
cuit Cellar project kits, circle 100 on the 
reader-service inquiry card at the back 
of the magazine. 



Make room for a new assistant. 




hAAA. 








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It puts answers on your desktop. 



The IBM Personal Computer Engineering/ 
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110 B YTE • JANUARY 1985 



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Inquiry 166 



JANUARY 1985 -BYTE 111 



A 



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Inquiry 150 



by Bill Benzon 



The Visual 
Mind and the 
Macintosh 



MacPaint 



provides a tool 



for thinking 



Late in 1974 Ed Roberts and 
Eddie Curry, principals in Micro 
Instrumentation and Tfelemetry 
(MITS). designed and began market- 
ing a microcomputer kit. That kit was 
featured in the January 1975 issue of 
Popular Electronics and the rest, as they 
say, is history. 

In my opinion, the Apple Macintosh 
is the most significant microcomputer 
since that original MITS kit, but its im- 
portance hasn't been adequately ex- 
plained. The Mac is user friendly, but 
even more important is what lies 
beyond that user-friendly interface- 
MacPaint. 
MacPaint provides visual power. It 




is fun to use— you can zap the mouse 
around, draw a zillion rectangles in a 
minute, put four reflecting planes in 
the drawing space, and create amaz- 
ing symmetrical designs with mere 
flicks of the wrist. Why is this impor- 
tant? As figure 1 indicates, one hemi- 
sphere of the brain is more or less 
verbal while the other is more or less 
visual (see reference 1). The Macin- 
tosh is a tool for the visual brain. 

The Mac allows us to do fascinating 
things with typography. We can crank 
out bar charts, pie charts, and line 
graphs. We can do maps 50 ways from 
Sunday and play with line drawings to 
our hearts' content. But we can also 
think visually and relate visuals to ver- 
bals with a facility not readily available 
before. 

The Macintosh is a tool for thinking. 
To understand the implications of this 
statement, we need to know some- 
thing about the thinking process. In 
this article I hope to discuss thinking 
in a way that will make the signifi- 
cance of the Macintosh more obvious. 
Consequently most of this article is 
specifically about thinking and only 
indirectly about the Macintosh. 

Visual Thinking 

The anecdotal literature on creativity 
is full of stories about great thinkers 
who work in images. Consider the 

[continued) 

Bill Benzon (language, Literature, and Com- 
munication, Rensselaer Polytechnic Institute, 
Troy, NY 12181) holds a Ph.D. in English 
from State University of New York at Buf- 
falo. He has done research on cognitive science 
and literary theory and has held a fellowship 
with NASA to work on a strategic computing 
plan. Bill also does consulting and freelance 
writing. 



ILLUSTRATED BY WILLIAM LOW 



JANUARY 1985 'BYTE 113 



THE VISUAL MIND 



following passage from a letter by 
Albert Einstein (see reference 2): 

The psychical entities which seem 
to serve as elements in thought are 
certain signs and more or less clear 
images which can be "voluntarily" 

reproduced and combined The 

above mentioned elements are. in 
my case, of visual and some of 
muscular type. Conventional words 
or other signs have to be sought for 
laboriously only in a secondary 
stage, when the mentioned associa- 
tive play is sufficiently established 
and can be reproduced at will. 

Thus it seems Einstein's primary 
mode of thought was not words or 
even mathematical symbols. He 
thought in images and then translated 
those image-born insights into verbal 
or mathematical form. 

Or consider Watson and Crick and 
the double helix. Why did they actual- 
ly build a three-dimensional model of 



the helix while they were working up 
the basic ideas (see reference 3)? 
Because however important visual 
thinking is, it is difficult to hold an im- 
age in your mind and work with it— 
especially if it is a three-dimensional 
shape. But if you can externalize the 
image and make a model as Watson 
and Crick did. then working with it 
becomes easier. 

Writing and drawing provide exter- 
nal support for thought. Writing sup- 
ports the work of the verbal brain. 
Learning the mechanics of writing- 
how to form the letters or use a key- 
board—is relatively easy, and once 
that is out of the way, you can go on 
to the tough stuff— writing things that 
make sense and may be beautiful as 
well. However, images, whether two- 
or three-dimensional, are different. 
Becoming proficient in the mere 
mechanics of freehand drawing— for 
example, drawing a picture of a horse 




Figure 1 : The left or verbal side and the right or visual side of the human brain. The 
tree is a McPic image. (McPic is a product of Magnum Software, 21115 Devonshire 
St., Ste. 337. Chatsworth. CA 91311, (818) 700-0510). 



By making it easy for 
you to create images 
and work with them, 
the Macintosh can 
help you to think. 



that looks more like a horse than like 
a camel or a rabbit— is difficult. Tech- 
nical drawing is easier but it is still 
more difficult than writing. 

By making it easy for us to create 
images and work with them, the 
Macintosh can help us to think. 
Perhaps our society will create a pool 
of images for thinking comparable to 
our pool of proverbs and stories. We 
have a large number of proverbs and 
countless stories, such as Aesop's 
fables, which we learn and use for 
thinking. We apply these proverbs 
and fables to situations that arise and 
from that we get some idea of how 
to act. Why not have a pool of images 
that we can use in the same way? 
What I have in mind can best be il- 
lustrated by an example. It is called 
the gestalt switch. 

The Gestalt Switch 

In 1962 Thomas Kuhn published a 
book on the nature of scientific revo- 
lutions that set off bombshells in the 
academic world (see reference 4). For 
example, Kuhn was interested in how 
Copernicus's heliocentric model of the 
solar system replaced Ptolemy's geo- 
centric model, how Newtonian mechan- 
ics replaced Aristotelian mechanics, 
and how Newtonian mechanics was 
then replaced by relativistic and quan- 
tum mechanics. You would think that 
as more observations came in and 
older theories didn't hold up, they 
would be replaced by newer ones. 
However, in the case of Copernicus's 
heliocentric model, the old theory fit 
the available data better than the new 
one. 
Kuhn's conclusion is a bit compli- 

[continued) 



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Inquiry 328 



THE VISUAL MIND 



cated but the basic point can be 
made rather easily with an image. The 
upper image in figure 2 shows one of 
those ambiguous pictures from fresh- 
man psychology textbooks. Is it a pic- 
ture of two men facing each other or 
is it a vase? You can see it either way, 
and you can switch back and forth be- 
tween the two interpretations easily. 

Kuhn concluded that scientific data, 
observations, and hard empirical facts 
are like this drawing. Before they have 
meaning, they must be interpreted by 
a theory; different theories describe 
them in different ways and lead to dif- 
ferent expectations about future ob- 
servations. In other words, if you see 
the ambiguous image as two men, 
you will talk about noses, lips, and 
chins and expect to find shoulders 
and arms beneath them. But if you 
see it as a vase, you will refer to the 
base, the rim. and the constriction in 
the middle and expect to see it on a 
tabletop or a shelf. 

Now, imagine that you give two peo- 
ple in two different rooms copies of 
this ambiguous figure. You tell one 
that it's a picture of two men and the 
other that it's a vase. If you give these 
people a phone and let them talk to 
one another, how long will it take 
them to discover they are talking 
about the same drawing? After all, 
one is talking about noses and chins 
while the other is discussing rims and 
bases. That, says Kuhn, is the problem 
between scientists with different 
theories about the same data: they 
live in different intellectual worlds. 

Of course these two people would 
communicate better if they described 
the image in terms of, for example, 
pixels. Why can't scientists do the 
same? Science isn't as simple as this 
visual analogy might lead you to 
believe. Like all analogies, this one is 
limited; it won't take you all the way, 
but it gives you a good start. 

The original ambiguous figure was 
created by a school of psychologists 
interested in perception. They be- 
lieved that we see images whole, not 
just as the sum of individual parts, 
and so they talked of gestalt (a German 
word meaning "whole") psychology. 
The phenomenon of switching back 




Figure 2: The gestalt switch. The 
drawing at the top is ambiguous: you can 
see it as either two men facing one 
another or as a vase. You can emphasize 
either one of these interpretations bij 
changing the drawing as shown in the 
middle and al the bottom. 



and forth from one interpretation of 
a visual image to another has come 
to be known as the gestalt switch and 
the ambiguous figures that evoke this 
switch are useful things to think with. 
They are the visual equivalent of a 
proverb or a fable. 

We all have our own visual proverbs 
but we don't think of them as such. 
Our society doesn't gather them 
together and pass them on like it does 
verbal proverbs and fables, partly 
because images are more difficult to 
reproduce and distribute than words. 
Talking is easy, but drawing requires 
that you have proper materials and 
skills, which aren't always at hand. 
Words are easy and inexpensive to 
print, but images are more difficult 
and therefore more costly. 

Images are much easier to create 
and distribute through the Macin- 
tosh's graphics facilities. You can ex- 
change printouts or disks or send the 
images through computer networks. 
As this power becomes available to 
more people, you may well begin to 
see people creating, exchanging, and 
collecting visual proverbs. 

Webs of Ideas 

The further development of a visual 
society is particularly important as we 
stand on the threshold of the informa- 
tion age because the intellectual 
world of information, of computing, 
is an intensely visual one. From circuit 
design to chip layout, from flowcharts 
to data structures, computing is visual. 
If good diagrams were easier to draw, 
then more would be drawn, and more 
people would grasp what computing 
is about. And the more people under- 
stand computing, the more they will 
use it. 

Consider the area of knowledge 
representation (a subfield of artificial 
intelligence). Many researchers use a 
notation called the directed graph (see 
figure 3). The ellipses are called nodes 
and the connections between them 
are called arcs. Nodes stand for con- 
cepts while arcs indicate the relation- 
ships between them. In this example 
VAR means "variety of" while CMP 
means "component of." Thus, maple 

[continued) 



116 BYTE • JANUARY 1985 



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Inquiry 325 



JANUARY 1985 'BYTE 117 



THE VISUAL MIND 



is a variety of tree while trunk is a 
component of it. 

The graph is not, however, the only 
notation you can use. If you want to 
prove theorems about the abstract 
properties of knowledge structure 
then you'll choose a propositional 
notation (see listing 1). If you want to 
program the propositional notation 
into a computer, then you'll have to 
think in terms of a complex list with 
addresses and pointers. But if you 
want to think about how ideas fit 
together and teach this material to 
others, then the graph notation is the 
most useful one. Further, if you are 
dealing with structures that are three 
or four times more complex than the 
one I've shown and if you typically 
work with structures 10, 100, or 1000 
times more complex, then the prop- 
ositional form is unreadable. You can't 
do any useful work with it. However, 
the visual representation is still useful; 



even if your graph covers half your 
desk and starts climbing up the wall 
you can work with it. 

The graph is a notation system in 
which the visual form can represent 
the structure of the information very 
clearly. Well-drawn graphs show im- 
portant and interesting information 
structures at a glance. The more you 
can encompass in a single mental 
operation, in this case, a glance, the 
better you can work with your 
material (see reference 5). A graph ex- 
tends the range of a single mental 
operation far beyond that available 
with a listing. A single glance at -a list 
of commands tells you nothing; you 
have to read each one, line by line, 
and painstakingly assemble them in 
your mind. 

Conceptual graphs were not, how- 
ever, invented yesterday. Many of us 
learned English grammar through 
sentence diagramming, which is a 



Listing I ; The propositional representation of the relationships shown in the 
directed graph in figure 3. 

VAR (maple.tree) 
VAR (oak.tree) 
VAR (pin oak.oak) 

CMP (leaves.tree) 
CMP (trunk,tree) 











CTree)^^ 




VAR^ 




^^CMP 


^— -^<^VARy 


CMF* 


^ (^Tenves^) 


(jnaple) / 






C° a *0 




[Irun^) 


VAR/ 




VAR: variety 


(pin oak) 




CMP: component 



Figure 3: A notation used in knowledge representation known as the directed graph. 
The nodes [ellipses) stand for concepts while the arcs (the connections between the nodes) 
indicate the relationships between those concepts. 



\f you think about how 
ideas fit, the graph is 
more useful than 
propositional notation 
or a complex list. 



technique for giving visual form to 
grammatical structure. One important 
contemporary form of this is called 
dependency theory, which, in one ver- 
sion or another, is important in com- 
puter models of language (see refer- 
ence 6). One dependency theorist, 
David G. Hays, says that he was in- 
spired, in part, by the sentence 
diagramming he did in his youth. 

Beyond this consider the work of 
Tony Buzan and Gabriele Rico, who 
have been developing techniques for 
helping people to think and to write 
better (see references 7 and 8). Both 
teach people to draw networks— 
Buzan calls them mind maps. Rico 
calls them clusters. Their networks are 
much freer than the ones knowledge 
representation theorists use, but their 
purposes are quite different. The 
theorists are developing formal 
models of how people think and they 
find the network notation useful for 
this. Buzan and Rico are interested in 
helping people think and they find 
that drawing networks is a much bet- 
ter way of working out preliminary 
ideas than trying to put thoughts in- 
to an outline. I suppose that the work 
of knowledge representation theorists 
could be used to justify these tech- 
niques for helping people to think. For 
example, if we in fact think with net- 
works, then doodling network dia- 
grams seems to take advantage of 
that. But that is a long and complex 
argument, one irrelevant to my main 
point— that diagrams help us think. 

The Method of Loci 

Public speaking was very important in 
ancient Greece and aristocratic youths 

[continued] 



118 BYTE • JANUARY 1985 



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Inquiry 14 6 



JANUARY 1985 -BYTE 119 



THE VISUAL MIND 



were extensively trained for it. Part of 
that training was in the art of memory 
and the central technique was the 
method of loci (see reference 9). 

To use this method you would 
choose some place complex enough 
to contain many nooks, corners, and 
views (that is, loci, or places)— a tem- 
ple generally was suggested (see 
figure 4a). You would then walk 
through this place according to some 
appropriate route (see figure 4b). This 
memorized walk, this visuo-kinetic im- 
age, is your memory map. Whenever 
you want to memorize a speech you 



start at the beginning and associate 
an image related to your first idea 
with the first place on your map, your 
second idea with the second place on 
your map, etc. To deliver the speech 
you conjure up the mental map and 
walk through it on the standard path. 
As you move from place to place the 
ideas you had associated with each 
place will come back to you. 

Consider, for example, the speech 
that Marc Antony delivered at 
Caesar's funeral (from Shakespeare's 
Julius Caesar, Act 111, scene ii, lines 72 
and following). For the first line- 




Figure 4a: A temple. The figures on the pediment are reduced versions of figures 
from McPic. 




Figure 4b: A set of loci associated, in this case, with a temple serves 
as a memory map. 



"Friends. Romans, countrymen, lend 
me your ears . . . "—Antony might 
have associated the image of a bunch 
of ears with the first locus, the first 
position in his walk through the tem- 
ple. A skull would be a natural 
association for the second line—The 
evil that men do . . . "—at the second 
position. Further lines would be linked 
to further loci through appropriate 
images. 

)ust how this works we don't know. 
Given our current knowledge of the 
brain, we can speculate that loci are 
established in the visual hemisphere 
while the words being memorized are 
stored in the verbal hemisphere. The 
visual brain is used to index and 
retrieve the contents of the verbal 
brain. Instead of assigning memory 
locations numerical values, as in a 
computer, they are given pictorial 
values. But the basic principle is the 
same— one part of a complex infor- 
mation system is being used to index 
and retrieve the contents of the other. 

The art of memory isn't as impor- 
tant to us as it was to the ancient 
Greeks and Romans. We have books, 
typewriters, and word processors 
(teleprompters too). But the integration 
of visual and verbal information is im- 
portant to us. A well-illustrated article 
is easier to understand and recall 
because the mind has more material 
to work with, more external support. 
Good illustrations help you conjure 
up your own images and diagrams, 
making it easier to understand and 
absorb the material. 

We all know that a picture is worth 
a thousand words and that there are 
many things that require pictures, 
diagrams, charts, graphs, etc., to be 
understood. And yet we still think of 
visuals as illustrating the text, when 
it is often the other way around. Col- 
lege courses in technical communica- 
tion generally have a section or two 
on graphics but they are mostly about 
tables, graphs, and charts. Very little 
is said about pictures (whether pho- 
tographs or line drawings) except that 
they are important and perhaps even 
essential. 

What kind of pictures do you need? 

[continued] 



120 BYTE • JANUARY 1985 



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THE VISUAL MIND 




Figure 5: Variations on a horse. The original in the upper right is preprogrammed 
on McPic. The variations were created using MacPaint to shorten, reduce, elongate, 
multiply, and reverse the image. 




Figure 6: Various uses of parts of the horse from figure 5. MacPaint was used 
to create these modifications. 



What makes them effective? When do 
you need them? Usually, we are 
taught little about using pictures and 
diagrams to illustrate abstract con- 
cepts (such as using the ambiguous 
vase/faces diagram to clarify Kuhn's 
concept of the relationship between 
scientific theory and observation). 
Some people know, intuitively, what 
sorts of pictures are good and effec- 
tive, but explaining that knowledge to 
others is difficult. And the only peo- 
ple who seem to be able to depict 
abstract ideas are illustrators for such 
magazines as Scientific American, who 
have to figure out, among other 
things, how to make two-dimensional 
representations of ^-dimensional 
spaces. 

The main problem is that writing 
and illustrating are thought of as two 
different tasks. Some people spe- 
cialize in writing, others in illustrat- 
ing—but few become adept at both. 
Yet both images and verbal proposi- 
tions are essential to thinking. This 
particular division of labor, in part, is 
caused by the difficulty of making 
good pictures; few people are adept 
at it. This brings us back to the Macin- 
tosh because its graphics capabilities 
can help bridge the gap. 

Reconstructing 
Visual Images 

The Macintosh isn't going to make 
you an artist if you can't draw a recog- 
nizable horse, but if you can use an 
image someone else has already pre- 
pared, perhaps you don't need to be 
an artist. The horse in the upper right- 
hand corner of figure 5 comes from 
McPic. one of the various disks of im- 
ages that is available for the Macin- 
tosh. The other images were derived 
from the original horse in obvious and 
simple ways using tools from Mac- 
Paint. 

In figure 6 the head and tail of the 
horse were cut away from the body, 
modified slightly (the mane was 
changed for the chessman, the left 
rear leg was removed from the tail), 
and treated as abstract design ele- 
ments. In other words, the images are 
used as lines and shapes in a visual 

[continued) 



122 BYTE • JANUARY 1985 



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The Sharp PC-5000, on the other hand, is a true portable. It's a compact 16 bit microprocessor , 128K RAM 
(expandable to 320K) with 192K of ROM, an 80 character display screen, removable bubble memory storage, 
built-in rechargeable power source and bundled software. It's also available with options like an integrated 
modem that lets you connect with your mainframe and an integrated correspondence-quality printer which 
doesn't increase the size of the system. And even with all these features, the PC-5000 fits neatly into a briefcase 
and weighs under 14 pounds. Almost 25% less than its nearest major 
competitor. At a price that's lighter, too. 

Of course, there's one thing about the PC-5000 that isn't small. Its 
working capacity. It functions as a desktop computer. And is compatible 
with a wide variety of MS-DOS® software. 

So if you need a truly portable computer, look into the Sharp 
PC-5000. The one that may be the 
smallest, lightest— and the best value for 
the money. In short, a computer that will 
lighten your work load. Not add to it. 

For more information call 
1-800-BE-SH ARP or fill in the coupon . ^ FROM SHARP MINDS 

MS-DOS® is a registered trademark of Microsoft Corporation. COME SHARP PRODUCTS 

A/V EQUIPMENT, AUDIO, BANKING SYSTEMS, CALCULATORS, CASH REGISTERS, COMPUTERS, COPIERS, ELECTRONIC TYPEWRITERS, 
FACSIMILE EQUIPMENT, MICROWAVE OVENS, PROFESSIONAL VIDEO CAMERAS & MONITORS, TELEVISIONS, VIDEO TAPE RECORDERS. 

Inquiry 316 




Sharp Electronic Corp. dept-SYS-byte-i-5 
Computer Systems Division 
1909 E. Cornell, Peoria, IL 61614 

□ Please send me more information 
about Sharp's PC-5000. 

□ Please set up a demonstration. 

Name 

Title 

Company 

Street 

City 

Phone ( ) 



_State_ 



_Zip_ 



THE VISUAL MIND 



composition and their abstract quali- 
ties as lines and shapes are more im- 
portant than the fact that they repre- 
sent parts of a horse. These manipula- 
tions are easy to do in MacPaint. And 
once you start doing them you are on 
the way to developing your own draw- 
ing skills. 

To draw well, you must learn to see 
the visual world in terms of lines and 
shapes, not simply in terms of objects; 
you must draw what your eye sees, 
not what your mind makes of what 



your eye sees (reference 10). Consider 
the nature of perspective drawing. In 
figure 7a, which shows the view look- 
ing up a temple column, your mind 
knows that the columns are only 
slightly tapered. But that is not what 
your eye sees from this point of view. 
Figure 7b shows the forms the col- 
umns present to your eye from this 
particular point of view. The trick is to 
get your drawing hand to override 
what your mind knows in favor of 
what your eye sees. 




Figure 7a: The view looking up a 
temple column. Note the intense 
foreshortening. 



Figure 7b: This shows the basic forms 
presented in figure la. 




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>: 

- 

11 

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Figure 7c: The vanishing point of the 
example in figure la. 



Figure 7d: The basic column forms from 
figure lb superimposed on the perspective 
grid given in figure 1c. 



Your drawing hand 
must override what your 
mind knows in favor 
of what your eye sees. 



The best way to learn perspective 
drawing is to study the tricks devel- 
oped during the Renaissance. Figure 
7c shows a bunch of lines radiating 
from the vanishing point (the point on 
the visual horizon where your gaze is 
focused). All lines in the image space 
that are perpendicular to the picture 
plane pass through the vanishing 
point. Figure 7d shows the forms of 
the columns superimposed on the 
perspective grid. By using an explicitly 
constructed perspective grid, you can 
overcome what your mind knows and, 
instead, draw what your eye sees. 

The techniques of perspective draw- 
ing didn't just happen. They were 
painstakingly created over a period of 
centuries ending about 400 years ago. 
And they were created at the same 
time that projective geometry was be- 
ing developed— in some cases by the 
same people (see reference 1 1 ). Thus, 
artists used projective geometry to 
help them reconstruct three-dimen- 
sional images on the two-dimensional 
space of the picture plane. The men- 
tal process involved in drawing is 
quite different from that in which the 
mind comprehends what the eye 
sees. To draw a picture of an object 
you must reconstruct what your eye 
will see in terms of hand and pencil 
motions (see reference 12). By mak- 
ing it easy to treat pregenerated 
images as abstract design elements, 
the Macintosh starts you along the 
road to this reconstruction. The 
essential first step is to see lines and 
forms, not objects. When you play 
with MacPaint it is quite clear that you 
are manipulating lines and forms, and 
that you are dealing with purely visual 
objects, not just representations of 
cars, horses, trees, buildings, etc. 

[continued) 



124 BYTE • JANUARY 1985 



Introducing SYSTAT 2 

"The System for Statistics" 



A comprehensive 
statistics, graphics, and 
database management 
package. 

Version 2 provides these 
expanded capabilities: 

■ Full screen spreadsheet data 
editor 

■ Missing data, indexed arrays, 
character variables 

■ Unlimited cases, variable record 
lengths 

■ Higher accuracy than popular 
mainframe statistical packages 

■ Relational database management 
and report generation 

■ Sort large files on one or more 
numeric and/or character variables 

■ Merge large files by multiple 
numeric and character variables 

■ Unlimited numeric and character 
transformations (if. ..then... else, 
for.. .next, go to) 

■ Transpose files 

■ Interactive or batch (macros) 

■ Pass data to and from mainframe 
and micro-spreadsheets, databases, 
and word processors 

■ Input rectangular (cases by 
variables) or triangular (e.g. 
correlation matrix) files 



SYSTAT is a trademark of Systat, Inc. 

MS-DOS is a trademark of Microsoft. 

CP/M is a trademark of Digital Research, Inc. 

Z-80 is a trademark of Zilog. 

HP9000 is a trademark of Hewlett-Packard. 

VAX is a trademark of Digital Equipment Corp. 



■ Scatterplots, contour, function 
plots, histograms, stem-and-leaf, 
boxplots 

■ Quantile and detrended probabi- 
lity plots 

■ Basic statistics by one or more 
groups 

■ Save aggregate data into files for 
further processing 

■ Multi-way tables with log-linear 
model 

■ Pairwise/listwise missing value 
correlation, SSCP, covariance, 
Spearman, Kendall Tau-b 

■ Linear, polynomial, multiple, step- 
wise, weighted regression 

■ Extended regression diagnostics 
(residuals, autocorrelation, leverage, 
collinearity) 

■ Multivariate general linear model 

■ One-way Anova with post-hoc 
tests (Newman-Keuls, Duncan Multi- 
ple Range, Tukey HSD) 

■ N-way balanced or unbalanced, 
crossed or nested, ANOVA, 
ANOCOVA, MANOVA 

■ Univariate or multivariate repeated 
measures designs 

■ Principal components with rota- 
tions, plots and scores 

■ Linear and monotonic multidimen- 
sional scaling 

■ Cluster analysis (hierarchical, 
single-, average-, complete-linkage, 
cases, variables, two-way, K-means) 

■ Nonparametric statistics (Sign 
test, Wilcoxon, Kruskal-Wallis, Fried- 
man two-way ANOVA, Mann-Whitney 
U, Kolmogorov-Smirnov one and two 
sample, Kendall coefficient of 
concordance) 

■ Time Series (smoothing, seasonal 
and nonseasonal Box-Jenkins 
ARIMA models, ACF, PACF, Cross 
Correlation Function, plots, transfor- 
mations forecasting) 



In every published review 
comparing it to other 
statistical microcomputer 
programs, Systat has been 
rated at the top of the list. 

Single copy price, $495. 

Site licenses and quantity 
prices available. 

Available for MS-DOS, CP/M 
with a Z-80, HP9000 and 
VAX. 

Call or write for detailed 
specifications and 
information. 

SYSTAT, Inc. 

603 Main Street 
Evanston, IL 60202 

312 864.5670 



SYSTAT 



Inquiry 342 



JANUARY 1985 'BYTE 125 



THE VISUAL MIND 



To generate a circle with a compass, 
you select the center point and rotate 
a radius around it. To generate the cir- 
cle with MacPaint, you select a point 
to be the corner of an invisible square 
in which the circle will be inscribed 
and drag the mouse diagonally across 
to the opposite corner. In the com- 
pass and straightedge method, the 
center plays an important role. With 
MacPaint, it does not. The world of 
MacPaint is different from the world 
of compass-and-straightedge geo- 
metry; hence an act of reconstruction 
is required if you wish to mimic 
compass-and-straightedge geometry 
in MacPaint. 

Listing 2 shows a bit of Logo code 
that constructs an equilateral triangle. 
The meaning of the code is not im- 
portant here. What is important is that 
it is clearly propositional. The com- 
pass-and-straightedge method and 
MacPaint are visual— more exactly 
visuo-kinetic. But computer code is 



clearly propositional. A computer lan- 
guage, though quite different from a 
natural language, is verbal and, there- 
fore, is in some sense a propositional 
reconstruction of a visual object. 

Simple geometrical figures are not 
particularly exciting, but consider 
moire patterns (figure 8). You can eas- 
ily construct them with MacPaint. And 
once you've spent a day or two play- 
ing around with them, you'll want to 
write short programs to generate 
them. Drawing all those lines is easy 
enough, but it's tedious: why not let 
the computer do it? But to do that you 
have to learn to program the com- 
puter, to make propositional recon- 
structions of visual objects. 

Years ago Alan Kay said that work- 
ing in a visual computing environment 
provides a natural incentive for learn- 
ing to program (reference 13). The 
graphics power that makes the Macin- 
tosh so user friendly also provides an 
incentive for users to learn enough 



Listing 2: Constructing an equilateral triangle in Logo. The four lines of code at 
the top specify a procedure for drawing polygons. The procedure has two 
parameters, the length of a side (size) and the angle through which the logo 
turtle must turn to move from drawing one side to drawing the next side. The 
line at the bottom specifies a side of 74 units and an angle of 120 degrees. 



TO POLY :SIZE :ANGLE 
FORWARD :SIZE 
RIGHT ;ANGLE 
POLY :SIZE :ANGLE 

POLY 74 120 




Figure 8: Various moire patterns created on the Macintosh with MacPaint. 



Working in a visual 
computing environment 
provides a natural 

incentive for 

learning to program. 



about programming so that they no 
longer need that user friendliness. 
But it is MacPaint that provides this 
incentive, not the icon-based inter- 
face. It is possible that Apple's efforts 
to produce a computer for people 
who know nothing about program- 
ming (and don't want to learn) may 
well inspire an increase in the number 
of such users who do learn to 
program. 

Perhaps we need a revised concep- 
tion of user friendliness. A user- 
friendly computer should not be one 
that lets you use it despite your ig- 
norance; it should provide you with 
an incentive for learning how to pro- 
gram it. The Macintosh meets this 
criterion. 

The Macintosh Emerges 

By now I hope it's obvious that I am 
attempting to produce a gestalt switch 
in the way we think about the Macin- 
tosh. In terms of figure 2 it was de- 
signed as an ambiguous figure and 
marketed as two men staring at each 
other. I suggested that we look at it 
as a flower-filled vase. If you consider 
personal computers, some are busi- 
ness machines, some home machines, 
and some are both. 

Business machines are used for 
word processing, accounting, financial 
modeling, inventory control, etc., and. 
if you allow for the necessary periph- 
erals and software, they are likely to 
cost between $3000 and $20,000. 
They will probably have a 16-bit 
microprocessor (or perhaps 32-bit), 
1 2 8K to 5 1 2 K bytes of RAM (random- 
access read/write memory), a hard 
disk, and compilers or interpreters for 

[continued] 



126 BYTE • JANUARY 1985 




What every Apple owner 
should know about 

WORD 

juggler: 





If you own an Apple lie or lie — or you're planning to 
buy one — here are a few things you should know about 
Quark's Word Juggler word processor. 

First of all , Word Juggler is the only word processor that 
gives you a powerful spelling checker and a built-in telecom- 
munications feature. So you can create a document — check 
it for spelling errors — and then send it via electronic mail. All 
with just one program. 

Plus, Word Juggler is the most easy-to-use, professional 
word processor you can buy for your Apple. Virtually every 
function — even complicated u cut-and-paste" tasks — can be 
accomplished with a single keystroke. 

There's nothing to memorize, either. Because Word 
Juggler comes with replacement keycaps — and a special 
keyboard template — which identify principal editing and 
formatting commands. So you can focus your efforts on 
using the program, not learning it. 

Fact is, no other word processor for your Apple He or 
lie gives you this unique combination of power, functionality 
and ease of use. And if all these advantages aren't compelling 
enough, check the price. Suggested retail is only $ 1 89. 

So visit your favorite dealer today. Ask for a complete 
demonstration — and for a copy of our brochure, "What 
Every Apple Owner Should Know About Word Juggler." If 
you don't have a favorite dealer, but would like one, just call 
1 (800) 543-7711. We'll fix you up. 






Quark 

HBBMHHI INCORPORATED 



2525 West Evans, Suite 220 
Denver CO 802 19 
Inquiry 291 

Quark and Word Jugg&r are trademarks of Quark Incorporated. Apple is a 
registered trademark of Apple Computer, Ine. 

Ask about our specially-priced educational version. 

Copyright 1 985. Quark Incorporated Photography by Barbara Kasten 



THE VISUAL MIND 









Figure 9a: This drawing represents the 
various niches that make up the personal 
computer marketplace. 



Figure 9b: Imagine that these are the 
various computers destined to fill the 
niches in figure 9a. 




Figure 9c: This represents the personal 
computer marketplace: the square holes, 
the interaction between the niches in figure 
9a and the computers in figure 9b. Notice 
that this interaction creates patterns of 
diamonds that don't exist in either of the 
constituent patterns when considered 
separately. These are called emergent 
patterns. 



Figure 9d: The differently patterned 
Macintosh—the round peg. 




Figure 9e: When you combine the 
round peg [figure 9d) with the square hole 
[figure 9c), something genuinely new 
emerges— jazzy squares. 



various programming languages. 

Machines for home use tend to be 
much smaller. They cost between 
$300 and $1 500 and use a color TV 
as a monitor. Mass storage is often a 
tape cartridge. These machines may 
run the same types of applications as 
their business-like siblings and in the 
same languages, but they are more 
likely to be used for video games and 
educational programs for the kids. 

Figures 9a through 9c contain an 
abstract representation of the per- 
sonal computer marketplace. There 
are certain niches (figure 9a) for all 
these machines (figure 9b) and they 
fit perfectly (figure 9c). Those who use 
microcomputers are generally doing 
well in their businesses and their kids 
have a ticket to the future. Those who 
manufacture and sell the machines 
are getting rich. When you put the two 
together, diamonds result from the in- 
teraction of two patterns, neither of 
which contains diamonds. The dia- 
monds are an emergent pattern. 

Consider the Macintosh, a different- 
ly patterned machine that doesn't fit 
into this picture at all (figure 9d). It 
doesn't yet have the power necessary 
for business computing. It is a lot of 
fun to use, but it is expensive for 
home users. And yet it is selling well. 
Who is buying these machines and 
what are they doing with them? If you 
combine this differently patterned 
machine (figure 9d) with the world of 
personal computing (figure 9c), you 
will find a new pattern— jazzy squares 
(figure 9e). Something genuinely new 
has emerged out of the interaction. 

The Macintosh doesn't fit into any 
of the current categories of personal 
computing. It is designed, marketed, 
and reviewed (for the most part) as 
one more personal computer that 
does the standard things that per- 
sonal computers do. The differences 
are: it has this easy-to-use icon-based 
interface: you don't really need a 
manual, just turn it on and start 
"mousing" around: and there is this 
program called MacPaint that's fun to 
use. 

People like to draw, and working 
with MacPaint is fun. It gives you a 

[continued] 



128 BYTE • JANUARY 1985 



w 




\ 



I: 









552 words per minute. 
Letter perfect 



Humanly impossible, yes* NEC impossible, no* In 
fact, in a head-to-head comparison with 1 ettei — quality 
printers, the NEC PC-PR103A Letter-Perf ect Printer 
not only prints three times faster (46 CPS), it gives 
you letter — quality performance, with true decenders* 
It's nearly impossible to tell the difference between 
print-outs from the PC-PR103A and 1 ettei — quality 
printers* 

But that's not all* Ulith the innovative Impact 
Line-Dot type Printhead, the NEC PC-PR103A tri-mode 
underscores its advantages by offering two additional 
printing modes — graphics and draft quality* It even 
eliminates "ghosting - with single-pass printing, and 
includes tractor feed* 

Best of all it costs much less* kt ~» 



Near Letter-Quality: 46 CPS 

Draft-Quality: 110 CPS 

and Graphics <\y|tfYfl 



/ 



I 



There really is no comparison after all* 



m 




C-PRI03A 



• • : . ■, ■. •■-., ■ ■ 




Inquiry 369 



c=;i=crK^:R! 




Multifunction Products for the Tl Professional Computers 



SEEKER St BOARD 

- Expandable memory from 
to 51 2K bytes, fully socketed 

- SCSI/SASI interface 

- RS-232 Sync/Async port 

- Optional clock 

- Completely Tl PC hardware 
and software compatible 

- Plugs into any open Tl PC 
expansion slot 

SEEKER S2 BOARD 

- RAM from OK to 192K 

- Fully Tl compatible 

- Will attach to SEEKER SI 



INTERNAL WINCHESTER 

Resides inside the Texas 
Instruments PC, interfaced to 
the SEEKER S1 board, 

- 1 & 20 Megabyte 

- Tl software compatible 

- Includes bootstrap EPROM 

- Format and test routines 
included 

EXTERNAL WINCHESTERS 

Cables to SEEKER S1 

- 1 & 20 Megabyte 

- Cabinet matches Tl PC 
• 1 1 0/220 VAC operation 



EXPANDABILITY 

Western Automation SEEKER 
products allow Tl Professional 
Computers to expand to their 
full 768K memory. The 
SEEKER S1 board will control 
eight SCSI/SASI Winchester 
disks and streaming tape 
drives, like the SEEKER 60MB 
streaming tape system. 

SEEKER SI board list $425 
SEEKER SI and 10 MB 
internal drive list $1895 



Ninety day warranty on all products. Available through Dealers and OEMs. 

— "~ WESTERN AUTOMATION LABORATORIES, INC. 

i 5595 Arapahoe Road, Boulder, CO 80303 

For Information write or call (303) 449-6400 or Toll Free (800) 227-4637 



labels 
on your list. 



Next time you shop for computer supplies, pick up a pack of 
Avery's new self-adhesive labels. By putting all your address 
lists on labels, you get more done in less time. Name badge 
labels, shipping labels, piggybacks and new clear labels are 
also available. 

The labels are designed especially for micro computers. 
And they're packaged to fit neatly behind your printer. Look 
for them wherever you buy computer supplies. 



Avery Label 



An Avery International Company 
Business Systems Division 



■_ £_ . L ■ L 



THE VISUAL MIND 



MacPaint actively 
involves you with the 
computer. The Mac 
is easy to use— 
and it is fun. 



much more active involvement with 
the computer than word processing 
or a spreadsheet program does. This 
involvement can lead you into pro- 
gramming. It can lead to deeper think- 
ing and more effective communica- 
tion. It is easy— and it is fun. ■ 

REFERENCES 

1 . Ornstein, Robert E„ editor. The Nature of 
Human Consciousness. San Francisco, CA: 
W. H. Freeman and Company, 1973. 

2. Hadamard, Jacques. The Psychology of In- 
vention in the Mathematical Field. New York: 
Dover Publications, 1954, pages 142-143. 

3. Watson. James D. The Double-Helix. New 
York: Atheneum Publishers, 1968. 

4. Kuhn, Thomas S. The Structure of Scientific 
Revolutions. Chicago, IL: University of 
Chicago Press, 1962. 

5. Simon. Herbert A. The Sciences of the Ar- 
tificial. Cambridge. MA: MIT Press, 1981. 

6. Sowa, John F. "Review of Associative Net- 
works-Representation and Use of Knowledge by 
Computers^' American journal of Computational 
Linguistics (1980) 6, 110. 

7. Buzan. Tony. Use Both Sides of Your Brain. 
New York: E. P. Dutton, 1983. 

8. Rico, Gabriele Lusser. Writing the Natural 
Way. Los Angeles, CA: j. P. Tarcher Inc., 
1983. 

9. Norman. Donald A. Memory and Atten- 
tion. New York: John Wiley and Sons, 1969. 

10. Gombrich, Ernst. Art and Illusion. 
Princeton. NJ: Princeton University Press, 
1969. 

1 1. Ivins, William M. Jr. Art and Geometry. 
New York: Dover Publications, 1964. 

12. Benzon. William L. "System and Ob- 
server in Semiotic Modeling," in Michael 
Herzfeld and Margot D. Lenhart, comp. 
Semiotics 1980. New York: Plenum Press, 
1982, pages 27-36. 

13. Kay, AlanC. "Microelectronics and the 
Personal Computer" in Microelectronics. San 
Francisco, CA: W. H. Freeman and Com- 
pany, 1977. 



130 BYTE • JANUARY 1985 



Inquiry 34 for Dealers. 
Inquiry 35 for End-Users. 



I 



I 




1 



1 



i 



I 



Efc* 



E 



Because they're already built-in. The 80/132- 
column printer. The 9-inch, high-resolution 
display There's even a built-in 360K disk 
drive. Which all make the Sr. Partner a com- 
plete computer as is. 
rM The Sr. Partner is IBM hardware and software 

compatible so you can run popular business pro- 
grams immediately. The software bundle cur- 
rently offered with the Sr. Partner is WordStar, 
— ^ VisiCalc, pfs;Graph, File, Report, 
| MS-DOS 2.11 and GW BASIC* 
. And with its 256K internal memory 

m expandable to 512K, the Sr. Partner 
W can run the new integrated software. 
Built-ins also include expansion slots 
and parallel and serial I/O ports. There's even a built-in 
RGB monitor port so you can take advantage of the 
Sr. Partner's color and graphics capability. 

If you want 10 megabytes of storage, choose the new 
hard disk Sr. Partner. 

Both the Sr. Partner and the hard disk Sr. Partner come 
with an exceptional Panasonic warranty** 

For the dealers nearest you, call: 201-392-4261. The 
Panasonic Sr, Partner. No peripherals needed. It makes 
the competition look like Jr. Executives. 

Panasonic 

Industrial Company 

Inquiry 270 



80/132-Column Printer 




9-Inch High-Resolution Display 



Optional 10-Megabyte Hard Disk or 
Optional Second 360K Disk Drive 








360K Disk Drive- Built-in 



IBM Compatibility - 




are bundle otter subject-to change or withdrawal at any time without* notice. * *One-year limited warranty, 6 months on thermal printer head. Carry-in or mail-in service. 
'5 a trademark of Matsushita Electric industrial Company Ltd; WordStar is the trademark of MicroPro International Corporation; VisiCalc is the registered trademark of VisiCorp 
3 Arts, inc.); pfs:Graph, File, Report are the registered trademarks of Software Publishing Corporation; GW BASIC, MS-DOS are the trademarks of Microsoft Corporation. 



IT ALL ADDS UP... 



IBM SYSTEMS 

Starting as low as 

$1399 

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KEYBOARD 




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5V4 1 ' 320K Floppy $169.00 

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VisiCalc IV $159.00 

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Color 300/audio $259.00 

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Color 710 Long Phosphor $579.00 

BMC 
1201 Plus (12" Green Hi-Res). $88. 99 

9191U Color $229.00 

9191 Color + $249.00 

NAP 
12" Amber $69.99 

NEC 

JB 1206 Green.... $109,00 

JB 1201 Green $139.00 

JB 1205 Amber $149.00 

JB 1215 Color $249.00 

JC 1216 RGB $379.00 

JC 1460 Color $269.00 

PRINCETON GRAPHICS 

MAX-12 Amber $199.00 

HX-12 RGB $489.00 

SR-12 RGB $629.00 



MONITORS SAKATA 

SC-100 Color $249.00 

SG-1000 Green $129.00 

SA-1000 Amber $139.00 

TAXAN 
100 12" Green $125.00 

121 IBM Green $149.00 

100 12" Amber $135.00 

122 IBM Amber $159.00 

210 Color RGB $269.00 

400 Med-Res RGB $319.00 

415 Hi-Res RGB $439.00 

420 Hi-Res RGB (IBM) $469.00 

USI 

Pi 1, 9" Green $99.99 

Pi 2, 12" Green $119.99 

Pi 3, 12" Amber $129.99 

Pi 4, 9" Amber $119.99 

1400 Color $249.99 

QUADRAM 

Quadchrome 8400 Color $489.00 

ZENITH 

ZVM 122 Amber $89.99 

ZVM 123 Green $84.99 

ZVM 124-IBM Amber $149.00 

ZVM 135-RGB/Color $459.00 



MODEMS 

ANCHOR NOVATION 

Volksmodem $59.99 J-Cat $99.99 

Mark IL Serial $79.99 Cat $139.00 

Mark VII (Auto Ans/Auto Dial)$99. 99 Smart Cat 103 $179.00 

Mark XII (1200 Baud) $259.00 Smart Cat 103/212 $399.00 

Mark TRS-80 $99.99 AutoCat $219.00 



9 Volt Power Supply $9.99 

HAYES 

Smartmodem 300 $199.00 

Smartmodem 1200 $479.00 

Smartmodem 1200B $399.00 

Micromodem He $269.00 

Micromodem 100 $299.00 

Smart Com II $75.99 

Chronograph $199.00 



212 AutoCat $549.00 

Apple Cat II $249.00 

212 Apple Cat $449.00 

Apple Cat 212 Upgrade $259.00 

Smart Cat Plus $339.00 

ZENITH 

ZT-1 $339.00 

ZT-10 $309.00 

ZT-11 $369.00 




VISA' 



west 
800-648-3311 

In NV call (702)588-5654 - 



Order Status Number: 588-5654 
P.O.Box 6689, Dept.100 



Canada 

Ontario/Quebec 800-268-3974 
Other Prouinces800 268-4559 

In Toronto call (416) 828-0866 

Telex: 06-218960 

2505 Dunwin Drive, Unit 3B, Dept.100 

Mississauga, Ontario, Canada L5L1T1 



DINERS CLUB 



east 
800-233-8950 

In PA call (717)327-9575 



(MasterCard) 



Order Status Number: 327-9576 

Customer Service Number: 327-1450 

47? E . 3rd St., Dept.1 00, Williamsport, PA 17701 



Stateline, NV 89449 

Open purchase orders accepted with net 30 days terms, subject to credit approval. Next day shipping on all stock items. No risk, no deposit 
on C.O.D. orders and no waiting period for certified checks or money orders. Add 3% (minimum $5) shipping and handling on all orders. 
Larger shipments may require additional charges. NV and PA residents add sales tax. All items subject to availability and price change. 
Call today for our catalog. 
132 BYTE • JANUARY 1985 



...THE BEST PRICES 




PRINTERS 



AXIOM 

AT-lOO Atari Interface Printers 169.00 
AT-550 Atari Bidirectional. ...$259. 00 

GP-100 Parallel Interface $189.00 

GP-700 Atari Color Printer...$489.00 

GP-550 Parallel Printer $269.00 

BMC 

401 Letter Quality $589.00 

BX-80 Dot Matrix ...$239.00 

BX-100 Dot Matrix $259.00 

C.ITOH 

Prowriter 8510P $339.00 

Prowriter 1550P $569.00 

A 10 (18 cps) Son of Starwriter$479.00 

Hot Dot Matrix CALL 

F10-40 Starwriter $949.00 

F10-55 Printmaster $1099.00 

COMREX 
ComWriterll Letter Quality.. $449.00 

DIABLO 

620 Letter Quality .$749.00 

630 API Letter Quality $1549.00 

DAISYWRITER 
2000 $949.00 

EPSON 

RX-80, RX-80FT, RX-100 CALL 

FX-80, FX-100 CALL 

LQ 1500, JX80 Color CALL 

JUKI 

6100 $449.00 

6300 $779.00 

MANNESMAN TALLY 

160L , $589.00 

180L $749,00 

Spirit 80 $259.00 



NEC 

2010/15/30 $719.00 

3510/15/30 $1299.00 

7710/15/30 $1699.00 

8027.... $349.00 

OKIDATA 
82, 83, 84, 92, 93, 2350, 2410.. CALL 

Okimate-64 $209.00 

Okimate-Atari $209.00 

OLYMPIA 

Compact 2 $469.00 

Compact RO $499.00 

Needlepoint Dot Matrix $329.00 

PANA80NIC 

1090 $239.00 

1091 $309.00 

1092 $449.00 

1093 $649.00 

SMITH CORONA 

TP-1000 $449.00 

Tractor Feed $119.00 

SILVER REED 

400 Letter Quality $279.00 

500 Letter Quality $349.00 

550 Letter Quality $459.00 

770 Letter Quality $799.00 

STAR 

Gemini 10X $259.00 

Gemini 15X $379.00 

Radix 10 , $549.00 

Radix 15 $649.00 

Powertype $329.00 

TOSHIBA 

1340 1 $799.00 

1351 $1369.00 



INTERFACES 



PRACTICAL PERIPHERALS 

Graphcard $84.99 

Seriall Card $109.00 

Microbuffer II + $179.00 

Microbuffer 32K $199.00 



m 



ORANGE MICRO 

Grappler CD (C64) $99.99 

Grappler + (Apple) $109.00 

Grappler 16K + (Apple) $189.00 

QUADRAM 

Microf azer - Printer Buffers starting at 

$139,00 

We carry interfaces and cables for most computers on the market today. Call to determine 
your requirements. 

SEC 

PC-8201 Portable Computer$299.00 

PC-8231 Disk Drive $619.00 

PC-8221A Thermal Printers. .$149,00 

PC-8281A Data Recorder $99.99 

PC-8201-06 8K RAM Chips.. ..$105.00 
PC-8206A 32K RAM Cartridge$329.00 

SHARP 

PC-1350 $159.99 

PC-1261 $159.99 

PC-1260 $109.99 

PC-1500A $165.99 

PC-1250A $88.99 

CE-125 Printer/Cassette $128.99 

CE-150 Color Printer Cassette$171.99 

CE-151 4K RAM $29.99 

CE-155 8K RAM $49.99 

CE-161 16K RAM $134.99 

CE-500 ROM Library ea $29.99 



HEWLETT 
PACKARD 

41CV $189.99 

41CX $249.99 

HP 71B $419.99 

HP UC... $62.99 

HP 12C $92.99 

HP 15C $92.99 

HP 16C $92.99 

HP 75D $999.99 

HPIL Module $98.99 

HPIL Cassette or Printer $359.99 

Card Reader $143.99 

Extended Function Module $63.99 

Time Module $63.99 

We stock the full line of 
HP calculator products 



KOALA 



Atari (ROM) $79.99 

C-64 $79.99 



HOME COMPUTERS 



A 

ATARI 

A Www Communic*1ioni ComtMny (^ 




CALL WHILE SUPPLIES LAST 
600XL Sc 800XL 



850 Interface $109.00 

1010 Recorder $49.99 

1020 Color Printer $79.99 

1025 Dot Matrix Printer $199.99 

1027 Letter Quality Printer. .$269.99 
1030 Direct Connect Modem,. ..$59. 99 

1050 Disk Drive $179.99 

Touch Table/Software $64.99 

Light Pen/Software $72.99 

CX22 Track Ball $39.9 

7097 Atari Logo $74.99 

4018 Pilot (Home) $57.99 

405 Pilot (Educ.) $99.99 

8036 Atari Writer $49.99 

5049 VisiCalc $59.99 

MEMORY BOARDS 

Axlon 32K $44.99 

Axlon 48K $69.99 

Axlon 128K $269.99 

Microbits 64K (600) $109.00 

SWP 

ATR-8000-16K Z80 CP/M $349.00 

ATR-8000-64K Z80 CP/M $499.00 

BIT 3 
Full View 80 $239.00 



CX30Paddles $11.99 

CX40 Joystick $7.99 

4011 Star Raiders $12.99 

4022 Pac Man $16.99 

4025 Defender $32.99 

8026 Dig Dug $32.99 

8031 Donkey Kong $32.99 

8034 Pole Position $32.99 

8040 Donkey Kong Jr. $32.99 

8043 Ms Pacman. $32.99 

8044 Joust..... $32.99 

8045 Pengo $16.99 

8052 Moon Patrol $32.99 

4003 Assembler $34.99 

8126 Microsoft Basic I or II $64.99 

DISK DRIVES 

Indus GT Drive (Atari) $279.00 

Rana 1000 $249.00 

Trak AT-D2 $389.00 

Trak AT-D4 $539.00 

MODEMS 

Micro Bits MB-1100 $129.99 

INTERFACES 
Microbits MB-1150 $79.99 



Qz commodore 



CBM 8032 $639.00 

CBM 8096 $869.00 

CBM 9000 $999.00 

B128-80 $99.00 

8032 to 9000 Upgrade $499.00 

2031 LP Disk Drive $299.00 

8050 Disk Drive $999.00 

8250 Disk Drive $1249.00 

4023 Printer $329.00 

8023 Printer $589.00 

6400 Printer $1449.00 

Z-RAM $369.00 

Silicon Office $499.00 

The Manager $199.00 

BATTERIES INCLUDED 

PaperClip w/Spell Pack $84.99 

The Consultant DBMS $69.99 

Bus Card II $149.00 

80 Col Display $149.00 

DISK DRIVES 

MSD SD1 $349.00 

MSD SD2 $599.00 

Indus GT/C64 $279.00 

PERSONAL PERIPHERALS 
Super Sketch Graphics Pad $39.99 



IBM $99.99 

Apple/Franklin $85.99 



SX-64 Portable $749.00 

Commodore Plus 4 $289.00 

CBM 64 $199.00 

C1541 Disk Drive $249.00 

C1530 Datasette $59.99 

C1520 Color PrinteiVPlotter.... $129.00 

M-801 Dot Matrix Printer $219.00 

C1526 Dot Matrix/Serial $299.00 

C1702 Color Monitor...: $259.00 

C1600 VIC Modem $59.99 

C1650 Auto Modem $89.99 

Simons Basic........... $29.99 

MCS 801 Color Printer $499.00 

DPS 1101 Daisy Printer $459.00 

PES 

File (64) $59.99 

Report (64) $59.99 

PRECISION SOFTWARE 

Superbase 64 $59.99 

PROFESSIONAL SOFTWARE 

Word Pro 2 Plus $159.00 

WordPro 3 Plus $189.00 

Word Pro 4 Plus/5 Plus each.$239.00 

Info Pro $179.00 

Administrator $399.00 

Power $69.99 

Word Pro 64 Plus $59.99 

Fleet System II $59.99 




(MostwCordj 



west . -^^ Canada 

nnn C/IQ 0011 ( I IS Ontario/Quebec 800-268-3974 
dUU-b4U-JJ11 ^ ^^ Other Provinces800-268-4559 

In NV call (702)588-5654 DlN ERSCLUB In Toronto call (416) 828-0866 
Order Status Number: 588-5654 Telex- 06-218960 

P.O.Box 6689, Dept.100 2505 Dunwin Drivei Uni t 3 B, Dept.100 

Stateline, NV 89449 Mississauga, Ontario, Canada L5L1T1 



AMERICAN 1 



east 
800-233-8950 

^=^ In PA call (717)327-9575 

Order Status Number: 327-9576 

Customer Service Number: 327-1450 

477E.3rdSt., Dept.1 OO.Williamsport.P A 17701 



CANADIAN ORDERS: All prices are subject to shipping, tax and currency fluctuations. Call for exact pricing in Canada. INTERNATIONAL 
ORDERS: All orders placed with U.S. offices for delivery outside the Continental United States must be pre-paid by certified check only. 
Include 3% (minimum $5) shipping and handling. EDUCATIONAL DISCOUNTS: Additional discounts are available to qualified Educational 
Institutions. APO <3e FPO: Add 3% (minimum $5) shipping and handling. 



Inquiry 76 



JANUARY 1985 -BYTE 133 



LOOK WHO BUYS 
SOFTWARE 
FROM US! 




If you order software from 
us, you're in good company. 
You see, some of our best cus- 
tomers are America's biggest 
corporations. 

Maybe they're attracted by 
our low, low prices (big compa- 
nies are price-conscious too!). 
Or maybe when you're an 
"IBM'; you're looking for some- 
thing extra. Like the personal 
service, giant inventory, and in- 
depth technical support you'll 
findatSOO-SOFTWARE. 



You see, when you call us, 
we'll take care of you like our 
business depends on it. Because 
it does. Which means when you 
place an order, you can be sure 
we'll fill it promptly. And that 
our unique Order Tracking 
System™ is keeping tabs on your 
order every step of the way. 

Most important, we'll be 
there if you need us after your 
software arrives. We'll make 
sure that you'll receive the finest 
technical support and customer 



service in the industry. And that's 
a promise. If you purchase in 
large quantities, you'll be delight- 
ed by the service our National 
Accounts Program provides. 

Next time you're looking 
for low price and great service, 
do what IBM, General Electric, 
and a lot of other big companies 
do. Pick up the phone and give 
us a call. 

We'll show you why some 
hard-headed companies buy 
their software from us. 



CHECK OUT ALL OUR INCREDIBLE BUSINESS SOFTWARE PRICES: 


Lotus 1-2-3 




dBase 11/111 


Framework 




WordStar 2000/2000 Plus 


$309 




$299/$379 


$379 




$269/$329 


Lotus Symphony 


Crosstalk 
$105 


SuperCalc 3 
$209 


Hayes Modems 1200/12008 
$489/$409 


AMDEK" 




LIFETREE" 




Fortran $269 


Monitors 


CALL 


Volkswriter Deluxe 


$179 


All Other Products CALL 


ASHTONTATE" 




LOTUS'" 




MICRDSTUF" 


dBase 11/111 $21 


)9/$379 


1-2-3 


$309 


Crosstalk $105 


Framework 


$379 


Symphony 


$439 


MULTIMATE" $299 


Friday! 


$219 


MAXELL" DISKETTES 


CALL 


NORTON UTILITIES '" $ 59 


AST "PRODUCTS 


CALL 


MEMOREX"DISKETT 


ES CALL 


0UADRAM" CALL 


ATI" &CDEX "TRAINING 


CALL 


MICROPRO 




R0SES0FT" 


DIGITAL RESEARCH" 


CALL 


WordStar 2000/2000 


Plus S269/S329 


Pro Key $ 99 


FOX&GELLEFT 


CALL 


WordStar Pro Package 


PP. Plus $259/$359 


SOFTWARE PUBLISHERS" 


HAYES" 




InfoStar 


CALL 


PFS:Flle/Graph/Write $ 84 


Smartmodems 




ChartStar 


$239 


PFS: Report $ 75 


120D/120DB $4 


39/$409 


TelMerge 


$ 99 


SDRCIM/IUS" 


All Other Products 


CALL 


All Other Products 


CALL 


SuperCalc 2/3 $159/$209 


HERCULES" 




MICR0RIM" 




EasyWriter II System $185 


Graphic Card 


$325 


RBase4000 


$289 


IUS Easy Business Accounting $299/mod. 


iMsr 




MICROSOFT® 




All Other Products CALL 


4-Point Graphics 


$ 99 


Multiplan 


$149 


WESTERN UNION EASY LINK® FREE 


PC Paintbrush 


$ 99 


Word w/Mouse 


$299 


PLUS MUCH, MUCH MORE! CALL 



WE ALSO CARRY HUNDREDS OF OTHER PRODUCTS! 



WRITE: 
800-SOFTWARE, INC. 

940 Dwight Way 
Berkeley, CA 94710 



^800-SOFTWARE 

TO ORDER CALL TOLL FREE: 

800-227-4587 or 415-644-3611 



gii:intilvili.*i-i.tiiitsavail;ih] t -thr«ii >: h(» 
National A.o.iiiitsPioinam. 
1'urchdMMirili'rsai-vi-iitiMi.I'lMi.si-i-allii 






shi|>]iiii(,'cluiru'-s."*'» i iiiil.'lit ik-li\ 
»t mid suivham- f.ii- m..Vu tanl 



WimIii 
,»utvha«*. 

□ Prices may dianjft-. Allow jniii-s :«v I'm 
IHM l"Cj»inlf..m|ialih]i'». 

I Inleriiatinnsiliirili'i's-wi-k-imi': 

TI':[.F:X»7:il7l;i<S(HlS()[TWAKh:iU) 
LI rnniim.si'iv.'K.-yWonl '<;(). KH." 

□ Mc-mh.TolDiii.ct.Mark.-iin^A^.Kiaii, 
B.'ttt'rlUisiiu-s.-.liun-au. 



134 B YTE • JANUARY 1985 



Inquiry 2 



by Joseph S. Nadan 



A Glimpse 
into Future 
Television 



A technology 



evolving in parallel 
with personal 
computers 



Editor's note: How will high-definition television [HDTV] open the window on the world for 
users of personal computers? This article presents the technical possibilities and describes a 
scenario for the evolution of television in the "information age!' The author explains the rela- 
tionship between HDTV and two-way interactive cable television (CATV). As envisioned, HDTV 
will have wider computer-type displays with increased resolution. This could support the prepara- 
tion of larger spreadsheets using databases located both inside and outside the home. Shop-at- 
home services could benefit from "video facsimile',' the ability to send a picture from one loca- 
tion to any other on a CATV system in about I second. We could see what we are interested 
in buying, rather than viewing simple graphical representations. 

When used as an entertainment device, the future television receiver probably will be very 
different from that of today. The author discusses new features made possible by digital memory 
within the receiver. Well be able to watch more than one program at once and use our per- 
sonal computers while also watching, for example, one or more sporting events. Or we could 
shop interactively while watching a movie. When operated in high-definition mode, the larger 
and wider picture could enable the viewer to experience a theater-like presentation. 



Color television has been in the 
American household for about 
30 years. It is somewhat ironic 
that the television industry, the 
storehouse of creativity that has 
stimulated the development of VLSI 
(very-large-scale integration) digital 
video memories and significant im- 
provements in rear-projection 
displays, is having so much difficulty 
in making the transition into the "in- 
formation age." The cost reliability, 
styling, and picture quality of color 
television have vastly improved over 
the years. However, color television 
still has its original display shape and 
one-way receive-only capabilities. 

Television Improvements 

The next generation of television 
receivers, in order to gain our accep- 
tance, will most likely have 

• a large display area with a wider 
aspect (width to height) ratio 

• flexibility and interactivity 

• approximately twice the perceived 
horizontal resolution and vertical 
resolution of NTSC (National Televi- 



sion System Committee) television 

• true high-fidelity stereophonic 
sound (not discussed here) 

• no artifacts (visible effects on the 
display; for example, shimmer and 
color flashing) that were not present 
in the original scene 

Because of economic, social, and 
technical considerations, we at Philips 
Laboratories believe that the opti- 
mum maximum size of a consumer 
display will be about one-half square 
meter. While researchers still work 
toward very large flat-panel displays, 
it appears that vastly improved rear- 
projection displays are more im- 
minently practicable. It is possible that 
in the next few years we will be able 
to purchase rear projectors that will 
have better subjective performance in 
normal room lighting than the 26-inch 
direct-view cathode-ray tubes (CRTS) 

[continued] 

\oseph S. Nadan (345 Scarborough Rd., 
Briarcliff Manor. NY 105 10) is director of 
electronics and optical systems research for 
Philips Laboratories, a division of North 
American Philips Corporation. 



JANUARY 1985 -BYTE 135 



FUTURE TELEVISION 



that are in use today. 

A second important display param- 
eter is the aspect (width to height) 
ratio (see the glossary on page 151). 
To more closely match the aspect 
ratio of human vision (1.80:1) and to 
better match film material, which is 
predominantly 1.66:1 and 1.85:1. we 
suggest an aspect ratio of 51/j: 3 (or 
1.78:1) in place of the standard 4:3 
(see photo 1). We selected 51/3:3 over 
5:3 because it is more noticeably dif- 
ferent than 4:3. (Note that 5:3 is a 25 



percent increase in width over 4:3 
while 51/3:3 represents a 33 percent in- 
crease over 4 : 3 .) It also supports new 
features made possible by digital 
memory in a television receiver. 

Digital Memory 

The availability of a low-cost digital 
memory within a television receiver 
makes possible new features, includ- 
ing both local- and network-level in- 
teractivity. (See the text box "Memory 
Technology for Digital-Feature Televi- 




Photo 1: A comparison of the standard 4:3 aspect ratio CRT (a) and the proposed 
5/3:3 version (b). 



sion" on page 148.) Digital signal pro- 
cessing within the receiver may be 
broadly classified into two categories: 
those that provide new features and 
those that replace existing analog 
signal processing at lower cost. Digital 
memory in the receiver falls into the 
first category and provides these new 
features: multiple-picture-in-picture 
(MPIP) display, single-picture-in- 
picture display, and frame storage 
(freeze-frame). 

When first powered on, the new 
receiver could show 1 2 channels— that 
is, multiple pictures in one display 
(see photo 2)— to enable us to preview 
what is "on the cable." This display 
could also indicate the programming 
mix; that is, those programs available 
in an HDTV format could have a flash- 
ing contrasted dot as an indicator 
mark. By pressing one button on the 
remote-control unit, we could choose 
another set of favorite channels 
(which we have previously loaded into 
the receiver). After using an MPIP 
preview, we could select one or two 
programs to watch in real time (see 
photo lb). For example, we might 
want to watch two sporting events 
simultaneously, switching the more in- 
teresting programming to the larger 
portion of the display almost instan- 
taneously by pressing one button. We 
could also watch one main program 
while "clicking through" other pro- 
grams on the smaller display area. We 
also will be able to store a picture in 
memory and retain it on the display 
for closer viewing later. 

The 51/3:3 aspect ratio is special in 
the respect that it synergistically 
relates to 4:3; in other words, one 
5 1/3:3 picture may be formed from one 
4:3 picture and three smaller 4:3 pic- 
tures. These capabilities may be com- 
bined for great flexibility. For exam- 
ple, we could use our personal com- 
puters while watching three different 
broadcasts. Preparing a wide spread- 
sheet or any type of document that 
is horizontally oriented is also 
facilitated by this aspect ratio. 

Interactivity 

A conventional CATV network con- 
sists of a head-end facility broadcast- 



136 B YTE • JANUARY 1985 



FUTURE TELEVISION 



ing perhaps 30 channels into several 
trunks, each having a bandwidth of 
about 400 MHz. These are then 
bridged into branches, split into sub- 
branches, and tapped into perhaps 
10,000 homes. Several immediate 
consequences come to mind: a vast 
underutilization of bandwidth; no in- 
teractivity except for a few "experi- 
ments" like QUBE (even QUBE inter- 
activity is responsive in only one way: 
from the home to the head end); and 
a large investment in installed plant, 
including the head end, cable, dis- 
tribution amplifiers, etc. 

When two-way network-level interac- 
tivity is available, we will be able to 
send data from our location to any 
other location on the system. We 
could watch one program on the large 
portion of the display, two smaller 
programs on the small displays, and 
use the remaining small display to 
monitor our electronic mail. Figure I 
illustrates a distributed interactive 
CATV system having this two-way net- 
work capability. When we want to in- 
teract with the head-end facility, we 
first communicate via an access 
method with the nearest upstream 
video switch. This switch determines 
the type of data and its destination. 
Routing of traffic in this system is 
much simpler than in a packet-switch- 
ing system because of the limited 
number of choices (upstream, down- 
stream, return to same branch, and. 
channel to be used). For this example, 
video switch 1 routes the message 
upstream using network-level protocol 
to video switch 0, which converts the 
RF (radio frequency) message to base- 
band for serial input to the head-end 
computer. The return message follows 
an analogous path to the origination 
address. 

The distributed nature of the net- 
work enables users 7 and 8 to interact 
via video switch 2 without affecting 
communication with the head end. In 
this manner, average throughput of 
the network may be increased and 
average message delay minimized; 
when traffic and revenue warrant fur- 
ther investment, the system operator 
can install more switching at appro- 
priate nodes to improve the network. 



Each video-switch node also could 
contain memory for user applications. 
This would serve two purposes. First, 
many messages would be highly cor- 
related, hence system performance 
may be improved. For example, at 
7:55 p.m. it is reasonable to anticipate 
that many messages would request 
broadcast programming information. 
Answers could reside at the nearest 
installed video switch to minimize 
trunk traffic. Weather, road conditions, 
news, and other information could be 
similarly located. The second purpose 
for "application memory" involves 
storing large amounts of information 
for users, as more fully explained in 
the next section. 

User-to-user Video 
Facsimile 

Because the receiver will be able to 
store digitally frames of information 
(pictures or data) and communicate 
between any two users on the system, 
video facsimile is possible. Using this 
capability a user can send one picture 
to any other user on the system with 
a similar interface capability. It must 
be emphasized that this is not real- 
time video (continuously sending one 
frame after another, each frame tak- 
ing 1/30 second) but rather the 
transport of one single frame between 
destinations in about I second. An 



example is offices transporting docu- 
ments between different locations on 
the system. 

Perhaps shop-at-home services 
would become economically viable 
when high-quality video pictures that 
would take about I second to trans- 
mit over a cable TV network replace 
cartoon-like "pictures" that take tens 
of seconds to transmit over telephone 
lines. After all, we like to "see" what 
we are buying. 

It is unreasonable to expect people 
to manually input each frame if they 
want to participate in multiple-request 
interactive services. Fully automated 
interactive service will require multi- 
frame storage capability. This should 
be economically viable, could be 
used to provide responsive informa- 
tion to all users of the network, and 
may be located conveniently at the 
bridge nodes or video switches. 

Firmware 

Reliable operation of both the re- 
ceiver/set-top converter and the net- 
work switches will require well-devel- 
oped firmware. This should not be dif- 
ficult to obtain because equipment 
manufacturers have considerable ex- 
perience in these areas. The receiver's 
remotely controlled tuner already 
operates under the control of a micro- 

[continued] 




Photo 2: An example of multiple-picture-in-picture display using the 5W3 aspect 
ratio CRT! The red dots in the two corners of the small windows indicate high-definition 
television display availability. 



JANUARY 1985 'BYTE 137 



FUTURE TELEVISION 



processor. Some addressable CATV 
set-top converters have as many as 
three microprocessors. These use a 
token-passing scheme to gain access 
to a shared NOVRAM (nonvolatile 
random-access read/write memory 
with a back-up array of electrically 
erasable programmable read-only- 
memory cells) that stores channel re- 
quests, favorite channels, and other 
control information. Packet switches 
typically have used the most modern 
technology; design of video switches 
will most likely include 32-bit micro- 
computers. 

It is important to emphasize that the 
video switch also most likely will have 
extensive mass-storage capability and 
perhaps even will include many video- 
disc storage systems. Firmware will 
have to be developed to support the 
single-frame queries of hundreds of 
users to a given videodisc database 
in a manner that will not noticeably 



degrade the performance of the 
system. 

Picture Quality 

The subjective quality of a picture is 
determined partly by its vertical res- 
olution, horizontal resolution, and ar- 
tifact content. The vertical resolution 
of a picture is defined as the number 
of horizontal lines that may be seen 
in one picture height. This depends 
on the number of lines actually 
scanned across the display, the quali- 
ty of the "spot" scanning each line, 
and our ability to perceive the light 
that is produced. In the current NTSC 
system. 52 5 interlaced lines are trans- 
mitted 30 times per second. Only 
about 480 of these lines appear on 
the display, 240 in each l/60th-second 
interlaced field. The remaining "lines" 
are not shown on the display and oc- 
cur during the vertical flyback inter- 
val. This is the time required for the 



scanning spot to travel from the bot- 
tom to the top of the display and is 
necessary for the receiver to syn- 
chronize the picture scan to the 
proper position on the display. The 
vertical resolution may be repre- 
sented by the relationship V = K d N a , 
where V is the vertical resolution, K d 
is the display factor, and N a is the 
number of "active" lines. 

The horizontal resolution of a pic- 
ture is defined as the number of ver- 
tical lines that may be seen in a width 
of the picture equal to the picture 
height. This is primarily determined 
by the maximum frequency at which 
the spot scanning each line may be 
modulated (turned on and off). In the 
NTSC system this frequency is 4.2 
MHz, although many color television 
receivers restrict this value to about 
2.5 MHz, as explained later. 

Artifacts are visible effects on the 

{continued) 



HEAD -END 
CATV SYSTEM 


VIDEO 
SWITCH 




VIDEO 






SWITCH 1 















t> 



VIDEO 
SWITCH 2 



fc 



O Q- (> Q- (► 



Ul 



IK 



O — Q— (>— Q— 



O D- 



U2 



U5 




U10 



Ar 



ua 



R/ — 9~ c > — Q- c > 9- 



U6 



U# USER NUMBER 



a 



NTERACTIVE 






BRIDGER 



2-WAY SPLITTER 



NON-INTERACTIVE ( M- COUPLER 



-9" -9- 



USER TAPS 



Figure 1: An example of a two-way interactive cable-television system. 



138 BYTE • JANUARY 1985 




A New Age Dawns for 
Microcomputer Programming 



Meet 

promal: 

The First Fast 

Structured 

Language 

That Lets You 

Program The 

Way You 

Always 

Wanted To. 

And For 

Only 



PROMAL™ is innovative. 

PROMAL (PROgrammer's Micro 
Application Language) was 
designed to achieve maximum 
performance from small comput- 
ers... performance previously 
impossible except with machine 
language. And it was developed, 
specifically to meetthe need for 
a development system for limited 
memory environments. 
PROMAL is complete. 
It's a fast, structured programming 
language. It's also a true develop- 
ment system, complete with its 
own command-oriented 
operating system executive; fast 
one-pass compiler; and full- 
screen cursor-driven editor. In 
short, PROMAL is the complete 
set of tools that microcomputer 
programmers have been 
waiting for. 
PROMAL is fast 



with saves to memory and com- 
pilation from memory workspace 
PROMAL is elegant. 

PROMAL overcomes the perfor- 
mance limitations inherent in all 
small systems. It gives you access 
to the power of the machine. But 
it doesn't require the complexity 
of machine language program- 
ming. With PROMAL, you can 
have performance the easy way... 
since it was developed from the 
very beginning to work on small 
s/stems... elegantly. 
PROMAL may be the answer 
to your programming needs. 
Finally, there's an answer to the 
need for a complete environ- 
ment for simple and rapid 
program development. Finally, a 
new age has begun for micro- 
corn puter programmers. Finally, 
there's PROMAL. 



Commodore 64 Benchmark /JP/4^ X^ / 

(Sieve of Eratosthenes) SjSrs& /c^ /r 

/4?/ <$ /oyf 


y4*/ 


Execution Time (sees.) 


30 


630 


490 


51 


55 




Object Cede Size (bytes) 


128 


255 


329 


181 


415 




Prosram Load Time (sees,) 


3,2 


3.8 


63 


11.2 


235 




Compile Time (sees.) 


8.5 


— 


™ 


3.9 


108 





As the benchmark results i n the 
table show, PROMAL is much 
fester than any language tested. 
From 70% to 2000% faster! And 
it generates the most compact 
object code. The PROMAL 
compi ler is so fast that it can 
compile a 100-line source 
program i n 10 seconds or less. 
And, not only is it fast in compile 
and run time, it also reduces 
programming development time 
PROMAL is easy. 
It's easier to learn than Pascal or C 
or FORTH. It makes use of power- 
ful structured statements, like I F- 
ELSE, WHILE, REPEAT FOR, and 
CHOOSE. Indentation of state- 
ments is part of the language's 
syntax, so all programs srz neatly 
and logically written. Thereare no 
line numbers to complicate your 
programming. And comments 
don't take up memory space, so 
you can document programs 
completely. And with the full- 
screen editor, you can speed 
through program development 



PROMAL is available for the 
Commodore 64 now. 

PROMAL is scheduled for 
release on the Apple He in 
December, 1984and on the 
IBM PC in 1st Quarter, 1 985. 



PROMAL FEATURES 

COMPILED LANGUAGE 

Structured procedural lansuase 
with indentation 

Fast, 1-pass compiler 

Simplified syntax requirements 

No line numberins required 

Lons variable names 

Global, Local, & Arsvariables 

Byte, Word, I nteser & Real types 

Dec or Hex number types 

Functions w/ passed arsuments 

Procedures w/passed arsuments 

Built in I/O library 

Arrays, strinss, pointers 

Control Statements: IF-ELSE, IF, WHILE, 
FOR, CHOOSE, BREAK, REPEAI) 
INCLUDE, NEXi; ESCAPE, REFUGE 

Compiler I/O from/to disk or memory 

EXECUTIVE 

Command oriented, w/line editins 

Memory resident 

Allows multiple user prosrams in 
memory at once 

Function key definitions 

Prosram abort and pause 

22 Resident system commands, 
8 user-defined resident commands, 
no limit on disk commands 

Prior command recall 

I/O Re-direction to disk or printer 

Batch jobs 

EDITOR 

Full-screen, cursor driven 

Function key controlled 

Line insert, delete, search 

Strins search and replace 

Block copy, move, delete & writeto/ 

read from file 
Auto indent, undent support 

LIBRARY 

43 Machine-lansuase commands 
Memory resident 
Call by name with arsuments 
I/O, Edit, Strins, Cursor control 
and much more 

PROMAL runson 
Commodore 64s with disk drive. 



HOWTO ORDER 

D Please send me my copy of PROMALf or the Commodore 64 at $49.95 plus $5.00 for 
shipping and handling at a total cost of $54.95. Satisfaction guaranteed. 

D Please send mea PROMAL demo diskette for the Commodore 64at$10forthe diskette 
plus $2.50 for postage and handling for a total cost of $12.50. (Non-refundable.) 

D My check is enclosed. □ Please charge my purchase to my... □ Visa D MasterCard 



Expiration Date 



Signature 



City, State, Zip North Carolina residents add 4Vi% sales tax. 

For quicker response on credit card ord ers,call„. 

Toll Free 1-800-762-7874 (in North Carol i na 919-787-7703) 
Our Guarantee i 



Try your copy of PROMAL for 15 days. If you are not completely satisfied, return it to us 
undamaged and we'll refund your money. N o questions asked. Dealer inquiries invited. 






SYSTEMS MANAGEMENT ASSOCIATES 

3700 Computer Drive, Dept. PB-1 
Raleigh, North Carolina 27609 



Inquiry 343 



JANUARY I985 'BYTE 139 



FUTURE TELEVISION 



display that were not present in the 
original scene. They are caused by the 
manner in which a scene is encoded 
for transmission and the way it was 
originally sampled and then dis- 
played. The most common are 

• cross color, in which narrowly 
spaced lines break out into a rainbow 
of colors; striped shirts and windows 
on a building, for example, often 
become more colorful in certain areas 
due to this effect 

• cross luminance, in which sharp ver- 
tical color transitions and large 
saturated color areas appear to have 
small moving dots 

• large-area flicker, in which very 
bright areas seem to flash on and off 
at the 60-Hz field rate 

• line flicker, in which stationary 



edges that are not perfectly horizon- 
tal appear to move slightly up and 
down (or twinkle) 

• line crawl, in which certain vertical- 
ly moving objects lose about half their 
vertical resolution due to the inter- 
laced display 

In an attempt to minimize transmis- 
sion bandwidth, the NTSC encodes 
chrominance and luminance informa- 
tion within the same bandwidth. 
Hence, the bandwidth from about 2.3 
to 4.2 MHz is shared; the luminance 
information is centered on frequen- 
cies that are a multiple of the line fre- 
quency, while the chrominance infor- 
mation is offset by half the line fre- 
quency from these values. Successful 
decoding of the chrominance and 
luminance signals requires true 



FIELD 1 r 



LINE 7 / 



FIELD 2 $* 



FIELD 1 T 




TIME 



Figure 2: The sequential-scan conversion process. X indicates a transmitted line: O 
indicates a locally interpolated line. The solid green line indicates line average (motion), 
green dashes indicate picture average (still), green dots indicate field insertion (still). 



Figure 3: Line structure visibility. There are twice as many horizontal lines in 
the sequential-scan representation. 



separation of this frequency-inter- 
leaved information. To decode 
luminance inexpensively, many manu- 
facturers separate the signals by low- 
pass filtering the luminance. This 
limits the horizontal resolution rather 
severely but eliminates the cross- 
luminance artifact. Line comb filters 
make it feasible to extend the hori- 
zontal resolution to the NTSC limit of 
4.2 MHz with reduced cross effects. 

Improved Picture Quality 

Picture quality may be improved by 
increasing vertical or horizontal res- 
olution and encoding the information 
in a different way that precludes cross 
effects. At Philips Laboratories we 
have shown that the subjective picture 
quality of an NTSC signal could be im- 
proved further by the use of digital 
picture-store memories in the receiver 
without changing the transmitted 
signal. Motion-compensated inter- 
laced-to-sequential scan conversion 
demonstrates that perceived vertical 
resolution could be increased and line 
flicker eliminated. Figure 2 illustrates 
the interlaced scanning of normal 
NTSC television. If the transmitted 
lines are represented by X, the user 
sees the Xs in field I during the first 
sixtieth of a second (lines one, three, 
five, seven, etc.) and the Xs in field 2 
during the second sixtieth of a second 
(lines two, four, six, eight, etc.). This 
alternate-line scanning repeats every 
other field. 

With our approach, the transmitted 
signal format is not changed at all, but 
the alternate lines (represented by Os) 
that would appear in field 2 are stored 
in the receiver by spatial and tem- 
poral interpolation, and then all the 
lines are scanned in sequence rather 
than being interlaced. This technique 
results in a quiet appearance (with no 
line flicker) of the sequential display 
and an apparent increase in vertical 
resolution. 

As illustrated in figure 3, the most 
striking effect is a noticeable reduc- 
tion in the visibility of line structure. 
We are "misled" into believing that 
the number of transmitted lines has 
been doubled from 52 5 to 1050. The 

[continued] 



140 BYTE • JANUARY 1985 



HIGH TECHNOLOGY AT AFFORDABLE PRICES 



Dot Matrix Printers 

Brother 2044L/Dynax DM-40 $ 1 039.88 

C. Itoh Prowriter (8510) 359.88 

C. Itoh Prowriter-2, (136 col) 589.88 

C. Itoh Prowriter BPI (IBM-PC) 389.88 

C. Itoh HotDot 509.88 

C. Itoh HotDot-2 (136 col) 729.88 

DMX-80 (Panasonic 1 090) 259.88 

Epson RX/FX/LQ Series CALL 

E pson/l magew riter upgrade CALL 

Inforunner Riteman 309.88 

Mannesmann Tally Spirit-80 329.88 

Okidata Microline 92 399.88 

w/IBM graphics compatibility 399.88 

w/ 1 magew riter compatibility 499.88 

Okidata Microline 93 . 639.88 

93 w/IBM graphics compatibility 639.88 

Okidata Microline 84 Step II 739.88 

NEC Pinwriter w/tractor (80 col) 699.88 

NEC Pinwriter w/tractor (1 32 col) .... 929.88 

Star Micronics Gemini 10X (PC) 269.88 

Star Micronics Gemini 15X (PC) 369.88 

Star Micronics Delta 10 (PC) 339.88 

Star Micronics Delta 15 (PC) 489.88 

Star Micronics Radix 10/1 5 (PC) CALL 

Toshiba P-1351 CALL 

Toshiba P-1340 CALL 

Printer Buffers (Quadram) CALL 

Letter-Quality Printers 

Brother/Dynax DX-1 5 $ 399.88 

Brother/Dynax DX-25 669.88 

Brother/Dynax DX-35 939.88 

C. Itoh A-10 Starwriter (18 cps) 549.88 

C. Itoh F-10 Starwriter (40 cps) 1079.88 

C Itoh F-10 Printmaster (55 cps). . . . 1379.88 

Diablo 620/630/Series 35 CALL 

NEC 2010/2030 (18 cps) 739.88 

NEC 2050 for IBM-PC (18 cps) 759.88 

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Qume Sprint 11/40 (40 cps) 1519.88 

Qume LetterPro 20 (1 8 cps) ... . 459.88 

Silver Reed EXP-770 (35 cps) 979.88 

Silver Reed EXP-550 (18 cps) 469.88 

Silver Reed EXP-500 (12 cps) 389.88 

Silver Reed EXP-400 (1 cps) 329.88 

Star Micronics PowerType (18 cps). . . 349.88 

Modems 

Anchor Volksmodem, 300 bd $ 69.88 

Anchor Mark XII, 1 200 bd 279.88 

Hayes Micromodem He (Apple) 249.88 

Hayes Smartmodem, 300 bd CALL 

Hayes Smartmodem, 1 200 bd CALL 

Hayes Smartmodem 1 200B (PC) CALL 

Novation AppleCat, 300 bd 239.99 

Novation AppleCat, 1 200 bd 449.88 

Novation SmartCat+, 

IBM-PC Internal, 1 200bd 349.88 

External, w/software (MS-DOS) 349.88 

USR Password, 1 200 baud 369.88 

Multi Phone-Line Junction Box 29.88 

Monitors 

Amdek 300G (green) $ 144.88 

Amdek 300A (amber) 159.88 



Amdek Color 300 (composite) CALL 

Amdek Color 600 (RGB) CALL 

Princeton Graphics HX-1 2 509.88 

Princeton Graphics Max-1 2 199.88 

Quadram QuadChrome 529.88 

Roland DG-1 21 (green/amber) 144.88 

Roland DG-122(TTL output, 

green or amber, w/cable) 169.88 

IBM-PC Peripherals 

64K Memory (41 64/200ns) 9/pkg $ 59.88 

Alloy 41 MB Hard Disk w/Tape CALL 

Alloy PC Tape Backup CALL 

Curtis Monitor Stand 39.88 

Curtis Monitor Extention Cable 39.88 

Curtis Keyboard Extention Cable 29.88 

Curtis System Stand 79.88 

Hercules Graphics Card 379.88 

Keytronics5151 keyboard 219.88 

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PC-Paint Software $ 69.88 

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Ask about our new PC Software selections! 

Quadram 384K Quadboards (64K) . . . 269.88 

Quadram Quad 512+ (64K) 239.88 

Quadram Quad 512 + (512K) 504.88 

Quadram QuadColor-1 219.88 

Quadram QuadColor-2 229.88 

QuadVue (TTL output) 259.88 

Quadram QuadLink 509.88 

STB Graphics Plus II 359.88 

STB Super I/O 769.88 

STB Super RIO (64K) 289.88 

STB Super RIO Plus (64K) 309.88 

Tandon TM 100-2 DSDD 799.88 

Titan Cygnus I/O (clock/parallel) 149.88 

Titan Cygnus I/O (clock/RS-232) 769.88 

TG Joystick 59.88 

Apple Peripherals 

ALS CP/M Plus Card (CP/M 3.0). ...$ 279.88 

ALS Smarterm II (80 col) 1 39.88 

ALS Dispatcher (RS-232) 74.88 

AMT MicroDrive (half height) 779.88 

Grappler+ Printer Card & cable 109.88 

Microsoft Softcard (CP/M) 244.88 

Microsoft Softcard He (CP/M, 64K, 

80 col. for He only) 279.88 

Pkasso-U Printer Card & cable 729.88 

Printer Card & cable 79.88 

Quadram E-Ram (He, 80 col/64K) .... 709.88 

Rana Elite-1 Disk Drive 279.88 

Rana Controller 84.88 



Titan/Saturn Memory Boards 

32K $ 154.88 

64K 244.88 

Neptune 64k/80 col (lie) 794.88 

System Saver Fan 69.88 

Titan Accelerator II 239.99 

Videx VideoTerm 7 99.88 

Videx VideoTerm/softswitch 279.88 

Videx UltraTerm (80/1 60 column) .... 244.88 
Videx Enhancer II 109.88 

Macintosh Peripherals 

1 st Base DB $ 139.88 

Diskettes (5-pk) 24.88 

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Habadex DataBase 7 39.88 

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Kensington Starter Pak 69.88 

Kensington Modem 7 7 9.88 

Living Video Think Tank 99.88 

MacForth (Level II) 7 79.88 

Microcom MacModem 499.88 

Micron Eye (digitizer) CALL 

Microsoft BASIC. , 709.88 

Microsoft MultiPlan 739.88 

Magnum McPic 39.88 

Main Street Filer 739.88 

Megahaus MegaMerge 89.88 

Odesta Helix PDSS 279.88 

Omnis 2 (mouse ver.) 7 99.88 

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PFS:File 89.88 

PFS: Report 89.88 

ProVUE OverVue 799.88 

Sargon III 39.88 

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TECHNICAL INFORMATION/SALES 

(603)881-9855 

TOLL-FREE ORDER DESK 

(800) 343-0726 

Hours: 9:00 to 5:30 EST, Mon-Fri 

■ FREE UPS ground shipping on all orders over $50 
(under $50 add $2.50 handling) 

■ MasterCard, VISA, American Express, Diners 
Club & Carte Blanche credit cards accepted 

■ No surcharges on credit card orders 

■ Credit cards are not charged until your order 
is shipped from our warehouse 

■ CODs accepted up to $1 000 (add $1 for COD 
handling). Payable with certified check, money 
order or cash. 

■ Allow 1 days for shipping from date of order 

■ All personal checks held 30 days for clearance 

■ Full manufacturer's warranty on all products sold 

■ Software can be returned for an exact exchange 
only; no credits or refunds issued 

■ Sorry, no APO/FPO or foreign orders 



THE BOTTOM LINE 



HIGH 

TECHNOLOGY 

AT 

AFFORDABLE 

PRICES 



MILFORD, NH 03055-0423 • TECHNICAL (603) 881-9855 • ORDER DESK (800) 343-0726 



Inquiry 43 



JANUARY 1985 -BYTE 141 



FUTURE TELEVISION 



transmitted signal remains unchanged 
(52 5 lines 30 times per second) but 
has its perceived value increased by 
conversion for display at 52 5 lines 60 
times per second. 

Sequential Scan Conversion 

Three methods can be used to con- 
vert a transmitted interlaced-scan 
signal to a displayed sequential-scan 
signal. Line averaging displays double 
the number of lines of information per 
picture but reduces the vertical reso- 
lution. However, line structure visibili- 
ty is reduced without introducing ar- 
tifacts on moving parts of the picture. 
Line flicker, however, is not eliminated 
by line averaging. Picture averaging (or 
field insertion) combines the information 
of all lines of both fields to preserve 
the vertical resolution and eliminate 
line flicker. However, in moving 
scenes, the relatively large time dif- 
ference between the two fields pro- 



duces jagged edges on moving con- 
tours. A third approach combines the 
previous two and adds motion-detection 
circuitry. 

R. Prodan, of our laboratory, has 
demonstrated motion-detection cir- 
cuitry that switches between the two 
methods to avoid new artifacts 
created by the scan-conversion pro- 
cess. Line-averaged and field-delayed 
information is combined in a com- 
plementary way based on the amount 
of motion in each picture element. A 
gradual switching from one interpola- 
tion technique to the other minimizes 
the visibility of the switching process. 
The scan conversion is accomplished 
by digitizing the composite video 
signal. T\vo field memories are used 
with the digitized input signal to pro- 
vide the three fields of information 
needed to produce a motion-adaptive 
sequential-scan conversion. In this 
way, displayed picture quality is im- 



proved without introducing any new 
scan-conversion artifacts. 

HDTV System 
Considerations 

The fundamental relationship be- 
tween the various factors that may be 
improved in a television picture is 



R H RvRw = N c 



Dn 

D Q 



where R H is the horizontal-resolution 
improvement factor, R v is the vertical- 
resolution improvement factor, R w is 
the width improvement factor, N c is 
the number of channels used, and D„ 
and Do are the display factors of the 
new and old systems, respectively. Of 
particular interest are two-channel se- 
quentially displayed systems for which 
N c = 2, D n = 0.8. and D G = 0.5. 

Doubling the perceived vertical res- 
olution of an NTSC display may be ac- 

[continued] 



CAMERA 





© — © 





HDTV RECEIVER 



CABLE TELEVISION 
DISTRIBUTION SYSTEM 



f 






PICTURE 


PC TEXT 
ON SCREEN 


PICTURE 


PICTURE 
) 





TUNER 
#1 


TUNER 
#2 






^SP 



EAKER SPEAKER- 



#1 



#2 



TUNER 



SPEAKER 
#1 



T 



□aaonnn 
oanaoDoo 

00000000 „" 



TELECINE 



NTSC RECEIVER 



Figure 4: A block diagram of a two-channel high-definition television system. 



142 BYTE' JANUARY 1985 



INSTANT LAN 



WITH STANDARD MICROSYSTEMS' NEW ARCNET-PC, ARCNET-S100 OR 
ARCNET-UNK, YOU CAN CREATE YOUR OWN LOCAL AREA NETWORK. 

The world's first single-chip local area network controller established 
Standard Microsystems as a leader in networking technology, Now we're 
devoting our technical expertise to bring you revolutionary LAN board prod- 
ucts, too, 

Our ARCNET-PC board interconnects up to 255 IBIvf-type personal com- 
puters, permitting them to share 
disk files and printer resources 




ARCNET-UNK 



ARCNET- 



ARCNET-S100 



at an extremely efficient 
2.5 Megabit data rate. 

The ARCNET-S100 board links up to 255 S100 computer systems, providing 
the S100 computer user with a high performance local area network. 

The ARCNET-LINK is a self-contained unit that provides a simplified inter- 
face between equipment with a programmable asynchronous RS-232 port 
and an ARCNET 8 local area network, 

All three products incorporate SMCs industry-standard MOS/VLSI local area 
network chip set to give you a totally integrated and cost-effective LAN solution, 
Soffware available from Standard Microsystems and others provides increased 
capability for your networking applications. Standard Microsystems Corpora- 
tion, 35 Marcus Boulevard, Hauppauge, NY 11788. (516) 273-3100. 

STANDARD MICROSYSTEMS 
CORPORATION^ 



IBM® is a Trademark of the International Business Machines Corporation. 
ARCNET® is a trademark of the Datapoint Corporation. 



r 



Inquiry 329 



JANUARY 1985 'BYTE 143 



FUTURE TELEVISION 



complished by simultaneously in- 
creasing the number of lines and the 
display factor. Because the required 
bandwidth of a system increases in 
proportion to the square of the num- 
ber of lines, it is preferable to use the 
minimum number of lines in an HDTV 
system. Hence, an 1125-line interlaced 
display has a perceived vertical reso- 
lution of about 562 lines, while a 
657-line sequential display has a vertical 
resolution of 526 lines while using 
only (657/1 12 5) 2 = 34 percent of the 
bandwidth. It is possible, therefore, to 
double the perceived vertical resolu- 
tion of an NTSC display by increasing 
the number of lines from 52 5 to 657, 
transmitting this interlaced signal, per- 
forming an interlaced-to-sequential 
scan conversion in the receiver, and 
finally displaying the result sequential- 
ly. For a 5 ] A : 3 aspect ratio (R w = 1.33) 
two-channel system, this results, how- 



ever, in only a 20 percent increase in 
horizontal resolution. 

Another point to consider is avail- 
able transmission bandwidth. A 
straightforward doubling of the 
number of lines from 52 5 to 1050, in- 
creasing the width from 4:3 to 5/3:3, 
and doubling the resultant signal 
bandwidth would require 5 ] A times 
the single-channel bandwidth. By in- 
creasing the display factor and in- 
creasing the number of lines from 525 
to 657, the required bandwidth is 
reduced to only 3 ] A times the single- 
channel bandwidth. 

These two approaches are unac- 
ceptable because they use an ex- 
cessive amount of bandwidth. The 
two-channel 657-line system offers 
only a 20 percent improvement in 
horizontal resolution; doubling the 
horizontal resolution would require 
' 3/3 times the NTSC bandwidth. We 





HDTV 








657 


LINES 5 1/3 


3 




p 








1 P 


A 








1 A 


N 




CENTER 




1 N 


E 








i E 


L 








1 L 
L 


5.5 M s 


















* 











CHANNEL 1 
525 LINES 4:3 



CHANNEL 2 
525 LINES 4:3 



CENTER 
(LOW PASS) 



-53/iS- 



1 

1 
1 
1 

L, r- 

1 
1 
I 


HIGH- 
FREQUENCY 
SUBSAMPLES 
(393 LINES) 


i 
1 
1 
1 

1 P 
1 A 
1 N 
1 E 
J L 


132 

EXTRA LINES 


1 

1 
1 
l 


- 5.5/isU — 

•* — 




1 


53 us 


> 



Figure 5 : A possible method for delivering a two-channel NJSC-compatible 
high-definition television transmission. 



feel that these problems may be over- 
come by better matching the trans- 
mitted television signal to the proper- 
ties of human vision. 

PSYCHOVISUAL ENHANCEMENT 

Drs. William Glenn and Karen Glenn 
at the New York Institute of Tech- 
nology have shown that it requires a 
finite time to perceive changes in 
images. Although the exact relation- 
ship is complex and not completely 
understood, the general principle is 
that the difficulty in perceiving an 
image increases as its subtended 
spatial angle decreases and/or its rate 
of motion increases. The operational 
impact is that it is unnecessary to 
transmit the high spatial-frequency in- 
formation in pictures at the standard 
rate of 30 frames per second (fps). 
The required transmission bandwidth 
may be reduced significantly without 
affecting the perceived horizontal 
resolution by transmitting low spatial- 
frequency information (below 4.2 
MHz) at the standard rate and refresh- 
ing high spatial-frequency information 
(above 4.2 MHz) below the standard 
rate. This, of course, requires digital 
memory in the receiver so that the 
60-Hz field rate sequential display 
may have the full horizontal resolution 
composed from the previous few 
fields. The doubling of horizontal res- 
olution at 30 fps, which normally in- 
creases bandwidth requirements by a 
factor of 20/1 5, may be reduced by a 
factor of 5 to 4/15. A two-channel 
HDTV system having about twice the 
perceived vertical and twice the per- 
ceived horizontal resolution of NTSC 
television may be realized by trans- 
mitting the higher frequencies at an 
equivalent of only 6 fps. 

Two-Channel 
NTSC-Compatible HDTV 

In a two-channel NTSC-compatible 
HDTV, signal sources may be dis- 
tributed over a cable system to either 
present NTSC receivers or new HDTV 
receivers (see figure 4). In this man- 
ner producers, distributors, and 
equipment manufacturers will be able 
to continue to operate as the evolu- 

[continued) 



144 B YTE • JANUARY 1985 



Inquiry 178 for Dealers. Inquiry 179 for End-Users. — ► 



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FUTURE TELEVISION 





HDTV DISPLAY 

657 LINES 

5 1/3:3 ASPECT RATIO 

30 FRAMES/second 
















\ 


1 




! 


< 




v 




V 


657 -TO -525 

LINE 

INTERPOLATOR 




PANEL 
EXTRACTOR 




132-LINE 
STRIPPER 




HIGH- 
FREQUENCY 
DECIMATOR 
(6 FRAMES/second) 


l 


' 























CHANNEL 1 
(STANDARD 
NTSC) 



CHANNEL 2 

(HDTV 

ENHANCEMENT) 



Figure 6: A block diagram of two-channel decomposition. 



CHANr 


JEL 1 CHANr 


JEL 2 










< 


! 




1 


























HIGH- 












132 -LINE 




FREQUENCY 




PANEL 








STRIPPER 




SAMPLER 

(6 FRAMES/second) 




EXTRACTOR 






' 


f ! 


t 




i 


1 








525 -TO -657 

LINE 

RECONSTRUCT 




HIGH- 
FREQUENCY 








INTERPOLATOR 

(30 FRAMES/second) 






^""--v^ 1 


1 ^s^*^ 




^^Qr 




HDTV DISPLAY 






657 LINES 






5 1/3:3 ASPECT RATIO 






30 FRAMES/second 







Figure 7: A block diagram of two-channel reconstruction. 



tion toward HDTV occurs. 

Figure 5 shows one possible 
method of delivering this HDTV signal 
over two standard NTSC channels. 
This approach separates the HDTV 
signal into a standard NTSC channel 
(channel 1) and an augmentation 
channel (channel 2). Channel 1 con- 
tains the "center" 4:3 aspect ratio por- 
tion of the HDTV picture that has 
been low-pass filtered to 4.2 MHz 
horizontally and converted from 657 
to 52 5 lines by a vertical filtering 
operation. This signal can be dis- 
played on all current NTSC receivers. 
Channel 2 contains 132 of the original 
657 lines, the side panels for the 5^:3 
aspect ratio display and the high- 
frequency information for the entire 
5/3:3 picture in the remaining 393 
lines between the side panels. The 
side panels and 132 extra lines are 
low-pass filtered to 4.2 MHz. The high- 
frequency subsampled information is 
shifted into the same 4.2-MHz low- 
pass region by a filtering and sample- 
rate conversion process. This signal 
also can be displayed on all current 
NTSC receivers. 

Figure 6 is a block diagram of the 
two-channel decomposition. The 657- 
to-52 5 line interpolator produces the 
horizontally low-pass filtered 52 5-line 
NTSC picture from the 657-line wide- 
band, wide-aspect ratio source. Dur- 
ing this process, 132 of the original 
657 lines are low-pass filtered and in- 
serted into channel 2. This informa- 
tion represents a linear transforma- 
tion of the original 657 lines, which 
makes the procedure reversible at the 
HDTV receiver. 

The panels outside the normal 4:3 
center portion are extracted after a 
52 5-line interpolation and similarly in- 
serted into channel 2. This permits 
reconstruction of the 5Vr3 aspect 
ratio low-pass information at the 
HDrV receiver. The high spatial- 
frequency information is subsampled 
temporally at a 6-fps rate, shifted to 
the baseband low-pass frequency 
region, and inserted into the 393 re- 
maining lines between the panels in 
channel 2. The two channels are trans- 
mitted simultaneously over two 

{continued) 



146 B YTE • JANUARY 1985 



THE 8087 AND 80287 ARE IN STOCK! 



MlcroWay Is the world's leading retail- 
er of 8087s and high performance PC 
upgrades We stock a complete selec- 
tion of 8087s that run at 5 and 8mhz. 
All of our coprocessors are shipped 
with a diagnostic disk and the best 
warranty in the business - 1 80 days! 
We also offer daughterboards for sock- 
etless computers such as the NEC PC 
and PCjr, and a board which increases 
the clock speed of the 80287 in the PC 
AT. Our new NUMBER SMASHER™ 
will run the IBM PC at clockspeeds up 
to 10mhz and achieves a throughput 
of.1 megaflopswith87BASIC/INLINE, 



SCIENTIFIC SOFTWARE 

87FFT'" performs Forward and Inverse FFTs 
on real and complex arrays which occupy up to 
5 1 2 K bytes of RAM. Also does convolutions, auto 
correlations, hamming, complex vector multiplica- 
tion, and complex to radial conversions. Callable 
from MS Fortran or 87BASIC/INLINE $1 50 

87 FFT^™ performs two-dimensional FFTs 
Ideal for image processing. Requires 87 FFT...$75 

MATRIXPAIC manages a MEGABYTE! 
Written in assembly language, our runtime 
package accurately manipulates large matrices 
at very fast speeds Includes matrix inversion and 
the solution of simultaneous linear equations 
Callable from MS Fortran 3.2, 87 MACRO, 
87BASIC/INLINE, and RTOS each $1 50 

DATA ACQUISITION PACKAGE 

Interactive, user-oriented language which allows 
the acquisition and analysis of large data 
streams CALL 

GRAPHICS PACKAGES 

Energraphics (stand alone) 295 

Grafmatic for MS Fortran or Pascal 1 25 

Plotmatic for Grafmatic 1 25 

Halo for Basic, C or Fortran each 1 50 

OTHER TOOLS 

Alpha Software ESP 595 

Borland Sidekick, Toolbox, or Graphics 45 

COSMOS Revelation 850 

PSI MATHPAK 75 

smARTWORK 895 

SPSS/PC 695 

STSC APL*PLUS/PC 475 

Pocket APL 85 

PC AT and 86-310 DRIVES 

30 MEGABYTE WINCHESTER 2000 

53 MEGABYTE WINCHESTER 2600 

SYQUEST FIVE MEGABYTE 950 

FIVE MEGABYTE CARTRIDGE 1 00 

MAYNARD WS1 HARD DISK 950 

MAYNARD WS2 or WS3 HARD DISK .... 1 1 09 



Micro 
May 



P.O. Box 79 
Kingston, Mass 
02364 USA 
(617) 746-7341 



Intel Fortran, or Microsoft Fortran. 
Software reviewers consistently cite 
MicroWay software as the best in the 
industry! Our customers frequently 
write to thank us for recommending 
the correct software and hardware to 
meet their specific needs. They also 
thank us for our same day shipping! In 
addition to our own products which 
support the 8087 and 80287, we stock 
the largest supply of specialized soft- 
ware available anywhere These include 
three FORTRANs, three PASCALS, 
APL, Intel's ASM-86 and PL/M-86, 
several Cs, 87BASIC/INLINE, 



87MACRO, 87FFT, and MATRIXPAK. 
For real time or multi-user applica- 
tions we offer RTOS" - our implement- 
ation of Intel's iRMX executive. Our 
new products include a professional 
debugger with 8087 support and a 
translator that converts object mod- 
ules into readable assembly language 
files. If you have a question about 
which computer, language, compiler, 
operating system or application pack- 
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can answer it. Just call: 

617-746-7341 




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Way 



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For the IBM PC, PC XT, PC AT and Compatibles. 



RTOS - REAL TIME OPERATING SYSTEM 

RTOS is a multi-user, multi-tasking real time oper- 
ating system. It includes a configured version of 
I nters iRMX-86, LINK-86, LOC-86, LIB-86, OH-86, 
and MicroWays 87DEBUG. Runs on the IBM-PC, 
XT, PC-AT and COMPAQ 400 

INTEL COMPILERS 1 

FORTRAN-86 750 

PASCAL-86 750 

PL/M-86 500 

87C (LATTICE/MICROWAY) 750 

ASM-86 200 

87 BASIC/ IN LINE" converts the output of 
the IBM Basic Compiler into optimized 8087 
inline code which executes up to seven times 
faster than 87 BASIC. Supports separately com- 
piled inline subroutines which are located in their 
own segments and can contain upto64K bytes of 
code. This allows programs greater than 1 28 K! 
Requires the IBM Basic Compiler and Macro 
Assembler. Includes 87BASIC $200 

87 MACRO™ - our complete 8087 software 
development package. It contains a "Pre- 
processor," source code for a set of 8087 macros, 
and an object iibrary of numeric functions includ- 
ing transcendentals, trigonometries, hyperbolics, 
encoding, decoding and conversions For the IBM 
Macro Assembler, Version 1 .0 or 2.0 $1 50 

OBJ --►ASM™ - a multipass object module 
translator and disassembler. Produces assembly 
language listings which include public symbols, 
external symbols, and labels commented with 
cross references Ideal for understanding and 
patching object modules and libraries for which 
source is not available $200 

87 DEBUG™ - a professional debugger with 
8087 support, a sophisticated screen-oriented 
macro command processor; and trace features 
which include the ability to skip tracing through 
branches to calls and software and hardware 
interrupts Breakpoints can be set in code or on 
guarded addresses in RAM $150 



You Can 
TalkToUs! 



HARDWARE AND LANGUAGES 

8087-3 5mhz $149 

Including DIAGNOSTICS and 1 80-day warranty 
For IBM PC and compatibles 

8087-2 8mhz $275 

For Wang, AT&T, DeskPro, NEC, Leading Edge 

80287-3 5mhz $275 

For the IBM PC AT 

64KRAMSet $30 

256KRAMSet $195 

128K RAM Set pc at $225 
NUMBER SMASHER" call 

10mhz 8087 coprocessor board for the IBM PC 
FORTRAN and UTILITIES 

Microsoft Fortran 3.2 239 

IBM Professional Fortran 595 

Intel Fortran-86 1 750 

FORLIB+ 65 

STRINGS and THINGS 65 

C and UTILITIES 

Lattice C 299 

Microsoft C 329 

C86 299 

C TOOLS 85 

C Trigs and Trans 1 50 

BASIC and UTILITIES 

IBM Basic Compiler 270 

87BASIC/INLINE 200 

Summit BetterBASlC™ 1 75 

Summit 8087 Module 87 

MACROASSEMBLERS 

IBM Assembler with Librarian 1 55 

87MACRO 1 50 

PASCAL 

Microsoft Pascal 3.2. 209 

Borland Turbo 45 

Turbo with 8087 Support 85 

1 Requires RTOS or iRMX-86. All Intel compiler 
names and iRMX-86 TM Intel Corp 

Formerly MicroWare, Inc. - not affiliated or 
connected with MicroWare Systems Cor- 
poration of Des Moines, Iowa. 



Inquiry 240 



JANUARY 1985 -BYTE 147 



Inquiry 110 



DISCOUNT 

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U.S. ROBOTICS 

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586-20 - $5695 586-40 - $7195 
SANYO 

550-1 -$679 555-2- $1049 



PRINTERS 



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F10 - $899 8510 -$1175 

DATASOUTH 

DS180-$1099 DS220-$1399 

DIABLO 

620 - $725 630- $1675 

EPSON 
RX80 - $220 JX80 - $560 

NEC 

3510 -$1215 3550- $1519 

OKIDATA 

182 -Call 93 - $575 

SILVER REED 

400 - $269 770 - $839 

TELEVIDEO 

TPC II -$1729 1605 -$1699 



SOFTWARE 



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123 - $295 SYMPHONY - $439 
MICROPRO 

Wordstar - $189 Wordstar Pro - $295 

D Base II - $299 Friday - $175 

Multiplan - $139 Supercal III - $200 

MBSI-$325 TCS-$75 



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Six Pac - $259 Combo + - $259 
QUADRAM 

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WYSE 

50 - $495 75 - $565 



DISCOUNT COMPUTER 

4655 N. ORACLE RD. #207 

TUCSON, ARIZONA 85705 

Prices Subject To Change. 



FUTURE TELEVISION 



separate NTSC channels. Standard 
receivers would receive either of 
these; the channel l signal is the 
equivalent of the present transmis- 
sion, the channel 2 signal is recogniz- 
able as the extra information neces- 
sary to build the perceived better 
picture. 

Figure 7 is a block diagram of the 
two-channel reconstruction. Channel 
1 carries the center portion of the 
wide-aspect ratio picture. The side 
panels are extracted from channel 2 
to give a 51/3:3, 525-line low-pass pic- 
ture. The extra 132 lines are stripped 
from channel 2, and a linear transfor- 
mation yields the original 657 lines in 
the low-pass region of standard NTSC 
horizontal resolution. The high-fre- 
quency information is extracted from 
channel 2, shifted up to the original 
high-frequency region to refresh a 
digital memory frame store that 
receives the information over the 
channel at 6 fps. The frame store is 
continuously read out at the standard 
30-fps rate. This increases the per- 
ceived horizontal resolution to dou- 
ble the standard NTSC resolution for 
still pictures. Horizontal detail will 



have lower temporal resolution due to 
the subsampling. The eye is less sen- 
sitive to fine detail that's moving; we 
will not perceive this loss in 
"theoretical" resolution. 

Non-Shared 
Bandwidth Systems 

A digital frame memory in the re- 
ceiver enables further improvements 
in picture quality. The noise perfor- 
mance of the receiver may be im- 
proved about 3 decibels by construct- 
ing a nonrecursive digital filter having 
a 30-Hz periodicity. This is more im- 
portant when relatively noisy sources 
(for example videocassette recorders) 
are used. "Frame combing" further 
reduces cross effects. 

Some video engineers say that this 
level of performance should be im- 
proved still further by completely 
eliminating cross effects. This may be 
done by frequency or time multiplex- 
ing the luminance and chrominance 
information in the video signal. To 
eliminate cross effects by frequency 
multiplexing, the encoding must not 
let the luminance and chrominance in- 
formation share the same bandwidth. 



Memory Technology for 
Digital-Feature Television 



Many new television features 
described in this article are 
made possible by low-cost digital 
memories used to store displayed 
images. The displayed portion of each 
of the 480 lines in the current 4:3 NTSC 
system takes about 53.5 fis to scan. 
When sampled at 13.5 MHz, this 
results in 720 I -byte samples per line. 
To facilitate signal processing, this is ex- 
panded to 720 + 180 + 180 = 1080 
bytes per line; the extra samples are 
added so that luminance and two 
color-difference signals are digitally 
available. Widening the screen to 5W. 3 
without increasing the horizontal res- 
olution increases this to 1080 x5 l A/4 
= 1440 bytes per line. Doubling hori- 
zontal resolution results in a total of 
2880 bytes per line. Because the 



657-line system has about 600 lines on 
the display, one HDrV image requires 
a total of 1,728,000 bytes of storage. 
Currently there are two competing 
technologies for implementing this 
store: high-speed DRAMs (dynamic 
RAMs) and charge-coupled devices 
(CCDs). DRAMs offer the advantage of 
easily handling multiple-picture com- 
position. CCDs, which operate as a 
FIFO (first-in/first-out) sequential store, 
do not require address generation. Fur- 
ther, the extremely high-speed require- 
ments. 2880 bytes in 42 /is. or 1 byte 
about every 1 5 nanoseconds, may be 
more readily attainable in this tech- 
nology. Components similar to line- 
addressable RAMs (LARAMs) could be 
developed by 1C manufacturers to fill 
this need. 



148 BYTE' JANUARY 1985 



Inquiry 275 



FUTURE TELEVISION 



Glossary 



Active lines: lines of the television 
signal that appear on the display; the 
NTSC television signal has 525 lines, of 
which about 480 are displayed; the re- 
maining lines are used for synchroni- 
zation and test purposes. 

Artifacts: visible effects, generated in 
a picture due to its transmission, that 
were not present in the original scene. 

Aspect ratio: picture width divided by 
picture height; standard television has 
a 1.33 (or 4:3) aspect ratio; high- 
definition television will have a wider 
(perhaps 1.66 or 1.78) aspect ratio 
more like that of motion picture film. 

Chrominance: part of the television 
signal that characterizes the color (hue 
and saturation) without reference to its 
luminous intensity (brightness). 

Comb filter: an electronic filter with 
a spectral response that consists of 
several equally spaced elements that 
resemble the teeth of a comb. 

Display factor: a constant that con- 
verts the number of active lines 
transmitted into the number of vertical 
lines perceived on a display. 

Field: a sample of the lines in a TV pic- 
ture (or frame); a field in NTSC TV con- 
sists of 262/2 lines transmitted in 1/60 
second; i.e.. all the odd- or even- 
numbered lines in the picture. 



Frame: smallest number of fields com- 
prising one complete television picture; 
in NTSC television, two fields having a 
total of 525 lines transmitted in 1/30 
second (i.e.. all the lines in a picture). 

Frame memory: a digital device using 
either RAMs or charge-coupled 
devices to store a complete television 
picture; for NTSC television, this re- 
quires about 500.000 bytes. 

Interlaced scan: a means of display- 
ing a picture whereby the lines of the 
second field of a frame are placed 
halfway vertically between the lines of 
the first field of a frame. 

Luminance: part of the television 
signal that characterizes the light inten- 
sity (brightness) without reference to 
its color (chrominance). 

Resolution: the number of lines that 
may be represented in a distance equal 
to the height of a display. 

Sequential scan: a means of display- 
ing a picture whereby all the lines of 
a frame are presented one after an- 
other in sequence; sometimes referred 
to as progressive scan. 

Video facsimile: transmission of one 
television picture from one to any 
other location on a CATV system in 
about 1 second. 



If all the luminance information from 
2 to 4.2 MHz is up-converted by 3 
MHz. then the chrominance and 
luminance information are easily 
separable, completely eliminating 
cross effects. 

Cross effects also may be elimi- 
nated by time multiplexing the 
chrominance and luminance informa- 
tion. Instead of encoding the 
chrominance and luminance informa- 
tion on each line into a shared- 
bandwidth composite-video signal, 
the information is individually time- 
compressed and shifted. For a typical 
MAC (multiplexed analog component) 
signal sound and sync information 
occupies the first 10 (is (microsec- 
onds) of each line; one of the color- 



difference signals, time-compressed 
by a factor of three, occupies the next 
18 ps of the line; and the luminance 
signal, time-compressed by a factor of 
three to two. occupies the remaining 
36 fis of the line. 

Time compression of the signal by 
an amount X increases the required 
bandwidth for transmission X times. 
Hence, the required bandwidth for 
transmission of the luminance is 1.5 
x 4.2 = 6.3 MHz. while the required 
bandwidth for the chrominance is 3 
x 1.5 = 4.5 MHz. The choice of the 
compression factors is based not only 
on bandwidth considerations but also 
on noise performance over the com- 
munication channel. In principle, any 

[continued) 




New 

graphics system 

otters wide 

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♦ Industry standard buses. 

♦ Adapts to thousands of tasks. 

♦ Expandable with modules from 
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♦ Obsolescence proof. 

♦ Color or monochrome. 

Our new Perigraf 1 is built around a 
standard Q-bus with slots for many extra 
cards to expand or customize your system. 

Peritek offers cards for color or 
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numerics, for low to high resolution, and 
for one or more display channels. 

You can choose a single unified bus 
or a bus split for two microprocessors. 
Choose a standard single-wide enclosure 
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You get a hard disk and two floppies 
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area networking by Ethernet. 

Complete development software is 
included. Image editor. Vector de- jagging. 
System diagnostics. GKS-compatible 
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Basic $14,500 price includes 11/73 
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Contact Peritek Corporation, 5550 
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(415) 531-6500. Eastern Regional Sales 
Office (516)931-4664. TWX 910-366-2029. 



Peritek 



JANUARY 1985 • BYTE 149 



"It reminded me of some of 

the early micro conventions, 

the fun ones before they 

got so large . . . there were 

also a number of industry 

heavyweights to make it likely 

that what was said would 

have an effect" 



— Jerry Pournelle on Sage Faire '84 



For three days in February, Stride 
Faire '85 gives you an opportunity 
to learn where high performance 
supermicrocomputer technology is 
going. Some of the heavyweights 
in the industry will discuss what's 
happening, and more importantly, 
what's about to happen. You'll see 
and hear panel discussions, speak- 
ers, demonstrations and workshops 
regarding products, companies and 
items like: 

Digital Research 

Modula 

UNIX 

RM/COS 

CAD/CAM 

Multiuser 

Flexware 

Local Area Networking 

Sales Techniques 

BOS • PDOS 

TOM Software 

CP/M • Forth 

Idris 

Wyse Terminals 

Flooring 

Retail Software 

DB Master 

APL • LISP 

MCBA 



We are very proud to announce that 
our keynote speaker will be Nik- 
laus Wirth, considered to be the 
father of Pascal and Modula-2. 

Stride Micro will also introduce 
some very important and exciting 
new products at the Faire. 

It all happens at the fabulous MGM 
Grand Hotel and Casino in Reno, 
Nevada. Besides attending the 
Faire, you may want to venture out 
into the picturesque scenery of 
Lake Tahoe for some of the best 
skiing in the world. Special hotel 
and travel rates are available 
through Stride Micro. 

Make plans to attend Stride Faire 
'85, February 8-10. It's your 
chance to stay a step ahead in the 
computer race, with a chance to 
win a Stride 420 computer (com- 
plete with software) valued at over 
$4 ,000, just for attending the Faire . 

Call today for an information pack- 
age on Stride Faire '85. 



Contact: 



Laura Smith 
Stride Faire '85 
(702) 322-6868 




FEBRUARY 8-10, 1985 



Stride Micro (Formerly Sage Computer), 4905 Energy Way, Reno, Nevada 895§2 



FUTURE TELEVISION 



choice of _J_ _J_ _ , 

Xc X L 

is possible; X c = 3 chrominance com- 
pression and X L = 1.5 luminance 
compression are selected to optimize 
subjective performance for signals 
having the same RGB (red-green-blue) 
inputs as European PAL (phase alter- 
nation line) over a direct broadcast 
satellite (DBS) system. 

E-MAC AND 

the Smart Receiver 

Unlike current TV systems, with both 
the two-channel NTSC-compatible 
HDTV and MAC coding systems, the 
time position of the transmitted signal 
no longer directly corresponds to the 
position of the information on the 
final display. The decoder uses the 
memory in the receiver to change the 
time sequence of the signal to re- 
assemble the picture according to a 
fixed predetermined mapping. S. 
Liong l^n (N.V. Philips) and Richard 
Jackson (Philips Redhill) suggested 
that a large number of different for- 
mats could be decoded by a "smart" 
receiver if the transmitted signal in- 
cluded format-decoding information. 
Recently the European Broadcasters 
Union modified the proposed MAC 
specifications to include signal format 
information in the last line. A 'smart" 
receiver could select the correct pic- 
ture format map from the information 
provided by the last line. 

Summary 

In this glimpse into future television, 
I have presented the technical basis 
for the evolution of color television in 
the "information age." This is made 
possible by the development of frame 
stores using VLSI. These new com- 
ponents increase the extent of signal- 
processing capabilities that are 
economically viable. Local- and net- 
work-level interactive capabilities will 
be emphasized, including interuser 
transmission of digital data and video 
facsimile. 

The exact format for HDTV and the 
extent of receiver flexibility are being 
evaluated. Once a path is cleared, the 
journey to future television may be 
completed in a few years. ■ 



150 BYTE • JANUARY 1985 



Inquiry 332 



'Despite the recent press notices, 
multiuser microcomputers aren't 

anything new!" 



This is the first in a series of 
discussions with Rod Coleman, 
President of Stride Micro 
{formerly Sage Computer) on 
the 68000 multiuser market 
audits current environment. 

Q: Why do you say that? 
RC: 'The technology to build a 
high performance multiuser sys- 
tem has been around for five 
years. And while some of the 
leaders in this industry have been 
pretending that micro multiuser 
didn't exist, we've been shipping 
complete systems for nearly three 
years. The benefits of multiuser 
are undeniable; it is more cost ef- 
fective, and offers greater flexibil- 
ity and utility. But until just re- 
cently, the marketing pressure to 
be compatible instead of being 
better, has blinded the industry." 

Q: What do you mean? 
RC: "Well, for example, the 
Motorola 68000 processor intro- 
duced 16/32-bit technology to the 
personal computer world a long 
time ago. It was fully capable of 




"A surprising feature is 
compatibility. Everybody 
talks about it, but nobody 
does anything about it." 



meeting high performance and 
multiuser design requirements in 
1980. Instead of this trend taking 
off, most energy was spent pro- 
moting 8088/8086 products that 

Inquiry 333 



were clearly inferior from a tech- 
nical point of view. This phenom- 
enon leads me to believe that they 
will soon rewrite the old proverb: 
'Build a better mousetrap and the 
world will beat a path to your 
door,' but only if they can find the 
way through the marketing fog." 
Q: Are things changing now? 
RC: "Yes and no. With the busi- 
ness world starting to take more 
and more interest in microcompu- 
ter solutions, the advantages of a 
solid multiuser system couldn't be 
kept hidden forever; companies 
like ours and a few others were 
beginning to make a dent. Instead 
of taking a fresh approach, some 
of the newest multiuser offerings 
will probably only give the tech- 
nology an undeserved black eye! 
Multiuser is far more than the 
ability to plug in more terminals. 
It involves things like machine 
compatibility, fast processors, 
adequate memory, large storage 
capacities, backup features, net- 
working, and operating system 
flexibility." 

Q: Is this what makes the new 
Stride 400 Series different? 
RC: "Exactly. That sounds self- 
serving, but it's true. Today a 
number of companies are intro- 
ducing their first multiuser sys- 
tem. We've been building and 
shipping multiuser machines for 
almost three years. We know the 
pitfalls, we've fallen into some of 
them. But we have learned from 
our mistakes." 
Q: Give me some examples. 
RC: A hard disk is almost manda- 
tory for any large multiuser in- 
stallation. Yet, backing up a hard 
disk can be a nightmare if you 
only have floppies to work with. 
That's why we've added a tape 
backup option to all the larger 
Stride 400 Series machines. It's 
irresponsible for a manufacturer 
to market a multiuser system 
without such backup. Another 
good lesson was bus design. We 
started with one of our own de- 
signs, but learned that it's impor- 
tant not only to find a bus that is 
powerful, but also one that has 
good support and a strong future 
to serve tomorrow's needs. We 




'The marketing pressure 

to be compatible 

instead of being better, 

has blinded the industry." 



think the VMEbus is the only de- 
sign that meets both criteria and 
thus have made it a standard fea- 
ture of every Stride 400 Series 
machine." 

Q: W hat are some of the other 
unique features of the 400 Series? 

RC: "A surprising feature is com- 
patibility. Everybody talks about 
it, but nobody does anything 
about it. Our systems are com- 
pletely compatible with each other 
from the 420 model starting at - 
$2900, through the 440, on to the 
powerful 460 which tops out near 
$60,000. Each system can talk to 
the others via the standard built-in 
local area network. Go ahead and 
compare this with others in the in- 
dustry. You'll find their little ma- 
chines don't talk to their big ones, 
or that the networking and multi- 
user are incompatible, or that they 
have different processors or 
operating systems, and so on." 
Q: When you were still known as 
Sage Computer, you had a reputa- 
tion for performance, is that still 
the case with the new Stride 400 
Series? 

RC: "Certainly, that's our calling 
card: 'Performance By Design.' 
Our new systems are actually fas- 
ter; our standard processor is a 10 
MHz 68000 running with no wait 



states. That gives us a 25% in- 
crease over the Sage models. 
And, we have a 12 MHz pro- 
cessor as an option. Let me add 
that speed isn't the only way to 
judge performance. I think it is 
also measured in our flexibility. 
We support a dozen different 
operating systems, not just one. 
And our systems service a wide 
variety of applications from the 
garage software developer to the 
corporate consumer running high 
volume business applications." 
Q: Isn't that the same thing all 
manufacturers say in their ads? 
RC: "Sure it is. But to use another 
over used- term, 'shop around'. 
We like to think of our systems as 
'full service 68000 supermicro- 
computers.' Take a look at every- 
one else's literature and then 
compare. When you examine 
cost, performance, flexibility, and 
utility, we don't think there's any- 
one else in the 
race. Maybe 
that's why we've I 
shipped and 
installed more 
multiuser 68000 
systems than 
anyone else." 




Formerly Sage Computer 

For more information on Stride or 
the location of the nearest Stride 
Dealer call or write us today. 
We'll also send you a free copy of 
our 32 page product catalog. 

Corporate Offices: 
4905 Energy Way 
Reno, NV 89502 
(702)322-6868 

Regional Offices: 
Boston: (617) 229-6868 
Dallas: (214) 392-7070 

JANUARY 1985 • BYTE 151 




And AT&T, Columbia, Compaq, Corona, Eagle, TI Professional, and 
QICSTOR-PLUS, PC-DISC, PC-BACKUR PC-CARD, and PC-9 TRACK. 



Alloy Computer Products, Inc., 100 Pennsylvania Ave., Framingham, Mass. 01701 (617) 875-6100, TWX: 710-346-0394 



152 BYTE • JANUARY 1985 




Zenith. With PC-QICTAPE, PC-STOR, PC-SLAVE/16, PC-QICSTOR, 
See Alloy's full line of innovative products in action at your local dealer. 

Europe: Alloy Computer Products (Europe) Ltd., Cirencester, Gloucestershire, Eng. Tel: 0285-68709, Tlx: 43340 
Inquiry 15 



Computer Products, Inc. 



JANUARY 1985 -BYTE 153 



Get the Picture 
with PHOTOBASE 



PHOTOBASE 



PHOTOBASE is a sof^ 
ware package that works 
with data base manage- 
ment systems such as; 
dbase //* R:Base 4000* 

and the IBM Filing 
Assistant*. 




PC-EYE is a high speed, 
high resolution video 
digitizer board that lets 
you capture anything you 
can see. 



Now you can open up a whole 
new dimension in data base 
applications by merging real-life 
pictures with popular data base 
management systems. Pictures 
of people, products, diagrams, 
maps, company logos — what- 
ever you want to photograph — 
can be integrated with your data 
base. Consider these typical 
applications: 

Security — verify those employees 
who have authorized clearance to 
limited access areas. A data base 
containing employee pictures and 
personnel records can be searched 
and displayed for visual 
verification. 

Signature Verification — increase 
the efficiency of credit checks by 
adding pictures of customer 
signatures to your financial data 
base records. 

Real Estate — add pictures of 
houses to on-line real estate 
listings for faster property identifi- 
cation and improved sales 
presentations. 

Electronic Cataloging — pictures 
of products can be combined with a 
data base system containing pro- 
duct specifications, pricing, 
availability and much more. 



Customers, distributors and sales 
personnel can quickly search data 
and view the resulting product/ 
picture information on one screen. 
Files can be updated easily, 
quickly. 




CHORUS 



It's Easy 

With a simple keystroke, pop-out of 
your data base system and into the 
PHOTOBASE menu. Capture 
images of text, photos, artwork and 
3-dimensional objects with an 
ordinary video camera and our 
high resolution PC-EYE™ video 
digitizer. Pop back into your data 
base system and add the picture 
name to your data base like you 
would any other piece of 
information. The full functionality of 
the data base system is preserved, 
but the resulting display is text and 
picture information on one screen. 

Pictures are displayed in the upper 
right quadrant of the screen at a 
resolution of 32Qx 200 with 16 
colors Or levels Of gray. Text 
information from data base records 
fills the rest of the screen. Pictures 
can also be exploded to full screen. 

Call or write and we will send you 
information on PHOTOBASE, 
PC-EYE, compatible cameras and 
other imaging equipment in the 
Chorus Family of products. 
(603) 424-2900 or 
1-800-OCHORUS. 

TM PHOTOBASE and PC-EYE are trademarks of 
CHORUS Data Systems. 
"dBase II is a trademark of Ashton-Tate; R-Base 
4000 is a trademark of Microrim, Inc.; IBM Filing 
Assistant is a trademark of International Business 
Machines Corporation. 

Inquiry 53 



CHORUS Data Systems, Inc., 6 Continental Blvd., P.O. Box 370, Merrimack, New Hampshire 03054 



by Gregg Williams 



Microsoft 
Macintosh BASIC 
Version 2.0 



Author's note: This article describes the fea- 
tures of the new version of Microsoft BASIC 
for the Apple Macintosh, available for $1 50. 
Because it is based on a prerelease copy of 
the software involved, this article does not in- 
clude any evaluation of the softwares perfor- 
mance. Since the softwares functionality had 
been "frozen (i.e., no new features were to 
be added to the product), this article should 
be an accurate description of the software's 
content and structure. A full software review 
will follow sometime in the future. 

Microsoft Corporation re- 
leased a version of its BASIC 
for the Apple Macintosh 
computer shortly after the machine's 
release. Although this version used 
few of the Macintosh's special fea- 
tures (windows, pull-down menus, 
etc.), it became popular, largely 
because it was the only BASIC avail- 
able. (Apple's Macintosh BASIC, as of 
this writing, was still not available.) 
Microsoft recently introduced 
Microsoft BASIC version 2.0 (I'll ab- 
breviate Microsoft BASIC for the 
Apple Macintosh as MBASIC 2.0 to 
contrast it with Apple's product, 
called Macintosh BASIC). Because 
most people are familiar with the 
generic Microsoft BASIC (which is 
similar to MBASIC version 1.0 for the 
Macintosh), I'll limit this description to 
those features that are new. MBASIC 
2.0 is upward-compatible with pro- 
grams and data files created using 
MBASIC 1.0. Figure 1 shows the List 
(program listing) window for an 
MBASIC 2.0 program and the con- 
tents of the Windows menu. 

Windows 

The WINDOW statement lets you 
create and close (eliminate) windows, 



direct program output to one of 
several windows, and get information 
about a certain window (for example, 
its size or the position of the cursor 
in the active window). The number of 
windows in your program is limited 
only by the amount and usage of the 
Macintosh's memory. 

In addition, the PICTURE ON state- 
ment causes a variable called 
PICTURES to accumulate, according 
to the manual, "a set of encoded 
Macintosh instructions which, to- 
gether, produce a screen image." The 

[continued] 
Gregg Williams is a senior technical editor for 
BYTE. He can be contacted at POB 372, 
Hancock, NH 03449. 



More Mac support 



and true 



parameter-passing 
subprograms 



r i 


File Edit Search Run 


LLHndoiifS | 








1 




Show Command 








Show List SSL 
Show Second List 
Show Output 










Z 

11111 


s 




' Micro Monsters 


h 


b 








G0SUB initsys 












ON MENU G0SUB processmenu 












MENU ON 












WHILE true 












G0SUB initgame 












WHILE alive 












G0SUB initwave 












WHILE alive AND morenemy 












IF NOT laststandTHEN G0SUB moveuser 












rnovcntrrskill 















C\ .,,. . 








11:111:111110 


i 










Command 


WiiWWiimMlMlMltMmiM^^ 





Figure I: Microsoft Macintosh BASIC 2.0. Note the lack of line numbers 
in the program and the selections in the new Windows menu. 



JANUARY 1985 -BYTE 155 



MBASIC 2.0 



MBASIC 2.0 comes 
in two versions that 



use different 



floating-point-number 
formats but are 
otherwise identical. 



programmer can use the stored value 
of this string to reproduce the con- 
tents of a window. With some addi- 
tional programming, you can use this 
statement to create a program that 
redraws the contents of an output 
window when an obscuring window 
is removed. (MBASIC 2.0 automatical- 
ly redraws List windows but not out- 
put windows.) 

Edit Fields, Buttons, and 
Dialog Functions 

The EDIT FIELD statement allows you 
to specify any rectangular area of an 
output window as an edit field. This 
lets the user of your program edit the 
contents of that field (which can be 
blank or contain a string of your 
choice) with the mouse and the edit 
functions (cut, copy, and paste)— just 
as you would be able to do with, say, 
MacWrite. 

The BUTTON statement allows you 
to place buttons of various kinds 
(push buttons, check boxes, or radio 
buttons) in a window and change and 
inquire about their status (among "in- 
active," "active, not selected," and "ac- 
tive, selected"). 

The DIALOG function returns a 
value that states whether or not some- 
thing significant has happened in the 
active windows. This includes such in- 
formation as whether or not a button 
has been pressed, whether an inactive 
window or the active window's "close 
box" have been clicked, or whether 
a window needs to be refreshed. 

With the above statements and the 
WINDOW statement, you can create 
windows that refresh their contents 



when needed and windows that look 
and behave like standard Macintosh 
alert and dialog boxes. 

Menu Bars 

The MENU statement lets you create 
up to 10 custom menus, each with up 
to 20 items; menu items can be inac- 
tive, selected, or selected and marked 
with a check box. MBASIC 2.0 makes 
no provision for a Command-key se- 
quence to substitute for a menu item 
(like, for example, Command-C to sub- 
stitute for the menu item "Cut"). The 
MENU function returns the values of 
the menu and item numbers of the 
last menu selection made. 

Event Trapping 

The numerous event-trapping state- 
ments let you control your program 
via various events without tedious 
programming— things like mouse 
clicks, button and menu selections, 
and window activations. These func- 
tions are the "glue" that will usually 
hold together a BASIC program that 
makes heavy use of the Macintosh 
user interface. 

In addition to the ON ERROR 
GOSUB nnnn from MBASIC 1.0, which 
executes the subroutine at line nnnn 
when the program detects an error, 
MBASIC 2.0 allows you to execute a 
subroutine: ON BREAK (whenever 
Command-period, the break se- 
quence, is pressed), ON DIALOG 
(when the value of DIALOG(O) 
becomes nonzero, indicating some 
dialog-box-related event), ON MENU 
(when a custom-menu item is 
selected). ON MOUSE (when the user 
presses or drags the mouse button), 
or ON TIMER (when an internal timer 
counts down to zero). In addition, 
sensing of these events can be en- 
abled (e.g.. MOUSE ON), disabled 
(MOUSE OFF), or stored for later use 
(MOUSE STOP). 

Sound 

MBASIC 1.0 had only the simple 
BEEP command, but MBASIC 2.0 
adds a SOUND command that lets 
you control the tone and length of up 
to four sound generators. In addition, 
sound commands (to an unspecified 



limit) can be queued up with the 
SOUND WAIT command, then re- 
leased with SOUND RESUME; this 
allows you. for example, to set up and 
then play several sound generators in 
synchronization. 

Another statement, WAVE, lets you 
use waveforms other than the default 
(a square wave). The parameter SIN 
specifies a sine wave; 2 56 elements 
from a selected integer array specifies 
any other arbitrary waveform. While 
the use of a single square-wave sound 
generator may slow program execu- 
tion about 2 percent, the use of multi- 
ple arbitrary waveforms can cut ex- 
ecution speed by more than 50 
percent. 

Two Versions 

Microsoft has made the unprece- 
dented move of supplying two ver- 
sions of MBASIC 2.0, which use dif- 
ferent floating-point-number formats 
but are otherwise identical. The BCD 
(binary-coded decimal) version is bet- 
ter for business and financial pro- 
gramming because it eliminates the 
rounding errors that sometimes occur 
when using binary floating-point 
arithmetic (the kind used by most 
BASICs). This version is compatible 
with programs and data files created 
by MBASIC 1.0 and defaults to dou- 
ble precision for numeric values. The 
binary version of MBASIC 2.0 (which 
adheres to the IEEE floating-point- 
number standard) is faster than the 
BCD version because it defaults to 
single precision for numeric values 
and for the calculation of trans- 
cendental functions. The binary 
MBASIC 2.0 icon and BASIC program 
icons show a small flowchart and a pi 
symbol. (The decimal-version icons 
look like their counterparts that are 
found in MBASIC 1.0.) 

Editing and Debugging 

MBASIC 2.0 adds a number of much- 
needed editing and debugging fea- 
tures. Find and find-and-replace menu 
selections automate the tedious pro- 
cess of looking through a program 
listing for things that need to be 
changed. A find-the-cursor menu 

[continued] 



156 BYTE • JANUARY 1985 



COfnPUTER WAREHOUSE 



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CR-4 



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420 

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DS180 $1149 

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620 $694 

630 API $1499 

630 ECS $1669 

630 ECS/IBM $1669 

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Tally Spirit80 $245 

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P1340 Parallel or Serial $709 



P1351 Parallel or Serial . .. 

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COLUMBIA COMPUTERS 

All systems include fifteen software packages 
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MPC4210 MPC4220 
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VIDEO TERMINALS 

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A-2 Green S4fiQ 


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910 


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Anchor Automation 

Mark XII 


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Smartmodem 1200 Baud 

Smartmodem 1200B Baud (IBM) 


. $459 
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. . $315 


RaCal-VadlC All Models 

US RobotiCS Password 1200 


Call 
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NEC 

PC-8201 Computer $315 

PC-8201A-90 Battery Pack $15 

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TPC-2 Dual Drive $1 749 

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121 Green $125 

121 Amber $134 

420 RGB $399 

425 RGB/Green $410 

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Order Line Hours: Mon-Fri 8:30-5:30 Saturday 9-1 



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Prices reflect 3% to 5% cash discount. Product shipped in factory cartons with manufacturer's warranty. Please add n/84 
$8.00 per order for UPS shipping. Prices & availability subject to change without notice. Send cashier's check or 
money order ... all other checks will delay shipping two weeks. 

JANUARY 1985 -BYTE 157 



MBASIC 2.0 



selection allows you to scroll through 
your program and return to your 
original location without the trial and 
error that you previously had to do. 
You can also do full Macintosh-style 
editing in the List window; this is a 
great improvement over MBASIC 1.0. 
which forces you to copy a BASIC line 
to the command window for editing. 



Another improvement is that MBASIC 
2.0 allows you to make only two List 
windows. In MBASIC 1 .0 you can have 
three List windows open, which 
wastes memory. 

MBASIC 2.0 adds a single-step 
capability to the TRON and TROFF 
statements available in MBASIC 1.0. 
Single-stepping, which is invoked 




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using the Step selection under the 
Run menu (or by pressing Command- 
T), causes MBASIC 2.0 to execute one 
statement and highlight it in the List 
window (if it is visible). Note that only 
one statement is executed; if a line 
contains multiple statements, only the 
current one is highlighted. 

New Language Features 

The Macintosh-environment enhance- 
ments to MBASIC 2.0 are certainly ex- 
citing, but Microsoft has made im- 
provements to the BASIC language 
itself that are actually more important. 
None of these features are new to 
BASIC itself, but their inclusion in a 
Microsoft BASIC tends to ensure their 
inclusion in future Microsoft BASICs, 
which will probably set a de facto 
standard for the microcomputer com- 
munity. The new features, which in- 
clude program-format changes and 
subprograms that pass parameter 
values, rectify most of the shortcom- 
ings that programmers have against 
the language and make it a serious 
competitor to Pascal for many users. 

The criticism of BASIC as an unread- 
able, monolithic language is largely 
due to its lack of formatting (indent- 
ing lines to clarify, for example, the 
body of a DO loop) and its require- 
ment of line numbers. MBASIC 2.0 
programs are stored as they are typed 
in— this includes any cosmetic use of 
spaces, even blank lines. MBASIC 2.0 
requires line numbers— or, equivalent- 
ly alphanumeric labels delimited by 
colons— only when needed to specify 
the destination of GOTOs, GOSUBs, 
or IF-statement branches. MBASIC 2.0 
also converts BASIC keywords (which 
may be entered in lowercase) to up- 
percase and boldface in the List 
window. 

The subprogram (delimited by SUB 
and END SUB statements) differs 
from the subroutine in that the former 
can pass values from the calling state- 
ment to the subprogram definition; 
this feature greatly increases the 
power of the language and is a part 
of most sophisticated programming 
languages (FORTRAN, Pascal, and 
Modula-2, among others). The vari- 

{continued) 



158 BYTE* JANUARY 1985 



Inquiry 7 



rThe Hard Disk With 
The Software Shell 




Internal 10 Meg $794 
External 10 Meg $944 



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Inquiry 292 



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MBASIC 2.0 



ables used in the SUB statement are 
called formal (or dummy) parameters 
because they are not actual variables 
that can conflict with variables of the 
same name elsewhere in the pro- 
gram—they are placeholders for the 
values that are passed to the sub- 
program when it is called. 
MBASIC 2.0 subprograms support 



call-by-reference and call-by-value 
parameter passing (in the latter, the 
subprogram cannot change the value 
of the variable used as a parameter 
in the calling statement). Simple vari- 
ables in the calling statement are 
called by reference (meaning their 
values can be changed) unless they are 
surrounded by parentheses, in which 



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case they are called by value. Calling 
statements can pass array names as 
parameters, and the size of the array 
does not have to be declared in the 
definition of the subprogram'. 

In addition to its formal parameters, 
which are local to the subroutine 
(meaning their values do not exist out- 
side the subprogram), the SUB state- 
ment can include a list of shared 
variables, variables that are global 
(meaning they have the same value 
both inside and outside the sub- 
program). The SUB statement can 
also declare that all the variables in- 
side it are static: the variables retain 
their values from one invocation of 
the subprogram to the next. 

Subprogram definitions cannot con- 
tain other subprogram definitions. 
This means that variables cannot have 
varying degrees of locality (as they 
can in Pascal, for example). However, 
you can limit the scope of some vari- 
ables by defining them as shared with 
some subprograms but not others. 

A subprogram can be called either 
by its own name or with the CALL 
statement (which is also used to call 
machine-language subroutines). For 
example, if a subprogram is defined 
with 

SUB POLY_AREA 

(SIDES.LENGTH.RESULT) 

it can be called as 

CALL POLY_AREA(5,12,area) 
or as 

POLY_AREA 5,12,area 

(note the lack of parentheses in the 
latter case). 

Documentation 

The MBASIC 1.0 reference manual has 
215 pages; the MBASIC 2.0 manual 
has 378 pages, which includes ex- 
amples of almost every feature de- 
scribed. For example, the "Access to 
Macintosh ROM Routines" appendix 
is five pages in the first manual and 
eleven pages in the second (which 
documents the same number of rou- 
tines, only in greater detail). The 
MBASIC 2.0 documentation spells out 

(continued) 



160 BYTE- JANUARY 1985 



Inquiry 172 





i^^fc- 




IEEE-488 



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Austin, Texas 78727 512/250-9119 



Inquiry 252 



Inquiry 198 



Once you choose Lattice, 
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MBASIC 2.0 



the language's functions more com- 
pletely, which allows most of us to 
more fully use the language without 
having to be wizards that understand 
the inner workings of the Macintosh. 

Miscellaneous Features 

MBASIC 2.0 contains too many other 
improvements to mention here, but 
some notable ones follow. 

You can now load in BASIC files 
using the "Open..." menu selection 
(which gives you the scrolling window 
display known as the Mini-Finder). 
Because the Mini-Finder has a "Disk" 
button, you can load (without know- 
ing the names of) files from your 
system's alternate disk drive. 

MBASIC 2.0 allows you to cut and 
paste pictures between it and an ex- 
ternal application (MacPaint, for ex- 
ample). This allows you to draw a pic- 
ture using MacPaint, then manipulate 
it within an MBASIC 2.0 program. 

You must interrupt a running 
MBASIC 2.0 program with the Com- 
mand-period keystroke instead of 
Command-C. This makes MBASIC 2.0 
consistent with other Macintosh ap- 
plications and frees the Command 
key to be used (as in a terminal-emula- 
tion program) as a control key. 

The FILES function allows a pro- 
gram to prompt the user for a file- 
name using either a fill-in-the-blank 
dialog box (as is used by MBASIC 1 .0 
itself to get a filename) or the Mini- 
Finder dialog box mentioned above. 
Both forms let you specify an optional 
prompt string, which allows you to use 
this statement to get something other 
than a filename. 

Closing Remarks 

This product description makes no at- 
tempt to evaluate the performance of 
MBASIC 2.0. By the time you read 
this, Microsoft BASIC for the Apple 
Macintosh version 2.0 (called MBASIC 
2.0 in this article) and Apple Com- 
puter's own Macintosh BASIC should 
be available. We will compare the 
published versions of both BASICS as 
soon as they are available. In any case, 
MBASIC 2.0 is a considerable im- 
provement over its predecessor, 
Microsoft Macintosh BASIC 1 .0. ■ 



162 BYTE • JANUARY 1985 



Inquiry 297 




GUTS, 

GLORY. 



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Five lull-length expansion slots 
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ROM BIOS AND MONITOR by 
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256K byte, parity- checked 




RAM on planar board 
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Serial (RS-232) communications port 
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Communications program included 



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Switch controls allow console I/O 
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Floppy disk controller on 
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Space-saving half-height 
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Monitor conveniently 
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We modestly consider it the finest personal 
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«) 1984, ITT Information Systems 



Inquiry 403 for Dealers. Inquiry 404 for End-Users. 



JANUARY 1985 'BYTE 163 




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handling charges found In Italics next to price.) 

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Apparat 256K Memory Board with OK S 67.00' 



(2 50) 
(250) 

(250) 
(250) 
(250) 
(2 50) 



(13 39) 
(29 70) 



DISK DRIVES & CONTROLLERS 



MMI 3" WM BLow Power Winchester 

Mounts Like Half Height Dme 
May n a rd Flopp y Dis k Controller 

► Maynard WS- 7 WMBInternal Hard Disk 

with Sandstar Multi Function Card 

► Maynard WS-2 same as WS- > but with 

Sandstar Floppy Controller (u.;es 1 slot) 
Maynard Floppy Controller/Serial Port 

► Panasonic Hall Height DSDD Drive Par 
PC Network Half Height Drive Pairs 

Our Volume Lets us Import These Name 
Brand Drives Directly from the Source 
They are the quietest, most reliable 
drives we've seen yet 
Qume Hall Height DSDD Drive Pair 
(same as used on IBM Portable) 

- Tandon TM 100-2FuilHeightDSDDDnve 

► Tandon 10MB Internal Winchester 

wilBM Controller 

- Tallgrass 20MB External Hard Disk 

with Tape Backup 



S 665.00* (14 36) 



145.00* 
225.00* 
200.00* 



(2 50) 
(540) 
(4 32) 



350.00* (7.00) 



• (3 09) 
' (14 80) 



2,150.00* (46 44) 



MEMORY CHIPS 

All chips guaranteed for lite 

64K Memory Upgrade Kits -(9 chips) $ 28.80' 

64K Dynamic Ram Chips (Each) 3.20* 

256K Dynamic Ram Chips (Each) 27.00* 

MODEMS 

AnchorMark XII LOWEST PRICE 1200BPS S 230.00* 

HAYES COMPATIBLE EXTERNAL MODEM' 
Hayes Smartmodem300 180.00' 

Hayes Smartmodem 1200B with new 366.90* 

Smancom II VV 00 Emulator 
R\xor\R212A Stand Alone 1200PBS 335.00* 

U.S. Robotics Password (Compact 290.00* 

1200BPS External) 



MONITORS 

Amdek Video 30OG Composite Green 
Amdek Video 300 A Composite Amber 
Amdek Video 310 A IBM Type Amber 
Amdek Color 300 (NEW) Composite 
Amdek Color 500 (NEW) 

CompositeiRGB/VCR 
Amdek Color 600 (NEW) High Res RGB 
Amdek Color 700(NEW) Ultra High Res 
Amdek Color 710 (NEW) 700 w:Non 

GlareiL ong Phosphor 
Prince to nHX- 12 RGB Monitor 
Princeton MAX- 121GB Mono 
Princeton SR- 12 Ultra High Res RGB 
► Quadram Ouadchrome II NEW! 

640x200 RGB w/14" Screen! 

Black Phosphor MaskllBM Case 
Taxan 420 Super High Res RGB Monitor 
Taxan 440 Highest Res RGB (720x400) 

Currently Available Works With Persyst Bob 
Zenith ZVM-123 Green High Res 

Consumer Reports Rated Best Buy') 



110.00* 
120.00* 
130.00* 
215.00* 
320.00* 

395.00* 
455.00* 
485.00' 

CALL 
CALL 
CALL 
370.00* 



380.00* 
525.00* 
Card 
76.00* 



Apparat Combo II w serpar- game 123.00' 

clocklstwr 
AST Six-Pack Pluswith64K 229.00" 

AST MegaPlus II with 64K 229.00* 

AST MO Plus II 105.00* 

► ORCHID BLOSSOM W/64K 205.00' 
Multifunction wan networking at an 
unbelievable price Up to 384 K/Ser' Par 
Clock.'Soltware'Net Slot 

Quadram Improved Ouadboard w OK 199.00* 

Tecmar Captain Multifunction Card O K 195.00* 

PRINTERS 

Amdek 5025 (NEW!) 25CPS LO 
w/2K Butter 

C. Itoh F 10/40 Starwnler 40 CPS LO 

C. Itoh Prownter 8510 AP 
+■ Epson RX-80 
r- Epson FX-80 
*> Epson FX- 100 

Epson LO1500 

Epson IBM-to-EPSON Parallel Cable 

NEC 203020CPS LO Parallel 

► NEC 2050 20CPS Letter Quality Printer 
NEC 353033CPS LO Parallel 

► NEC 3550 33CPS Leter Quality Printer 
NEC 8850 55CPS LQ New Model 

IBM Version 

► Okldata ML84P200CPS 132 Col 

► Okldata ML92P 160CPS 80 Col Printer 

► Okldata ML93P 160CPS Wide Platen 

► Okldata 24 I0P Pacemaker 350CPS 
Okldata IBM-to-Okidata Parallel Caole 
Qume Sprint 1 1 45 45CPS Letter Qual/ty 
Qume Sprint 1 1 90 90CPS Letter Quality 

New 1 Fastest Daisywheel Out' 
Qume IBM Cable and Inter! ace (required) 72.00* II 00) 

► Star Ml cronies Gemim 10X 120CPS 225.00* (4 86) 
w-Tractor EpsonGraprncs Compatible 

► StarMlcronlcsGeww 75X l OX Features 
wl 132 Col 

► Star Mlcronlcs Power Type 18 CPS 
LQ Diablo Code Compatible 

Texas Instruments 855 DP'LO wiTractor 
Toshiba P- 1340 80 Col Version of P- 135 1 
Toshiba P- 135 1 160 lOOCPSDraftiLQ 
LO Printer 

VIDEO CARDS 

► Eagle Monochrome Display Card 160.00' (2 50) 
Hercules Color Card w Parallel Port CALL 

► Hercules Monochrome Graphics Cards 298.00 (2.50) 

► Paradise New Modular Multidtsplay Card 255.00* (250V 
" DJL " Persyst Bob Card Ultra High Res Color 365.00* (2 50; 

Card wilh Mono Quality Text in Color 

Quadram Quadcolor I Color Card 

STB Graplvx Plus II NEW 
(3 00) (simultaneous Mono Graphics & Color) 

(3 00) 

(3 op) ACCESSORIES AND SUPPLIES 

(4 64) ► BrandName DSDD Diskettes S 16.00* (1 00) 

(6 9 1) Guaranteed tor Life ' ' Not Generic 

Curtiss PC Pedestal ll 36.00* (2 50; 

(8 53) ► KeytronlcKS5J57De/L/xe/8M Keyboard 170.00 (4 00) 
(9 83) pc Network Replacement 130 Watt IBM-PC 165.00* (3 56) 

( 10 48) Power Supply — Gives your PC (Old or New) the same 

capacity as an XT Good lor add in tape drives (without need 
lor a piggyback unit) and large capacity disk drives 
WP Printer Paper 2600 Sheets 17.00* (WOO) 

Microhne Perts (invisible when torn) 



(100) 
00) 
(1 00) 



(360) 
(2 50) 



S 525.00* (10 48) 

875.00* (18 90) 

285.00* (6 16) 

220.00* (4 75; 

370.00* (7 99) 

525.00* (1 1 34) 
CALL 

21.00* (100) 

625.00* (73 50; 

625.00* (73 50; 

1.185.00* (3! 54) 

1,260.00* (27 22) 

1,650.00* (35 64; 

620.00* (73 40; 
350.00* (7 56) 
550.00* (7 7 88; 
1,640.00* (35 42; 
20.75* (1 00) 
1.155.00 (24 00J 
CALL 



325.00* (7 20) 

300.00* (6 48) 

716.00* (75 50J 

696.00* (75 03; 

1,200.00* (25 92; 



170.00* (2 50; 
295.00* (2 50; 



(8 27; <pc NETWORK Members pay just 8% above the wholesale 

(1 1 34) price, plus shipping. All prices reflect a 3% cash discount. 

Minimum shipping S2.50 per order. 
(2 50; 



fRENT BEFORE YOU BUY— Members are eligible to join The NETWORK'S Business and Game Software 
Rental Libraries and evaluate products for a full 14 (Regular) or 28 (VIP) days to see if it meets your 
needs. And The NETWORK'S rental charges are far less than other software rental services— JUST 20% 
OF THE MEMBER WHOLESALE PRICE. 



Hardware prices highlited by 



reflect recent major price reductions 



164 BYTE- JANUARY 1985 



COMPLETE 



PC SYSTEMS 




NETWORK 



IBM PC STARTER SYSTEM 
IBM PC w/64K (256K capacity) 



$1 ,620.50* (35.00) 



Oensitv 320/360 Disk Drive 



Zenith ZVM- 123 Display 



jroqram and qr 



Dertect starter system tor you! I he combination ot 
r card and printer pari allows you to run most any 
iut need tor replacing any component you buy nov 



IBM PC BASE SYSTEM 
IBMPCW/256K 



$1,581 .40* (34.16) 



1 bided Double ue 



"he Base System is your lowest cost starting point for configuring the ex 
iystem of your choice. Combine it with any of the monitors, video cards, 
nultifunction cards and accessories listed in this ad. i 
;an't be beat as your system source. 




IBM PC PROFESSIONAL 

HARD DISK SYSTEM (XT) $2,1 46.40* r«u 

IBM PC W/256K 

Floppy Drive Controller 

1 Double Sided Double Density 320/360K Disk Di ' 
w/MMl new technology 3" 10MB Hard Disk. 

Uses less power than a floppy. 

Shock mounted '/.-height installation leaves room ,w, 

Automatic Hard Disk Boot Feature. 
This system increases productivity in any business or professional situation. 
The 10Mb hard disk eliminates cumbersome flnnnv disk nhannes simnfififis 
operations and dramatically speeds progn 
buying power provides you with better than XT performance al 
a price lower than you'd expect to pay for a standard PC. 

*PC Network Members pay just 8% above this wholesale price plus shipping. 
These prices have been prepared in November, 1984 and may have been 
changed with new product announcements. Call for latest prices. 



LATEST ISSUE REDUCTIONS! 

64K MEMORY EXPANSION KITS . . $ 28.80 

Set of 9 chips Guaranteed for Life. 

LOTUS 1-2-3 $270.00* 

New Best Price! 

MMI 10MB INTERNAL 

HARD DISK 665.00 

Low Power Automatic Boot 

PAN ASONIC SHUGART per pair 225.00 

1 / 2 Height DSDD Disk Drives with Mounting Kit 

STAR MICRONICS GEMINI 10X ..... 225.00* 

120 CPS Epson IBM Graphics Compatible w/Tractor 
TANDON TM 100-2 DRIVES 143.00* 

ORCHID BLOSSOM 64K installed 205.00* 

New Price! Full Six-Pack Features 
with networking capability! 

AMDEK MONITORS 

V300G Composite Green 11 0.00* 

V300A Composite Amber 1 20.00* 

V310A IBM Amber 1 30.00* 

HERCULES MONOCHROME CARD 298.00* 

HAYES 1 200B with new Smartcom II 366.90* 

NEC SPINWRITER 2050 625.00* 

20 CPS-Letter Quality Printer 

BRAND NAME DISKETTES 16.00* 

DS/DD Box of 1 Guaranteed for Life Not Generic 

"NETWORK members pay just 8% above these wholesale prices plus shipping 



CALL TOLL FREE 1 -800-62 1-S-A-V-E (nSnSerswp.) 

• only * 

In Illinois call (31 2) 280-0002 validation code B315 



. . . WITH THESE 15 
UNIQUE BENEFITS 

1COST + 8% PRICING — The NETWORK purchases millions 
of dollars in merchandise each month. You benefit in receiving 
the lowest price available and all at just 8% above published dealer 
wholesale price. 

2 OUR 500 PAGE WHOLESALE CATALOG — Members 
receive our 500 page wholesale catalog containing over 20,000 
hardware and software products for the IBM PC, APPLE and over 50 
other popular computer systems. THE NETWORK'S CATALOG IS 
THE LARGEST SINGLE COMPILATION OF PERSONAL COM- 
PUTER PRODUCTS AVAILABLE TODAY. 

3 IN-STOCK INSURED FAST HOME DELIVERY — The NET- 
WORK maintains a giant multi-million dollar inventory of 
most popular products, allowing us to ship many orders from stock. 
Non-stock items are typically maintained in local warehouses just 
days away from The NETWORK and YOU. We pay all insurance ex- 
penses on your shipment. EMERGENCY OVERNIGHT SERVICE IS 
AVAILABLE ON REQUEST 

4 10 DAY RETURN POLICY — If you are not satisfied, for any 
reason with any hardware component purchased from The 
NETWORK within 10 days of receipt, we will refund your entire 
purchase (less shipping) with no questions asked. 

5 MEMBERSHIP SATISFACTION GUARANTEE— If for any 
reason you are not satisfied with your membership within 30 
days, we will refund your dues IN FULL. 

6 EXPERIENCED CONSULTANTS — The NETWORK hires 
consultants, not order takers, to aid you in productselection. Our 
consulting staff possesses in excess of 150 man years of personal 
computer product experience. We back our consultants with our 
money back guarantee: IF ANY PRODUCT RECOMMENDED BY 
OUR CONSULTING STAFF FAILS TO PERFORM AS PROMISED — 
OR IS INCOMPATIBLE WITH YOUR SYSTEM —WE WILL TAKE IT 
BACK AT OUR EXPENSE FOR A 100% REFUND. 

7 FREE TECHNICAL SUPPORT — The NETWORK supports 
every product it sells. Our qualified TECH-SUPPORT staff will 
helpyou assemble your system, interpret vendordocumentation and 
get your software and hardware to work. WE WILL GIVE YOU ALL 
THE HELP YOU NEED, WHEN YOU NEED IT — FREE! 
tQ OPTIONAL BUSINESS RENTAL LIBRARY — All members 
O can join our BUSINESS RENTAL LIBRARY featuring over 1000 
available titles for just $25 PER YEAR above the base membership 
fee. This entitles you to rent business software AT JUST 20% of 
the DISCOUNTED PRICE FOR A 14 DAY PERIOD If you decide to 
keep the software, the entire rental fee is deducted from the pur- 
chase price. VIP MEMBERS GET A FULL 28 DAYS for just $30 
above the V.I. P. base fee. This also includes the game library 
privileges for a $5 combination savings. 
t QOPTIONAL GAME SOFTWARE RENTAL LIBRARY — The 

vGame Rental library is available to members for just $10 PER 
YEAR and permits evaluation (or just enjoyment) of any game or 
educational software product as above. 
A f\ SPECIAL SAVINGS BULLETINS — THE PRINTOUT — 

l\J The NETWORK seeks every opportunity to save 
money for its members. We buy excess dealer inventories, and store 
bankruptcy closeouts regularly. We then turn around and make this 
merchandise (only top quality name brand products) available to our 
members at fantastic savings via THE PRINTOUT, our newsletter and 
savings bulletins. 

•4 A DISCOUNT BOOK LIBRARY — Working with numerous 
publishers and distributors, The NETWORK has assembled 
a library of over 1000 computer related books and manuals at savings 
of up to 75% from the normal store price. 
A*\ MEMBERSHIP REFERRAL BONUS — Our most 

I 4L, valuable source of new members is you! To date almost 40% 
of our members have been referred by word of mouth from other 
satisfied members. For those of you who refer new members, THE 
NETWORK will credit a cash bonustoyouraccountapplicabletoany 
future purchase. 
A O CORPORATE ACCOUNT PROGRAM —Almost 50% of 

I O The NETWORK'S members are corporate buyers and users 
(see opposite page left). The NETWORK can establish open account 
status and assign designated account managers to expedite orders, 
and coordinate multiple location shipments. 
A A QUANTITY DISCOUNTS — For large corporations, clubs 

I ^T and repeat or quantity buyers The N ETWORK can extend ad- 
ditional single order discounts, when available to us from our 
manufacturers and distributors. 
•4 jr PRICE PROTECTION — The PC Industry is crazy!! Prices 

I O change not yearly or monthly or even weekly butoftenday by 
day! These changes are sometimes up but are mostly down/.'/ THE 
NETWORK GUARANTEES THAT IN THE EVENT OF A PRODUCT 
PRICE REDUCTION, BETWEEN THE TIME YOU PLACE YOUR 
ORDER AND THE TIME THE PRODUCT SHIPS YOU WILL ONLY 
PAY THE LOWER AMOUNT!! 

Inquiry 272 



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Inquiry 2 ^ 

CaU or w"te today: 
NCGA , 

Dept. HC 

assess* ' 

Fairfax, VA 22031 ( 

(703) 698-9600 




QZ2aa7T> 



CONDUCTED BY GREGG WILLIAMS AND ROB MOORE 



The Apple Story 

PART 2: MORE HISTORY 
AND THE APPLE III 




An interview 



with Steve Wozniak 



Last month, Steve talked about his back- 
ground, the evolution of the Apple I 
andU, and the early days of the com- 
pany. \n this part, the conversation switches 
to various aspects of the Apple II design, later 
personal history, and Steve's thoughts about 
the personal computing industry. 

SWEET-16 

BYTE: One of the more interesting things in 
the Apple II ROM was your 1 6-bit pseudo- 
machine called "Sweet-\6'.' How did you come 
up with that? 

Wozniak: While I was writing my 
BASIC I had been thinking about 
ways to save code. There were several 
places where I had to handle 16-bit 
pointers with an 8-bit processor, and 
that was pretty awkward. 

So I decided to write a little 
emulator and implement a 16-bit 
machine that could interpret pseudo- 
codes and implement registers to 
1 5 in the 6502 base page. It ran about 
30 times as slow as 6502 assembly 
language, but it saved tons of code 
every time I used it in a program. 

BYTE: Did you actually use it in your In- 
teger BASIC? 

Wozniak: No, I never had the time to 
reimplement the BASIC to use it. But 
I did use it in later years to write 
things like BASIC renumbering rou- 
tines totally in Sweet-16. It was easy 
to mix SweeM6 code with assembly 
language. 

BYTE: Isn't Sweet-\6 still used in Apple 
DOS and ProDOS editor/assemblers? 
Wozniak: Yes, it's used in EDASM |the 
Apple Ibol Kit 6502 editor/assembler|, 
mostly in the editor portion. Randy 
Wigginton wrote EDASM. He's worked 
here since before we even had a com- 



pany. Lately he's written the Macin- 
tosh word processor— MacWrite. He's 
done a lot for the company, and he's 
used Sweet-16 in several things he's 
done. 

The Disk Drive 

BYTE: Can you tell us a little about how you 
came up with the Apple II disk drive and how 
you ended up picking your form of group- 
coded recording? 

Wozniak: The disk design was my 
most incredible experience at Apple 
and the finest job I did. I never really 
knew what a disk controller was or 
what it had to do. But at Hewlett- 
Packard 1 had looked through a 
Shugart manual to see what signals 
were used and what they did. There 
were signals to make the head step in 
and out and signals to cause magnetic 
flux changes. It was similar to audio 
recording, and I knew about that. It 
was like a signal on a tape where you 
write it and then you read it back. So 
I figured out a simple little circuit to 
write signals at changing rates and 
read them back. I didn't know how 
disk controllers worked, so I assumed 
that I was doing something totally dif- 
ferent. Maybe it wasn't as efficient, 
but at least I could write some data 
and read it back. 

Well, Mike Markkula was annoyed 
because the cassette tape was too 
slow. He had a favorite checkbook 
program, and it took two minutes to 
read in the program and another two 

[continued) 

Gregg Williams is a senior technical editor at 
BYTE. Rob Moore is a hardware designer and 
frequent contributor to BYTE. They can be 
contacted at POB 372, Hancock, NH 
03449. 



PHOTOGRAPH COURTESY OF APPLE COMPUTER INC. 



JANUARY 1985 • BYTE 167 



WOZNIAK INTERVIEW 



'Hobbyists are a tiny 
part of our market, 
but they're faithful 
to the company! 



minutes to read in his check files. He 
was complaining about this at a staff 
meeting, and I mentioned that I had 
this clever little five-chip circuit that 
could read and write a floppy disk. At 
the time, all the existing floppy-disk 
controllers were 40 or 50 chips, so I 
knew there must be something impor- 
tant that I wasn't doing. 

I went off and tried to figure out 
what it was that I wasn't doing. One 
of our technicians had a North Star 
system, so I looked through their 
manuals. 1 read their schematics and 
figured out what every chip did. And 
I looked through their listings until I 
understood exactly what they were 
doing. 

I was doing a lot more. I didn't even 
have to look at the sector holes, so 
I could use any disk drive, any floppy 
disk in the world. It was then that I 
new I had a really clever design. 

The next week was Christmas vaca- 
tion. Randy Wigginton and I spent the 
entire week, including the holidays, 
trying to get this disk reading and 
writing with a very simple operating 
system. We did the bottom levels of 
an operating system in that week. You 
could type R (for "read") followed by 
a program name like STARTREK, and 
it would load STARTREK into memdry. 

We were highly motivated because, 
at the end of the week, a show called 
the CES |Consumer Electronics Show| 
was starting in Las Vegas, and we 
wanted to go. 

We worked all night the day before 
we had to show it |the disk drive| at 
CES. At about six in the morning it 
was ready to demonstrate. Randy 
thought we ought to back it up, so we 
copied the disk, track by track. When 
we were all done, he looked down at 
them in his hands and said, "Oh, no! 



I wrote on the wrong one!" We 
managed to recover it and actually 
demonstrated it at CES. 

BYTE: Had you been exposed to group-code 
recording before, or did you invent yours 
independently? 

Wozniak: The first version of the 
floppy-disk routines did not have 
group coding. I had followed the 
Shugart manual, which showed that 
you had alternate clock bits and data 
bits, so every other bit was wasted. I 
couldn't understand why it was nec- 
essary, but I started that way. 

Then I came up with this idea to use 
coded recording. I knew the technical 
rule was that you could only have one 
or two zeros in a row. You could have 
either 4 or 8 microseconds between 
flux transitions. I didn't really know 
what group-coded recording was; I 
just knew that I could fit 1 3 sectors on 
a disk instead of 10. I had to write a 
program to take bytes off the disk, 
convert them to 5-bit chunks, and re- 
assemble them into 8-bit data bytes. 

It was a difficult routine to write. It 
was about a 20-hour job, and I'd work 
through the day for 10 or 12 hours 
and I wouldn't quite get there. The 
next day I'd come back and find out 
that I was starting exactly where I had 
the day before. This went on for 
almost a month. I was not quite get- 
ting the routines, and we were getting 
within a month of shipping the disk 
drives. Finally I stayed up all night until 
I got all five routines that had to work 
together done. So we were able to 
ship it the first time with the group- 
coded recording in place. Later, we 
changed the encoding method and 
stepped up to 16 sectors. That was 
DOS 3.3. 

BYTE: The Macintosh uses a custom chip 
called the IWM— Integrated Woz Machine- 
that does the same sort of recording. Can you 
tell us anything about that? 
Wozniak: My design was basically a 
little sequencer, or state machine. It 
used a PROM and a latch and cycled 
through various states depending on 
the input data coming off the floppy 
disk. The IWM takes that design and 
adds other features like the ability to 
go twice as fast— it can also do IBM 



format, double-density recordings. 

BYTE: It sounds like a fascinating part. Do 
you think we'll see Apple II owners benefit 
from it in any way? 

Wozniak: Well, it's our standard disk 
controller now, and it's cheaper than 
the older design. It's used in the 
Apple He. 

BYTE: Could you use it to get higher-density 
recording on an Apple II VA-inch disk? 
Wozniak: No, because the disk drives 
themselves aren't certified for double- 
density recording. You need heads 
with the proper gap, and they're more 
expensive. 

BYTE: You're a former hobbyist. Could a 
hobbyist buy one of these chips and a spec 
sheet and start playing with it? 
Wozniak: I don't think Apple would 
give out the spec sheet. I totally dis- 
agree with that policy because I'm 
very respectful to the hobbyists. 
They're a tiny part of our market, but 
they're loyal supporters and faithful 
people to the company. If they had a 
spec sheet, they could start playing 
with it and figure out a lot more in- 
credible things that we never planned 
it to be used for— even using it as a 
communications channel from Apple 
to Apple, Macintosh to Macintosh. 
There are a lot of great tricks you 
could do with that little part. It's a 
beautiful random I/O device that has 
too many things that have not been 
taken anywhere. 

Personal Details 

BYTE: \n 1981 you were in a plane crash 
and you left Apple for a while shortly after 
that. How long did it take you to recover from 
the accident? 

Wozniak: That was in February 1981. 
For about five weeks I had a type of 
amnesia that prevents you from form- 
ing any new long-term memories. 
After I recovered, people would show 
me pictures of myself in the hospital, 
playing games with my computer with 
my face all battered up. They would 
tell me stories of how I tried to sneak 
out of the hospital to visit my wife, 
Candy, or how I went to parties and 
rode my motorcycle. I didn't remem- 

[continued) 



168 BYTE • JANUARY 1985 



THE SHOOP PROOF DISK 




Vault Corporation, producer of the advanced Prolok™ 
andTelelok™ security disk technology, introduces Filelok™ 
the inexpensive, effective means of protecting confidential 
data files from unauthorized access and duplication. Now you 
can instantly protect all kinds of sensitive information, includ- 
ing word processing, spread sheets and graphics, as easily as 
saving a file. 

Filelok data security disks provide file-by-file security 
selection, protected back-up copies, optional passwords, and 
hard disk compatibility. It works with virtually all PC® /MS- 
DOS® software, including the popular Lotus® 1-2-3® dBase II® 
and III,® and WordStar.® All this comes on a U.S.-made 5V*- 
inch, double side/ double density disk of the highest quality. 
With reinforced hub and lifetime warranty. Certified 100% 
error-free. The same kind of high performance disks you 
require every working day with one important difference — 
they're protected. 

Filelok's genius is its simplicity of use coupled with an ex- 
tremely high level of protection. It looks like an unprotected 
disk and works like an unprotected disk. Simply tell the com- 
puter which f ile(s) to protect and on which disk drive they're 
located. Instructions can be as simple as B:FL A: (applications 
software) . 



Filelok eliminates the need for expensive add-on hard- 
ware. All the technology is on the disk itself. Filelok disks are 
marked with unique physical "fingerprints." And no two are 
alike. A precise description of the print is encoded on each 
disk. Prints and descriptions are compared whenever a pro- 
tected file is accessed and an exact match must occur before 
any decrypted data is released. Protected back-ups are easily 
made. However, to read them the original Filelok disk must be 
present in the system. Unauthorized copies having a different 
or non-existent fingerprint yield only encrypted — and use- 
less — data. 

For the Filelok dealer nearest you, 
call 1-800-445-0193. 
In California, call 1-800-821-8638. 
We're adding dealers as quickly 
as possible but if you can't find 
one nearby, simply call either 
of the numbers above. Or write 
Vault Corporation, 2649 Townsgate 
Road, Suite 500, Westlake Village, CA 
91361. And do it now. Because some 
people are more nosy than you think. 




VAULT 

CORPORATION 



FILELOK. 
DRTR SECURITY, MOOT OH THE DISK 

Copyright © 1984 Vault Corporation. Filelok, Prolok and Telelok are trademarks of Vault Corporation. PC-DOS is a trademark of International Business 
Machines Corporation. MS-DOS is a trademark of Microsoft Corporation. Lotus and 1-2-3 are trademarks of Lotus Development Corporation. dBase II and 
III are trademarks of AshtonTate. WordStar is a trademark of MicroPro International Corporation. Dealer inquiries welcomed. 



Inquiry 360 



JANUARY 1985 -BYTE 169 



WOZNIAK INTERVIEW 



ber any of that. I had all of my old 
memories, but I'd forget new things 
from one day to the next. Finally I 
came out of it one night, but 1 never 
got those memories back. 

BYTE: Why did you leave Apple? 
Wozniak: We had a hundred engi- 
neers at that point, and 1 was no 
longer really important to the com- 
pany. I didn't want to be a manager; 
I was just an engineer, and I wasn't 
really needed there. But I didn't feel 
comfortable going to Steve Jobs or 
Mike Markkula and saying 1 wanted to 
take off. The plane crash was a good 
excuse. After five weeks of amnesia. 
I simply didn't go back. I decided that 
if I was going to take a year off I might 
as well finish college. It was the hard- 
est year of my life. 

BYTE: We've heard that you went to UC- 
Berkeley and had some run-ins with your in- 
structors. Could you tell us about that? 



Wozniak: I was going under an as- 
sumed name— Rocky Clark— so they 
didn't know who I was. I took com- 
puter science courses, economics, 
statistics, and a few other courses. 

My computer science courses were 
interesting, but I have to criticize them 
a little because they taught only 
specific problems with specific solu- 
tions. You spent your time memoriz- 
ing standard problems and solutions 
and then tried to recognize variations 
of them in the tests. You weren't sup- 
posed to explore new avenues or try 
things that nobody else was doing. 
You were only supposed to learn the 
proper answer. They thought that you 
could be trained to know all the prob- 
lems and the standard solutions. 
Once you learned them all you could 
solve them. It was wrong because 
they weren't really teaching you to 
solve problems— they taught you to 
identify them. 



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My economics course was interest- 
ing also. We had a socialist TA (teach- 
ing assistant] who taught us that com- 
panies made money by cheating the 
consumer. All the kids in the class 
thought that companies would make 
a lot of profit if they could figure out 
a way to cut the costs of a product 
down, to make it cheap and screw the 
consumer. 

I contrast that with the way we did 
things at Apple. Every product design 
decision was based on what con- 
sumers wanted, what would compete 
the best, what they would buy. We 
tried to do what customers wanted, 
in our best judgment, and give them 
high-quality products. 

So I would stand up in class and 
argue about what the TA was saying. 
After a while he started telling me to 
shut up, or that he would kick me out 
if I interrupted him again. Apple was 
the greatest business success in 
history, but I couldn't tell him who I 
was. 

BYTE: So you came back to Apple after 
about a year. What would you say is the most 
important thing that you've worked on since 
you came back? 

Wozniak: There isn't too much. When 
I came back I started getting a little 
bit involved with this division's man- 
agement, but it was unofficial. Official- 
ly I took the title of Engineer. Mostly, 
I've stayed involved with the Apple II 
because that's where I've got the most 
to offer. 

Because I'm a founder at Apple, I 
could take almost any role I want, but 
I've tried to avoid the newest, most 
far-reaching projects because there 
are other capable people to do them. 
I try to stick to small projects where 
I can sit down and handle them my- 
self. 

Current Work 

BYTE: Do you have anything interesting 
going on now? 

Wozniak: There are not many in- 
dividual projects in this whole busi- 
ness. The floppy disk may have been 
the last one for Apple. I have got a few 
projects that I'm working on now, but 
they're not all going at once. 



170 BYTE • JANUARY 1985 



Inquiry 126 



Inquiry 107 



WOZNIAK INTERVIEW 



The language Fifth is one of them, 
but I haven't written it yet. I'd like to 
combine the best features of BASIC, 
FORTH, and Pascal and leave out the 
worst ones. You could have the formal 
structures of Pascal the immediate- 
ness of BASIC, and the extensibility 
of FORTH. In FORTH or Logo, new 
words become part of the language, 
and you can use them immediately. 
It's really helpful for debugging. In 
Macintosh Pascal you can define a 
procedure and run it immediately. I 
also want some level of globalness, 
like BASIC. I don't want to always have 
to declare a variable before I can use 
it. I like variables with scope, but I'd 
like undeclared variables to be total- 
ly global. 

Another project is an operating sys- 
tem, like the one on the Macintosh, 
only a bit different and a lot more 
relational. 

I also have a hardware project that 
I'd like to do, a personal computer 
based around consumer video 
sources like TVs, videotapes, and 
videodiscs. It would switch them 
around, synchronize them, and mix 
them, sort of like a little home editing 
studio. I think it's possible because 
memories are getting so cheap. You 
could hold a frame from each of your 
video sources in memory and let the 
software accommodate the sync 
variations. There are a lot of new chips 
available that do NTSC modulation 
and demodulation, so there ought to 
be a minimal chip solution. 

My main interest is still the Apple 
II— the home computer we started 
with. I'd like to see Apple do more 
with speech. There are some really in- 
expensive speech chips now, and 
that's the way the rest of the personal 
computer world is heading. I think 
we've been deficient in that area. 

Speculations 

BYTE: Are you thinking about using the new 
65816 processor for anything? 
Wozniak: We're thinking about it and 
doing some R&D with it, but I don't 
know if we'll use it. Anything we do 
has to be compatible with the Apple 
11. If we found out that the 65816 

{continued) 



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Inquiry 1 70 



JANUARY 1985 -BYTE 171 



WOZNIAK INTERVIEW 



THE Spreadsheet 



In late 1982, A.P.P.L.E., a national Apple 
users group, offered an astounding value 
to its members. For $22.50, A.RP.L.E. 
members could purchase a fully functional Visi- 
Calc-like spreadsheet program called "THE 
Spreadsheet'' At the time, various versions of 
VisiCalc and other popular spreadsheet pro- 
grams were selling for between $200 and 
$300. THE Spreadsheet offered most of the 
features found in VisiCalc and added a few of 
its own. What's more, it was coauthored by the 
now legendary Steve Wozniak. Mysteriously. 
THE Spreadsheet was available for only one 
month, after which it was permanently discon- 
tinued. Since that time, original copies of THE 
Spreadsheet have become one of the few 
legitimate microcomputer collector's items. In 
the following segment, Steve describes how THE 
Spreadsheet came about. 

Wozniak: It started because Mike Scott 
was having difficulty negotiating with 
Personal Software [now VisiCorpI 
about VisiCalc. They just wouldn't do 
what he felt was right as far as giving 
Apple breaks on price or doing new 
enhancements to it. So he came by one 
day and he said to me, "Would you like 
to do a VisiCalc?" It wasn't even known 
as a spreadsheet then. 

1 was really scared. VisiCalc was the 
only spreadsheet for a long while, and 
none of us had really been in business 
before. Was it legitimate to go out and 
do your own spreadsheet? Or was it 
equivalent to just copying and ripping 
somebody off? 1 didn't want to get 
close to this whole thing because 1 
didn't want it to look like I was copy- 
ing somebody else. 

Mike got Randy Wigginton and 
Randy said, "Sure, I'll do it." 1 said I'd 
do the arithmetic routines because 
they were general— something that 
could be used by any program— and I 
had some good algorithms that I had 
picked up at Hewlett-Packard that I 
wanted to implement. 

So we started working on it and, a 
little ways in. Randy finished it. He 
wrote 4K of code in a couple of weeks, 
and I was shocked that he came in so 
quick; 1 hadn't even started mine. So, 
I was getting to work on my arithmetic 
routines and my first demo was almost 
ready but still a few days off. 

At the time, everyone was trying to 
get the Apple III into production. Mike 



Scott was camped out in the Apple III 
building, forcing the things that had to 
get done to get it finished and 
delivered on schedule. 

He was in a bad mood. Everywhere 
anyone ran into him in the company, 
he had a sour face— no laughs, no 
jokes. And because Randy finished his 
first part of the spreadsheet and I 
hadn't finished my first part, he'd 
always come to me. The way he was 
talking to me, I was afraid I was going 
to get fired. He was in a bad mood. 

It was the scariest time of my life at 
Apple. I was really getting badly ad- 
dressed just for not being on time with 
something. I had three more days to 
go, and I didn't dare run into him once 
more because I was already way over- 
due. So I said, "I've got to get him in 
a good mood for three days." 

Well, he's a Star Wfors fan. He gets the 
T-shirts the cast gets before they get 
them because he knows who prints 
them. So I had a friend of mine call his 
secretary saying, 'This is George Lucas. 
Is Mike Scott in?" Of course he 
wouldn't leave a phone number, but he 
said, "I'll call back." It actually worked. 
Mike was in a good mood for a few 
days, and I got my routines done. 

Anyway, we finished the spreadsheet, 
and Apple started looking it over. 
Originally it had been defined to be as 
accurate as VisiCalc, and we were so 
much faster than VisiCalc it was 
ridiculous. The exponential routines 
that I really wanted to write for so long, 
because I had a good algorithm, were 
30 times faster than VisiCalc's. 

All of a sudden we started hiring ex- 
perts on precision and things like that, 
and they started redefining the project 
from what Mike Scott had originally 
defined. They added a lot of features 
that Randy had to implement. This 
made life very difficult here at Apple, 
so we finally decided, "No, it won't be 
a Special Delivery Software product [a 
line of software offered by Apple a few 
years ago|." 

After a long, long time, Randy went 
to Call-A.P.RL.E. |the magazine put out 
by A.PPL.E! One night we were out 
to dinner and he said to Steve. "Well. 
I'm going to sell that to Call-A.P.RL.E." 
or'Tm going to give this spreadsheet 
to Call-A.P.RL.E." Steve said, "Well, 



that's good" or something like that. It 
was not official or formal. Randy went 
ahead and hit on it and gave it to Call- 
A.P.RL.E. It was sold for $22.50— really 
cheap. We didn't want any money out 
of it. It was just the old Homebrew 
Computer club spirit of "Give to help 
others." 

It was a good product, and it had 
been delayed well over a year. If Apple 
didn't want it, they should have just 
gotten rid of it, and it would have been 
out a year sooner. As soon as it 
popped up from Call-A.P.RL.E. and was 
advertised. Apple got in a real huff 
about it. They forced Call-A.P.RL.E. to 
only sell it to members, and only one 
copy per member. So Apple basically 
put it out of business— only allowed it 
to be sold for one more month. 

It's really funny, because how did 
Apple get started? I designed the 
Apple while I was at Hewlett-Packard. 
Hewlett-Packard has a policy of decid- 
ing about these things very quickly. 
They would check with their legal 
department and other divisions and 
decide very quickly. So they gave me 
a formal release on it quickly because 
they didn't want it. But here was Apple, 
which didn't want it but wasn't going 
to release it. 

If you use much Apple II software, 
you'll be surprised when you take the 
spreadsheet that Randy and I wrote 
and boot it in. It boots in so fast, you 
can't believe what's going on. 

BYTE: Is that because there's no copy- 
protection on if? 

Wozniak: No. Believe it or not, I used 
those routines that I did for Apple II 
Pascal. 

BYTE: You, Randy Wigginton. and Guil 
Banks were listed as the authors. Who is Guil 
Banks'? 

Wozniak: Guil is right here in this build- 
ing. I did the boot stuff, and he had 
written a lot of the other fast disk rou- 
tines in there. He did all the routines 
that managed the disk and read and 
wrote DOS files appropriately without 
using DOS. 

This was basically an all-volunteer 
project that we did all on our own time. 
And it was really neat, so we decided 
that we'd give it to the rest of the 
world. 



172 BYTE • JANUARY 1985 



WOZNIAK INTERVIEW 



wasn't, it would be a serious question. 
It's too new a part right now. 

BYTE: How is its performance compared to 
the 68000? 

Wozniak: It should be available soon 
in an 8-MHz version that will beat the 
pants off a 68000 in most applica- 
tions, and in graphics applications it 
comes pretty close. Some of the 
Macintosh people might disagree 
with me, but there are ways around 
most of the problems they see. An 
8-MHz 65816 is about equivalent to 
a 16-MHz 68000 in speed, and a 
16-MHz 68000 doesn't exist. 

BYTE: The Apple II family has been a great 
success, and many innovations have come 
along to extend its life. What things do you 
think were responsible for its success? 
Wozniak: For three years we were 
one of the biggest business successes 
in history. We had three years of fan- 
tastic business success, and lately 
we've had three years of sort of 
dismal business. We've grown, but any 
additional revenues have just re- 
placed the stock dilution, and the 
price remains about the same. 

During that three years there were 
two main factors that led to our 
success— our floppy disk and VisiCalc. 
Out of the original home computers, 
which included the TRS-80 and the 
Commodore PET. ours was the only 
one that had enough memory to run 
VisiCalc. VisiCalc and the floppy disk- 
sent this company into the number- 
one position. 

We were also very faithful to our 
users— we tried to support everybody. 
When we changed over to floppy 
disks. we still supported cassettes 
heavily. When we moved up to the 
Apple 11+ with floating-point BASIC 
built in, we still supported the original 
Apple II. 

.Lately our strategies seem to be 
changing. When we come up with a 
new enhancement, we start moving 
away from the prior version much 
more quickly. This could be harmful 
to our good relationships with a lot 
of our faithful users. 

The Apple He is a good example. 
Most new software that really uses the 
features of the Apple He won't run 



properly on an Apple 11 or II + . A lot 
of good software for the Apple 11+ 
won't run on the Apple He. It's an in- 
compatible world. 

BYTE: How do you think the Apple II fami- 
ly will be extended and improved in the future? 
Wozniak: There are obvious areas. 
We're always trying to come up with 
better combinations of features and 
still reduce the cost. We're looking 
into improved processors like the 
65816 we discussed before. Video res- 
olution is always improving. We're try- 
ing to increase speed and the amount 
of memory in the machine because 
it's critical to certain applications. 

The IBM PC is very successful, and 
it had no competition from Apple for 
the last three years because we made 
sure that it didn't. We would not allow 
the Apple II to compete in that market 
for three years. 

PCSD is the most difficult division 
in the company. |Steve is referring to 
the Personal Computer Systems Divi- 
sion, responsible for the Apple II and 
Apple III products.| We're hamstrung 
by the need to be compatible; Macin- 
tosh isn't. 

So we will continue to make im- 
provements and produce new ma- 
chines, but they'll always be compat- 
ible. With the Apple He we went to 
128K, 80-column display, and double- 
resolution graphics. We came out with 
the He portable. 

Apple versus IBM 

BYTE: What did you mean when you said 
that the Apple II was not allowed to compete 
in the IBM market? 

Wozniak: Apple has never really sup- 
ported the Apple II in the business 
market. If you walk around a trade 
show and look at the software running 
on the IBM PC, you'll see that most 
of it is a step above what's possible 
on today's Apple II. They have more 
RAM that's easily addressed and bet- 
ter access to hard-disk drives. Pro- 
grams like 1-2-3 cannot be easily im- 
plemented on a 128K Apple II, but 
IBM has a capable machine for that 
level of software. Our machine has to 
be able to address more memory and 

{continued) 



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JANUARY 1985 -BYTE 173 



WOZNIAK INTERVIEW 



x l have positive and 
negative feelings about 
things Apple has done'. 



handle larger disk drives before we 
can really start to compete with 
equivalent software because IBM 
beats us in capability today. We need 
better screen resolution, more mem- 
ory, and better speed. A 16-bit pro- 
cessor would help, although "16-bit" 
really doesn't mean that much. 

Whatever we do will be compatible, 
because we don't want to alienate our 
existing customer base. If we can 
come up with the right machine, then 
we can start to talk about some really 
good software and compete well with 
IBM. Even if we do, the new features 



won't really be used right away. 

BYTE: Have you said all that you meant to 
say about where Apple is vis-a-vis IBM and 
where you personally feel that Apple has 
made its mistakes? 

Wozniak: I have both positive and 
negative feelings about things Apple 
has done, but I'm always honest. 
There is one real mistake that Apple 
made, in my opinion, and this is very 
subjective. It is symbolic of what could 
happen to IBM with its PCjr. 

We had become a huge business 
success in 1979. We had really made 
it with our floppy disks and VisiCalc, 
and it looked like we were going a 
long way. So we decided it was time 
to start putting together a real com- 
pany a big company We needed to 
start staffing up and hire a lot more 
engineers. So we set the Apple III 
project in motion. 

The executive staff felt it understood 



the Apple II market. After VisiCalc, it 
was perceived that 90 percent of all 
Apple lis sold were going to small 
businesses. Only 10 percent were go- 
ing into this home hobby market that 
we originally thought was going to 
grow to be billions. Originally we were 
a home hobby computer. Now, sud- 
denly small businesses were buying 
Apple lis, and they wanted more fea- 
tures—an 80-column display, lower- 
case characters, maybe more graphics 
modes and colors, and more memory 
These were all the things that one 
product VisiCalc, led to. 

According to any research we could 
dig up, many people were buying the 
Apple II for small business because 
it had a disk drive and it could run 
VisiCalc. These weren't the people 1 
was closest to, so I kept my mouth 
shut because I was only one out of 
the staff of 1 5. So we started staffing 

{continued) 



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174 BYTE • JANUARY 1985 



Inquiry 318 















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Telex: 650-186-3130 
Outside Illinois: 1-800-Dial-USR 



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Computers: 

Apple™ 11,11 + ,110, lie 

Columbia™ 

Compaq™ 

Corona™ 

Heath™ H-100 

IBM™ PC, PC/XT, PC Jr., 

PC Portable or AT 
Kaypro™ II, 10 

Northstar™ Horizon/Advantage 
Televideo™ 1605.TPCII 
Zenith™ Z-1 00, Z-1 51 
Most other systems running 

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Moderns: 

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Datec™ (Pal Modems) 

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Rixon™(R212A,PC212A) 
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VT is a registered trademark of Digital 
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'Emulates VT ,M 52/100; Televideo* 910; 
TTY (ASCII) 
Inquiry 354 



WOZNIAK INTERVIEW 



up and building an organization and 
a management structure based 
around doing this new product— the 
Apple III. 

The Apple III 

We had some problems getting things 
done on time with the Apple III 
because of (a) our lack of experience 
as a group working together, and (b) 
not being able to predict project 
lengths well enough. 

We started hiring intermediate levels 
of managers. Sometimes the man- 
agers were getting hired at a rate that 
added a completion date to the pro- 
ject faster than it was getting com- 
pleted. 

Around this time we started devel- 
oping a perception of market separa- 
tions—good strong separations be- 
tween products so they don't overlap. 
You don't want to design a product 
that competes heavily with your own 
existing product. I claim that's untrue. 
What you really don't want to do is 
design a product that doesn't offer 
any more than your existing product. 

So we started setting up strong 
boundaries. The Apple III would be 
our 80-column business machine and 
have 90 percent of our market. The 
Apple II would be our 40-column 
home/school machine and have I0 
percent of our market. The entire ex- 
ecutive staff was sure that once the 
Apple III was out, the Apple II would 
stop selling in six months. I felt really 
down, because this 10 percent were 
my friends— the hobbyists and home 
users. 

The Apple III hurt Apple in many 
ways, but it was a very well conceived 
product. And because we were so 
successful with the Apple II. we de- 
cided to build in an Apple II emula- 
tion mode to take advantage of all the 
software that was out there. The emul- 
ation mode did get built in, but. 
because of our concept of market 
separations, jt was a very limited 
emulation. While our Apple II custom- 
ers were adding 80-column cards and 
16K RAM cards to their machines, we 
actually added chips to the Apple 111 
to prevent access to many of its 
features during emulation mode. In 



emulation mode you only had access 
to 48K of memory— you couldn't use 
the 80-column display the extra 
graphics modes, or the extra memory. 
The emulation mode wouldn't even 
run much of the existing Apple II 
business software, and there wasn't 
much Apple III software available. 

Originally, we planned to deliver 
four applications with the Apple Ill- 
word processing, a spreadsheet, busi- 
ness graphics, and a database pro- 
gram. Steve Jobs's thinking at the time 
was, "People don't really want to buy 
a computer. They don't want to know 
about microprocessors or cards or 
buses. They want to buy VisiCalc— 
they want to buy a solution." So we 
were going to provide the four major 
solutions. But because we were hav- 
ing problems managing the Apple III 
project while we were building our 
management structure, we were only 
able to deliver our operating sys- 
tem—SOS—and VisiCalc, which was 
done by Personal Software |which 
later became VisiCorp|. 

The Apple III shipped very late and 
had 100 percent hardware failures. 
This is very subjective, and some 
people might disagree with me, but 
I think we were trying to be too pure. 
We wanted to do it on one PC board, 
not two. and it didn't fit on one PC 
board. So we got a company that 
could put three traces between two 
IC pins, had them do the PC board, 
and 100 percent of the Apple Ills 
failed. 

The Apple 111 is really very good, but 
we spent three solid years keeping the 
Apple II down, and now it's finally be- 
ing allowed to grow in that direction. 
We've come out with ProDOS. which 
is a major improvement, and the Pro- 
File |hard disk] is available for the 
Apple II now. It's a good start. I think 
they are going to find out that allow- 
ing the Apple II to get there will im- 
prove the whole Apple image. 

The III will do very well in its estab- 
lished vertical markets forever, but it 
really won't make the huge success 
we thought it would. It may have the 
best chance it's ever had. ProDOS is 
the best way to get someone closer 

[continued) 
JANUARY 1985 • BYTE 177 



WOZNIAK INTERVIEW 



*We did SOS 
3 years ago, and 
the rest of the world 
hasn't caught up! 



to SOS. We did SOS three years ago, 
and the rest of the world hasn't 
caught up or come close to it. Macin- 
tosh went in a different direction, so 
I can't compare the two systems. 

BYTE: Is SOS really that good? 
Wozniak: I think it's the finest oper- 
ating system on any microcomputer 
ever. It's the greatest thing in the 
world, but I wish we gave out listings 
of it. 

BYTE: Wasn't it the first commercial system 
that actually had installable device drivers? 
Wozniak: Yes, the Apple II uses 
device drivers in ROM, on the I/O 
cards, but they won't work on the III 
because they depend on specific 
memory locations. On the III. you 
load a device driver into RAM for any 
device you add to a system, so it's in- 
finitely flexible. You can always change 
it, correct bugs, and it's clean. But it's 



more difficult for outside manufac- 
turers, because they have to supply 
a disk and instructions on how to up- 
date your system. It would have been 
the best of both worlds if you could 
plug in a card with a ROM on it and 
if the first byte in the ROM were a 1 2, 
for example, the system would 
recognize that the ROM holds a 
device driver and link to it auto- 
matically. That would have made it 
much easier for the card manufac- 
turer. It would have been really easy 
to allow both techniques, but the Ap- 
ple III engineering group didn't want 
to do anything the way it was done 
on the II. Marketing just didn't have 
enough leadership and control. 

Anyway, having the Apple IN as a 
failure didn't really hurt the company 
much. The Apple II was still very 
healthy, but for the next three years 
the Apple III hurt the company tre- 
mendously because everyone in 
Apple knows how great a machine the 
Apple III really is. It's a very clean 
machine, it's easy to use, and it's really 
been organized right with the oper- 
ating system. 

Unfortunately, we made it very dif- 
ficult for anyone to get access to the 
insides of the machine. We had hired 
some very bright people who figured, 
"This is the right way it should be 



done. So we'll give out enough infor- 
mation to do this and we won't give 
them any more, because they might 
try to do something they're not sup- 
posed to do." The right way for one 
person is not the right way for an- 
other. We closed that machine up to 
where somebody could have a very 
difficult time finding out how to add 
their own I/O drivers. We did not make 
it easy for the outside world. We 
thought we wanted all of the markets 
for ourselves. 

You have to let the end users devel- 
op their own standards. You've got to 
give them the freedom to discover 
how they're going to use an operating 
system, what sort of things they're go- 
ing to buy. And if you're really right 
and have provided a good solution, 
that's where they're going to settle. 
The thinking on the III was very much 
like a religion in that it could only be 
done one way— our way. We made it 
very difficult for outside developers, 
instead of providing all the informa- 
tion as we did with the Apple II. 

BYTE: Has that attitude changed now? 
Wozniak: No. It's still the most nega- 
tive thing in our whole company, and 
it will be for years. 
I think that when a new market 

(continued) 



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178 BYTE* JANUARY 1985 



Inquiry 44 






IBM PC $4CQC 2drvs: 

or 2 drives/256K. !ll^n --• 




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IBM XT 



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COLOR 


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145 

165 

419 

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114 

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1200 468 

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Inset 



7/Z7 



WOZNIAK INTERVIEW 



evolves, like personal computers did, 
there's a period of time when you've 
got to let the world go in all random 
directions, and eventually it will sub- 
side because it wants standardization. 
Then, once it's obvious what the stan- 
dards are, they should be heavily sup- 
ported by the manufacturer. You can't 
try to dictate a standard. 

The Apple II and the Apple III 

When we came out with the Apple 111, 
the engineering staff canceled every 
Apple II engineering program that 
was ongoing, in expectation of the 
Apple Ill's success. Every single one 
was canceled. We really perceived 
that the Apple II would not last six 
months. So the company was almost 
all Apple III people, and we worked 
for years after that to try and tell the 
world how good the Apple III was, 
because we knew. 

There is a lot to somebody's per- 
ception or image of a machine and 
how good it is. How many of my 
friends have them? How many people 
in the world have them? The Apple III 
was a failure the first year as a 
product— it had a bad image. When 
you give a bad first impression, you 
can go for five years trying to over- 
come it. 

If you looked at our advertising and 
R&D dollars, everything we did here 
was done first on the III, if it was 
business related. Then maybe we'd 
consider doing a sub-version on the 
II. To make sure there was a good 
boundary between the two machines, 
anything done on the II had to be 
done on a lower level than on the III. 
Only now are we discovering that 
good solutions can be implemented 
on the II. 

The Apple II was kept out of the 
business market to keep the III going, 
to give our users only one choice. We 
wanted to make the III the success it 
hadn't become and that it deserved. 

Unfortunately we made sure that 
the Apple II was nowhere close to the 
market that the |IBM| PC took. We 
made sure the Apple II was not al- 
lowed to have a hard disk or more 
than 1 28K of memory. At a time when 
outside companies had very usable 



schemes for adding up to a megabyte 
of memory, we came up with a 
method of adding 64K to an Apple 
He, which was more difficult to use 
and somewhat limited. We refused to 
acknowledge any of the good 80-col- 
umn cards that were in the outside 
world— only ours, which had a lot of 
problems. 

At one point during the Apple III 
development, I wrote some fast disk 
routines for our Pascal system on the 
II. And I got a lot of flak from Apple 
III engineers who felt that they 
shouldn't go on the Apple II. Nothing 
on the II should be allowed to run as 
fast or faster than the Apple III. That 
was the thinking that stuck with the 
company for three solid years. 

It was unfortunate the way things 
worked out, because we probably put 
$100 million in advertising, promo- 
tion, and research and development 
into a product that was 3 percent of 
our revenues. In that same time frame, 
think what we could have done to im- 
prove the Apple II, or how much 
could have been done by Apple to 
give us products in IBM's market. 

BYTE: Are you putting more resources to 
work in that direction now? 
Wozniak: Yes, but things don't change 
in six months. In the Apple III we had 
a beautiful machine, and we spent a 
lot of money to try and emphasize 
that. We were trying to force the world 
to finally accept the machine because 
we knew just how good it was. 

The PCjr had a poor initial reception 
like the Apple III did. It came out in 
the wrong month— the month when 
Macintosh was going to be perceived 
as the leader. The PCjr was perceived 
as an uninteresting product. 

They may try for three years to over- 
come its bad first impression. They 
may put a lot of their corporate 
resources into trying to promote the 
PCjr and lose sight of the PC. The PC 
will keep selling because it's been ac- 
cepted and there are a lot of after- 
market companies out there selling 
software and hardware for it. But if 
IBM neglects it enough, we may have 
a chance to turn it over on them in 
the next few years if we have a better 
product. ■ 



180 BYTE • JANUARY 1985 



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IBM 

Hercules Color Card 199 

VutekCPSCd \229 

Keytronic 5151 — 5151 Jr. 

209, 

Bi-Graphics 1 459 

Bi-GraphicsH 229 

Smart Cable by I.Q. 64 
Jr. Extender by 

Falcon CALL. 

UltraPak byTSENG 489 
UltraRam by TSENG 199 
Multidisplay by PS . . 239 
Plantronics Color Plus 299 
Orchid Blossom .... 299 

Orchid PCnet 389 

Orchid Combo . . . CALL 



ISssss 



AST-6 PAK 239 

Quad Link 469 

PC Saver 39 

TG Joystick 44 

64K Ram Chips . . CALL 
GALL FOR PRICE LIST!! 

APPLE 

DiscWasher Cari ... 199 
PrinterFace by P.P. . 64 I 
Graphicard by PP. . 79 

Z-SOCard 69 

Touch Pad by Koala 84 
Microsoft Acces. . CALL i 

Grappler Plus 109 

Vtdex 80 Col w/Sft Switch 

179 

Wesper Full Graphics 78 
System Saver FAN 67 



J 





SHIPPING 



"MODEMS" 

HAYES RIXON 



II C Compatible w/Sft ' 259 
MicroModemlle -.. 229 

Hayes 1200B 3b9 

SmartModem 300-RS23? , 219 
SmartModem 120ORS232 . 539 
ChronoGraph RS232 199 

U.S. ROBOTICS 

IBM PC Modem 369 

Password 300/1200....357 

VEN-TEL 
1200 Plus 384 



R 103J ASYNC .... 

PC 212A IBM Internal 
PC 212A-WA 
w/ASYNCPort ... 
R212AIRS232 .... 



229 
429 



499 
429 



NOVATION 

Access 1-2-3 

J-Cat 

103 Smart Cat ..... 189 
212 Auto Cat ..,,:. 397 
Apple-Cat D 229 



399 
99 



DISK DRIVES 

FLOPPY DRIVES HARD DISK 



Tandom 100-2 . . 
Slim Line Drives 



169 
149 

Apple Compatible . . 159 
FUJI DISKETTES 

SSDD 22 

DSDD 27 



10 Meg Internal 895 

QuarterMaster ON SALE! 
10 Meg External ... 1095 
15 Meg External . CALL 
Bernoulli by Iomega 2799 
QUADRAM »TECMAR» 
CONTROLL DATA 



Roland DG-121-G . . . 139 
Roland DG-121-A.... 249 

Roland CB-141 319 

Roland CC-1 41 595 

Taxan 420 389 

Taxan Amber 119 

Taxan 415 499 

TGB-80 col He 139 

RGB Card lie .89 

Quadchrome 559 



Quadscreen w/Card 1650 

Zenith 131 319 

Zenith 135 487 

Zenith 122 109 

Amdek 310/.; 159 

Amdek Color IV-T . 597 

NEC JC 1215 269 

NEC JC 1216 397 

Amdek 300 G; 134;, 

Amdek 300. A 144 '' 



TERMINALS CALL 



NEW NEVADA 
LOCATION! 

680 GREENBRAE DR., #234 
SPARKS, NEVADA 89431 

toll-free 1-900 - 621-0852 ex 988 

NO SALES TAX! 



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id Alaska (619)466-4895 




All prices subject to change and availability ^ 
Apply, IBM are registered trademarks. 



P.O.'S ACCEPTED 

On All Pre-paid Cash Orders In Cont US. ON APPROVAL 



Inquiry 82 



JANUARY 1985 -BYTE 181 





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Statpro is a trademark of Wadsworth Professional Software, 
Inc. Apple is a registered trademark of Apple Computer, Inc. 
IBM is a registered trademark of International Business 
Machines Corp. 




182 BYTE • JANUARY 1985 



Inquiry 367 



by William Rynone 



Uninterruptible 
Power Supplies 



71 dvertisements for uninterrup- 
ZA tible power supplies (UPSs) 
x V proliferate in computer 
magazines. But do you know what 
they are or how to buy one? This arti- 
cle should help answer your 
questions. 

Many users of small computers 
have suffered the nasty consequences 
of an electrical power loss while oper- 
ating their systems. You can lose a 
long file that is in working memory. 
Your disk head may crash, destroying 
a floppy disk or doing irreparable 
damage to a Winchester or cartridge 
disk. Most disk destruction occurs 
when the computer is reading from or 
writing to the disk at the instant of 



Devices to save 

you from losing data 
in the dark 



power failure. Consequently, serious 
damage can result should you panic 
at the flickering of your overhead 
lights and attempt to "save" your 
work. 

One way to temporarily retain your 
working data during a power failure 
is to connect batteries to the power- 
supply bus lines. For an S-100 system 
you'll need three different battery 
voltages: +8 volts (V), + 16 V, and - 16 
V. This is a short-term solution, ac- 
ceptable only if power returns within 
a reasonable period (that is, before 
the batteries die). 

Though the preceding measure may 
protect data in working memory, your 
computer must maintain 1 17 V AC in 



order to store and retrieve data. 
Unless full power returns, you won't 
be able to save your data. And. of 
course, if the batteries can maintain 
only bus voltages, your disk hardware 
remains unprotected; you may have 
already experienced a head crash. 

Another alternative to protecting 
both data in active memory and your 
hardware is to use a source of 1 1 7-V 
AC power that is independent of the 
anomalies of your local public utility. 
There are two approaches to this 
method: continuously supply power 

{continued) 

William Rynone teaches in the department 
of electrical engineering at the U.S. Naval 
Academy (Annapolis, MD 21402). 



ILLUSTRATED BY STEVE SALERNO 




JANUARY 1985 • BYTE 



POWER SUPPLIES 



to your computer with a continuous- 
duty UPS or supply power only when 
the electricity fails, using a standby 
power supply, (In this article, I'll use 
the term UPS to describe both types 
of units, differentiating when neces- 
sary.) 

A continuous-duty UPS supplies 
power to your computer all the time. 
The 1 1 7-V AC power is developed by 
a static inverter that uses a storage 
battery, or batteries, depending upon 
your power requirements. The batter- 
ies are continually charged by power 
from your local utility. Simultaneous- 
ly, the inverters are synchronized to 



the utility-line frequency— 60 Hz— to 
eliminate any undesired effects upon 
the computer system. Such an effect 
might be a beat frequency between 
the utility's power and the frequency 
of the power generated by the free- 
running static inverter. 

Under normal operation, the in- 
verter frequency is maintained in 
power-line sync via a phase-locked 
loop circuit quite often operated in 
conjunction with a ferroresonant cir- 
cuit, which may be thought of as a 
tuned inductance-capacitance 
oscillator. When the line power disap- 
pears, the inverter frequency drifts 



slowly to a factory-preset 60 Hz. The 
line frequency must change gradual- 
ly so as not to induce any transients. 
Similarly when power returns, the fre- 
quency of the inverter is gradually 
synchronized with the power com- 
pany's line frequency. Many 
continuous-duty UPSs are designed to 
switch the computer input connec- 
tions back to the utility's power line 
when the inverter fails. 

Standby UPSs are maintained in a 
ready state with their battery, or bat- 
teries, receiving a trickle charge. 
When the utility's power-line voltage 
falls below a preset level, the inverter 



Tkble 1: Standby uninterruptible power supplies compared according to 
Some information may have changed since press time. 

PRICE 
MANUFACTURER MODEL PER UNIT 


manufacturer specifications. 

POWER 

RATING CUT-IN 

(WATTS) VOLTAGE 


TRANSFER 
BACK 
TO LINE 


Cuesta Systems Inc. 

3440 Roberto Court 

San Luis Obispo, CA 93401 

(805) 541-4160 


9012060 
20012060 


$350 
$495 


90 
200 


102 V 
102 V 


106 V 
106 V 


Electronic Protections 
Devices 

POB 673 

Waltham, MA 02254 

(800) 343-1813 


Grizzly 200 

(with surge protection) 


$895 


200 


93 V 


97 V 


General Power Systems 

1400 North Baxter St. 
Anaheim, CA 92806 
(714) 956-9321 


GPS-0.1K126R 
GPS-0.2K126R 
GPS-0.3K126R 
GPS-0.5K126R 


$495 
$595 
$695 
$895 


100 
200 
300 
500 


102 V 
102 V 
102 V 
102 V 


109 V 
109 V 
109 V 
109 V 


Kalglo Electronics Co. 

6584 Ruch Rd. 
Bethlehem, PA 18017 
(800) 524-0400 


LS-240 

LS-480 

(both have multistage 
surge suppression and 
RFI filtering) 


$485 
$795 


240 VA 
480 VA 


102 V 
102 V 


106 V 
106 V 


Meirick Inc. 

Power Systems Division 
POB 298 
Frisco, CO 80443 
(303) 668-3251 


Ml 400 

Ml 800 

(both have surge pro- 
tection and spike and 
line filtering) 


$495 
$795 


400 
800 


102 V 
102 V 


106 V 
106 V 


PTI Inc. 

320 River St, 

Santa Cruz, CA 95060 

(408) 429-6881 


Datashield PC-200 

XT-300 

MU-800 

(all have spike, EMI, 

and RFI protection) 


$359 
$499 
n.a. 


200(240 VA) 
300 (380 VA) 
800(1000 VA) 


108 V 
108 V 
108 V 


102 V 
102 V 
102 V 



184 BYTE • JANUARY 1985 



POWER SUPPLIES 



is switched in. A simple relay coil that 
detects the loss of power-line voltage 
can trigger the switch. In other cases, 
very elaborate electronic sense cir- 
cuits can trigger the standby UPSs, 
based upon parameters such as the 
absolute line voltage, the rate of 
decay of the line voltage, the occur- 
rence of line transients, or whether 
the frequency and phase of the in- 
verter are in sync with the decaying 
utility-line voltage. 

UPSs are classified in different ways. 
Manufacturers may specify a voltage 
level at which the standby UPS will be 
activated— the "cut-in level"— or they 



may specify a switching time for the 
UPS to come on line— the "reaction 
time"— when there is a complete loss 
of power. Neither figure by itself is 
adequate for making a purchase deci- 
sion. One UPS cut-in voltage may be 
sufficient to power your system, but 
it may have a long reaction time. A 
long reaction time can result in a loss 
of data in working memory. Even 
more serious is the probability of disk- 
drive damage that can occur during 
a lapse of 117-V AC power. Another 
manufacturer rates the reaction time 
of its standby UPS at less than one 
cycle of the AC line voltage, equal to 



16 2 /3 milliseconds (ms). However, the 
cut-in level when the line voltage is 
decreasing slowly is 80 V rms (root 
mean square), well below the neces- 
sary 117V AC. The effect on your 
computer components at this level is, 
at best, unpredictable. 

How critical is the reaction time 
relative to your hardware? Your main 
system box contains large filter capac- 
itors if it uses linear power supplies 
(with switching power supplies, capac- 
itor filtering may be minimal), and a 
10- to 25-ms reaction time for a UPS 
won't significantly affect operation. 

(continued) 



ALLOWABLE 

LOAD 

POWER FACTOR 


TRANSFER TIME 
OF UTILITY TO UPS 


OUTPUT VOLTAGE 


EXTERNAL BATTERY 
TERMINALS 


OPERATING PERIOD 
ON INTERNAL BATTERY 
AT RATED LOAD 


does not matter 
does not matter 


10 ms maximum; 8 

typical 

10 ms maximum; 8 

typical 


ms 
ms 


102 - 132 V, stepped 
sine wave 

102- 132 V, stepped 
sine wave 


yes, 10.8 - 14 V 
yes, 10.8 - 14 V 


at least 5 minutes at full load; at 
least 15 minutes at half load 
at least 5 minutes at full load; at 
least 15 minutes at half load 


1.7 A at 200 W 


8 ms maximum 




102 V AC, stepped sine 
wave 


no 


20 minutes at full load 


0.8 
0.8 
0.8 
0.8 


less than 2 ms 
less than 2 ms 
less than 2 ms 
less than 2 ms 




115 V AC 
rms 
rms 
rms 


yes 
yes 
yes 
yes 


9 minutes at full load 
16 minutes at full load 
18 minutes at full load 

10 minutes at full load 


0.6 
0.6 


4 ms maximum 
4 ms maximum 




120 V AC, modulated 
pulse-width output 
120 V AC, modulated 
pulse-width output 


yes, 12 V nominal 
yes, 24 V nominal 


11 minutes at full load; 27 
minutes at half load 
11 minutes at full load; 27 
minutes at half load 


00 00 

o o 


4 ms ± 2 
4 ms ± 2 




140 V square wave; 
115 V AC under load 
140 V square wave; 
115 V AC under load 


yes, 12 V nominal 
yes, 24 V 


20 minutes at full load; 45 
minutes at half load 
9 minutes at full load; 20 minutes 
at half load 


doesn't matter for 
these models 


10 ms maximum; 4 ms typical 120 V AC, phase- no 

shifted square wave 

4 ms maximum; 1 ms typical 120 V AC, phase- yes, 12 V 

shifted square wave 

10 ms maximum; 4 ms typical 120 VAC, sine yes 

wave 


at least 5 minutes at full load; at 
least 20 minutes at half load 
at least 5 minutes at full load; at 
least 20 minutes at half load 
at least 6 minutes at full load; at 
least 25 minutes at half load 



JANUARY 1985 • BYTE 185 



POWER SUPPLIES 



Tkble I: continued 






POWER 




TRANSFER 








PRICE 


RATING 


CUTrIN 


BACK 




MANUFACTURER 


MODEL 


PER UNIT 


(WATTS) 


VOLTAGE 


TO LINE 




Qubie' 


SB200 


$329 


200 


108 V 


108 V 




4809 Calle Alto 














Camarillo, CA 93010 


X7300 


$429 


300 


108 V 


108 V 




(800) 821-4479 


(both have surge and 
EMI protection) 












R. H. Electronics Inc. 


Guardian Angel 


$495 


200 


102 V 


106 V 




566 Irelan Dr. 


(20012060) 












Buellton, CA 93427 














(805) 688-2047 


Power Angel 


n.a. 


800 


102 V 


106 V 


■ 


SAFT America 


200 VA 


$549 


200 VA 


102 V*** 


106 V 




Electronic Systems Division 












2414 West 14th St. 


400 VA 


$749 


400 VA 


102 V*** 


106 V 




Tempe, AZ 85281 


(both have spike 












(602) 894-6864 


protection) 












Sun Research Inc. 


M60 


$400 


150 VA 


104 V 


110 V 




POB 210 


M60 + S 


$475 


150 VA 


104 V 


110 V 




Old Bay Rd. 


M60 + 3 


$525 


300 VA 


104 V 


110 V 




New Durham, NH 03855 


M60 + 3S 


$700 


300 VA 


104 V 


110 V 




(603) 859-7110 


M60 + 6 


$900 


600 VA 


104 V 


110 V 






M60 + 6S 


$1140 


600 VA 


104 V 


110 V 






Mayday 


$240 


150 VA 


104 V 


110 V 






Mayday + S 


$325 


150 VA 


104 V 


110 V 




■ 


Mayday + 3 


$350 


300 VA 


104 V 


110 V 






Mayday + 3S 


$500 


300 VA 


104 V 


110 V 






SR3 


$595 


300 VA 


104 V 


110 V 






SR6 


$995 


600 VA 


104 V 


110 V 






( + S indicates surge 
protection) 












Topaz Electronics 


84461 


$760 


400 VA , 


102 V 


110 V 




9192 Topaz Way 














San Diego, CA 92123 


84462 


$820 


400 VA 


102 V 


110 V 




(619) 279-0831 
















84462-01* 


$870 


400 VA 


102 V 


110 V 






84864 


$970 


800 VA 


102 V 


110 V 






84864-01* 


$1020 


800 VA 


102 V 


110 V 






84126-01* 


$1085 


1000 VA 








Tripp Lite 


BC-200 


$359 


200 


85 V** 






500 North Orleans 














Chicago, IL 60610 


BC-425 


$559 


425 


85 V** 






(312) 329-1777 














I 


BC-1000 


$1179 


1000 


85 V** 






- 


(all have surge 












protection) 












* with status monitor 














** may be used in series with 


vendor's brownout protection system; as 


supplied, the 








BC series is for complete t 


Dlackout protection only 












*** option for higher specificat 


on available 













186 B YTE • JANUARY 1985 



POWER SUPPLIES 



ALLOWABLE 






EXTERNAL 


OPERATING PERIOD 


LOAD POWER 


TRANSFER TIME 


OUTPUT 


BATTERY 


ON INTERNAL BATTERY 


FACTOR 


OF UTILITY TO UPS 


VOLTAGE 


TERMINALS 


AT RATED LOAD 


doesn't matter for 


10 ms maximum; 4 ms typical 


120 V 


yes, 12 V 


5 minutes at full load; 20 minutes 


these models 








at half load 




4 ms maximum, 1 ms typical 


120 V 


yes, 12 V 


6 minutes at full load;. 20 minutes 
at half load 




10 ms maximum; 4 ms 


102 V - 132 V rec- 


yes 


2-6 minutes at full load; 15 




typical 


tangle sine 


■> r,- t k 


minutes at half load 




10 ms maximum; 4 ms 


120 V ± 3.5 V sine 


no 


12 minutes at full load; 35 




typical 


wave 




minutes at half load 


0.8 


6 ms maximum; 4 ms typical 


117 V ± 15%, 
square wave for 


optional, 24 V 


20 minutes at full load; 50 
minutes at half load 


0.8 


6 ms maximum; 4 ms typical 


both models 


optional, 24 V 


10 minutes at full load; 24 
minutes at half load 


. 


16 ms maximum; 8 ms typical 


120 V rms; 


all models except 


at least 30 minutes at full load for 




16 ms maximum; 8 ms typical 


+ 3 V over 80% 


SR6 have external 


all models except SR3 and SR6, 




16 ms maximum; 8 ms typical 


of battery energy; 


battery terminals; 


which have a period of at least 




16 ms maximum; 8 ms typical 


sine wave; 


SR6 has an internal 


15 minutes at full load 




16 ms maximum; 8 ms typical 


5% harmonic 


gel 




*-r*fi ■ =#.'. 


16 ms maximum; 8 ms typical 
8 ms maximum 
8 ms maximum 


distortion 

120 V, square wave 

120 V, square wave 


■ 






8 ms maximum 


120 V, square wave 




V 




8 ms maximum 


120 V, square wave 






; 


8 ms maximum 


120 V, square wave 








8 ms maximum 


120 V, square wave 




doesn't matter for 


10 ms maximum; 4 ms typical 


120 V ± 3.5 V, sine 


no for all models 


at least 9 minutes at full load; 25 


these models 




wave for all models 




minutes at half load 




10 ms maximum; 4 ms typical 




: 


at least 35 minutes at full load; 








"■ | ■ ,&#,* 


75 minutes at half load 




10 ms maximum; 4 ms typical 






at least 35 minutes at full load; 
75 minutes at half load 


,:.. ... : . 


10 ms maximum; 4 ms typical 




■ 


at least 12 minutes at full load; 35 
minutes at half load 




10 ms maximum; 4 ms typical 






at least 12 minutes at full load; 35 




■ 






minutes at half load 

at least 9 minutes at full load; 30 

minutes at half load 


doesn't matter for 


10 ms maximum 


120 V AC, rec- 


no for all models 


10 minutes at full load; 30 


these models 




tangular wave for all 




minutes at half load 




10 ms maximum 


models 




10 minutes at full load; 30 
minutes at half load 




10 ms maximum 






16 minutes at full load; 38 
minutes at half load 




< 






■ 



JANUARY 1985 'BYTE 187 



POWER SUPPLIES 



T^ble 2: Continuous-duty 


uninterruptible power supplies compared according to manufacturer 


specifications. 




Some information may have changed since press time. 












.\-'r. 


l;>-: i :|N 


POWER 












RATING 


POWER 


BYPASS UPS 


MANUFACTURER 


MODEL 


PRICE 


(WATTS) 


FACTOR 


TO UTILITY 


Computer Power Inc. 


OUPS48-500 


$1650 


500 


0.75 lag to 0.9 


yes, 1 second 


124 Main St. 


OUPS48-750 


$1750 


750 


lead for all 


yes, 1 second 


High Bridge, NJ 08829 


OUPS48-1000 


$1975 


1000 


models 


yes, 1 second 


(201) 735-8000 


UPS36-500M 












- with lead-antimony 


$1690 


500 




yes, less than 1 




battery 








second for all 


- with small gel battery 


$1710 


500 


■ 


UPS36 and 




- with large gel battery 


$1795 


500 




UPS48 models 


■ 


UPS36-750M 












- with lead-antimony 


$1795 


750 






. 


battery 












- with small gel battery 


$1860 


750 






. 


- with large gel battery 


$1940 


750 








UPS36-1000M 












- with lead-antimony 
battery 


$2075 


1000 


■ 






- with small gel battery 


$2140 


1000 








- with large gel battery 
UPS48-1500M 


$2220 


1000 


T '"* 






- with lead-antimony 


$3500 


1500 








battery 




i: v':;- ;: . i; ;. ;.;:Sv' : 




■.. 




- with small gel battery 


$3565 


1500 








- with large gel battery 


$3645 


1500 






Electronic Protections 


Grizzly 500 


$2400 


500 


0.8 


standard at 


Devices 


Grizzly 1000 


$5200 


1000 


0.8 


125% overload 


POB 673 


(both have surge 








for both models 


Waltham, MA 02254 


protection) 






•■•i \ 




(800) 343-1813 












RTE Deltec Inc. 


3056 


$1995 


500 


1 


standard 


2727 Kurtz St. 












San Diego, CA 92110 


DSU-720 


$2995 


700 


0.8 to 1 


optional 


(619) 291-4211 


DSU-1220 


$3395 


1200 


0.8 to 1 


optional 




DSU-1820 


$3895 


1800 


0.8 to 1 


optional 




7026 


$6295 


2500 


0.7 to 1 


standard 


Sun Research Inc. 


Mayday 60 + 3C 


$800 


300 VA 


1 for all models 


optional on all 


POB 210 


Mayday 60 + 6C 


$1325 


600 VA 




models 


Old Bay Rd. 


Mayday 60+ 10C 


$2295 


1000 VA 






New Durham, NH 03855 


SR30 


$995 


300 VA 






(603) 859-7110 


SR60 


$1495 


600 VA 








SR100 (220 V in, 


$2395 


1000 VA 




.. 




110 V out) 












SR150 (220 V in, 


$3195 


1500 VA 








110 V out) 











188 BYTE • JANUARY 1985 



Inquiry 302 



POWER SUPPLIES 













BATTERY CONNECTION 




OR INTERNAL BATTERY 


OUTPUT VOLTAGE 


AT RATED LOAD 


120 V AC, sine wave 


OUPS48 models operate on ex- 


for all models 


ternal battery 




120 minutes at full load 




50 minutes at full load 




120 minutes at full load 




75 minutes at full load 




30 minutes at full load 




75 minutes at full load 




50 minutes at full load 




20 minutes at full load 


"• : -r 


50 minutes at full load 




40 minutes at full load 




20 minutes at full load 




45 minutes at full load 


120 V AC, sine wave 


both models have 60-V external 




battery; 15 minutes at full load, 




12 minutes at half load 


120 V AC, sine wave, 


48-V external battery 


5o/o THD 


72-V external battery on all DSU 


DSU models offer user- 


models 


selectable sine wave, 




5% THD 




120 V AC, sine wave, 


72-V external battery 


5% THD 




120 V AC, sine wave 


24-V external battery 


for all models except 


24-V external battery 


SR100 and SR150; for 


48-V external battery 


those models, 110 V 


12-V internal gel 


AC, sine wave 


24-V internal gel 




SR100 and SR150 offer choice of 




lead-sulfate battery or internal gel 







rUausiiiSB 3.9 




For the IBM PCr*XT**and IBM "COMPATIBLES 

KEYSWAP is the most advanced Macro Processor 

available for the IBM PC** - including WINDOWING 

and Keyboard filtering. 

KEYSWAP creates yet another dimension in 

USER FRIENDLINESS. 

In addition to the standard 

macro features, the user can: 

Create custom Help Menus that can 

be recalled from within any program. 

Create "lessons" that can be played back af 

variable speed for tutorial or demo purposes 

ONLINE FULL SCREEN MACRO EDITOR Create and 

Modify your macros at any time. 

Create a single macro definition as large as 64K 

ONLINE MACRO LISTING 

See a listing of your macros at any time - instantly! 

IMAGINE: automatic time and date display; fixed and 

variable definition fields; audible feedback on toggle keys; 

alternate cursor control selection; Keyboard customization; 

Condensing many keystrokes into just one. 

KEYSWAP - State of the Art keyboard utility software. 

PRICE 

$129.00 (RETAIL) 

+ 2.50 Shipping & Handling. MA res add 5% Sis, TX. 

FOR ORDERS OR INFO CALL OR WRITE 

RICKERDATA 

PO BOX 998 MELROSE, MA 02176(617) 662-0856 

MC & VISA ACCEPTED 
* * Registered Tredemar* IBM J 





Our complete line says it all: Touchdown'" Keytop Expanders fit over 
existing keys on IBM PC and most PC lookalikes. Adhesive provided 
insures easy removal without damage to keyboard. Touchdown™ 
Key Overlays re-assign, clarify or blank-out PC keytop commands; 
durable, non-glare surface looks and feels like original keytops. 

"Smwny P. 0. Box 201, Dept. B, Comville, AZ 86325 

DEALER INQUIRIES INVITED— M6 these unique items to your software line and reap immediate profits. 
Write us today or phone 602-634-7517 for complete details. 



KEYTOP EXPANDERS DBIk. DGrey 

Qty. Price* 

IBM PC. PC/XT. PC Port. (12 keys) $21.95 

IBM 5291 Display Station (13 keys) 21.95 



Qty. 



.Compaq. Columbia (10 keys) 
.Corona, Eagle Spirit, Oubie, 
Keytronic (10 keys) 



Price* 

$21.95 I 

21.95 



KEY OVERLAYS 

5250/5251 (48 keytops/fronts) 

5520 (95 keytops) 

Display Write 2 (36 keytops) 

Dvorak (43 keytops) 

Wordstar (29 keytops) 

Control Key English (5 keytops) 

D Check □ Money Order 

D Visa □ MasterCard Exp. Date_ 

Card # 



$21.95 
28.95 
21.95 
26.95 
26.95 
6.95 



Visa or MC orders phone 602-634-7517 

Company Name 

Attention 



Blank Overlays (99 keytops) 

Do-it-yourself Kit (154 pieces) 

MultiMate 

EasyWriter II 

Lotus 1-2-3 

WordPertect 

VolksWriter 

AppleWriter tl 

*Alt prices include postage TOTAL $_ 

Arizona residents add 5% tax _ 

TOTAL ENCLOSED $_ 



21.95 
29.95 
29.95 ■ 
29.95 I 
29.95 
24.95 
24.95 ■ 
29.95 I 



I 

I 



Custom Overlay, Other Software Kits. — 
Write for information. | 



Address. 
City 



-Zip_ 



Inquiry 163 



JANUARY 1985 -BYTE 189 



POWER SUPPLIES 



Constructing 

AN 

Emergency 
Light Source 



Unless you enjoy programming in 
the dark, an auxiliary light source 
adjacent to your UPS-protected com- 
puter is a wise idea. I use a high- 
intensity desk lamp that incorporates 
a 1 2-V automobile taillight bulb and a 
built-in 1 2-V transformer. Break the lead 
to the lamp where shown in figure A, 
add relay Kl, and connect the battery 
and other wires. While the 1 1 7-V power 
is available, the lamp is lighted from the 
11 7-V line. During a power failure, the 
relay contacts switch the lamp to the 
12V battery. You can add a single-post, 
single-throw switch, SI, if you want the 
option of turning the emergency light- 
ing on and off to conserve battery 
power. 

Another alternative, albeit more com- 
plicated, is shown in figure B. With this 
design, you can modify your high- 
intensity lamp with all solid-state (no 
relay) circuitry and include battery- 
charging capabilities. When nearly fully 
charged, the 12-V car battery will 
receive a trickle charge of about 
30 milliamperes, guaranteeing many 
hours of emergency lighting from a 
fresh battery. 



A photocopy of the printed-circuit board art- 
work is available from "William Rynone Sr., 
POB 292. Ocean Gate. NJ 08740. You 
must include a stamped self-addressed 
envelope. 



HIGH 



117 VOLTS AC 
INPUT 



BREAK HERE 



> 



12V 

#93 LAMP 



ORIGINAL LIGHT WIRING 



117 VOLTS AC 
INPUT 



N- 



NC 
-° — w 



tl_12V 



" BATTERY 



n 



NO 

Kl 



12 V 

#93 LAMP 



EMERGENCY LIGHT SOURCE WIRING 



NOTE: Kl IS A 117-VOLT AC COIL WITH SPOT CONTACTS. 
CONTACT POSITION SHOWN WITH COIL ENERGIZED 



Figure A; This emergency lighting setup powered by a UPS can keep you 
from computing in the dark. (Original schematic by Barbara Campo.) 



IN 5821 

BRIDGE DIODES 
(NO SUBSTITUTES) 



117VAC 



n 




1N914 



*TO-66=PNP POWER 
TAB 

TRANSISTOR 
*FE> 100 © 
l c =l AMP 



GE#93(cEfc 



lOOil 

1/2W 

— w\ — 



1N9H TO-66 




L_100/xF 
*® 25V 



100ft 

1W 



680& 
1/2 W 



2.6V OR 3.2V 
'ZENER 
@ 1/2\N 



12V CAR -dr 
BATTERY _= 



Figure B: A high-intensity lamp modification with backup power source and 
battery-charging capabilities. Schottky diodes must be used in the bridge in order to 
maintain adequate lamp brilliance. Any PNP power-tab mount (TO-66) transistor 
with a gain of 100 At I ampere will work with this design. 



190 BYTE • JANUARY 1985 



Inquiry 67 — ► 




The Choice is Yours 



The time has come when one computer just 
isn't enough. You have a choice. . .add more 
personal computers or move up to multi-user 
with the CompuPro 10 PLUS. 

Personal computer networks are one 
alternative. But in a four-user network, you'll 
need four personal computers plus a net- 
working package. . . Cost. . .$18,000/ 

In contrast, the CompuPro 10 is specifi- 
cally designed to be a four-user microcom- 
puter. One fully-integrated system with 
multi-user capability. . . Under $10,000.** 

Price isn't the only advantage CompuPro 10 
has over networked personal computers. 



The CompuPro 10's multi-user operating 
system allows you to run both 8- and 16-bit 
software at the same time. So you can 
choose from a library of over 3,000 pro- 
grams, as well as use your existing CP/M^ 
software. And our innovative multi-processor 
design lets you work faster without the per- 
formance degradation associated with per- 
sonal networks. 

For a complete demonstration, visit one of 
our Full Service CompuPro System 
Centers. Or call (415) 786-0909, ext . 206 for 
the System Center nearest you. 
Don't get personal, get CompuPro. 



ompuPro 



3506 Breakwater Court, Hayward, CA 94545 

'Suggested list price for four popular personal computers, 40 Mb of hard disk storage and network package. "Includes CompuPro 10 PLUS with 1 Mb RAM, 
40 Mb hard disk and applications programs ($7995 list), plus four terminals. CP/M is a registered trademark of Digital Research, Inc. © 1984 CompuPro 



POWER SUPPLIES 



Floppy-disk drives are not as well 
protected. They can generally be 
divided into two types: those with DC 
motors and those with AC motors. 
Those with DC motors are de- 
energized when not reading or writing 
to disk, but they have heads that are 
in continual contact with the disk. 
Drives with AC motors contain read/ 
write heads that are lowered into posi- 
tion only during data transfer. As long 



as the filter capacitors are large 
enough to sustain voltage above TTL 
(transistor-transistor logic) minimum 
levels, you will not lose data. However 
if the head is traveling across the disk, 
a sudden power loss— below 11 7 V — 
can result in a scratched floppy disk. 
Winchester drives are an exception. 
Their heads require a nominal 15 
seconds to be lifted to the normal 
operating position and a comparable 



UPS 
Shopping Questions 



Here are some appropriate ques- 
tions to ask when shopping for a 
UPS device. Questions 2 through 9 are 
particularly applicable to standby UPS 
units. 

1. Should I purchase a continuous-duty 
or a standby UPS? (A quality standby 
UPS may perform acceptably at a con- 
siderable savings.) 

2. What is the power rating of the UPS? 
If it has a built-in battery how long will 
the battery supply power at a usable 
voltage level? Will the vendor supply 
an output-voltage versus time curve for 
its UPS unit under rated power con- 
ditions? 

3. You may wish to purchase a UPS 
with reserve power to accommodate 
future computer components. How 
much 1 17-V rms output voltage varia- 
tion will occur if the unit is not used 
at its rated load power? That is. how 
well is the output voltage regulated? 
Will the vendor supply an output- 
voltage versus percent-of-rated-load 
power curve for its UPS? (This question 
is appropriate because the intermittent 
operation of disk drives and printers 
causes variations in the load current 
that must be supplied by the UPS.) 

4. Are terminals available on the case 
of the UPS whereby an external bat- 
tery may be employed (thus enabling 
a longer operating period)? If so. what 
voltage must the external battery be? 
(TWelve volts is desirable, so a low-cost 
car battery may be used.) 

5. Will overheating problems occur if 
operated with an external battery for 
an extended period? How long can you 
operate? 



6. Is the UPS unit available without the 
internal battery? (You may decide to 
use a 12-V car battery.) 

7. lb what voltage must the power line 
decrease before the UPS activates? 
Does the UPS activate at the same 
voltage value for slowly as well as 
rapidly decaying line voltages? Does it 
employ a phase-locked loop circuit 
with gradual line frequency capture cir- 
cuitry? 

8. In the event of a sudden and com- 
plete loss of power, what is the switch- 
ing time for the standby unit to "cut 
in"? 

9. Is delay circuitry included in this 
product? (Delay circuitry can keep the 
unit on line for a period of time after 
it has been activated by line transients, 
thus giving the power company's line 
voltage an opportunity to settle.) If so. 
what is the delay period? 

1 0. Is the output of the UPS sine wave 
or square wave? (Some printers mal- 
function with a square-wave power 
source. If you're content to save some 
data and power down your computer, 
the UPS output waveshape might not 
be important, and you could purchase 
a lower-cost unit. A sine-wave unit may 
cost two to three times as much as an 
equivalent square-wave unit.) 

1 1 . Most microcomputer users already 
have line transient suppressors. Is the 
UPS available without this built-in cir- 
cuitry? If not. can you connect an exist- 
ing multi-outlet power strip with surge- 
suppression capability to the output of 
this UPS without excessive voltage 
drop? 

12. Who sen/ices the UPS? (Hong Kong 
is rather inconvenient.) 



time to be de-energized. It appears, 
therefore, that a 2 5-ms loss of power 
should have no detrimental effect. 
Some 5^-inch Winchesters do have 
an electromechanical brake that ac- 
tivates at approximately 9 V, making 
it difficult to predict what will happen 
to them at different levels of power 
loss. 

The Price of Power 

The price of uninterruptible power is 
a purchase factor. A low-power con- 
tinuous-duty UPS may cost three to 
four times more than a standby UPS 
of equivalent rating. Power ratings of 
UPSs may be as low as 1 00 watts or 
up to many kilowatts. Your home com- 
puter doesn't need that much protec- 
tion. These high-kilowatt units are 
used by banks and hospital operating 
rooms. 

You can determine the UPS power 
required to protect your system by 
adding the individual power ratings of 
each component. You'll find the 
power ratings for the central process- 
ing unit, disk drives, video-display ter- 
minal, and printers on each manufac- 
turer's nameplate or in the accom- 
panying data sheets. If you own a 
totally integrated computer system, 
you'll find only one power rating. You 
may want to purchase a UPS with a 
slightly greater power rating than your 
system requires. The extra power will 
enable you to add one or more new 
components. 

Tables 1 and 2 are based upon in- 
formation supplied by UPS manufac- 
turers. In some instances their data 
was incomplete and would not help 
a reader answer the "consumer" 
questions that accompany this article 
(see "UPS Shopping Questions" at 
left). 

A common power rating for stand- 
by UPSs used in typical home com- 
puter systems is 150 to 200 watts. 
These units operate on their built-in 
battery, or batteries, for about 20 
minutes. This is just enough time to 
complete important data entry, albeit 
by flashlight or candlelight, and save 
your work (see "Constructing an 
Emergency Light Source" on page 
190). ■ 



192 B YTE • JANUARY 1985 



Today's business microcomputers have generated an informa- 
tion explosion that today's data storage devices-including 
the highly-touted, high-capacity Winchesters-have been ill- 
prepared to contain. 



NifdiniiiiiHiiiipriiiiiHurr 




With one notable exception. The Bernoulli Box" from 
IOMEGA. Available for the IBM PC, XT, most compatibles, the 
TI Professional, and Apple's Macintosh? the Bernoulli Box 
delivers unparalleled data base dynamics. Thanks to its 
removable 10-megabyte cartridges (5 -megabyte for the 
Macintosh) and its proprietary removable disk technology. 

And that, more and rpore, is what your business needs today. 
Not centralized, monolithic banks of information, but data 



bases defined by job function and software application. Data 
bases that give people the versatility to work more productively. 

But there is more. More performance and reliability. Transfer 
rates and access times faster than most Winchesters. No 
head crashes ever. And cost per megabyte that Winchesters 
cannot touch. 

The Bernoulli Box's cartridge capacity, portability, and absolute 
interchangeability give your business more options. You can 
easily build primary data bases. You can package individual- 
ized data bases, software and all— for payroll, accounting, 
marketing-in convenient, dedicated cartridges. You can secure 
them quickly and economically in backup. And you can pack 
all of the data into a briefcase, an interoffice envelope, or even 
a file drawer. 

For the dealer nearest you, call 1-800-556-1234 
ext. 215. In California call 1-800-441-2345 ext. 215, 



L-MZGA 

IOMEGA Corporation 

1821 West 4000 South 
Roy, Utah 84067 



Inquiry 182 



y&£ 









THE 




BOX" 



FANTASTIC COMPUTER PRINTER SALE!!! 



COM-STAR T/F 

Tractor 
Friction 
Printer 



only 



** 



nfiiTiriniinrnfmrTifmifiTTTmiTiin'nninrrfTrfnnfHiitrinmTTTifJ 



COMSTAR 



• Lowest Priced, Best Quality, Tractor-Friction Printers in the U.S.A. 
Fast 80-120-160 Characters Per Second • 40, 46, 66, 80, 96, 132 Characters Per Line Spacing 
• Word Processing • Print Labels, Letters, Graphs and Tables • List Your Programs 
Print Out Data from Modem Services • "The Most Important Accessory for Your Computer" 



** DELUXE COMSTAR T/F 
80 CPS Printer — $169.00 

This COMSTAR T/F (Tractor Friction) 
PRINTER is exceptionally versatile It 
prints 8 1 //' x 11" standard size single sheet 
stationary or continuous feed computer 
paper. Bi-directional, impact clot matrix, 
80 CPS. 224 characters. (Centronics 
Parellel Interface). 

Premium Quality 120-140 CPS 
10" COMSTAR PLUS+ 
Printer $249.00 
The COMSTAR PLUS+ gives you all the 
features of the COMSTAR T/F PRINTER 
plusa 10" carriage. 120-140 CPS. 9x9 dot 
matrix with double strike capability for 18 x 
18 dot matrix (near letter quality), high 
resolution bit image (120 x 144 dot 
matrix), underlining, back spacing, left 
and right margin settings, true lower 
decenders with super and subscripts, 
prints standard, italic, block graphics and 
special characters It gives you print 
quality, and features found on printers 
costing twice as much!! (Centronics 
Parallel Interface) (Better than Epson 
FX80). List $499.00 SALE $249.00 



Premium Quality 120-140 CPS 
1 5 ft" COMSTAR PLUS+ 
Business Printer $349.00 

Has all the features of the 10" COMSTAR 
PLUS + PRINTER plus 15" carriage and 
more powerful electronics components to 
handle large ledger business forms! 
(Better than Epson FX 100) List $599 
SALE $349.00 

Superior Quality 

10" COM-STAR+ H.S. 

HIGH SPEED 160-180 CPS 

Business Printer $369.00 

This Super High Speed Com-Star+ Business 
Printer has all the features of the 10" COM- 
STAR* PRINTER with HIGH SPEED 
BUSINESS PRINTING 160-180 CPS, 100% 
duty cycle, 8K Buffer, diverse character 
fonts, special symbols and true decenders, 
vertical and horizontal tabs. A RED HOT 
BUSINESS PRINTER at an unbelievable low 
price (Serial or Centronics Parallel 
Interface) List $699.00 Sale $369.00. 



Superior Quality 

15W COM-STAR PLUS+ H.S. 

High Speed 160 - 180 CPS 

Business Printer $469.00 

This Super High Speed COM-STAR+ 15'//' 
Business Printer has all the features of the 
10" COM-STAR BUSINESS PRINTER witha 
15'//' Carriage and more powerful 
electronic components to handle larger 
ledger business forms! Exclusive bottom 
feed. (Serial Centronics Parallel Interface) 
List $799.00 Sale $469.00 



OOlympia 

Executive Letter Quality 
DAISY WHEEL PRINTER $379.00 

This is the worlds finest daisy wheel printer 
Fantastic Letter Quality, up to 20 CPS 

bidirectional, will handle 14.4" forms 
width! Has a 256 character print buffer, 
special print enhancements, built in 
tractor-feed (Centronics Parallel and 
RS232C Interface) List $699 SALE $379. 



• 15 Day Free Trial - 1 Year Immediate Replacement Warrant 



i 



■PARALLEL INTERFACES- 



For VIC-20 and COM-64 - $49.00 For Apple computers - $79.00 Atari 850 Interface - $79.00 For ALL IBM Computers - $89.00 



Add S14 50for shipping, handling and insurance. Illinois residents 
pleas«pdd 6% tax. AddS29 00 for CANADA. PUERTO RtCO HAWAII. 
ALASKA. APO-FPO orders. Canadian orders must be in U.S. dollars. 
WE DO NOT EXPORT TO OTHER COUNTRIES. 

Enclose Cashiers Check, Money Order or Personal Check. Allow 14 
days for delivery. 2to7 days for phane orders. 1 day express mail! 
ViSA-MASTER CARD-We Ship C.O.D to U S Addresses Only 



ENTERPRIZES m^™****™* 

BOX 550, BARRINQTON, ILLINOIS 60010 
Phont 312/382*5244 to ordtr 



COM-STAR PLUSh 
Print Example: 



ABCDEFGHIJKLMNOI 
ABCDEF6HX JKLMN0P0R8TUVWXYZ 1 2: 



UVMXVZ 



194 BYTE • JANUARY 1985 



NEW 128K —MEGA BYTE DUAL DISK DRIVE-80 COLUMN 

COMPUTER SYSTEM SALE! 

HOME • BUSINESS • WORD PROCESSING 

M 




L OOK AT ALL YOU GET FOR ONL Y 



$895. 

(T) B128 COMMODORE 1 28K 80 COLUMN COMPUTER 

(2) 4023 - 100 CPS - 80 COLUMN BIDIRECTIONAL PRINTER 

(3) 8050 DUAL DISK DRIVE (over 1 million bytes) 
® 12" HI RESOLUTION 80 COLUMN MONITOR 

• BOX OF 10 LORAN LIFETIME GUARANTEED DISKS 

• 1 100 SHEETS FANFOLD PAPER 

• ALL CABLES NEEDED FOR INTERFACING 

TOTAL LIST PRICE 



LIST PRICE 

$ 995.00 

499.00 

1795.00 

249.00 

49.95 

19.95 

102.05 

$3717.95 




PLUS YOU CAN ORDER THESE BUSINESS PROGRAMS AT SALE PRICES 



Professional 80 Column 
Word Processor 
Professional Data Base 
Accounts Receivable 
Accounts Payable 



LIST 

$149.95 
S149.95 
S149.95 
S149.95 $99.00 



SALE 

$99.00 
$99.00 
$99.00 



Payroll 
Inventory 
General Ledger 
Financial Spread Sheet 
Order Entry 



LIST 
S149.95 
S149.95 
S149.95 
S149.95 
S149.95 



SALE 
$99.00 
$99.00 
$99.00 
$99.00 
$99.00 



PRINTER REPLACEMENT OPTIONS 

(replace the 4023 with the following at these sale prices) 



Olympia Executive Letter Quality Printer 
Comstar Hi -Speed 1 60 CPS 1 5 Vb " Business Printer 
Telecommunications Deluxe Modem Package 
IEEE to Centronics Parallel Printer Interface 



LIST SALE 

S699.00 $379.00 

S779.00 $469.00 

S199.00 $139.00 

SI 79.00 $139.00 



15 DAY FREE TRIAL. We give you 15 days to try out this SUPER SYSTEM PACKAGE! J If it doesn't meet your expectations, just send it back 
to us prepaid and we will refund your purchase price! ! 

90 DAY IMMEDIATE REPLACEMENT WARRANTY. If any of the SUPER SYSTEM PACKAGE equipment or programs fail due to faulty 
workmanship or material we will replace it IMMEDIATELY at no charge! ! 



Add S50.00 for shipping and handling!! 
$100.00 for Alaska and Hawaii orders. 

WE DO NOT EXPORT TO OTHER COUNTRIES 

Enclose Cashiers Check. Money Order or Personal Check. Allow 14 days for 
delivery, 2 to 7 days for phone orders, I day express moil! We accept Visa 
and MasterCard. We ship C.O.D. to continental U.S. addresses only. 



pMTpppP|7pC WElOvEOURCuSTOMERS 

BOX 550, BARRINGTON, ILLINOIS 60010 
Phont 312/382-5244 to ordtf 



Inquiry 287 



JANUARY 1985 • BYT'E 195 



You already own a 
computer that can talk. 

Now let it. 



Now you can upgrade almost any personal computer 
and make it more powerful than ever, by giving it the power of speech. 



The Votrax Personal Speech System is the least 
expensive sophisticated voice synthesizer available today. 
The PSS's text-to-speech vocabulary is virtually unlimited, 
and you can define an exception word table and custom- 
ize your translations. So the PSS can say just about anything! 

It's a speech and sound specialist. 

The PSS can also mix speech and sound effects or speech 
and music. It contains its own speaker; a programmable 
master clock, 256 programmable frequencies, a program- 
mable speech rate for a more natural rhythm, and 16 
programmable amplitude levels for incredible control of 
word emphasis. You can control the volume. Plus, it 
doesn't use any of your computers valuable memory. 

It's computer friendly. 

The PSS is unbelievably easy to use. It doesn't need an 
interface card for most computers. It comes with standard 
serial and parallel ports. Speech, music, and sound effects 
are as simple as printing out a document. 

What do you do with a talking 
computer? 

There are countless practical applications. Businesses may 
want the PSS for spoken transmission of information, 
narration of displays, and product demonstrations. It 
makes verification of data input possible for the blind. 
It can be part of a burglar alarm system. 
Children can use the PSS as a study 
aid. And it helps games come alive, 
speaking while you play. 

Whatever your computer can 
do, the PSS can help it do it better; at 
a cost that makes it all worthwhile: 
only $395* Call (3 1 3) 583-9884 to hear an actual voice 
demonstration of the PSS. 

*5uggested retail price 



There's also the Type 'N Talk. 

If you want a less sophisticated unit and want to spend a 
little less, consider the Votrax Type 'N Talk (TNT). Its vocab- 
ulary is also limited only by what you can type. It doesn't 
use any computer memory it's compatible with most 
computers, and it's only $249* Just plug it in to your own 
speaker and go! 

For more information about the Personal Speech 
System or the Type 'N Talk, see your local computer 
retailer; call toll-free or write: 



1394 Rankin 

Troy Michigan 48083 

I -800-521 -1 350 

(In Michigan, call collect 

313-588-0341) 




Q 




196 B YTE • JANUARY 1985 



Inquiry 366 



by Richard S. Shuford 



An Introduction 
to Fiber Optics 

PART 2: 

CONNECTIONS AND NETWORKS 



Optical fibers are 
becoming practical 
for use in applications 
such as local networks 



Editor's note: Last month we looked at the 
new technology of optical- fiber waveguides and 
examined their fundamental principles. This 
month we'll concentrate on the more practical 
aspects of fiber optics: how they are connected 
together and how they are being used in com- 
puter communications. 

The rapid development and 
change of the fiber-optics in- 
dustry is evident in microcosm 
in the little parts that enable the ma- 
jor components of a fiber-optic 
system to be fitted together: the con- 
nectors. Established electronic- 
connector companies are in hot com- 
petition with unknown upstarts to 
develop, patent, and sell the fiber- 
optic cable connector that will 
become the equivalent of the audio- 
equipment "phono" plug or the 
coaxial-cable PL-2 59. The SMA 905 
and 906 connectors for multimode 
fibers, made by Amphenol. AMR Op- 
tical Fiber Technologies Inc., and a few 
others, are candidates (at least in 
commercial systems), but their role is 
not yet a dominant one. 

To the user of a fiber-optic system, 
the continued competition indicates 
that none of the connectors hitherto 
available have been really satisfactory 
in all respects. Among their defects 
have been high price, fragility, high 
loss, noninterchangeability difficulty 
of installation, and uncertainty of sup- 
ply. Fortunately, the majority of the 
products on the market have over- 
come most of these flaws, but the 
connectors all seem to have at least 
one drawback. 

Most of the connector designs now 
in wide use require a good deal of ex- 
pertise as well as special polishing or 
test equipment for proper installation. 



Many of the ones with low loss must 
be assembled using an epoxy adhe- 
sive to hold the optical fiber in align- 
ment; the epoxies often require ex- 
posure to an ultraviolet curing light or 
high temperatures. Furthermore if, 
once the epoxy has cured, the fiber 
alignment is unsatisfactory, the con- 
nector has to be cut off and dis- 
carded. 

Engineers laying out a fiber-optic 
communication link have to pay close 
attention to the total signal loss in the 
system. Transmitter and receiver gain 
are weighed against the losses caused 
by each passive system component; 
the balance sheet of gain and loss is 
called the flux or power budget. In sys- 
tems that have many connections be- 
tween the transmitter and receiver, as 
is often the case in a computer local 
network, the connectors usually intro- 
duce more loss than any other factor. 
There is also a trade-off between the 
quality of the connection produced 
and the ease of installing the connec- 
tor: the easiest to install are the most 
lossy. With really tight power budgets, 
installers have to resort to the difficult 
but effective fusion splice for joining 
fibers, in which the cloven, stripped 
fiber end faces are precisely aligned 
and then melted together by subject- 
ing them to an electric arc. 

But new kinds of connectors and 
splices are being invented, and one 
of them may yet combine the virtues 
everyone is waiting for. For example, 
promising developments have ap- 
peared in the multimode expanded-beam 
lens (EBL) connectors. The lens in an 

[continued] 
Richard S. Shuford is BYTE's special-projects 
editor. He can be contacted at POB 372, 
Hancock. NH 03449. 



JANUARY 1985 -BYTE 197 



FIBER OPTICS 



EBL connector spreads the light 
emerging from the attached fiber into 
a larger exit angle or, on the other 
side of the connection, gathers light 
from a larger region of space than 
would normally be permitted by the 
fiber's numerical aperture. Compared 



to other connectors, EBL connectors 
reduce the precision of fiber align- 
ment required, but they tend to be ex- 
pensive simply because they incor- 
porate lenses, which have to be 
ground and then coated chemically to 
prevent power loss from extra reflec- 



tion. However, at least one simplifica- 
tion has been made possible by new 
EBL designs now available from 
General Telephone and Electronics 
and from the Deutsch (pronounced 
"doysh") Corporation; these can be in- 

{continued) 



Driving the Fiber-Optic Ethernet Bus 



The Ethernet was designed to use 
a network-access protocol called 
carrier-sense, multiple-access with col- 
lision detection (CSMA/CD). The in- 
spiration for this, according to inven- 
tor Robert Metcalf. was the so-called 
"cocktail party algorithm": a man at a 
party wishes to speak, but first he 
listens, finding out if anyone else is 
already speaking. If he hears silence, 
he begins to talk. But if the woman next 
to him begins to speak at the same in- 
stant, neither will be understood by 
their listeners. So, each hearing the 
other, they both stop. After waiting for 
a brief moment, the man tries again to 
speak, and if the woman is inclined to 
wait for a slightly longer interval, the 
man succeeds in communicating. 

A CSMA/CD computer network 
works essentially the same way. The 
transceivers at each node sense the 
state of the transmission medium 
(usually a coaxial cable) before at- 
tempting to transmit, looking for a car- 
rier signal from another station's 
transceiver. Sometimes two devices at- 
tempt to transmit at once, but when 
this collision is detected, both stop and 
pause for a random interval before try- 
ing again. The likelihood of a collision 
is increased by delays of propagation 
along the length of the cable: by the 
time the signal from one station has 
traveled down the cable, another sta- 
tion has already started its own trans- 
mission, having heard nothing. 

In Ethernet, a station can easily tell 
that a collision has occurred by sens- 
ing the DC voltage level on the coax- 
ial cable, which becomes higher than 
usual when two stations are transmit- 
ting simultaneously. But a network in 
which signals travel through glass in the 
form of light waves cannot use DC 
voltages to detect collisions. Nor can 
it use comparison of the levels of light 
present in the optical fiber. Different 



levels of light arrive at various points 
in the system because of the attenua- 
tion of the light at each connection. 
Furthermore, the power emitted by op- 
tical transmitters varies— some emit 
twice as much light as others, and the 
sensitivity of receivers also varies. 
There is no practical way to use direct 
measurement of the transmitted signal 
as a reliable collision detector. A team 
of researchers headed by Richard P. 
Kelly at Siecor FiberLAN took this as 
a challenge in designing a fiber-optic 
network that would be compatible with 
Ethernet. 

The researchers looked at some pre- 
vious efforts to use an active central 
controller with a hybrid signal path (in- 
cluding work at Xerox's Palo Alto 
Research Center, where Ethernet was 
developed). In many such previous 
designs, transmissions coming over op- 
tical fibers from each network station 
were fed into an optical transceiver at 
the central node. The transceiver con- 
verted the signal into electrical form 
and then placed it on a metallic elec- 
trical bus. permitting collision detection 
to occur the same way as in the original 
Ethernet. The signal was then recon- 
verted into modulated light and sent 
out on a second set of fibers to the 
other nodes. 

But an active central node for prop- 
agating the signals negates one of the 
basic reasons for using the bus top- 
ology: the network could fail totally if 
anything goes wrong with the active 
central controller. (The same principle 
applies if active T-taps are used on a 
pure fiber-optic bus, although possibly 
only part of the network would fail.) So 
Kelly's team devised a clever alter- 
native in which the physical bus of 
Ethernet is emulated by a passive op- 
tical multiplexer, the transmissive star 
coupler, For each network node, sep- 
arate transmit and receive fibers (in a 



dual cable) are used, physically laid out 
in a star configuration and converging 
at a wiring center. The transmit lines 
enter the input side of the transmissive 
coupler, which divides the incoming 
light equally and broadcasts it to all the 
stations on the network over the 
receive lines (as shown in figure 4). Any 
collisions of transmissions occur inside 
the coupler. 

However, at some point in the 
transmit line coming from the remote 
stations, an optical tap diverts a small 
amount of the optical power (around 
10 percent) to separate fibers that feed 
a separate active collision detector. The 
collision detector has individual inputs 
for each network station, each feeding 
a receiver connected to one gate of a 
logical comparator. Whenever signals 
arrive simultaneously on more than 
one collision-detection line, a collision 
is known to be occurring. With multi- 
ple inputs active, the comparator emits 
an output signal to activate a "jam" 
transmitter that feeds the central 
coupler with a distinctive signal subse- 
quently broadcast to all nodes. To find 
out if there has been a collision, the 
network nodes merely have to detect 
the special jam signal. If there is a 
failure in the collision detector, the net- 
work falls back into a somewhat less 
efficient mode of operation, without 
collision detection; data, however, can 
still flow throughout the system. 

In this design, the passive transmis- 
sive coupler maintains the robustness 
of the bus topology, while the active 
collision detector allows complete 
interconnection and protocol com- 
patibility with existing coaxial-cable 
Ethernet installations. And the efficien- 
cy of optical-fiber transmissions results 
in longer network segments, increas- 
ing from 500 meters to 2800 the 
distances that can be handled between 
nodes before repeaters are needed. 



198 BYTE • JANUARY 1985 



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FIBER OPTICS 




stalled on multimode cables without 
special polishing of the fiber's face. 

Intercomputer 
Communication 

Optical fibers are becoming an in- 
creasingly attractive medium for com- 
munication between computers. Or- 
ganizations with large data-processing 
chores are discovering the efficiency 
and security of fiber optics for con- 
necting computation centers that are 
a few miles apart. The small physical 
size of fiber-optic cables is no small 
advantage in upgrading an installation 
where cable ducts are already 
crowded. And fiber-optic links are 
beginning to appear where engineers 
planning for greater capacity recog- 
nize the potential for expanding the 
bandwidth by merely upgrading the 
interface equipment. 

A significant new area of use is in 
the so-called "back-end" networks, 
connecting large-scale, high-speed 
processors to their attendant memory 
and peripheral devices. One of the 
projects of technical subcommittee 
X3T9.5 of the American National 
Standards Institute (ANSI) is the Fiber 
Distributed Data Interface, a back-end 
interface designed to use fiber-optic 
links at data rates of 100 megabits per 
second (Mbps). 

But the application of most interest 
to users of personal computers is the 
lower-speed general-purpose local- 
area network (LAN), which connects 
workstations, file servers, and miscel- 
laneous peripherals in an office or fac- 
tory environment. Any local network 
that needs wide bandwidth, long 
cable runs between stations, immuni- 
ty to electromagnetic interference, or 
high security is a candidate for fiber- 
optic cabling. And although an 
optical-fiber-based system costs ini- 
tially somewhat more than an equiv- 
alent network built from copper 
twisted-pair wire or coaxial cable, the 
bandwidth of a fiber-optic system can 
be easily expanded later by merely 
changing the interface equipment. 

Local Networks 

If you've been following the recent 
commercial developments in local 



200 BYTE • JANUARY 1985 



Inquiry 118 



FIBER OPTICS 



networks, you know that battles are 
being waged over what is the best 
general-purpose network-node con- 
nection and layout scheme, or topology. 
The three major systems are the bus, 
the ring (or loop), and the star. The 
champions are well known: Xerox and 
Digital Equipment Corporation attack- 
ing on behalf of the bus, IBM stoutly 
defending the ring, and AT&T recent- 
ly launching a kind of Star Wars 
offensive. 

The inherent characteristics of fiber- 
optic technology cause its most 
natural network implementations to 
take the form of the ring or star. But 
currently, bus-type networks seem to 
have the best strategic position in the 
topology skirmishes, largely because 
of the success of the Xerox-developed 
Ethernet and its imitators. This poses 
somewhat of an obstacle to the use 
of fiber optics in many currently exist- 
ing local networks; however, it is not 
an insurmountable one. 

In figure I, the bus, ring, and star 
topologies are shown in their ideal- 
ized forms. A bus network has all its 
nodes connected directly to a single 
distribution medium; a signal broad- 
cast by any node can be received by 
every other node. In a ring network, 
each node communicates directly 
only with the nodes immediately ad- 
jacent to it (in the logical sense), 
receiving on one side and transmit- 
ting on the other. Provisions are usual- 
ly made to bypass a malfunctioning 
node. The star network features a cen- 
tral switching point that receives 
transmissions from the originating 
nodes and redirects or retransmits the 
data to the destination nodes; each 
node talks only to the central switch. 

(Another distinction can be drawn 
between different kinds of networks. 
If the signals are transmitted in more 
or less raw form, the network is called 
baseband. If the data signals are 
modulated onto a very-high-fre- 
quency carrier signal, the network is 
called broadband. A broadband system 
can mix the computer data with other 
kinds of signals; telephone conversa- 
tions, video images, etc. But the inter- 
face equipment for broadband is 

[continued) 



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Inquiry 119 



JANUARY 1985 • BYTE 201 



FIBER OPTICS 



somewhat more complex.) 

In addition to the physical connec- 
tions between nodes, a network must 
have a traffic cop: some means of 
deciding what data from which nodes 
can be passed over the system. Several 
schemes for enabling the system to 
make this decision exist, each with 
good and bad points. The topology 
selected for a network will be a chief 
factor in deciding which network- 
access protocol is appropriate. 



Both IBM and AT&T have an- 
nounced support for fiber-optic links 
as part of a computer local network. 
At the time of this writing (November), 
IBM's commitment is limited to speci- 
fying an option in the IBM Cabling 
System for use of fiber-optic cables (in 
pairs, multimode 140-micron-clad- 
ding/100-micron-coretype). IBM says 
it intends to implement a local net- 
work with a logical ring topology im- 
posed on a star-shaped physical wir- 



ing setup, as in figure 2. Access to the 
network will be granted by a protocol 
based on passing a logical "token" 
around the ring. The centralized wir- 
ing closets in the announced cabling 
system are well suited to use of op- 
tical fibers. Some installations will 
probably be hybrids, with copper 
twisted-pair wire used for short runs 
and fiber-optic cables for longer links 
to distant nodes or between wiring 

[continued) 



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202 BYTE • JANUARY 1985 



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Inquiry I3l 



JANUARY 1985 'BYTE 203 



FIBER OPTICS 



closets; any interface needed from 
metallic to fiber-optic links would be 
installed in the wiring closet. 

AT&T's Information Systems Net- 
work (ISN), tied closely to the tech- 
nology of telephone private branch 
exchanges, will not use fiber-optic 
links to individual network stations; 
conventional four-pair metallic wiring 
will be run in a star layout from nodes 
to the central controller or to remote 
concentrators. However, the linkage 
from the concentrators to the con- 
troller will be over multimode fiber- 




(b) RING 




(c) STAR 



D- 




-D 



Figure I : The bus, ring, and star 
topologies (or connection configurations) 
shown in their idealized forms. 



optic links operating at 8.64 Mbps 
over distances up to I kilometer. The 
fiber-optic connections serve as ex- 
tensions of two metallic signal buses 
inside the central controller, on which 
packets of data are passed according 
to a time-division multiple-access pro- 
tocol before being redirected to their 
destinations (see figure 3). 

Token-ring networks have been 
popular among Japanese designers, 
with Hitachi offering its fiber-optic 
SigmaNet and NEC (Nippon Electric 
Company) selling its C&C-Net Loop 



6770. These systems contain several 
redundant features to assure con- 
tinuous service in the event of a par- 
tial network failure, including dupli- 
cate transmission paths in the ring. 
Fujitsu Ltd. has exhibited the Optical 
Data Highway local network, but this 
ring (or loop) configuration uses time- 
division multiplexing instead of token 
passing. And some ring-based net- 
works have appeared in Great Britain, 
where pioneering work was doneon 
the Cambridge ring system. 

[continued] 



DUAL CABLE 







D^^: 




WIRING CLOSET 



^^o 






Figure 2: IBM's predicted local network uses a logical ring topology imposed on a 
star-shaped physical wiring setup, with a token-passing access protocol. Centralized 
wiring closets in the cabling system are well suited to use of optical fibers. 



204 BYTE- JANUARY 1985 




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FIBER OPTICS 



applied and workable solutions 
found. 

One successful solution is em- 
bodied in the Fiber Optic Net/One 
network being sold by Ungermann- 
Bass Inc. The underlying Net 10 op- 
tical transmission system, developed 
for Ungermann-Bass by the FiberLAN 
Division of Siecor Corporation, uses 
a cabling setup similar to IBM's in that 
a star-like formation of cables is used 
to connect devices on the network 
with a central wiring point, called the 
Star Wiring Center (SWQ. The SWC of- . 
fers flexibility in that the individual op- 
tical fibers may be interconnected in 
various ways, but the Ethernet-com- 
patible arrangement requires a pas- 
sive star coupler that lets the data- 
bearing light propagate throughout 
the network (see figure 4). The 
CSMA/CD access control is assisted 
by an active collision-detection-deter- 
mination module. (See the text box 
"Driving the Fiber-Optic Ethernet Bus" 
on page 198.) Net/One can serve as 
a self-sufficient network or be con- 
nected through a repeater to an exist- 
ing metallic Ethernet system. 

Other network topologies besides 
the three just described have been 
suggested. Canstar Communications 
Ltd. of Tbronto developed a dual- 
rooted tree topology for its Hubnet. 
And a group at Hewlett-Packard has 
proposed a topology called Anarchy, 
in which nodes are connected by ar- 
bitrary bidirectional point-to-point 
links (some ingenious software has 
also been proposed to sort out the 
routing of data traffic). Especially 
fault-tolerant schemes with multiple 
propagation paths include the FORE- 
MAN design, which uses a four-way 
optical Y-coupler on each node, and 
the Discobus, in which several small 
star couplers are placed around the 
network. Perhaps further develop- 
ment will some day bring one of 
these, or other new ideas, into com- 
mon acceptance. 

Possibilities for the Future 

Most computer local networks that of- 
fer use of fiber-optic cables allow 
some intermixing with conventional 
copper wiring because the interface 



FIBER OPTICS 



equipment needed for fiber-optic 
cables is still somewhat more costly 
for short distances and noncritical 
links. Net/One, for example, is priced 
about 20 to 30 percent higher than 
an equivalent baseband coaxial-cable 
system (a configuration with 200 ports 
would cost about $135,000). But the 
day may soon come when costs are 
brought down even further, and we 
may yet see hair-thin threads of glass 
begin to replace the venerable cop- 
per wire. 

As the technology of photonics 
begins to catch up with electronics, in- 
tegrated electro-optics may begin to 
provide completely optical amplifiers 
and logic gates, which would open up 
whole new realms of applications. 

And widespread use of fiber-optic 
data links could have unexpected side 
effects. For instance, current computer 
architectures are developed with the 
assumption that input/output (I/O) 
operations will be slower than com- 
putation. But if the computer is con- 
nected via a wide-bandwidth optical 
connection, the I/O channel might be 
able to outrun the processor. If this 
traditional bottleneck suddenly opens 
up, we can look for the appearance 
of new and exciting ideas in building 
computers. ■ 

REFERENCES 

1. Allan, Roger. "Local Networks: Fiber Op- 
tics Gains Momentum." Electronic Design, 
June 23, 1983, page 97. 

2. "AT&T Local Network Draws Mixed 
Reactions." Data Communications, August 
1984, page 41. 

3. Balbus, Peter G., and Joseph L. Healey. 
"Out of the Labs and Into the Streets." 
Datamation, September 1, 1984, page 96. 

4. Bartik, Jean. "IBM's Token Ring: Have 
the Pieces Finally Come 'together?" Data 
Communications, August 1984, page 12 5. 

5. Feldt. 'ferry. "CLEO Lights Way to Op- 
tical ICs." Electronics, June 28, 1984, page 
102. 

6. Kelley, R. P., J. R. Jones, V. I. Bhatt, and 
P. W. Pate, "'fransceiver Design and Imple- 
mentation Experience in an . Ethernet- 
Compatible Fiber Optic Local Area Net- 
work." Proceedings of \nfocom 1984, Institute 
of Electrical and Electronics Engineers. 

7. Storozum, Steven L., and Roger W. 
Uhlhom. Taulttblerant Fiber Optic LANs." 
Photonics Spectra, September 1984, page 61. 



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by Paul A. Nilson 



Algorithms for a 
Variable-Precision 
Calculator 



A pseudocode 



is used to describe 
the logic behind 
the algorithms 



I developed the algorithms de- 
scribed here in the process of 
building a variable-precision calcu- 
lator, which is now an integral part of 
a commercial spreadsheet package. I 
believe the material covered in this ar- 
ticle will be valuable to people who 
need to perform decimal computa- 
tions on large numbers. 

I have a 68000-based microproces- 
sor running a UNIX operating system 
with C as the main programming lan- 
guage. Using my version of C on the 
68000, 1 can represent numbers as in- 
tegers (16 bits) or long integers (32 
bits). I have no floating-point arith- 
metic package. Because 32 bits limits 
me to nondecimal numbers with a 
range of -2,147.483,648 to 
+ 2,147,483.647, 1 neededthe capaci- 
ty to handle more digits and the dec- 
imal point. I thought, "How many 
digits are enough?" 

I had only two routes to follow. The 
first was to pick a number (perhaps 
100 digits) and develop fixed-pre- 
cision algorithms using that as a base. 
The other approach was to let users 
specify what precision they needed 
and develop the necessary algorithms 
to support variable precision. I chose 
the second approach because the al- 
gorithms for a variable-precision cal- 
culator are really not much more com- 
plicated than those for fixed-precision 
calculators, and because they do not 
have the internal string space over- 
head common to fixed-precision cal- 
culators. 

I gave considerable thought to com- 
putation speed. Using division as an 
example, I am able to divide a 40-digit 
number by an 8-digit number to 100 
places of accuracy in 71 milliseconds 
(ms). Considering that I am dealing 



with numbers represented as digits 
within character strings, that is a fair- 
ly quick computation. If I were to 
code the calculator in assembly 
language it would speed it up even 
more. 

Preprocessing 

The calculator is set up with virtually 
no internal string space. The user rou- 
tine that calls the calculator defines 
within itself three character arrays and 
passes pointers to those arrays to the 
calculator. r IWo of these arrays (first 
and second) hold the operands while 
the third array (results) holds the 
results from the computation. The ar- 
rays are defined externally to the cal- 
culator so that a user can have the 
flexibility of defining only as much 
string space as is necessary, based on 
the precision of the computation. The 
user routine also passes to the calcu- 
lator an integer that defines the preci- 
sion of the computation and a char- 
acter (+, -. *. /) to indicate the 
operand. Decimal points, signs, and 
leading or trailing blanks can be used 
in the number strings. The number 
strings (first and second) are un- 
modified by the calculator. 

Upon being called, the first thing the 
calculator routine does is establish a 
set of integers related to each of the 
number strings. These integers point 
to the first digit, the last digit, the 

[continued) 
Paul A. Mson (6635 Southwest Hyland 
Highway. Beaverton, OR 97005) is an ap- 
plication development manager at Graphic 
Software Systems in Wilsonville. Oregon. He 
has an M.S. in mathematics from San ]ose 
State University, California. He is the founder 
of Midnight Oil Inc.. a software marketing 
firm. 



JANUARY 1985 -BYTE 211 



CALCULATOR ALGORITHMS 



decimal point, and the current posi- 
tion within the number string. Using 
the first (addition) operand as an ex- 
ample, the integers are represented as 
/head. /tail, /point, and /current. Figure 
1 shows the results of pointing to the 
fourth character position in the first 
array. The second and results number 
strings have similar integers, and their 
variable names start with an s or r. re- 
spectively. 

(The algorithms presented here are 
written in a pseudocode. This code is 



not a real language; it merely serves 
as a shorthand notation to describe 
the logic of the algorithms.) 

Addition 

Addition is a snap. All you need to do 
is determine which of the two oper- 
ands has the longest tail following the 
decimal (i.e.. /tail-/point vs. stail-spoint). 
You then place the current pointers 
for both numbers the same distance 
to the right of the respective decimals 
and proceed from the right to the left. 



Array position 01234567890123456 
first = +12 3.4 



/head = 2 


/head digit 


= 1 


/tail = 6 


/tail digit 


= 4 


/point = 5 


/point digit 


= . 


/current = 4 


/current digit 


= 3 



Figure I : An example of the pseudocode labeling. 



Addition Example 

1 2 3.4 
+ 5 6.7 


8 




1+0 2 + 5 3 + 6 4 + 7 
110 


+ 8 



Carry 


1 8 0.1 

Addition Pseudocode 

length = /tail - /point or stail - 
/current = /point + length; 
scurrent = spoint + length; 
rcurrent = rtail; 
carry = 0; 


8 
spoint; (whichever is longer) 



while (( /current > = head ) or ( scurrent > = shead )) 

{ 

rcurrent digit = /current digit + scurrent digit + carry; 
if ( rcurrent digit > = 1 ) 

{ 

rcurrent digit = rcurrent digit - 10; 
carry = 1; 

} 
else 

{ 

carry = 0; 

} 

decrement /current, scurrent, and rcurrent; 



Figure 2: Addition algorithm example and pseudocode. 



adding the corresponding digits of 
both numbers and bringing forward 
a carry. If a number does not have a 
digit for that position, then is as- 
sumed (see figure 2). 

To handle cases in which the return 
value array is not long enough to hold 
all the digits resulting from the addi- 
tion, shift the digits right 1 byte each 
time a new digit is computed to pro- 
duce a full return string. You can do 
this as long as there is some tail left 
after the decimal point. If you find 
that a right shift will destroy digits to 
the left of the decimal, an error 
should be returned. Note also that an 
addition of two numbers with dif- 
ferent signs is really a subtraction and 
should be handled as such. 

Subtraction 

Subtraction, like addition, is very easy. 
Once again, we work from the right 
to the left, bringing along a borrow 
(see figure 3). Note that the subtrac- 
tion of two numbers with different 
signs is really an addition and should 
be handled as such. Note also that a 
smaller number always is subtracted 
from a larger number, with the appro- 
priate sign affixed. This eliminates the 
need to worry about complement 
arithmetic while performing the algo- 
rithm. 

Multiplication 

With multiplication, things start to get 
interesting. Once again, the action is 
from right to left and includes bring- 
ing along a carry. In multiplication and 
division you do not need to worry 
about the length of the longest tail. 
The computations are independent of 
decimal-point location (see figure 4). 
The final position of the decimal in 
the array results is determined after 
the computation is complete. 

lb multiply, all you need is to define 
two loops. The inner loop carries over 
the number of digits of the second 
operand (in this case, four: the digits 
5, 6. 7. and 8). The outer loop carries 
over the sum of the number of digits 
in the two operands (in this case, 
eight). Once again, the digits in the 
return string must be shifted to the 

{continued) 



212 BYTE • JANUARY 1985 



*■ m ** 




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A 



1 W 




.>€. 




CALCULATOR ALGORITHMS 



right if there is not enough room to 
hold all the digits returned from the 
multiplication. If a shift will result in 
loss of digits to the left of the decimal, 
an error should be returned from the 
multiplication. 

The integer example in figure 3 
works for any two numbers, but it in- 
volves a lot of multiplications. In cer- 
tain cases, things can be done to 
speed up the multiplication. Because 
I can represent any number with nine 
or fewer digits as a long integer, I can 
take advantage of that fact. If either 
first or second can be represented by 
eight digits, I can convert it to a long 
integer and multiply it as a whole by 
each character of the other number, 
obtaining a number that will always be 
nine digits or less. This eliminates the 
inner loop in the multiplication and 
speeds up the algorithm considerably. 
Figure 3 also shows the results of con- 
verting the second operand (5, 6, 7, 



8) to a long integer. 

As can be seen, the algorithm using 
long integers requires far fewer multi- 
plications than the one using charac- 
ters. If, however, neither number is a 
candidate for a long-integer opera- 
tion, then an approach using charac- 
ter manipulation must be used. There 
is a speed advantage in the charac- 
ter algorithm if the first operand is the 
longer number, however. 

Division 

Division is totally different from the 
other three operands. While addition, 
subtraction, and multiplication are 
straightforward algorithms that work 
from the right to the left, division is 
a process of successive approxi- 
mations that works from left to right 
(see figure 5). 

As you learned in grammar school, 
the process for finding each digit in 
the quotient involves making a guess 



Subtraction Example 



. 


1 


2 

5 


3 . 
6 . 


4 

7 


8 





1-0 

-1 


2-5 

-1 


3-6 

-1 


4-7 

-1 


0-8 




First 

Second 

(note: 0-8 <= = > 10-8 

borrow 1 ) 

Borrow 

Results 



Subtraction Pseudocode 

length = flail - fpoint or stail - spoint; (whichever is longer) 
fcurrent = fpoint + length; 
scurrent = spoint + length; 
/-current = rtail; 
borrow = 0; 






while (( ^current > = head ) or ( scurrent > = shead )) 

{ 

/-current digit = ^current digit - scurrent digit - borrow; 
if ( /-current digit < ) 

{ 

/-current digit = /"current digit + 10; 
borrow = 1; 







borrow = 0; 



} 

decrement ^current, scurrent, and /-current; 



Figure 3: Subtraction algorithm example and pseudocode. 



for the digit, multiplying the digit by 
the divisor, and subtracting the result 
of the multiplication from the re- 
mainder of the previous process, re- 
membering to bring down either a 
or a digit (depending on what's left in 
the dividend). Because a computer 
can't guess at a trial digit, what is 
generally done is a series of trials for 
each digit. First, a 1 is tried as a target 
digit in the quotient. If the remainder 
is negative, then is the proper digit 
for that position in the quotient. If the 
remainder is positive, then 2 is tried. 
This continues until the remainder 
turns negative, at which time the h~ 1 
digit is placed in the quotient. This ap- 
proach results in about five trials for 
each digit returned to the quotient. 

My approach is a little different. 
While I first try the digit 1. 1 save the 
remainder and divide that by the 
divisor to determine what the actual 
digit should be. In general, only one 
trial per digit is necessary with this 
approach. 

As shown in the long-integer ex- 
ample in figure 5. I start out by 
multiplying the second by a 1 to get 
a product. I then subtract the product 
from the first and look at the re- 
mainder. In the first four tries, the re- 
mainder was a negative number, 
which implied that I was too big and 
that should be used in its place. On 
the fifth try. 1 got a nonzero remainder 
(+6662). Dividing this remainder by 
the second (+ 5678) yields a factor of 
1. Adding this factor to the trial digit 
(1) shows that the actual digit in the 
results array should have been 2. This 
number is then placed in the results 
array at the fifth position to compute 
the sixth position. 

As in multiplication, there are two 
cases to consider for division. If the 
number of significant digits in second 
is less than or equal to eight, you can 
use a long-integer algorithm (in which 
the divisor is placed into a long vari- 
able) and call a routine that will use 
the long-integer algorithm. If. how- 
ever, the number of digits in the divi- 
sor is too large to let it be placed in- 
to a long-integer algorithm, you must 
call a character-based algorithm. This 

[continued) 



214 BYTE • JANUARY 1985 



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CALCULATOR ALGORITHMS 



algorithm also will do the preceding 
computation, although not nearly as 
quickly as the long-integer algorithm. 
As an example of a division using 
the character algorithm, consider for 
a moment the last case in the long- 
integer example, in which 000021731 
is multiplied by 5678 and then sub- 
tracted from 123400000. The specific 
purpose of that exercise is to produce 
a remainder. Because multiplication 
and subtraction work from the right 
to the left, you also can develop each 



digit in the remainder from the right 
to the left by doing the multiplication 
and subtraction simultaneously. 

The character algorithm works from 
right to left, developing each digit in 
the remainder as it works its way to 
the left. As should be clear from this 
example, the character algorithm in- 
volves many more multiplications and 
subtractions than the long-integer al- 
gorithm. In fact, the loops nest three 
deep with the character algorithm and 
only one deep with the long-integer 



Multiplication Example (integer) 



1 



9 8 

6 3 

4 




4 

_8_ 
2 



6 



6 



First 
Second 



Results 



Example (long integer) 

X 




1 
5 


2 
6 


3 

7 


4 
8 


First 
Second 


5678x0 


5678x0 


5678x0 


5678x1 


5678x2 


5678x3 


5678x4 






7 



70 



700 


5678 
1328 


11356 
1930 


17034 
2271 


22712 



Product 
Carry 


7 








6 


6 


5 


2 


Results 



Example (character) 











1 


2 


3 


4 


X 








5 


6 


7 


8 


0x8 


0x8 


0x8 


0x8 


1x8 


2x8 


3x8 


4x8 


0x7 


0x7 


0x7 


1x7 


2x7 


3x7 


4x7 


0x7 


0x6 


0x6 


1x6 


2x6 


3x6 


4x6 


0x6 


0x6 


0x5 


1x5 


2x5 


3x5 


4x5 


0x5 


0x5 


0x5 














8 


16 


24 


32 











7 


14 


21 


28 











6 


12 


18 


24 











5 


10 


15 


20 














5 


16 


34 


60 


61 


52 


32 





2 


4 


6 


6 


5 


3 






First 
Second 



Product 

Carry 

Results 



Figure 4: Multiplication algorithm examples and pseudocode. 



216 BYTE • JANUARY 1985 



CALCULATOR ALGORITHMS 



algorithm. The character algorithm 
does have one saving grace, though: 
it works for any number of any size. 
In using the character algorithm, a 
very important point to consider is 
the handling of the remainder. The 
character routine is called only 
because the divisor is too big to fit 
into a long integer. This means that 
the remainder also will be too big to 
fit into a long integer. In this case, as 
the remainder is developed, the first 
eight digits of the remainder are 



stored in an array. When it is time to 
figure the factor, the remainder from 
the array and the first eight digits of 
the divisor (second) are moved to a 
long-integer algorithm and divided 
one by the other to figure the factor. 
This usually gives satisfactory results, 
enabling the correct factor to be pre- 
dicted accurately. Consider, though, 
the case where the remainder is very 
nearly an exact multiple of the divisor. 
While this doesn't happen very often, 

{continued) 



Multiplication Pseudocode (character algorithm) 



( First's length ) 

( Second's length ) 

( total length ) 

( start at the right and work left ) 






/length = /tail - fhead + 1; 
slength = stail - shead + 1; 
flength = slength + /length; 
/"current = Atari; 
carry = 0; 
offset =0; 

while ( offset < flength ) 

{ 

product = carry; 

j = 0; 

while ( j < slength ) 

{ 

scurrent = stail - j; 

fcurrent = /tail + j - offset; 

product = product + ^current digit x scurrent digit; 

increment j; 

} 

/-current digit = product mod 10; 
carry = ( product - /-current digit ) / 10; 
increment offset; 
decrement /-current; 
} 

Multiplication Pseudocode (long-integer algorithm) 



/length = /tail - /head + 1; 

slength ■ stail - shead + 1; 

flength =* slength + /length; 

/-current ■ rtail; 

slong - Second as a long integer 

carry = 0; 

offset ■ 0; 



( First's length ) 

( Second's length ) 

( total length ) 

( start at the right and work left ) 



while ( offset < flength ) 

{ 

product = carry; 
^current = /tail - offset- 
product = product + ^current digit x slong; 
/-current digit = product mod 10; 
carry = ( product - /-current digit ) / 10; 
increment offset; 
decrement /-current; ) 






} 






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JANUARY 1985 -BYTE 217 



CALCULATOR ALGORITHMS 



Division Example 



Second 5 









8 T 






Results 

First 

Product 

Remainder 

Product 

Remainder 



Example (long integer) 



Example (character) 



Division Pseudocode 
(long-integer algorithm) 



1 
- 1 



Trial 
Results 

1 

01 

001 

0001 

00001 

000021 

0000211 

00002171 

000021731 

0000217331 



Second 



x 5678 = 

x 5678 = 

x 5678 = 

x 5678 = 

x 5678 = 

x 5678 = 

x 5678 = 

x 5678 = 

x 5678 = 123388618 



Trial 
Product 

5678 

5678 

5678 

5678 

5678 

119238 

1198058 

12326938 



First 



Remainder Process 



etc 

Actual 
Results 



1 

12 

123 

1234 

12340 

123400 

- 1234000 

- 12340000 
-123400000 

etc. 



- 5677 

- 5666 

- 5555 

- 4444 

+ 6662 / 5678 
+ 4162 / 5678 
+ 35942 / 5678 
+ 13062 / 5678 
+ 11382 / 5678 



-1 + 1 

-1 + 1 

-1+1 

-1 + 1 

= 1 + 1 

= + 1 

= 6 + 1 

= 2 + 1 

= 2 + 1 

















2 


1 


7 


3 


1 


X 












5 


6 


7 


8 


0x8 





x8 


0x8 


0x8 


2x8 


1x8 


7x8 


3x8 


1x8 


0x7 





x7 


0x7 


2x7 


1x7 


7x7 


3x7 


1x7 


0x7 


0x6 





x6 


2x6 


1x6 


7x6 


3x6 


1 x6 


0x6 


0x6 


0x6 


2 


x5 


1x5 


7x5 


3x5 


1 x5 


0x5 


0x5 


0x5 
















16 


8 


56 


24 


8 













14 


7 


49 


21 


7 













12 


6 


42 


18 


6 













10 


5 


35 


15 


5 
















10 


17 


55 


80 


80 


83 


31 


8 


1 




2 


6 


8 


8 


8 


3 








1 




2 


3 


3 


8 


8 


6 


1 


8 


1 




2 


3 


4 

















1 




2 


3 


3 


8 


8 


6 


1 


8 


1-1 


2 


-2 


3-3 


4-3 


0-8 


0-8 


0-6 


0-1 


0-8 













-1 


-1 


-1 


-1 


-1 






Results 
Second 
Multiply 



Carry 

Product 

Subtract 

First 

Product 

Borrow 

Remainder 



remainder = 0; 

rcurrent = rhead; 

slong = second in a long variable; 

while ( rcurrent < = rtail ) 

{ 

rcurrent digit = 1; 

rlength = current length of the results string; 

rcurrent = fhead + rlength - 1; 

dividend = remainder x 10 + /current digit; 

rcurrent digit = dividend / slong; 

remainder = dividend - rcurrent digit x slong; 

dividend = remainder; 

increment rcurrent; 



( trial digit ) 



( drop next digit ) 

( divide ) 

( get remainder ) 

( set up next pass ) 






Figure 5: Division algorithm examples and pseudocode. 



218 BYTE • IANUARY 1985 



Inquiry 51 



CALCULATOR ALGORITHMS 



Division Pseudocode (character algorithm) 

remainder = 0; 
rcurrent = rhead ; 

while ( rcurrent < = rtail ) 

{ 

rcurrent digit = 1; 

flength = ftail - mead + 1; 

slength = stail - shead + 1; 

factor = carry = borrow = offset = 0; 

while ( offset < flength ) 
{ 



product = carry; 

J = 

while ( j < slength ) 

{ 

scurrent = stail - j; 

^current = ftail + j - offset; 

product = product + ^current digit x scurrent digit; 

increment j; 

} 

rcurrent digit = product mod 10; 

rcarry = ( product - rcurrent digit ) / 10; 






trial digit ) 



( multiply ) 



( subtract ) 



remainder digit = ^current digit 
if ( remainder digit < ) 



remainder digit 
borrow = 1; 



rcurrent digit - borrow; 
remainder digit + 10; 



} 

else 

{ 

borrow = 

} 

add remainder digit to remainder array; 



rlong = convert remainder array to a long integer; 
slong = convert Second to a long integer; 
factor - rlong / slong; 
if ( factor > = 10 ) 

{ 

increment ( rcurrent - 1 ) digit; 
try rcurrent again; 

if ( factor x ( divisor + 1 ) > = remainder ) 

{ 

rcurrent digit = factor; 

} 

else 

{ 

rcurrent digit = factor + 1; 

} 

increment rcurrent; 



( handle remainder ) 

( eight digits ) 
( eight digits ) 




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JANUARY 1985 -BYTE 219 



CALCULATOR ALGORITHMS 



it can, in certain circumstances, make 
things difficult, as shown in figure 6a. 
As shown, division of the actual 
numbers results in a quotient of 2, 
while taking only the first eight digits 
results in a quotient of 3. lb handle 
this, the factor is checked each time 
it's developed. If 1 is added to the 
divisor and the sum multiplied by the 
factor, the product can be compared 
with the remainder (figure 6b). 



Generally, the product should be 
less than the remainder. If it is greater 
than or equal to the remainder, you 
cannot be absolutely sure that a fac- 
tor of 3 is correct. Therefore, you must 
assume the worst case and decre- 
ment the factor by I and use that 
value to predict the actual digit. In this 
case, you would assume that the fac- 
tor of 2 was correct. It could be, 
though, that 3 was the correct digit to 



(6a) 


Actual numbers 
First eight digits 


Remainder Divisor Factor 
370370365 / 123456789 = 2 
37037036 / 12345678 = 3 


(6b) 


Divisor + 1 
(12345678 -h 1) 


Factor Product Remainder 
x 3 = 37037037 >= 37037036 



Figure 6: Comparison of factor-determining approaches: actual numbers vs. the first 
eight digits (a) and comparing the product and the remainder (b\ 



use; this will be discovered on the 
next pass through the character rou- 
tine when the factor produced is 
greater than 9. At that time, you must 
go back and increment by I the ac- 
tual digit used in the previous case, 
taking care to handle strings of 9s cor- 
rectly (e.g., 399 + 1 = 400) and tell 
the division routine to call the char- 
acter routine again for the current 
digit. What all this means is that in this 
special case you will at worst have to 
make two trials to get a given digit for 
the result. Generally, though, one trial 
is sufficient. 

Summary 

In this article, I've described addition, 
subtraction, multiplication, and divi- 
sion algorithmic approaches used in 
a commercial spreadsheet. The logic 
behind the algorithms is described 
using a pseudocode— not an actual 
programming language. ■ 



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220 BYTE • JANUARY 1985 



Inquiry 71 



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JANUARY 1985 -BYTE 221 



ST ANq 




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by Vince Banes 



Build IB M PC 

accessories to 
analyze your stereo 



In this construction project I'll 
show you how to chart the fre- 
quency response of your stereo 
using your computer. If high fidelity 
is not your cup of tea, you'll still learn 
how to interface a DAC (digital-to- 
analog converter), a VCO (voltage- 
controlled oscillator), and an ADC 
(analog-to-digital converter) to the 
IBM Personal Computer (PC) using a 
general-purpose I/O (input/output) 
device. 

Figure I is a block diagram of the 
entire project, which is pictured in 
photo 1. The computer selects a con- 
trol voltage for the VCO via the I/O 
section of the board and DAC. The 
sine-wave output signal from the VCO 
goes through the stereo's Aux (aux- 



Audio-Frequency 
Analyzer 



iliary) jack, through the stereo, and 
out the speaker. A microphone 
receives the audio energy from the 
speaker and feeds it through a full- 
wave rectifier to an ADC. The com- 
puter then reads the output of the 
ADC through the I/O section of the 
board. The system does not measure 
harmonic distortion; it just measures 
the power hitting the microphone 
when the system outputs a known fre- 
quency. 

You could use a sine-wave generator 
and a very sensitive AC (alternating 
current) voltmeter to make these mea- 
surements. The results would be the 
same, but using the computer will 
make the tests easier and faster. 

System Considerations 

This system measures the stereo's re- 
lative responses at different frequen- 
cies. The idea is to have the stereo 
sound as loud at 100 Hertz (Hz) as it 
does at 10,000 Hz, provided, of 
course, that the two signals have the 
same input-signal power. Therefore, 
we are not concerned with the exact 



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pares with the responses at the other 
frequencies. Also, we want to deter- 
mine what effects the room has on 
the stereo's sound. 

The system must cover the normal 
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has less than 1 percent distortion, and 
have a constant power output for all 
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Tb reduce noise, you need shielded 
cables for the first stage of the input 
circuit. The inside of a computer is 
probably the worst place in the world 
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interference) noise down, but the 
shielding is good enough for this proj- 
ect. Since the noise level is constant, 
all of the input signals are biased 
equally. Thus, the difference between 

[continued] 
Vince Banes (2020 Sierra Dr., Lewisvilk TX 
75067) is an engineer with Texas Instru- 
ments. His interests include trying to find a 
perfect commodity-tracking system. 




Photo 1: Audio-frequency analyzer board. 



JANUARY 1985 • BYTE 223 



AUDIO ANALYZER 



readings is constant. Keeping the 
noise less than 12 decibels (dB) below 
the signal being measured keeps the 
noise sufficently low. It is true that 12 
dB sounds like a large signal-to-noise 
ratio, but for this application, we are 
looking only for deviations from the 
standard flat response curve. If the 
response differs by more than 12 dB 
from another signal, then an adjust- 
ment must be made to bring that fre- 
quency back to normal. 

The microphone is the weakest link 
in the system, so try to use the best 
one you can find. I used a Pioneer 
DM-2 1, and the specifications on the 
box said that the response was flat 
from 20 to 12,000 Hz. The signal from 
this dynamic unidirectional micro- 
phone was just a few millivolts. I had 
to amplify it 300 times to get a usable 
2-volt (V) signal. 

Make sure you connect the output 
from the VCO to either the Aux or 
l£pe input on the stereo. If you con- 
nect to the Phono input jacks, you will 
have the added response of the RIAA 
(Recording Industry Association of 
America) recording standards. Since 
the frequency response of a needle 



on a record is far from level, the 
record industry has changed the 
response curve to counteract this 
phenomenon. For a short experiment, 
after you have adjusted your stereo to 
a flat response, connect the output to 
the Phono input and observe the dif- 
ference in the curves. 

I could have used just a DAC and 
some fancy software to construct the 
sine wave, but that would have meant 
added problems writing a machine- 
language routine. I spent a few extra 
dollars for the VCO, which eliminated 
the problems. The VCO is simply a 
set-and-forget output device. The soft- 
ware can go off and start some other 
task and the VCO continues output- 
ting the selected sine wave. 

Theory of Operation 

The I/O section of the board, shown 
in figure 2, has 24 software-control- 
lable I/O lines. It uses the NEC 
82 55A-5 I/O chip. This chip was origi- 
nally designed to work with the 8080 
family of micros, but since the 8088 
microprocessor uses many of the 
same I/O methods as the 8080, the 
82 5 5A will work with the higher-level 



chip. The 40-pin 82 5 5 A has three 8-bit 
I/O ports that tie directly into the sys- 
tem bus, with only a few decode logic 
chips to select the proper I/O address. 

The control voltage for the VCO 
starts out as the output of port A on 
the 82 55 chip and goes to an R-2R 
ladder network. The network acts as 
the DAC, "adding" the bit voltages 
from the 82 5 5 into a single voltage 
whose value depends on the number 
of Is output from the 82 5 5, The signal 
from the 82 5 5 then goes through a 
summing operational amplifier (op 
amp) to change the range of the 
signal from 0-3.5 V to 8.5-12 V, as 
measured at test point A of figure 3. 
This voltage controls the frequency of 
the VCO. 

The heart of the VCO circuit is the 
ICL8038, which is a precision wave- 
form generator and voltage-controlled 
oscillator. If you look at a spec sheet 
for this versatile chip, you will see that 
it can be used for many types of wave 
form generation, such as square 
waves, sine waves, and triangular 
waves. Basically, the chip needs a tim- 
ing capacitor connected from pin 10 

[continued) 



VOLTAGE- 
CONTROLLED 
OSCILLATOR 



D/A 
CONVERTER 



' 




XI 



STEREO 



SPEAKER 



MICROPHONE 




CAP 

CODE 

SELECT 



FULL- 
WAVE 
BRIDGE 



PORT B 



PORT A 



A/D 
CONVERTER 



PORT C 






-WSr- 



8255 






IBM PC 






Figure I : System block diagram. 



224 BYTE* JANUARY 1985 



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Producing a brochure. Introducing a 
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When management needs detailed 



Microsoft and Multiplan are registered trademarks and MS is a trademark of Microsoft 

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Machines Corporation. Lotus and 1-2-3 are trademarks of Lotus Development Corporation. 



status or budget reports, it prints them 
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For the name of your nearest Microsoft 
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Should you decide you can face an- 
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AUDIO ANALYZER 



to ground to select the frequency 
range, and a control voltage on pin 8 
to vary the frequency. The capacitor 
should range from 1 microfarad (pF) 
to 500 picofarads (pF). The control 
voltage must be between 8.5 and 12 
V. This gives a 4-to-l dynamic frequen- 
cy range for each capacitor. 

The timing capacitor is selected by 
an output through port B. The output 
transistor of a TTL (transistor-tran- 
sistor logic) open-collector chip, the 
7406 chip in figure 3, controls the 
capacitors' ground leads. When the 
output of the chip is OFF. one side of 
the capacitor is at a high impedance 
and therefore has no effect on the 
VCO. When the chip's output is ON, 
the capacitor is grounded and then 



can affect the VCO's output. This 
allows the computer to select the 
capacitor (or capacitors) needed for 
the desired frequency range. 

The sine-wave output from the VCO 
has an output impedance of about 
1000 ohms. This is too high to drive 
anything except another op amp. 
Thus, I've included a simple noninvert- 
ing buffer amplifier to drive the stereo. 
By the way, only one channel of the 
stereo is driven at a time. During 
testing, the opposite channel's 
volume should be off. 

The full-wave rectifier, shown in 
figure 4, converts all the negative 
parts of the signal to positive, because 
if we did the integration on the unrec- 
tified input signal the average would 



work out to zero at all frequencies. By 
inverting the negative half of the signal, 
we can integrate the resulting wave- 
form to get a voltage level that is pro- 
portional to the input power. This is 
the signal that is fed directly to the 
ADC in figure 4. Figure 4 also shows 
the signal before and after the rec- 
tifier. The humps of the rectifier's out- 
put may not be equal; you can adjust 
the DC bias on the input amplifier so 
that they are. But, for this project, a 
slight difference will not affect the 
results. 

The ADC0804 is an 8-bit micropro- 
cessor-compatible ADC. The chip's 
spec sheet shows many different con- 
figurations. I've chosen the free- 
running mode for this circuit. If you 



IBM PC BUS 

I 
AEN |(A11)> - 

A13 |(A18)> - 

A12 |(A19p 



I7ci 

| 7404 



n> 



ite* 



A10 |(A21)> 
A9 |(A22)> - 
A8 |1A23J> - 
A7 |(A24£ >- 



^J>o± 



All |(A20)> L_L^o2 



7p= 



l 
l 
l 

A6 |(A25)> - 

A5 |U26)> - 

A4 |(A27)> - 

A3 |tA28)>- 



A2 |(A29)> - 



Al |(A301> - 

AO |(A31)> - 

RESET 1<B2)> - 

lOW |(B13i>- 



I0R l<B14J> - 
D7 <@>- 
D6 <©>- 
D5 <©>- 
D4 <@>- 
D3 <©>- 
02 <^A7T>- 
Dl <@> 



DO ^A9^- 




MSB 



PORT A 



LSB 



MSB 



> PORT C 



LSB 



MSB 



> PORT B 



LSB 



Figure 2: Diagram of the I/O section of the board. 



226 BYTE • JANUARY 1985 



AUDIO ANALYZER 



are looking at this circuit as a basis 
for some other project, get a hold of 
the spec sheet to see how to connect 
the V,„(+), V„H. and V ref /2 signal 
lines to activate the other modes. I 
used a resistor divider network with 
a large capacitor for V re/ /2. It was 
good enough for this application, but 
for other projects it should be con- 
nected to a more stable voltage 
source. 

Since the ADC is in a free-running 
mode the 8255's port C is updated 
automatically approximately every 
200 microseconds (j*s). The exact up- 
date rate is determined by the value 
of the 1 50-pF capacitor and the 1 5K- 
byte resistor connected to pin 4 of the 
ADC0804 chip. On the other hand, if 



the chip were connected directly to 
the bus lines, then the software would 
have to output a "start conversion" 
command, wait for the chip to convert 
the frequency, then input the data 
from the converter. Therefore, in the 
interest of saving software, the hard- 
ware keeps restarting itself when a 
conversion is completed. 

The chip may not start free-running 
when the power is first applied. To 
prevent this, connect the last gate 
from the 7406 chip to the WR and 
INTR lines (pins 5 and 3). At the start 
of the program, the software gen- 
erates a 1 on the MSB (most signif- 
icant bit) of port B, and then a on 
the same line. This pulls the WR line 
low then high again. After the first 



software initialization, the INTR line 
goes low when the chip finishes con- 
verting. This wraps around back to the 
WR line and starts the chip converting 
the next voltage. 

I/O Construction 

The construction of the I/O section of 
the board is straightforward and has 
no tricky isolation requirements. The 
best part about this section is that the 
I/O lines can be accessed directly 
from BASIC without any special 
machine-language routines. The up- 
date rate in BASIC is about 1 5 to 2 5 
milliseconds (ms), so if more speed is 
required, you have to use machine 
language. 

[continued) 



+ 5V IC5.IC6 

4050 



TEST POINT 




IC9 
8038 



SWEEP 

IN 



DUTY f 

CYCLE J 

FREQUENCY] 

ADJUST L 



TIMING 

CAP SQUARE 

OUT 

SINE 

WAVE 

ADJUST 

SINE 
OUT 



+12V 
6 



15K 



+ 5V 



IK 



SQUARE 
OUTPUT 



m 



82K 



+ 12V 




1K& 



AUDIO 
OUTPUT 



1 SEE TEXT 



Figure 3: Voltage-controlled oscillator and driver circuitry. 



JANUARY 1985 -BYTE 227 



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PWrWlE R INTERFACES and BUFFERS: 

IBM PC Parallel Printer Cable $ 60 $ 35 

Apple II l/F &Cablefor Epson or Gemini $ 95 $ 59 
ORANGE MKRO,Grappler+ for Apple $ 165 $ 119 
Pf|ACTICAL,Wcrob l jtflrvljne64K,Pafa. $ 349 $ 259 
Mbobufltolir«640. $ 349 $ 259 
QUADRAM, Al eumMfe |N/oopy to 513Q Pupon to 640 
Ma^azer,«/Gopy,PP l 8K.NMP8w/PS $ 179 $ 139 
Mk7ofazer,w/Copy,PP, 64K.»»MP64w/PS $ 299 $ 229 
Mfcrotazer, w/Copy, PP, 128K. w/PS $ 375 $ 345 

MKrofa2er.Snapon.8K. PP. Epson w/PS $ 169 $ 129 
Mkiolazer, Snap^, 64K, PP, Epson w/PS $ 299 $ 229 



UTILITY & SYSTEM 



BeagKGPLE or Alpha Ftot each $ 35$ 27 

p. Mechanic, Disquick or Pronto DOSea. $ 30 $ 19 

Double Take or Utility City, each $ 30 $ 19 

Typefaces, Tip Disk # 1 or DOS Boss.each $ 20 $ 15 

Central Point, Filer, DOS 13 &LM. $20$ 15 

♦ Copy II Plus (bitcopier) $ 40 $ 30 

Enstmn, Compiler $ 129 $ 95 

Epson, Graphics Dump $ 15 $ 9 

Funk Software, Sideways NEWS 60 $ 40 

Hayes. TernvialrVogporSmartmodern) $100$ 65 

♦Insoft. GraEORTH II by Paul Lutus $ 90 $ 65 

Microsoft. AIDS $ 125 $ 85 

Fortran 80 $ 195 $ 129 

COMPLETE MICROSOFT UNE IN STOCK 

Omega. Locksmith $ 100 $ 75 

Penguin. Complete Graphics System II $ 80 $ 54 

Graphics Magician $ 60 $ 41 

Phoenix. Zoom Grafix $ 40 $ 34 

QuaEty. Bag of Tricks $40$ 29 

Terrapin, Logo $ 99 $ 65 

United SWI, ASCII Express-The Pro $ 130$ 87 

Utiico. Essential Data Duptcator III $ 80 $ 49 



HOME & EDUCATIONAL 



Barrons, Study Program for SAT $ 90 $ 60 

Beagle Bros., Beagle Basic NEW$ 35$ 27 

Beagle Graphics NEW$ 60 $ 45 

Fat Cat NEWS 35$ 27 

Triple Dump NEWS 40 $ 30 

Beagle Bag $30$ 19 

Bluechip, Millionaire $ 60 $ 32 

dcdwtamd Flint Shop NEW $ 50 34 

CBS, Mastering the SAT $150$ 95 

Chas Goren Learn Bridge $ 150 $ 95 

♦Continental, Home Accountant $ 75 $ 49 

Davidson. Speed Reader II $ 70 $ 45 

Word Attack! or Math Blaster! ea. $ 50$ 32 

Dow Jones. Home Budget $ 95 $ 69 

Edu- Ware, Large Inventory m Stock CALL 40%off list 

Electronic Arts, Financial CookbookNEWS 50 $ 33 

Music Construction Set NEWS 40 $ 29 

Pinball Construction Set NEWS 40 $ 29 

Harcourt, Computer Prep for SAT $ 80 $ 49 

Knoware, Knoware NEWS 95 $ 64 

Koala, Full line in stock, CALL 35% off list 

Learning Co.Large Inventory in SbcKCALL 35% off list 

Microsoft. TypingTutor III $25$ 17 

Monogram, Dollarsand Sense $100$ 69 

SAM. $ 100$ 59 

Scartnxxigh /Lightning, Mastertype $ 40$ 27 

Sfmon & Schuster, Typing Tutor III $ 50 $ 33 

Sub Logic, flight Simulator II $ 50 $ 35 

Terrapin, Logo $ 99 $ 65 



Atari, Centipede or PacMan. ea. $ 35 $ 28 

Donkey Kong or Jungle Hunt ea $ 35 $ 28 

doderta#^Ch^pf^rxLodeRunner^ach$ 35$ 23 

Arcade Machine $ 60 $ 40 

Apple Panic $ 30 $ 20 

Aztec or Zaxxon, each $ 40 $ 27 

Arts. Sky Fox NEW $ 40$ 29 

RnballCoretructwnSet NEWS 40$ 29 

Music Construction Set NEWS 40 $ 29 

Hayden. Sargpn III (Chess) $ 50 $ 34 

mfocom. Zbrk 1,11,111, each $ 40 $ 27 

*fcw0ft,3 Games, Zarg/SpxJer Raid/Gr apple $ 82$ 25 

Ongin, lltima III $ 60 $ 40 

Penguin, Transylvania $ 35 $ 24 

PftStaaBonst Tcrvia Fever $ 40 $ 25 

SJerra/On-Line, Ultima II $ 60 $ 40 

Sir-Tech, Wizardry $ 50 $ 35 

Spinnaker. FuU b ne in stock. CALL 35% off list 

Sub Logic, Flight Simulator II $ 50 $ 35 

Night Mission Pinball $ 35 $ 22 



ACCESSORIES 



ria1is.ttanwd 
Em**) 



50$ 29 
60$ 35 



90$ 
% 

60$ 



$ 90$ 

$ 140$ 



Sapphre 
EPD, Lemon 

lime 

Ctan# 

Rjach $ 98$ 63 

KaTxangtorv PC Saver" 1 Ltoe Cord w/fitor $ 50 $ 39 

Mxtepkx NEW $ 140 $ 95 

Nefetrt. Wretree. 4 outlet, w/fltf^surge $ 70 $ 32 



CALCULATORS 

mrr-m 41CX.Cakuutrx NEW! $ 325 $ 275 

WnOM 41C Calculator $ 195 $ 149 

WL^rM 41CV, Calculator W/2.2K $ 275$ 185 



PLOTTERS 

AMDEICAmpfot If. 6pen, I0x 14Bed $1099 $ 899 



PRINTER SUPPLIES 

Tractor Feed Paper. Rtbhons. Daisy Wheels. CALL 



J" FREE GIFT 

I Use ourorder farms and 

I get a free gift with your 
order. Get on our mailing 
I list now far order forms, 
. sate flyers and our 
I newskfler. Our customers 
I are already on the list 



CITY N B13 STATE ZIP | 

COUgOfl j* AJ± ra 12060SV^ Garden Plac&fortland 'Oft 97223J 



ORDERING INFORMATION & TERMS: 



MAIL TO: 12060 SW Gardan R»c«. Rvtland, OR 97223 Include your telephone number; 

double check your figures for Shipping. Insurance and Handling (SIR). Al Kerns usually in stock 
NO COD. Cashieis checks, money orders Fortune 1000 checks and g*envnent checks— we immediately honor. F&sonai and other company checks— allow 20oays to dear. 
Prices rehect 3%eash discountso ADO 3%to above prices for VISA. MasterCard or American Express. Add 9H CHARGES:U.S Mainland. 3% (SSmirumum) far Standard UPS 
ground; UPS Hue. 6% ($10 mirimum); for US PosH APO or FPO. 12% ($15 minimum). Hawai-4JPS Btoe For Alaska or Canada-UPS in some areas only, al others Postal-cal 
or write, or speofy Postal Foreign orders except Canada, 18% ($25 minimum). Monrtore by posti or to foreign courtne. 30% {$50 minimum). Mez received with irtsu1f»«nt S1H 
charges wil be refunded. All prices, avatebity and specifications subject to errors or change without notice, so cal to verify. Al goods are new.incbde warranty and are guaranteed 
to work Due to our tow prices and our assurance that you will get new, unused products— ALL SALES ARE FINAL Cal before returning goods tor repair or replacement 
ORDER DESK HOURS-6AM to 6PM PST. Monday through Frid*y, Saturday 10 to 4 (6AM here is SAM in New York) 
FconoMI!-:Faitr*™iiKl{>oeik~jr»traa>mBlBof 



228 BYTE • JANUARY 1985 




LOW PRICES TO PROFESSIONALS WHO KNOW WHAT THEY WANT AND KNOW HOW TO USE IT!*' 93 ' **j^£ta£j£ 



COMFUIER 
SYSTEMS 

— Call for Details — 



256K IMm 



360K 

Disk Drives 

by CDC 

90 Day 

Limited Warranty 

By Us 



LIST OUR 

COMPAQ. Portable, 

256K, 2 360K Disk Drives $2995 CALL 

% SANYO s 

256K. 2 320K Disk Drives $1499 CALL 

"lel^/ldea pc, 

256K, 2 360K Disk Drives, 8088 Chip $2499 CALL 




JJMOM 



zisa 

256K. 2 320R Disk Drives, 

MS DOS 2.1. 8088 Chip, 2 S/P $2799 CALL 



for the 
IBM-PC or XT 



ALLOY 



DRIVES ACCESSORIES 



usr our 

PRICE PRICE 



PC-Backup 16MB. Cartridge Tape System $2195 $1795 
PC-ST0R.41M8/17MB Dck&Backup System $5995 Cat 



>4aacbc 



Amd^V.VSteght internal, 320/36OX $ 658 $ 498 
Amdch III rOual Hoppie^SOOX $ 299 $ 249 




DISK DRIVES 

320K/360K 

DS/DD 



CONTRpL 
DATA 



£SIS|169 FULL HEIGHT 
$149 HALF HEIGHT 

30 Day limited Warranty by Factory Authorized Distributor 

CDC, V, Hi Dual Drive Installation Kit $ 30 $ 16 

MAYNARD, Floppy Corrt r>/ParaPort) $ 300 $ 239 

Intel ace w /Para Port. $ 300 $ 185 

Interfacew/Ser. Port $ 310 $ 195 

QtiAOKAM Quaddisk Internal Hard Disks w/Controller 

IN STOCK CALL 



10 MEG IXTI DISK KITS 



one of the following INTERNAL IIARD'dTSK MfEMS Kits 
are quality engineered to work with DOS 2.0/2.1. Com- 
pletely XT compatible. All you need is your DOS manual. 
Easy to install. Includes 10 Megabyte Hard Disk. Controler 
Card and Instructions. 

♦ComX'ntanilOmegHanJDBk&l/f MIW $ 869 
Megaflighl 100, 10 mbyte Hard Disk Kit NEW $ 869 

MAYNARD 

10 meg Hard Disk K* WS1 Sandst* 

ControleTwi accept 3 Sandbar modules $1395 $1150 



it MEANS A BEST BUY 



SUPPLY CENTER for IBM-PC or XT 



LIST OUR 
$395 $265 
$695 $495 



SxP3kP!us,64K,S/P/a>S/W 

Sb(PakFk*256KS/P/DC+S/W 

S*PakPt*384<,S/P/D>S/W $895 $595 

Game Port for SixPak $ 50 $ 39 

l/OPIusll.S/P/CC $215 $150 

1/0 Plus II, S/P/CC/G $265 $185 

l/0Plusll,2S/P/TC/G $315 $215 

Ma»&ari>fWPya:(fcrLotus) $495 $375 

PCNet, Starter Kit. PC002 $1490 $795 

Pt^OrajrtBoard,PC001 $695 $365 

GomboPkis Products Cat 

MegaPlus Products Cal 

* ComX EconoRAM™ 256K RAMCardw/Fastrak'-RAM disk 

emulator and spoolei software $495 $256 

EconoRAM»384K RAM Card $549 $350 

f% t iryne UNRMonitor«& swivel base $ 50 $ 39 

UUKIIO 3 to 9 foot key board caUe $ 40 $ 30 

Vertical CPU "System Stand" $ 25 $ 19 

Monochrome Ext. Cable Par $ 50 $ 35 

HAUPPAGE 8087Cnip NEW $175 $159 

/ur*un 8087 Math Pak NEW$295 $235 

(HOW) 8087 Software Pak NEW $ 180 $138 

8087 Macro Pak NEW $245 $195 



LICD/*! II CC Cotor Card w/para 
ntKL/ULtO Graphics Card, Mono 
KENSINGTON. Masterpiece 

PC Saver'Tine Cord w/TiKer 
Uou Trnnir KB515a Std. keyboard 
rVey llOniC KB5151, Std. keyboard 

KB5151 jr. keyboard 
Kg-i-al-a Koala Pad ™w /PC Design 
I lUdld Programmer's Guide 

MAYNARD 

SAND 



$245 
$499 
$140 
$ 50 
$209 
$255 
NEW $255 
$150 
$ 15 



STAR 
SERIES 



Multifunction (6} toe- MFC 
Memory Card no RAM 
Memory Card 259< 
HardDiskl/F Module (HDM) 
HardDisk Cabte 
Para Port Module (PPM) 
Serial Port Module (SPM) 
Dock CaL Module (CCM) 
Game Adapter Module(GPM) 
Memory Module tTK(MMO) 
Memory Module 256K(MM2S6) 
XTlOmegHardDisk&l/FWSl 



$169 
$329 
$ 95 
$ 39 
$159 
$199 
$199 
$ 89 
$ 14 

$ 79 
$169 
$395 



$ 89 
$199 
$495 
$499 $399 



$ 30 
$ 59 
$ 95 
$ 55 
$ 49 
$122 



$ 27 
$ 49 
$ 79 
$ 48 
$ 43 
$ 99 



$422 $357 
$1395 $1150 



MIOKWOvJr F Mouse $ 195 $ 139 

PC jrBoofer win Mouse NEW $ 495 $329 
System Card. 64K $ 395 $ 275 

MOUSE SYSTEMS.PC Mouse w/Software $295 $189 

MAGNUM, PC MastBCard™. L.536K, MuWuncfon 
S/FVG/CC with SofRAM™ software which provides printer 
spooler, RAM disk & many other functions $3995 $ 1995 

PARADISE Mrjdufr&aphGCard NEW $ 395 $285 

PLANTR0NICS 



Color Board& Cotarmagt, 16 coJor.w/Para 
Color Board & Draftsman, 16color. w/Para 



$559 $395 
$559 $395 



QUADRAM 



i Quadlink 



NEWEST VERSION $680 



Quadboard. no RAM. expand to 384K $ 295 

Quadboard 64K, expand to 384K.S7P/CC $ 395 
Quadboard 256K. expand to 384K.S/P/CC $675 

* Quadboard, 384K, S/P/CC/G $ 795 
Quadboard II, no RAM expand to 256K $ 295 
Quadboard IL 64K.expandto 256K.2S/CC $ 395 
Quadboard IL 256K. 2S/CC $ 595 
Quad 512 + 64K plus serial port $ 325 
Quad 512 + 256K plus serial port $550 
Quad 512 + 5 12K plus serial port $ 895 
Quadcoior I, board, 1 6 colors $ 295 

* UpgradeQuadcolor Ito II kit $ 275 
Quadvue, board, Mono/S/P/CC 

* Quadchrome, 12" RGB Color Monitor $ 795 
Quadchrome II, 14" RGB Color NEW $ 650 
Amberchrome, 12" Amber NEW $ 250 
Quad 3278 NEW $1195 
QuadnetVI NEW $2295 
QuadnetlX NEW $1995 



$449 

$225 
$275 
$525 
$625 
$215 
$265 
$395 
$265 
$420 
$625 
$195 
$199 
Cal 
$495 
$450 
$ 165 
$1090 
$1545 
$1745 



Titan 4ccete3trPC(B086>128K) $ 995 $ 750 
TG PRODUCTS, Joystick $ 45 $ 29 




©1983 
Conroy-LaPointe, Inc. 



• Memory #OC CallforbrgM 
Chip Kit 30*9 Quantity Pric* 
9 Each. 41 64 200 ns 



Prices 



90 Day Warranty by us 



•ComX EconoRAM'" 256K BOARD 



$256 



•ComX EconoRAUP 384K BOARD 



$350 



Wrth Fastrak^RAM Disk Emulator and Spooler Software 
Fully Compatible, 1 Year Limited Warranty by ComX 

WorksonD0S1.1.2.0or2.1 
Prices and availability subject to change. Call 



SOFTWARE for I1MPC or XT 



BUSINESS & TRAINING 



BUSINESS-STRAINING 



APPLIED SOFT, VersaFonn 
ARXTRONICS. Jane w /Mouse 
ASMTON-TATF, Friday! 

Framework 

dBase III 

• dBasell, freq. PC-DOS & 128K) 
dBase II to III upgrade 
dBase II User's Guide (Book) 
Everyman's DB Primer (Book) 

ATl.Trawr* Programs —Wdeine in stock $ 75 

• BROOERBUND. Bank Street Writer $ 
BPI. Gen'l Acrt&ARAP or PR. each 

Personal Accounting 
CDEX. Training for _ (Urge Inventory) 
CHANG LABS, Micro Plan 

• CONTINENTAL, Ultra file 

Tax Advantage 
Home Accountant Plus 
FCM (Filing, Cataloging, Mailing] 
Property Management 



$389 
$295 
$295 
$695 
$695 
$495 
$200 
$ 30 
$ 15 



$595 
$195 
$ 70 
$495 
$195 
$ 70 
$150 
$125 
$495 



DC(7r«UM PRKa^to MACSBack NEW $ 100 

DOW JONES. Malu* Anafya* $350 

MarteManage* $300 

Martcel Mcrasrope $349 

FOXAGELLER, 

Quidu3ide.dGrapri.GrafoxorOz.2ach $295 

dUbl(MSDOSorCP/M86,each) $ 99 

HARVARD. Harvard Project Mana^y NEW $395 

HAYDEN. IBM Pie Writer $200 

FfeSpeleiorSargonllLeach $ 50 

HOWARDSOFT. 

Tax Preparer. 1984-4or 1983year $ 295 

HUMAN EDGE. Managers* or Sate* ea $250 

lUS.EasyWrite II System $350 

EasySpellerll $100 

Business System: GL+AR*AP $1495 

GURAP.0EorlNV.each $595 

*INSOFT.foH)RTHtaninated3DgrarjKc) $125 

*ISNS1IWJTON£25yUnkMaJMngr. NEW$ 95 

KNOWARE. Knoware (reft graphics) NEW $ 95 



UFETREE.Vbllcwrite»1.2 
Vol kswritef Deluxe 
• LOTUS. 12 3 

Symphony 



$195 
$395 
$495 
NEW $695 
$ 15 



QUE. Using 1-2-3 (Book) 
LIVING V1DEOTEXT, Think Tank NEW $ 195 
MDBS.Knowledgeman NEW $500 

MECA, Andrew Tobias' 

Managing Your Money NEW $ 195 

MICROPRO, WordStar* $ 350 

WordStar Professional Plus $ 695 

* WordStar Professional, 4 Pak $495 

VfordStar 2000 $495 



$220 
$159 
$259 
$ 68 
$995 
$375 
$ 95 
$ 65 
$ 64 
$130 
$189 
$309 
$465 
$ 12 
$115 
$300 

$125 

$189 
$365 
S265 
$295 



$ 99 $ 54 

$195 $109 

$195 $105 

$495 $259 

$495 $285 

$150 $ 89 

$195 $125 

$250 $165 

$ 195 $ 129 

$375 $235 

$475 $289 

$165 $110 

$495 $295 

$695 $429 



MICROPRO. MailMerge~ 
Starlndex"" 
ProOpfions, SS/MM/SI 
lnfoStar"+ 

• MKROMM. Rtase, Series 4000 

Extended Report Writer 
R base Clout 
MICROSOFT. Chart or Pruject.each 
MutbpJan 
Word 

Word with Mouse 
MONOGRAM. Dollars & $ense 
MULTIMATE, Muftimate 
OPEN SYS. GUWRlNVor PO.each 

* OSBORNE/COMX. {Book & Business. 

& Math Programs on DS/DD Disks) 
Some Common Basic Programs(70ea.) 
Pr actcal Basic Programs (40each) 
PEACHTREE, Peach Pak (GLAR&AP) 

Peach Text 5000 
PERFECT. Perfect Writer 
QUADRAM, Tax Strategy NEW 

Investment Strategy NEW 
SOFTWARE PU8USHlNG.PfSJteport $ 125 
PFS«e,PFSWitE,PFS&aph $ 140 

PFSfroof $ 95 

SORCIM,SuparCalc3 
SS/5ATTUJTE. WordPerfect 

Persona) WordPerfect 
STONEWARE. Advanced DB. Master 
SUMMA, Trader's Forecast NEW 

Trader's Data Manager NEW] 
Trader's Accountant NEW J 
Complete System NEW 1 

T/MAKERT/Makerlll 1 

THOUGHTWARE. Mgl Series 
V!SICORP,V«sCafc4 j 

FulUne In Stock 



UTILITY & SYSTEM 



BORLAND. Turbo Pascal NEW $ 50 $ 35 

Sidekick NEW $ 50 $ 35 

* CENTRAL POINT. Copy II PC NEW $ 40 $ 30 

* COMX Fastrak™ RAM /Disk emulator 
and printer spooler program. Works on any 

PC/DOS version or RAMCard. Menu Driven $100 $ 59 

DIGITAL RES., CP/M-86™ (PC/XT) $ 80 $ 39 

Concurrent CP/M- 86™ w /windows $835 $225 

CBASIC86™{CP/M86) $200 $135 

CBASIC Compiler (CP/M-86 or PCD0S,ea) $600 $395 

a/1 (PC DOS) $750 $525 



$100 $ 69 

$100 $ 69 

$395 $239 

$395 $239 

$349 $219 

$395 $295 

$395 $295 

$ 79 

$ 89 

$ 59 

$395 $245 

$495 $275 

$195 $149 

$595 $395 



UTILITY & SYSTEM 



DIGITAL RES.. PL/1 (CP/M-86) $ 750 

Speed Prog Pkg (CP/M-86) $200 

DRL0GO-86(CP/M86) $100 

FUNK SOFTWARE. Sideways NEW $ 60 

HAYES, Smartcom II (Data Com.) $ 149 

r INSOFT. GraFORTHtanimated 3D graph) $ 125 

LIFEBOAT, Lattice C. NEW $ 500 

MICROSTUF. Crosstalk XVKOata Com.) $ 195 

MICROSOFT. rnuMath/muSimp $ 300 

Business BASIC Compiler $ 600 

Pascal Compiler $ 300 

C Compiler $ 500 

BASIC Compiler $395 

FORTRAN Compiler $350 

COBOL Compiler $700 

NORTON. Lralrbes 2. 0, 14 programs $ 80 

ROSESOFT, Prokey $ 130 



HOME & EDUCATIONAL 



• ARMONK, Executive Suite $ 40 

BLUE CHIP. Millionaire or Tycoon.each $ 60 
BPI SYSTEMS, Personal Accounting $ 99 
CBS. Mastering the SAT $ 150 

Chas.Goren Learn Bridge NEW $ 80 
COMPREHEND PC Tutor(l. lor 2.0, ea.) $ 60 
CONTINENTAL Home Accountant Plus $ 150 
$ 75 
$ 50 
$139 
$ 80 
$ 50 
$165 
$145 
$ 50 



$479 
$135 
$ 69 
$ 40 
$ 99 
$ 95 
$295 
$129 
$199 
$399 
$199 
$329 
$259 
$229 
$459 
$ 54 
$ 87 



DAVIDSON. The Speed Reader II 

Word Attecklor MathUasterL each 
DOW JONES, Home Budget 
HARCOURT. Computer SAT 
MICROSOFT. Flight Simulator il 
MONOGRAM. Dollars & Sense 
PBL CORP.. Personal Investor 
SCARBOROUGH. MasterType 
SIMON L SCHUSTER. TypingTutorH $ 



ATARI, Centipede, PacMan or Donkey,each 

* BRODERBUND, Apple Panic (Color) 
Lode Runner or Serpentine, each 

ELECTRONIC ARTS.Full Line in Stock 
EPYX, Auto Sim or Temple of Apshai 
HAYDEN, Sargon III (Chess) 
I NFOCOM, Deadline or Suspended, ea. 
Zork I or Zork II or Zork III, each 

• INSOFT, Mystnx.Wordtrix or Quotrix.ea 
MICROSOFT, Flight Simulator II 
ORIGIN. Ultima II 
SPINNAKER, Snooper Troops (1 or 2) 

Story Machine or Face Maker 
SUB LOGIC. Night Mission Pinball 



$ 35 
$ 30 
$ 35 



$ 28 
$ 19 
$ 23 

CALL 
$ 27 

* 34 
33 
27 
25 
33 
39 
29 
24 
27 



CASH-n-CARRY COMPUTER STORES. INC. 

Over-the-counter sales only. Open Monday through Saturday, 10:00 to 6:00. 
SAN FRANCISCO — NEW STORE! 550 Washington Street 
(at Montgomery, opposite the Pyramid). Interstate 80, to Highway 
480: take Washington Street Exit. CALL (415) 982-6212. 
PORTLAND. OREGON — At Park 217, Tigard af intersection of 
Highways 217 and 99W. CALL (503) 620-5595. 
SEATTLE, WASHINGTON — 3540 128th Ave. SE, Bellevue, WA 
98006 In Loehmann's Plaza near Factoria Square, South East of 
Highway 405 & 90 and at South East 36th and Richards. CALL 641-4736 



OUR AD 

#B13 



[^ 



OUR REFERENCES: 

We have been in computers and electronics since 
1958, a computer dealer since 1978 and in compu- 
ter mail order since 198Q Banks: 1st Interstate 
Bank. (503) 643 4678 We belong to the Chamber of 
Commerce (503) 228 9411 and Direct Marketing 
Assoication, or call Dunn and Bradstreet if you are a 
subscriber. 




NO SALES TAX 



S£& k TOLL FREE 
(800) 547-1289 

OREGON ONLY (800) 451-5151 



FfXBff} 
& 

Portland 
(503) 620-9877 



HOT LINE I ORDER DESK HOURS 

Information on your order Mon-Fri— 6AM to 6PM PST 
(503) 620-9878 S*«iiy-10AMto 4PM PST 

V ^EK0AYS0NLY I I6W here B 9AM n New York) 



Inquiry 84 for IBM Peripherals. Inquiry 85 for Apple. Inquiry 86 for all others. 



JANUARY 1985 • BYTE 229 



AUDIO ANALYZER 



SHIELDING 
AUDIO ( ^ r \ 



V 



© 




T—%— 



300K 










-12V 




V V 



__ IN9U 

ll OR 

"^ SIMILAR 




4136 



30K 
-WAr- 



15K 

4 — va — *- 



: io/i f 



/?7 



15K 



ft? 



jt~-a 



(4a) 




IC11 ^NJ_ 

4136^ 



30K 

-vw- 



TO A/D 
CONVERTER 



+ 5V 



FROM IC11 p-^_ 

PIN 4 •— ^~ 

8255-PIN 10 p^_ 

(FROM FIG. 2) ■— "^ 



+ 5V 






VlNl+1 
VI NM 



WR 

INTR 



v C c 



IC12 
ADC0804 



AGND LSt 

DGND 

CLKIN CLKR 



-CM 



-On 



-Ol2 



-D>13 



-O" 



-Ol5 



-c>™ 



8255 
PORT C 



150pF 



D, 



(4b) 



+ 5V O — t 

(B3) 



GND £> f 

(81) L ^ 



; *v F 



:imf 



+ 12V ,-> 4 

(B9) ' 



-12V £>_ 

(B7) *-r 



; o.iftF 



;o.i^f 



:i m f 



TO DIGITAL 
ICs 



! °- 1 A tF 



-*» TO ALL ICs 



; o.i^f 



TO ANALOG 
ICs 



(4c) 



Figure 4: Audio input and full-wave rectifier (a), ADC (&), and power connections (c). 



230 BYTE • JANUARY 1985 



Inquiry 242 — ► 



YOUR COMMODORE 64 
CAN NOW USE STANDARD 
APPLE ll+HARDWARE 
AND SOFTWARE 












. 






A'ARE PUBLISHING GAF SOFT 1 
ORCIM APPARAT MICROPRO 
JITAL RESEARCH STONEWARE 4, 
ICROSOFT 



/-\ 






IN COf* 



is #■ 




WITH THIS 



At Mimic we believe that you and your computer should 
dictate the choices or hardware and software you can use. 

The Spartan™ was developed to allow you to choose the 
hardware and software that best suits your needs. 

Our goal in designing the Spartan™ was simple. 
To take what you already have and give you more. 

Mimic Systems is proud to give you the Spartan™ 
The Apple™ II + emulator for the Commodore 64™ 

Spartan™ Suggested Retail Prices: 
The Spartan™ (includes BUSS, CPU and DOS cards) $599.00 

BUSS card $299.00 



CPU card (requires BUSS card) $ 1 99.00 
DOS card (requires BUSS and CPU card) $199.00 

(All prices in U.S. Funds. Freight not included.) 
American Express. Visa and MasterCard accepted. 
Commodore 64 and Commodore logo are trademarks ol Commodore Electronics Ltd. and/or 
Commodore Business Machines. Inc. Apple" II + Is a trademark of Apple Computer, Inc. 
Spartan" Is a trademark of Mimic Systems Inc., and has no association with Commodore 
Electronics or Apple Computer, Inc. The Spartan Is manufactured by Mimic Systems Inc 
under license granted by ATG Electronics Inc. of Victoria, B.C., Canada. 



FOR INFORMATION WRITE 

MIMIC SYSTEMS INC. 

1112 FORT ST., FL.6H 
VICTORIA, B.C. 
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To Order Call: 

1-800-MODULAR 

(663-8527) 



AUDIO ANALYZER 



CONTROL WORD 



D 7 



D 6 



D 5 



D 4 



D 3 



DON'T 
CARE 



Di 



Do 






BIT SET/ RESET 
1 = SET 
0=RESET 



PORT C B|T SELECT 



BIT SET/RESET FLAG 
= ACTIVE 



Figure 5: Setting the portC bits of the 8255A using the control word. 



-fable 1: 


I/O addresses. 




Pin number 


Name 


I/O address 








(hex) 


15 




YO 


0780-0783 


14 




Y1 


0784-0787 


13 




Y2 


0788-078B 


12 




Y3 


078C-078F 


11 




Y4 


0790-0793 


10 




Y5 


0794-0797 


9 




Y6 


0798-079B 


7 




Y7 


079C-079F 



Tkble 2: Control words that control the data direction of the 82 5 5 As ports. 


Bits 2 


5, and 6 are 0. Bit 7 is 1. 


















PORTC 




PORTC 


D 4 


D 3 


Di 


Do 


PORTA 


(UPPER) 


PORTB 


(LOWER) 














OUTPUT 


OUTPUT 


OUTPUT 


OUTPUT 











1 


OUTPUT 


OUTPUT 


OUTPUT 


INPUT 








1 





OUTPUT 


OUTPUT 


INPUT 


OUTPUT 








1 


1 


OUTPUT 


OUTPUT 


INPUT 


INPUT 





1 








OUTPUT 


INPUT 


OUTPUT 


OUTPUT 





1 





1 


OUTPUT 


INPUT 


OUTPUT 


INPUT 





1 


1 





OUTPUT 


INPUT 


INPUT 


OUTPUT 





1 


1 


1 


OUTPUT 


INPUT 


INPUT 


INPUT 













INPUT 


OUTPUT 


OUTPUT 


OUTPUT 










1 


INPUT 


OUTPUT 


OUTPUT 


INPUT 







1 





INPUT 


OUTPUT 


INPUT 


OUTPUT 







1 


1 


INPUT 


OUTPUT 


INPUT 


INPUT 




1 








INPUT 


INPUT 


OUTPUT 


OUTPUT 




1 





1 


INPUT 


INPUT 


OUTPUT 


INPUT 




1 


1 





INPUT 


INPUT 


INPUT 


OUTPUT 




1 


1 


1 


INPUT 


INPUT 


INPUT 


INPUT 



The 74LS138 provides eight strobe 
lines. Only one of these is used for the 
82 55. The other seven are spare and 
can be connected to more 82 5 5As for 
even more I/O lines. These strobe 
lines are normally high and go low for 
approximately 1 /as. The I/O address 
for the 82 5 5A is 0780 hexadecimal 
(1920 decimal). Table I gives the I/O 
addresses for the eight strobe lines 
from the 74LS138. 

The decode logic does not use lines 
A14 and Al 5. That means that if any 
other part of the IBM PC uses an I/O 
address higher than 3FFF hexadeci- 
mal, there could be an I/O conflict. 
Most of the boards built to be com- 
patible with the IBM PC and the com- 
puter itself use I/O addresses of 03FF 
hexadecimal or less. This puts these 
I/O addresses safely above the system 
I/O. 

There are three basic software- 
selectable operation modes for the 
82 5 5 A: Mode (basic input/output), 
Mode 1 (strobed input/output), and 
Mode 2 (bidirectional bus). The chip 
has three separate data ports: A, B, 
and C. The mode selected for ports 
A and B can be different, but port C 
is configured to follow what is 
selected by A and B. The upper half 
of port C is configured with port A 
and the lower half of port C is con- 
figured with port B. This mixture of 
mode selection along with the I/O 
modes for each of the ports may 
seem confusing at first, but the follow- 
ing review of the main I/O operations 
will clear up the matter. 

Port C may be written to differently 
from the other ports; that is. individual 
bits may be changed in the port 
without affecting the other bits of the 
port. The bit pattern required to 
either set or reset a single bit is shown 
in figure 5. lb set bit 5 in port C to 
a 1, output an 11 (decimal) to the 
control-word register. To make bit 2 a 
0. output a 4 to the control-word 
register. 

There are four internal registers in 
the 82 5 5A chip. The first three are for 
the three data ports and the fourth 
one is the control-word register that 
1 mentioned earlier. In the configura- 

{continued) 



232 BYTE • JANUARY 1985 



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Inquiry 263 



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(415) 490-8586 Telex: 709289 

JANUARY 1985 -BYTE 233 



AUDIO ANALYZER 



Listing 1: 


Output to all three ports. 


10 BASE = 


1920 




20 INPUT 


'DATA FOR PORTA"; A 


30 INPUT 


'DATA FOR PORT B";B 


40 INPUT 


'DATA FOR PORT C";C 


50 OUT BASE + 3, 128 


:REM SET ALL LINES TO OUTPUT 


60 OUT BASE.A 


:REM OUTPUT TO PORT A. 


70OUTBASE + 1.B 


:REM OUTPUT TO PORT B. 


80 OUT BASE + 2.C 


:REM OUTPUT TO PORT C. 


90 STOP 







Listing 2 


Input data from all ports. 




10 BASE = 


1920 




20 OUT BASE + 3.128+ 16 + 8 + 2 + 1 


REM SET CONTROL WORD. 


30 PRINT 


'DATA FROM PORTA =" 


INP(BASE) 


40 PRINT 


'DATA FROM PORT B =" 


INP(BASE + 1) 


50 PRINT 


'DATA FROM PORT C = " 


INP(BASE + 2) 


60 STOP 







Listing 3: TWo output ports and one input port. 

10 BASE =1920 

20 OUT BASE = 3,128 + 2 :REM SET CONTROL WORD 

30 INPUT "DATA FOR PORT A";A 

40 INPUT "DATA FOR PORT C";C 

50 OUT BASE.A 

60OUTBASE + 2.C 

70 PRINT "DATA FROM PORT B = ";INP(BASE + 1) 

80 STOP 



Listing 4: Machine-language routine to test the 82 5 5 A. 




0500:0000 B080 MOV 


AL.80 


0500:0002 BA8307 MOV 


DX.0783 


0500:0005 EE OUTB 


DX 


0500:0006 90 NOP 




0500:0007 BA8007 MOV 


DX.0780 


0500:000A BOFF MOV 


AL.FF 


0500:000C EE OUTB 


DX 


0500:000D B000 MOV 


AL.00 


0500:000F EE OUTB 


DX 


0500:0010 EBF8 JMPS 


000A 







J 


- CHASSIS GROUND - 


A 




\ 


STEREO 


i . 


100ft 


\ 


COMPUTER 


1 


\ i 


i 




















VOLT 
METER 




f A 






v POWER 
[©J PLUG 












vr runtn 

[©J PLUG 



Figure 6: Potential ground problem test configuration. 



tion given by the decode logic, port 
A has an I/O address of 1920 
(decimal), port B has an I/O address 
of 1921, port C has an I/O address of 
1922, and the address of the control 
word is 1923. 

Tb change the direction of the ports, 
set the control-word register as shown 
in table 2. For example, to set all the 
ports to outputs, set the control word 
to 128. Tb make all the ports inputs, 
set the control word to 155. For the 
last example, make port A an output 
port, port B an input port, and port 
C one-half input and one-half output, 
This would give an output word of 
128+8+2 or 138 to the mode control 
word. 

The output pins of the 82 5 5A can 
produce or sink about 1.5 milliamps. 
This is more than enough for most ex- 
periments. The biggest problem is if 
the experiment is located more than 
about 4 meters from the computer; 
the outputs might be loaded down by 
too much capacitance on the cables. 
If the experiment does require long 
lines, then it will be best to use line 
drivers and receivers. Fortunately, in 
this project, the lines to the DAC are 
short, 

Software Examples 

The three BASIC routines in listings 1, 
2, and 3 show how to control the data 
on the I/O ports by using the INP and 
OUT commands. The first example 
asks the operator for three data words 
and then outputs them to the three 
ports. When the program is finished, 
the data is latched on the output pins. 
The second example makes all three 
ports into input ports and displays the 
data present on the I/O lines. The third 
example is just a mixture of the two. 
Data is output to ports A and C. and 
input from port B. 

The machine-language routine in 
listing 4 produces a pulsed pattern on 
all pins of port A. This is useful in 
checking out the board during con- 
struction. Simply connect an oscillo- 
scope probe to any of the port A pins 
and observe the square-wave output. 
The routine was produced with the 
DEBUG utility. Once the routine 
begins, the only way to stop the pro- 



234 BYTE • JANUARY 1985 



Inquiry 225 



AUDIO ANALYZER 



gram is to hit the reset switch. This ex- 
ample also shows the machine-lan- 
guage instructions needed to control 
the 8255A. 

Before you go any further, 1 want to 
warn you about the possibility of a 
dangerous voltage difference be- 
tween the ground of your stereo and 
your computer. First, connect the 
chassis of the two machines with a 
100-ohm resistor. This is shown in 
figure 6. If the resistor does not get 
hot. then the stereo and the computer 
power supplies are not exchanging 
angry words over which side of the 
power line is ground. If you take a 
voltmeter and measure the difference 
between the two grounds without the 
resistor, you could get a 60-V reading. 
That is because the two power sup- 
plies are floating with respect to earth 
ground. The 100-ohm resistor will 
allow the two floating grounds to ad- 
just themselves to each other. When 
the resistor is used, there should be 
less than a 10-V potential between the 
two systems. If there are more than 
10 V. then you have a grounding prob- 
lem that must be fixed before any- 
thing else can be done. Maybe you 
need to flip the stereo's power cord. 
But do not connect the two if there 
is a grounding problem. 

DAC, VCO, AND 
ADC Construction 

Since we want to keep some of the 
noise out of the system, keep the 
leads as short as possible. I used a 
mixture of wire-wrap and soldered 
printed-circuit board material but you 
can use whatever is best for you. I 
built the system in sections so 1 could 
test each separately. This made it 
easier to find errors without subject- 
ing the computer to my hacking. Re- 
member to make some test points on 
the boards. This will help in both cali- 
bration and in testing. 

DAC Calibration and Testing 

The first step in calibrating the system 
is to adjust the 5k-ohm potentiometer 
(pot) on the output amplifier of the 
DAC. This pot adjusts the offset of the 
DAC to get it into the 8.5- to 12-V 
range. First, set all the inputs to the 



4050 chips to 0. Do this by either out- 
putting a to port A or. if the DAC 
is not connected to the 82 55 yet, by 
connecting them to ground with clip 
leads. Then measure the output at 
point A of the drawing. Adjust the 
level of the 5k pot until the voltage is 
8.4. Now bring all the inputs to the 
4050s to 1. The voltage at point A 
should be close to 12 V. If not, go 
back and check for errors. 

VCO Calibration and Testing 

The calibration of the output section 
now depends on selecting the proper 
values for the five capacitors used on 
the 8038 chip. 'Try to find the follow- 
ing five capacitors either at a store or 
in your junk box: 0.33 /xFlO.l /aE 0.033 
/aF. 0.01 fiF. and -3300 /xF. You might 
have to connect capacitors in series 
or parallel to get these values. But 
anything close will do. As you experi- 
ment with the selection, you might be 
able to expand the range beyond the 
20- to 20 ( 000-Hz limits. By selecting 
the right capacitor, the system will 
work at up to 400,000 Hz. 

There are 32 different combinations 
of capacitors, l&ke the five capacitors 
you have collected and put them in 
the circuit as shown in the drawing. 
Don't worry about which goes where, 
because it doesn't make a difference. 

Now comes the problem of measur- 
ing the frequency. If you have access 
to an audio-frequency counter, just 
connect the counter to the square- 
wave output line of the VCO. Most 
people will probably have to use the 
computer to help tune the system. As 
you know, IBM BASIC has the SOUND 
command. This command will pro- 
duce a tone at a particular frequency 
for a given length of time. The built- 
in speaker should generate a tone 
loud enough to be heard. 

If you have an oscilloscope, then 
you can use the Lissajous figure tech- 
nique to determine the frequency of 
the system's output. For this, first 
place the output from the VCO in the 
x-axis input and then connect the wire 
going from the computer's speaker to 
the i^-axis input. Adjust the frequen- 
cy from the computer's speaker with 

[continued] 



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JANUARY 1985 -BYTE 235 



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AUDIO ANALYZER 



Listing 5: Program to determine 


endpoints of the VCO ranges. 


10 OUT 1923,128 + 9 


20 OUT 1921,128:OUT 1921,0 


30 INPUT "CAP C0DE",CC 


40 OUT 1920.CC 


50 INPUT "FINE FRECT.FF 


60 OUT 1920.FF 


70 INPUT "COMPUTER FREQUENCY",F 


80 SOUND F.20 


90 GOTO 70 



the SOUND command to make the 
display stop rolling. When the display 
is in the shape of a circle or some- 
thing close to a circle and it does not 
cross itself, then the frequency of the 
speaker is the same as the frequency 
of the system. The third method is to 
make both the stereo and the com- 
puter's speaker sound at the same 
time. Then you just listen and adjust 
the computer speaker's tone until the 
two tones match. The difference be- 
tween two tones going at the same 
time should be rather easy to detect, 
unless you are tone-deaf, in which 
case this entire system will not be of 
much use anyhow. The short BASIC 
program in listing 5 should make this 
process easier. 

If you have the frequency counter, 
delete lines 70. 80. and 90. In any 
case, measure the frequency at the 
upper and lower ends of each of the 
32 different capacitor-combination 
ranges. Make a chart of these mea- 
surements similar to the one in figure 
7 and show what areas of the frequen- 
cy spectrum are covered by what 
capacitor combination. From this 
chart I was able to select the 
capacitors needed to cover the entire 
audio range. The VCO response is 
linear over most of the control-voltage 
range, except for the upper and lower 
10 percent of the range, which you 
should avoid. 

The graph in figure 8 shows the fine- 
frequency code versus the output fre- 
quency for one of the capacitor 
codes. The actual numbers are not im- 
portant; the point of the graph is to 
show the slight nonlinearity at the 
ends of the control-voltage range. On 

[continued) 



236 BYTE* JANUARY 1985 



Inquiry 243 




ANTEX 

DATA 

SYSTEMS 



ADS 2000 DOT MATRIX PRINTER 



165 CPS CORRESPONDENCE QUALITY 9X9 DOT MATRIX 
40 CPS VERY NEAR LETTER QUALITY 17X17 DOT MATRIX 




The Antex Data Systems ADS 2000 prints at 165 characters per second in 
correspondence quality using a 9x9 dot matrix. By turning on the "FINE" mode 
with a push of a button or through software command it is possible to obtain 
Very Near Letter Quality (VNLQ) at 40 characters per second using a 17x17 dot 
matrix. Typestyles included with the ADS 2000 include Pica. Elite, Proportional 
and Italics and the ability to design up to 256 characters. Subscript and Super- 
scripts can be used for scientific equations, notations and formulas. The ADS 
2000 can interface to almost any computer on the market using the Centronics 
parallel interface. 

SuperFont, is an optional software program designed to utilize all the special 
features of the ADS 2000. With SuperFont. the user can create : save and down- 
load custom fonts or choose one of the 20 fonts already available on diskette. 



ADS 821 2 Data Exchange/64K Spooler 



ADS 8214 Winchester/Tape Storage* 

ADS 8214 5.25 inch Winchester storage with tape back-up 
systems are designed for the IBM PC and XT. The systems are 
combinations of the ADS 8213 and ADS 8218 systems. All 8213 
and 8218 specifications are applicable to the 8214. In addition 
to the above, the PC can communicate independently to the 
Winchester or tape. The tape unit can back-up the Winchester data 
without read and write through the PC. 



mil 




The ADS-8212 DATA EXCHANGE/64 is a computer independent 
interface converter and print spooler. It can be installed between virtually 
any computer and any peripheral. A microprocessor controls the exchange 
of data. Input the data in one form and the DATA EXCHANGE/64 stores it 
in the 64K bytes of buffer memory and then outputs it in another form to 
the peripheral. The DATA EXCHANGE/64 also allows the user to make 
multiple copies of the buffer memory. 



FEATURES: RDY/BSY, Xon/Xof f or 

ETX/ACK for input/output 











* m ^s 






,s " 











ADS 821 3 Winchester Mass Storage System 
-IBM PC/XT 



The Antex System hard disk systems 
are designed to upgrade the IBM PC, 
or compatible to a system that operates 
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own ROM, you can "boot" without a 
floppy diskette. All systems come 
complete with interface and controller 
boards, necessary cabling, and easy 
step-by-step instructions. Available in 
12, 20. 33 and 46 MB with power 
supply, fan. controller and cables. 



6 


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ADS 8218 Tape Back-Up Systems* 



* TAPE SYSTEMS FEATURES: 

• STREAMER BACK UP/RESTORE — 5 MB/MIN. 

• FILE BY FILE BACK UP/RESTORE 

• DIRECTORY OF TAPE 



6 


M 

r / 





ADS 8218 5.25 inch tape backup 
system is designed to back-up data 
from an IBM PC with an internal or 
external hard disk system or an IBM 
XT. ADS 8218 offers an easy to use. 
reliable high speed tape backup at an 
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ADS is a registered trademark of International Antex. Inc. 
IBM, IBM PC. IBM PC XT are registered trademarks of 
International Business Machines Corporation. 



Inquiry 24 



JANUARY 1985 -BYTE 237 



AUDIO ANALYZER 



























31 
30 




1 










29 












28 












27 












26 












25 












24 












23 
22 






















21 
















20 
















19 
- 18 

u 16 
iij 

S 15 


- 












-CROSSOVER FROM ONE SUBRANGE 










Hi 14 

o 

° 13 


_ 










TO ANOTHER 




£L 12 

< 

O 11 


- 














10 


- 










/—SELECTED RANGE WITHIN A 




9 


- 










/ CAPACITOR RANGE TO COVER 




8 


- 










/ THE ENTIRE SPECTRUM 




7 












6 










5 










4 
3 












2 

1 


- 















1 1 1 1 1 1 1 1 1 [ 1 1 1 1 1 1 1 


i 


i i 


1 





20 40 60 80 100 300 1000 3000 10.000 


30.000 




FREQUENCY (Hz) 







Figure 7: Spectrum coverage by each capacitor range. 



my selection of codes, I had to use the 
lower end of the range twice, but I just 
used a different slope in the conver- 
sion equation when I was near the 
ends. If you study the data I used, you 
will see that I divided one of the 
ranges into three separate subranges, 
each of which has a different slope. 
Tkble 3 shows my selection of ranges 
and the codes, slopes, and starting 
points for each range. These values 
give me an accuracy of better than I 
percent over the entire audio 
spectrum. 

The procedure I used to compute 
the values in the BASIC routines is 
this: first, take the difference between 
the lower and upper limits of the 
selected ranges. Now, try various fine- 
frequency codes to find the code that 
will produce the frequencies required 



for the ends of the ranges. Second, 
take the difference between the fine- 
frequency codes required to generate 
these frequencies. Divide the fine- 
frequency code delta (difference) by 
the frequency delta. This becomes the 
slope of the selected capacitor. The 
DATA statements have the information 
organized as lower-frequency limit, 
capacitor code, slope, and lower fine- 
frequency code. 

The 1 k pot adjusts the output level 
of the VCO to match the particular 
stereo you are testing. Most require 
a 200-millivolt (mV) signal for the best 
frequency response. 

ADC Calibration and Testing 

lb calibrate and test the input section, 
use a resistor divider network similar 
to the one in figure 9 to reduce the 



voltage from the output section to 
about 5 mV. Feed this 5-mV signal to 
the input section and check that 
everything is okay. If you run the 
Sweep program in this configuration, 
you will see a straight line, as shown 
in figure 10a. (The program actually 
plots using plus (+) symbols. For 
discussion purposes, we've used a 
solid line in this and subsequent 
figures.) Just to check the theory con- 
nect a capacitor across the input con- 
nection of the resistor network. Figure 
10b shows the classic low-pass filter 
response. Connecting a coil produces 
the opposite effect. 

Software 

I used BASIC in these software ex- 
amples because all IBM PCs and their 

[continued) 



238 BYTE • JANUARY 1985 




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Inquiry 402 



JANUARY 1985 -BYTE 239 



Inquiry I 



1st PLACE 

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OTHER INFORMATION: 602-867-9897 




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AUDIO ANALYZER 



250 














240 


- 












230 


- 












220 
210 


. 












200 


- 












190 


- 












180 


- 












170 


- 












S 160 

8 "o 


- 












>- 140 

O 

Z 130 

UJ 

=> 120 

O 

ui no 

II 100 


- 












Z 90 
u. 80 


_ 












70 


- 












60 


- 












50 


- 












40 


- 












30 


/ 












20 


/ 












10 


1 X 1 


i i i i i i i i 


i i 


l 






6 8 10 12 14 16 18 20 22 24 


26 28 


30 








FREQUENCY (KHr) 











Figure 8: Graph of fine frequency versus output frequency. 



Tkble 3: Calibration data. 








Capacitor Frequency 


Fine Frequency 


Delta 




Code 


Low 


High 


Low 


High 


Freq Fine Fr 


Slope 


31 


8 


20 





110 


12 110 


9.16670 


30 


21 


35 


70 


95 


14 25 


6.78570 


19 


36 


70 


31 


86 


34 55 


2.52940 


7 


70 


124 


90 


114 


54 24 


2.11110 


22 


126 


200 


15 


45 


74 30 


0.60810 


22 


201 


300 


45 


59 


99 14 


0.59600 


16 


301 


552 


78 


118 


251 40 


0.46990 


6 


553 


1007 


23 


69 


454 46 


0.15210 


2 


1005 


2002 


58 


118 


997 60 


0.11840 


4 


2009 


3994 


26 


86 


1985 60 


0.04332 


4 


4001 


6660 


112 


128 


2659 16 


0.04814 





6670 


7744 





16 


1074 16 


0.01490 





7785 


14279 


16 


65 


6494 49 


0.01001 





14280 


30116 


81 


159 


15836 78 


0.01004 



V co OUTPUT > f- 



I 
I 

I TEST 
^ CAPACITOR 
j (SEE TEXT) 



300K& 



> IKil 



V MICROPHONE 
^ INPUT 



Figure 9: Input section calibrate and test setup. 



240 BYTE- JANUARY 1985 



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JANUARY 1985 -BYTE 241 



Inquiry 106 



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AUDIO ANALYZER 









































UJ 

CO 

z 
o 

Q. 
CO 
UJ 

cr 

UJ 

> 

< 
UJ 

cr 


i 


i 


i 




i i i i i i i i 






700 


1900 


3100 


4300 


5500 6700 7900 9100 10300 11500 12700 13900 










FREQUENCY (Hz) 
















(i( 


3a) 












UJ 
CO 

z 
o 

Q_ 
CO 
UJ 

ce 














UJ 

> 

_i 

UJ 
CE 














\ 


S VA 














700 


1900 


3100 


4300 


5500 6700 7900 9100 10300 11500 12700 13900 
FREQUENCY (Hz) 




(I Ob) 













Figure 10: Straight connection through a resistor divider network (a): 0.47/aF 
capacitor across the input [b). 



Listing 6: BASIC input and output routines. 

10 OUT 1923,137: ' SET-UP THE 8255 FOR OUTPUTS ON 

PORTS A AND B, AND INPUT ON PORT C. 
20 OUT 1921,128:OUT 1921,0:' CLEAR THE FREE RUNNING MODE. 
30 INPUT "RANGE CODE",RC:' INPUT THE CAPACITOR SELECT CODES. 
40 OUTPUT 1921 ,RC:' OUTPUT THE CAP CODE TO HARDWARE. 
50 INPUT "FINE FREQ CODE",FF:'INPUT THE VALUE USED 

FOR THE DAC. 
60 OUTPUT 1920,FF:' SEND THE DATA TO THE HARDWARE. 
70 REM NOW WASTE SOME TIME TO LET THE HARDWARE SETTLE 

TO THE CORRECT VALUE. 
80 FOR I = 1 TO 200:X = X + 1 :NEXT 

90 ADC = INP(1922):'GETTHE ADC DATA FROM THE HARDWARE. 
100 PRINT "RESULTS = ";ADC 



242 BYTE- JANUARY 1985 




Not long ago, PC Magazine called MDBS III "The most complete and flexible data base 
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MDBS III is an amazingly powerful software package. So powerful, in fact, that it lets you build 
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Inquiry 228 



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MDBS III is a trademark of Micro Data Base Systems. Inc. 



AUDIO ANALYZER 



clones have BASIC. If you want to use 
another language, then just convert 
the input and output commands to 



the appropriate command in the new 
language. If you are the type to tackle 
a project like this, then you should 



Listing 7: The lUne program. 



10 ' AUDIO FREQUENCY ANALYZER [TUNE] 

20 
30 ' 

40 CLS:OUT 1923,137:DIM FL(14),CC(14),SL(14),FCL(14) 
50 OUT 1921,128:OUT 1921,0:OUT 1920,255 
60 ' 

70 ' Read the calibration data from the DATA statements. 
80 ' 

90 FOR l= TO 14 
100 READ FL(I),CC(I),SL(I),FCL(I) 
110 NEXTKEY OFF 

120 LOCATE 12,20:INPUT "FREQUENCY = ";F 
130 IF (F<30000) AND (F>8) THEN GOTO 170 
140 LOCATE 2,25 :PRINT"BAD FREQUENCY" 
150 LOCATE 12,30:PRINT" 
160 GOTO 120 
170 LOCATE 2,25 PRINT- 
ISO ' 

190 ' Convert the frequency [hertz] to cap code and fine freq code. 
200 ' 
210 1 = 1 

220 IF F>FL(I)THEN l = l + 1:GOTO 230 1 = 1-1 
240 DF = INT(.5 + (F - FL(I))*SL(I) + FCL(I)) 
250 IF DF<0 THEN OUT 1921,0:OUT 1920,255:GOTO 120 
260 ' 

270 ' Output the codes to the VCO. 
280 ' 

290 OUT 1920.DF :OUT 1921,CC(I):II = 
300 ' 

310 ' Average the data over eight iterations. 
320 ' 



330 FOR J 


= 1 TO 8 




340 ll = ll + 


NP(1922) 




350 NEXT 






360 II = 255 


-II/8 




370 LOCATE 16,20 : PRINT "ADC VALUE =";INT(II) 


380 A$ = INKEY$;IF A$<>"" 


THEN GOTO 120 


390 GOTO 290 




400 DATA 


8,31,9.1667 , 





410 DATA 


21,30,6.7857 , 


70 


420 DATA 


36,19,2.5294 , 


31 


430 DATA 


71, 7,2.1111 , 


90 


440 DATA 


126,22,0.6081 , 


15 


450 DATA 


201,22,0.5960 , 


61 


460 DATA 


301,16,0.4699 , 


78 


470 DATA 


553, 6,0.1521 , 


23 


480 DATA 


1005, 2,0.1184 , 


58 


490 DATA 


2009, 4,0.04332, 


26 


500 DATA 


4001, 4,0.04814,112 


510 DATA 


6670, 0,0.01490, 





520 DATA 


7785, 0,0.01001, 


16 


530 DATA 14280, 0,0.01004, 


81 


540 DATA 30000, 0.00000 






have no trouble with these examples. 
I expect that you will modify these 
listings to fit your situation. 

Listing 6 shows the basic operation 
of the hardware without any fancy 
software to get in the way. It just takes 
the inputs from the operator and 
sends them directly to the VCO. It 
lacks the ability to convert a frequen- 
cy to the proper capacitor code and 
fine-frequency value. The next ex- 
ample, the Time program in listing 7, 
shows the software getting a frequen- 
cy from the operator and converting 
it to a capacitor code and fine- 
frequency code. The numbers in the 
data statements will be different, de- 
pending on the capacitors you use in 
the VCO circuit and the adjustment of 
the 5k-ohm pot on the DAC output. 

After the software checks to see if 
the frequency is a valid number, it 
searches the table for the correct VCO 
range for this frequency. When the 
computer has determined the range 
to use, it computes the delta between 
the selected frequency and the lower 
frequency of the band. This delta is 
then multiplied by the slope factor 
and added to the lower fine-frequency 
code to get the final fine-frequency 
code. This is just straight-line inter- 
polation. The software then takes this 
fine-frequency value and sends it to 
the DAC. This method gives a l per- 
cent accuracy across the band. If you 
have a good frequency counter and 
want to get better accuracy, you can 
write a program that checks all the 
possible capacitor codes to select the 
one that matches the selected fre- 
quency the closest. 

There are two unused output lines 
on the 82 5 5 that could be connected 
to two more capacitors. This will allow 
you to provide some intermediate 
values. Now the software will keep 
looping around, inputting the results 
and displaying the results on the 
screen. When the operator hits any 
key the software will accept a new fre- 
quency to tune. 

The Sweep program in listing 8 is 
similar to the single Time program. 
This time the operator gives the start- 
ing frequency and the ending fre- 

[continued) 



244 BYTE • JANUARY 1985 . 




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ML84(P) .... SCall Pacemark. .... SCall 

PANASONIC KX-P1091/1093 $299/$Call 

STAR MICRONICS 

Gemini 10X. . . . $249 Gemini 15X .... $349 

Delta 15 $459 Radix 10 $499 

TEXAS INSTRUMENTS 

850 RO $489 855 RD. .... . $759 

TOSHIBA 

P1340 SCall P1351 $1289 



LETTER QUALITY PRINTERS 



ABATI LQ-20 (18 CPS, 15" Carriage) $359 

AMDEK 5040 (40 CPS) $1299 

BROTHER/DYNAX 

HR-15 (13 CPS. Diablo Compat.) $369 

HR-25/HR-35 , S619/S869 

CORONA Laser Printer faster than HP . . . $2699 
DIABLO 

620 API $809 630 ECS/IBM. . $1979 

JUKI 6100 (17 CPS, Diablo Compat.) SCall 

6300 (40 CPS, Diablo Compat, 3KBuf.) . . . SCall 
NEC 

2030 $659 3510 $1269 

3550. ...... SCall 8850 $1879 

OLYMPIA Compact RO/2 S379/S419 

QUADRAM Quadjet (Ink Jet Printer) $759 

DUME Sprint 1140/1155 $1299/$1479 

Letterpro 20 SCall" 

SILVER-REED EXP 500 (parallel or serial) . . $369 

EXP 550 (p or s, 15" carriage) $449 

STAR MICRONICS Power Type (18 CPS) . . . $339 
TRANSTAR T120/T130 S409/S569 



■ /■HKMHlliM 



NEW!! POLAROID PALETTE!! SCall 

AMDEK DXY-100/Amplot II S599/S749 

ENTER COMPUTERS 

Sweet-P SCall Six Shooter. . . . $799 

HOUSTON INSTRUMENTS 

PC-595/PC-695 New!! SCall 

DMP-40-2 .... $749 DMP-29 .... $1799 
DMP-41/42 . , $2349 DMP-51/52. . . $3529 

DT-11 Digitizer (1-Button Cursor) $679 

DT-114Digitizer(4-Button Cursor) $739 

PANASONIC VP-6801A $1449 

ROLAND DXY-101/OXY-800 S529/S699 

STROBE Model 200/ Model 260 S519/S729 



AMDEK 

Video 300/300A/310A $135/145/159 

Color 300 .... $259 Color 500 $389 

Color 600 .... $459 Color 700 $529 

DYNAXFortisFC10(13"RGB) SCall 

MONITECH 12" Green/Amber $80 

PRINCETON GRAPHICS HX-12 $469 

SR-12 (690x480) $609 

Max-12 (12" Amber, TTL) $179 

OUADRAMOuadchrome $489 

Ouadchrome II $459 

ROLAND 

MB-121G .... $135 MB-122G $155 

CB-141 $269 CC-141 $559 



l ■ 

t.-.ii..MHJLL^Uy_I . 



TAXAN 

KG-12N $109 KG-12N/UY. . . . $119 

210(380x262).. $259 420 (640x262) .. $439 
ZENITH 

ZVM-123A $85 ZVM-122A .... $90 

ZVM-135/136 SCall 



TERMINALS 



ESPRIT 

Esprit I SCall Esprit II $479 

Esprit III SCall ESP-6310 $559 

QUME 102/102A S469/S489 

103/108 (Green) S849/S519 

TELEVIDED 914/924 S519/S675 

950/970 SCall 

Personal Terminal $419 

w/300 Baud Modem $528 




VISUAL 50/55/60 $559/$689/Call 

102/300 $839/5769 

WYSE 

WY-50 $519 WY-75 $609 

WY-100 SCall WY-300 $819 

ZENITH 

Z-29 $649 Z-49 SCall 

ZTX-10 $329 ZTX-11 $389 



COMMUNICATIONS FOR IBM 



BLUE LYNX 3278 . SCall 

DCAIrma/lrmaline/lrmaKey SCall 

IDEAcomm3278 SCall 

ANCHOR 

MarkVI $179 Mark XII $259 

HAVES 

Smartmodem 300/1200 $199/$Call 

Smartmodem 1200B w/SmartCom II $399 

NOVATION 

Smart Cat Plus 300/1200 w/Mite , $329 

PRENTICE POPCOM CI00/X100 S289/S299 

PROMETHEUS Promodem 1200 SCall 

OUADRAM Duadmoilem SCall 

TRANSEND PC Modem Card 1200 $419 

VEN-TEL 300/1200 Haif Card $439 



1 SOFTWARE 








ASHTON-TATE dBase Ill/Framework . . 


. , . SCall 


PRENTICE HALL VCN ExecuVision . . 


. . . SCall 


REAL WORLD MBSI Accounting . . . 


. . . SCall 


LOTUS 1-2-3/Symphony 


$319/SCall 


MICROPRO WordStar 2000/Pro pack. 


. . . SCall 


MICRORIM R:Base 4000/Clout. , . . 


$285/$Call 


MICROSOFT Multiplan 


. . . $129 


SAMNA Word III. 




. . $375 


SATELLITE SOFTWARE WordPerfect . 


. . . SCall 


SOFTWARE PUBLISHING PFS:Write . 


... $97 


CENTRAL POINT Copy 11 PC/PLUS . . 


... $29 


FOR APPLE ll/lle 






APPLE Maclntosh/lleSYSTEMS. . . 


. . . SCall 


ALSCP/M Card . 




. . . $279 


Smarterm II (80 Column Card) . . . 


. . . $129 


AST RESEARCH INC, Multi l/D Card . 


. . . SCall 


DIGITAL RESEARCH CP/M Gold Card w/64K . $339 


FOURTH DIMENSION I6K RAM Card . 


... $55 


80 Column Card w/64K (He Only) . 


. . . $129 


HAVES 




Micromodem lie w/$martCom 1 . . 


. . . $239 


Smartmodem 300/1200 


$199/5479 


INTERACT. STRU. PKASD Universal. . 


. . , $125 


MICROSOFT Premium Softcard (lie) . 


. . . SCall 


Softcard (Apple/Franklin) 


. . . $229 


MICROTEK Dumpling-GX 


. . . $69 


NOVATION 




J -Cat (Auto Drig/ Answer, 300 Baud) 


$99 


Apple Cat II (300 Baud) 


. . . $209 


212 Apple Cat II (1200 Baud). . . . 


. . . $389 


103/212 Smart Cat (1200 Baud). . . 


. . . $389 


ORANGE MICRO Grappler* 


. . . $109 


Buffered Grappler+ (16K) 


. . . $169 


Grappler Interface for ImageWriter. 


. . . SCall 


PCPI Applicard 6 MHZ. 


. . . $249 


RANA Elite l/ll/lll 


. . . SCall 


TRANSEND ASID 


. . . $125 


Modemcard w/Source 


. . . $239 



MISCELLANEOUS 



RAM CHIPS 

64KSET SCall 256K SET .... SCall 

DOUBLE-SIDED DISKETTES 

**SKC (10 box min) . . .$12 same as 3M** 

3M. $30 Dysan $31 

Maxell $30 Verbatim $30 

PRINT BUFFERS 
QUADRAM Microfazer 

Parallel/Parallel - 

16K . . $139 64K. . $185 128K. . $239 

Serial/Serial, Serial/Parl. Parl/Serial 

8K. . . $145 16K. . $155 64K . . $209 
INTERACTIVE STRUCT. ShuffleBuffer 32K. ... $269 
PRACTICAL PERIPHERALS Microbuffer 32K. . $209 



s. ATARI 
RANA 1000. $245 



SURGE PROTECTORS 

EPD/CURTIS All models. . . SCall 

NETWDRXWireTree/Wire Tree Plus. . $45/560 

ULTIMA SF-600 $39 

EMERGENCY POWER SYSTEMS 

TrippLite BC200-1D (battery incl) $270 

TrippLite BC425-FC (425 Watts) ...... 5429 

SOLA ELECTRIC Mini UPS SCall 



CUSTOMER SERVICE 



401-781-0020 



ORDERS ONLY 



800-843-4302 

150 Broadway, Suite 2212, N.Y., NV 10038 

NO CHARGE FOR CREDIT CAROS. 

Money Order, Cashier's Ck. Personal Ck (2 Weeks To Clear). 

APO Orders Add 6% (minimum $7). Add 3% For Met Terras 

All Returned Non-Oefective Merchandise Are Subject To 

20% Restocking Charge. 

GenTech Reserves the Right to Change Advertised Prices. 



r AMERICAN 1 
IXPHESS, | 



Inquiry 145 



(MasterCard) 


VtSA* 



Inquiry 74 

Now used by Aerospace 
Industry, TV Networks, 
Law Firms, Consultants, 
Research Labs, 
Academia . . . 




At last! 



At last, WordStar and other word proc- 
essing programs can now be perfected — 
thanks to MagicPrint™, Magiclndex™, 
and MagicBind™ from CES, the leader in 
precision software. 

True proportional spacing, footnoting, 
multiple line heading/footing, file merg- 
ing, indexing of legal citations, 3-tray 
sheet feeder control — MagicSeries™ 
provides over 70 features that will 
enhance the quality of your documents 
and improve your professional image. 

More and more reviewers and users 
discern the superior quality and perfor- 
mance of MagicSeries: 

"I, for one, wouldn't want to do without it." 
(Creative Computing, June/83) 

"MagicBind supersedes MailMerge." 

[Microsystems, March/84) 

"If you're fussy about print quality, and if 
you want the best possible output from 
your [computer] system, there is nothing 
to compare with Magiclndex." 

(PC, October 30/84) 

"A set-up of WordStar and Magiclndex is, 

I think, the ultimate in word processing." 

(Pennsylvania law firm) 

"Thanks to MagicBind, the 'missing link' 
in my system [IBM PC] has been found. 
With so many things in the world which 
don't work, it's marvelous to find a prod- 
uct that does what you expect— and 
even more." (Network TV news producer) 

Yes, we run into many users who have 
spent much time (and money and frustra- 
tion) tyring out every program offering 
proportional spacing or footnoting only to 
find the results unsatisfactory— until, that 
is, they try MagicSeries. 

For dealers, MagicSeries will serve as 
an effective sales tool and help build a 
satisfied customer base. 

The cost for all three packages is only 
$295! You will save this amount in paper 
alone, because proportional spacing puts 
up to 20% more words on a page. But .the 
real pay-offs are in (1) increased ease of 
operation, (2) savings in time and money 
through efficiency, and (3) a much im- 
proved professional and corporate image 
through typeset quality documents. 

For more information, call or write: 



Computer EdiType Systems 

509 Cathedral Parkway Suite I0A 
New York. NY I0025 

(212)222-8148 



AUDIO ANALYZER 



Listing 8: The Sweep program. 

10 ' AUDIO FREQUENCY ANALYZER [SWEEP] 

20 

30 ' This system will sweep through a frequency range and 

40 ' display the responce to each frequency. 

50 ' 

60 CLS:OUT 1923,137:DIM FL(14),CC(14) ,SL(14) ,FCL(14) 

70 PRINT: PRINT" AUDIO FREQUENCY ANALYZER" 

80 ' 

90 ' Output the pulse to start the ADC conversion. 

100 ' Also, park the VCO at the lowest frequency. 

110 ' 

120 OUT 1921,128:OUT 1921,31:OUT 1920,0 

130 ' 

140 ' READ THE CALIBRATION DATA FROM THE DATA STATEMENTS. 

150 ' 

160 FOR l= 0TO 14 

170 READ FL(I),CC(I),SL(I),FCL(I) 

180 NEXT 

190 KEY OFF:IX = 5 

200 ' 

210 ' Input the lower and upper bounds of the range to sweep. 

220 ' 

230 LOCATE 10,15:INPUT "FREQ LOW =";FL 

240 LOCATE 12,15:INPUT "FREQ HIGH = ";FH 

250 FD = (FH-FL)/72 

260 CLS 

270 IF (FD>0) AND (FH<30000) AND (FL>8) THEN GOTO 330 

280 CLS: LOCATE 3,30:PRINT"BAD FREQUENCY LIMITS" 

290 GOTO 230 

300 ' 

310 ' Print the axis on the screen. 

320 ' 

330 FOR I = 1 TO 22:PRINT "- ".NEXTPRINT 

340 FOR I = FL+FD*3 TO FH STEP FD*6:PRINT USING " #####"; I;: NEXT 

350 FOR F = FL TO FH STEP FD 

360 ' 

370 ' CONVERT THE FREQUENCY [F] FROM HERTZ TO CAPACITOR CODE AND 

380 ' FINE FREQUENCY CODE. 

390 ' 

400 I = 1 

410 IF F>FL(I)THEN l = l + 1:GOTO 410 

420 I = I - 1 

430 DF= INT(.5 + (F + FL(I) )*SL(I) + FCL(I) ) 

440 ' 

450 ' If an incorrect code appears, then abort the run and start over. 

460 ' 

470 IF DF< THEN OUT 1921,0:OUT 1920,255:GOTO 230 

480 OUT 1920,DF :out 1921,CC(I):II =0 

490 ' 

500 ' Delay to let the stereo settle to its response. 

510 ' 

520 FOR T = 1 TO 50:l = I + 1:NEXT 

530 IF F = FL THEN FOR I = - TO 300: T = T+3: NEXT 

540 ' 

550 ' Take eight samples and average. 

560 ' 

570 FOR I = 1 TO 8 

580 ll = ll + INP(1922) 

590 NEXT 

600 ll = ll/8 

[continued) 



246 BYTE • JANUARY 1985 



Giant Killer 




$195.00 (BK) 



Thinking of buying a multi- 
function board? You owe it to 
yourself to check out the 
BT6Plus. 

There's a new entrant into the 
IBM PC multifunction board 
market and we are proud to be 
the first company to sell their 
products. Basic Time's BT6Plus is 
a functional equivalent to AST's 
SixPakPlus™ and Qiiadram's 
Quadboard™, but at a fraction of 
the price. 

BT6Plus is made with scrupu- 
lous attention to quality and 
detail. Basic Time runs all their 
boards through a battery of tests 
throughout the production pro- 
cess with all options installed 
This insures that if you buy a 64K 
board today, it will function nor- 
mally when you upgrade it later. 
BT6Plus comes with memory 
sockets for adding up to 384K, 
parallel printer port, asynchronous 
communications port (RS-232C), 
electronic disk emulation and prin- 
ter spooling software, and cable 
mounting bracket. All functions are 
folly IBM compatible. Our price, 
$195.00, includes a one year war- 
ranty. 64K memory, installed and 
tested, is available for $35. An 
optional game port for $20. 



Qubie' has been a pioneer in 

marketing quality products, provid- 
ing service to back them up and 
off ering them at low prices. You 
don't supply companies like IBM, 
Exxon, General Motors and Lock- 
heed unless you have first-rate 
products and service. Join the tens 
of thousands of corporations, insti- 
tutions and PC owners who have 
come to Qubie* for enhancement 
products. 

Good service starts with an- 
swering your questions before 
and after you buy. It continues 
with same or next day shipment of 
your order. Since we only sell a 
few selected products, we have 
the information and inventory to 
help you fast. 

We perform repairs in our own 
service department within 48 
hours, should you ever need ser- 
vice during the one year warranty 
period. 

Our price is the whole price. 

All prices include UPS surface 
charges and insurance. In a huiry? 
Two day UPS air service is just $5. 

Corporations, dealers and insti- 
tutions, call for volume purchase 
price inf ormatiorL 

Inquiry 293 






No Risk Guarantee 

If you are not completely 
satisfied withyour purchase, 
you may return it within 30 
days for a full refund, in- 
cluding the cost to send it 
back. If you can get any of 
our competitors to give you 
the same guarantee, buy 
both and return the one you 
don't like. 



Order Today, Shipped Tomorrow! 

For fastest delivery, send cashiers check, 
money order, or order by credit card. Per- 
sonal checks, allow 1 8 days to clear. 
California residents, add 6% sales tax. 
Hours: Mon.-Fri. 8:00 a.m.-6:00 p.m. PST 
Sat. 9:00 a.m.-l:00 p.m. PST 

(800) 821-4479 

Toll Free Outside California 



(805) 987-9741 

Inside California 

QUBIE' 



& 



4809 Calle Alto 
Camarillo, CA 93010 



London (01) 223-4569 
Paris (01) 321-5316 
Sydney (02) 579-3322 

© Qubie' 1984 







Other daisy wheel printers still make you choose. 



^ Is ****** C o*V*™ 
% e vel0P^ enue 




DaisyMax320"&830 





you can buy. 

And that means you no longer have 
to sacrifice image quality to increase 
productivity! 

Speed and superb quality are but 
two of a long list of benefits you get 
with the DaisyMax 830. 

Multiple users can share the 
DaisyMax 830 since it is designed for 
heavy volume word processing envi- 
ronments. Plus, you get standard 




interfaces for easy installation, and 
friction, tractor and cut sheet feeders 
to handle all your office forms. All 
these great features also are available 
in the DaisyMax 320, offering print 
speeds up to 48 cps. 

And of course both printers feature 
rugged reliability — a hallmark of 
Fujitsu products earned from over 30 
years as a teclinology leader and equip- 
ment supplier to companies worldwide. 
Reliability backed by TRW service 
nationwide. 

Contact your nearest distributor for 
your local dealer. 

Inquiry 139 



Fujitsu Printers 

Maximum Quality Maximum Value, 



Authorized 

Fujitsu 
Distributors 



Algoram Computer Products (415) 969- 
4533, (714) 535-3630, (206) 4534136, (916) 
481-3466; Allen Edwards Associates 
Inc. (213)328-9770; Four Corners Tech- 
nology (602) 998-4440, (505) 345-5651; 
Gentry Associates Inc. (305) 859-7450, 
(305) 791-8405, (813) 886-0720, (404) 998- 
2828, (504) 367-3975, (205) 534-9771, 
(919) 227-3639, (803) 772-6786, (901) 683- 
8072, (615) 584-0281; Inland Associates, 
Inc. (913) 764-7977, (612) 343-3123, (314) 
391-6901; Logon Inc. (201) 646-9222, 
(212) 594-8202, (516) 487-4949; Lowry 
Computer Products, Inc. (313) 229-7200, 
(216) 398-9200, (614) 451-7494, (513) 435- 
7684, (616) 363-9839, (412) 922-5110, 
(502) 561-5629; MESA Technology Corp. 
(215) 644-3100, (301) 948-4350, (804) 872- 
0974; NACO Electronics Corp. (315) 
699-2651, (518) 899-6246, (716) 223-4490; 
Peak Distributors, Inc. (An affiliate 
of Dytec/Central) (312) 394-3380, (414) 
784-9686, (317) 247-1316, (319) 363-9377; 
R* Distributing, Inc. (801) 595-0631; 
R 2 Distributing of Colorado, Inc. (303) 
455-5360; Robec Distributors (215) 368- 
9300, (216) 757-0727, (703) 471-0995; 
S&S Electronics (617) 458-4100, (802) 
658-0000, (203) 878-6800, (800) 243-2776; 
The Computer Center (907) 456-2281, 
(907) 561-2134, (907) 789-5411; USD ATA 
(214) 680-9700, (512) 454-3579, (713) 681- 
0200, (918) 622-8740. In Canada, Micos 
Computer Systems, Inc. (416) 624-0320, 
(613) 230-4290, (514) 332-1930, (204) 943- 
3813; SGV Marketing, Inc. (416) 673- 
2323, (1-800) 387-3860 (outside Ontario); 
Systermlnc. (514) 332-5581. 

Additional Ribbon Distributors 

Altel Data (403) 259-7814; EKM Associ- 
ates, Inc. (416) 497-0605; Metropolitan 
Ribbon & Carbon (703) 451-9072, (800) 
368-4041; The Very Last Word (415) 552- 
0900, (800) 652-1532 CA, (800) 227-3993 
USA. In Canada, Tri-Media, Inc. (514) 
731-6815. 



Fujitsu Printers 

Maximum Quality. Maximum Value, 




Inquiry 140 



AUDIO ANALYZER 



610 ' 










620 ' Convert the data to a range 


of 1 to 22 for the screen. 


630 ' 










640 l = INT(22-(255- 


l)/4 




650 X$ = "4 










660 ' 










670 ' Check for out-of-range conditions 


680 ' 










690 IF l<1 


THEN l = 


1 :X$ = "~ 


" 


700 IF l>22 THEN l = 


22 :X$ = "i 


r 


710 ' 










720 ' Place the mark on the screen. 


730' 










740 LOCATE I.IX: 


PRINT X$; 




750 IX = IX + 1 








760 NEXT 










770 OUT 1921,31:OUT 1920,0 




780 LOCATE 23,1 'END 






7g0 ' 










800 ' - CALIBRATION DATA - 




810 ' 










820 ' FREQ LOW, CAP CODE 


SLOPE, FINE FREQ LOW 


830 ' 










840 DATA 


8, 


31, 


9.1667 , 





850 DATA 


21, 


30, 


6.7857 , 


70 


860 DATA 


36, 


19, 


2.5294 , 


31 


870 DATA 


71, 


7, 


2.1111 , 


90 


880 DATA 


126, 


22, 


0.6081 , 


15 


890 DATA 


201, 


22, 


0.5960 , 


61 


900 DATA 


301, 


16, 


0.4699 , 


78 


910 DATA 


553, 


6, 


0.1521 , 


23 


920 DATA 


1005, 


2, 


0.1184 , 


58 


I 930 DATA 


2009, 


4, 


0.04332, 


26 


| 940 DATA 


4001, 


4, 


0.04814, 


112 


950 DATA 


6670, 


0, 


0.01490, 





960 DATA 


7785, 


0, 


0.01001, 


16 


970 DATA 


14280, 


0, 


0.01004, 


81 


980 DATA 


30000, 


0, 


0.00000, 






X_^- 



_J L I !__ 



82 205 328 452 575 698 822 945 1068 1192 1315 1438 

FREQUENCY (Hz) 



Figure 1 1: Frequency response with all controls even. 



JANUARY 1985 -BYTE 249 



AUDIO ANALYZER 

































UJ 
(/> 

z 
o 

D. 

w 

UJ 

tr 






















UJ 

> 

< 

_J 
UJ 

cr 


- 












A 














- 


1 








i i i i 


i 


i 


i 


i 






82 


205 


328 


452 


575 698 822 945 


1068 


1192 


1315 


1438 












FREQUENCY (Hz) 











Figure 12: Frequency response with full bass on. 

























; 1 








~"\ 


UJ 

in 
O 

CL 

in 

UJ 


; 








\ 










Ul 

> 
i- 
< 

Ul 

cr 


1 








X^ 












/ 


82 


205 


328 


452 


575 698 822 945 
FREQUENCY (Hz) 


1068 


1192 


1315 


1438 



Figure 13: Frequency response with loudness filter on. 























Ul 

(/) 

z 
o 

0- 

(/> 

Ul 

cr 




















Ul 

> 

< 

_l 
Ul 

cr 








< 














r^~ 


82 


205 


328 


452 


575 698 822 945 
FREQUENCY (Hz) 


1068 


1192 


1315 


1438 



Figure 14: Frequency response with full bass off. 



quency. The software then sweeps 
through this range and records the 
results. These results are shown on 
the screen as a graph with the fre- 
quency across the bottom and the 
computed value of the input up the 
side. There are no units for the ver- 
tical axis, it is just the relative power 
of the signal. The character " ~ " means 
that the signal went off the top of the 
chart. The character "#" means the 
signal went off the bottom of the 
chart. 

Sample Results 

1 placed the microphone on a pillow 
to reduce noise. I connected the sys- 
tem to the right-channel Aux input of 
the stereo and set all the tone con- 
trols to the middle position: I set all 
the filter switches (loudness, high, and 
low) off. The most dramatic change 
happened in the lower frequencies, so 
I ran the Sweep program with limits 
of 20 to 1 500 Hz. Figure 1 1 shows the 
results of this test. There was a peak 
at 200 Hz and at 500 Hz. Next. 1 
turned the bass control full on. which 
gave the results shown in figure 12. 
Between 100 and 575 Hz the re- 
sponse went off the top of the scale. 
Above 800 Hz the two curves are 
similar. I then set the bass back to 
even and switched on the loudness 
filter. Figure 13 shows a boost in the 
frequencies below 500 Hz. The last 
test was to turn the loudness filter off 
and turn the bass control off. The 
results are shown in figure 14; they 
show that there was a small hump 
around 500 Hz. With some more fid- 
dling with the controls, I reduced the 
hump and then adjusted the upper 
half of the spectrum. 

Conclusions 

You can use this system to test audio 
filters, graphics equalizers, or musical- 
instrument amplifiers. You can also 
use the output section alone as an 
audio-frequency generator or the in- 
put section with a microphone to 
monitor for a rapid change in sound 
or for an upper limit on the sound. 
Finally the I/O section can be adapted 
to many other projects besides the 
one I described. ■ 



250 BYTE • JANUARY 1985 






,,- 



xC 




\ 



Join The Leader 



. . . and be a Leader! 

MicroAge is the computer solution leader. Through- 
out the United States and Canada, businesspeople 
rely on MicroAge for advice, leading products, and 
service when computerizing their companies. 

But remaining the leader takes talented profession- 
als who are willing to invest in their own community. 
People who are willing to assume a leadership 
position. That's why MicroAge is meeting with indi- 



viduals who want to own and operate a MicroAge 
sales organization. 

Owning a MicroAge franchise is more than running 
a store. We sell multi-user systems, local area net- 
works and telephone systems. . .along with per- 
sonal computers. We provide service, installation 
and training for our customers. 

If you would like to develop a long-term relation- 
ship serving the businesses in your area, let's talk 
business! Call or write 



/MicroAge 

coMPUTer srares 

"The Solution Store" 9 



1457 West Alameda • Tempe, AZ 85282 
1-800-245-4683 

In Arizona or outside the continental U.S. call (602) 968-3168 
"The Leader In Multi-User Technology" 



Inquiry 226 



JANUARY 1985 -BYTE 251 



74ALS00 



Digitalker 




il HAND (Sale 

NDKC.iV 

Ouad2-1nput ANOGate 
Ttipl 3-lnpul NANOGale 
Ouad 2 Inpul ORGate 
Ol.iI D FlipFlop. 
QiuiilExiliMrHiOJltiili: 
[Jil.il JK N)'ii!i'.r f-liji-f li[;l 



EkJi:.i 
C-ii.i:! ;■ In 



KM!(; ni.Mllmc Onu'i Nrivx-r!.;; ■] I 
S!.i:fOrMll mi; Drivel . . . 
Sui:f Qiwd ?-)iijuj| Multiplexer 

20 In Siait Octal Latch 

20 Iri-Sttte Octal I) flip-flop 



/AM SOI) 
,'.IAIS!I.' 
74ALSQ4 
74ALS08 
74ALS10 

;.;ais:;;< 

74AIS/4 
/■lALSIlH 
/.]AISi:l!i 
71AIS.MI! 
74ALS244 
74ALS245 
74ALS373 
7-1ALS3M 



Uu.i.l ;' Iriuul NA.'JN li.llu 

0uad2-lnpul NOR Gate 

4 Hex Inverter 

CukJ 21npul ANOGat 

Tuple 3-lnpul MANO Gale 

6-lnput NANO Gate . 
14 Oii d 2-lnput ORGate 

Dual D FlipFlop 

Dual JKR>s Edge Flip-Flop 

Expandable 3/8 Decoder 

lii-Slatc Dcial Line Ofivei Imitating). . 

To-Stale Octal Line Oliver. 

Oclal Bus liansceiver INon-lnv) 

Tri-Stale Oclal Uteri 

fti-Stale Octal FlipFlop 



MICROPROCESSOR COMPONENTS 



MICROPROCESSOR CHIPS - 

Kg Fwictim 



0765AC 40 Floppy Disk I 

D3242 28 Add! Multiple »er & Ffclrtsh Counter 

JMS5501 40 SynchlOWOS D.iU Interface iSlRC) 

— Z80, Z80A. Z8QB. Z8000 SERIES - 

40 CPU (MK3880N) (78QC) 2MHr . . 

28 Countei Timer Circuit ... 

40 DuntAsyricliioricjs Rec/Irans 

40 Direct Memory Access CuceiL . 

40 Parallel I/O Inlerfoce Cailioiler 

40 Sctial 1/OHxCB andRxCBBonded) 

40 Serial 1-0 (Lacks OTRQ) . 

40 Serial I/O (Lacks SYNCB) 

40 Senall/O 

40 CPU lMK3880rt 4H780C-1) 4MHr 

Z8 Cojnlei Timer Circuit 

40 Dual Asynchronous Rcc/Trans. . . 

40 Direct Memory AccessCucuiL . 

40 friallcl I/O interface Contioltei 

40 Serial I/O lT»CB and RxCQ Bonded) 

40 Serial I/O (tacks DTRU) 

40 Serial I/O (LacksSYtiCU) . 

40 ScuaM/0 

40 CPU IMK3880N-6) 6MHr 

28 Counter Timer Drcuil 

40 OualAsyncruonous Rec.iTrans 

40 Parallel I/O InlurtaccContiollei.. . 

48 CPU Segmenled (lOMHr) 

40 CPUNori-ScqmcniciUIOMH;) , , 

6500/6800/68000 SERIES 

40 WJwithClockllMH/| 

40 MPUvfllh ClKk )2MHr) 

40 MPU w,lh Clock 13MH2) 

40 Peripheral Intc Adaptei 

40 Peripheral Inter Adaplci 

28 Async.Cornm Intcrl cc Adaptei, 



MPU. 

40 MPU with Clockand RAM. ... 

40 CPU - 8-fJil IDnCinp Oscillator). 

40 CPU - 8-B.I (Exlernal Clocking) 

40 C PU - 8-Bd lExl Cfoclung) 2MHr 

24 I?8x8 Sialic RAM (2Mlt/) 

40 Peripheral tntei Adapl (MC68201 

40 Penjiheial Interlace Adapter (2MHv) 

40 CRTCont/ollei (CMC) . 

40 CFTT Controllfi 1CRTC) 

24 Asynchronous Coiurn Adapter . 

24 600tips Digital MODEM . . 

64 MPU I6-Bil (BMHr) . 

40 Geneial Puiposc Ini Adapter 

8000/80000 SERIES 

40 Contiol Oriented CPU w;RAM i I/O 

MPU - 8-Bit 

40 CPU-Sgl ChipBlM|128Ms RAMI 

40 CPU (256 Bytes RAMI 

40 CPU - B-EJitNMOS , . 

40 CPU (64 bylcs RAMI . 

CPU w/HasicMitru Interpreter. 

CPU 

CPU 

CRJ 16-bit8MH/ 

40 AnthnieliCPioccssoi 

40 CPUB/lGBil 

40 HMOS RAM I/O PtitTimei 

40 RAM with 1/GPuM arid Timer. 

16 Hi Spued I mil (it 8 Binary Decoder 

24 8-Ditlnput/OutpuH74S4l2l 

16 Clock Geneintoi/Unvci. 

28 System Cont/Bus Onvet (74S42B) 

40 High (til Piog OMACont (5M1|;1 

28 System Controltei (74S43B) 

24 I/O Expander I oi 4 6 Series 

40 Async Cornm Eliiinent 

28 Protj. Cornm I/O lUSAHT). 

28 Piotj Cornm Inteitacc (USAHI) 

24 Prng. Interval limin . 

40 Prog Peripheral I/O (I'l'll 

40 Prng R'riphcriil I/O (I'l'l) 5MHr . 

28 Ping.lntenupl Contiol 

40 Sgle/Dhle Density Floppy DiskCont 

40 Mulli Protocol Serial Cont. (7201) . 

40 Piog Kcyboard/Oisplay Inlcrlace. 

20 OclalLalch 

18 Clock GencLitoi/Urtwii 

20 Ortil Bus Ttnns.cetvui 

20 Oclal tins liansceiwr (liiwdcd) 

20 OiisCiifiliOllur 

20 8-liit Tri Slate 01 Directional Ir;ins 

20 8-Bit ui-Dirci:iional Hoceivei 

20 Oclal Lalched Peripheral Otivei. . 

40 8 Bit Umv Peiirtficral Inlcrlace . . 

40 HMOS EPROM MPU. 

40 MPU B-Oil (EPKOM Version ot 804'.)). . 

40 16K;EPROM with I/O 

58 High In legation 16 flil MPU 

DISK CONTROLLERS 

40 Single llensily 

40 Single/Dual Density (Irwl 

40 Single/OojUle Density (duel . 

40 OualOensiIy/SideS led dm'). 

40 Oual Ocnsity/Snlc S led (True) 

SPECIAL FUNCTION 

8 Oual MOSCIock Dinmi (5MH^) . . 

28 Coinimjinration Chip 

18 Floppy Disk Hfi.id Amp System 

IB TV Camera Syce. Generator 

24 Asynchronous Tiansmillcr/Receivei. 

24 MiciopiDccssoi (leal TimcClock 

16 Micro. Compatible Time Clock . 

8 Prog Oscillator/Divider 16011/) . . 

8 P«og. OscilMtor/Orvider OOOHO 



16 95 
2495 
2695 
2695 
2995 



Low Profile Ifinl Sockets 

Fart Na. 19 10-99 IQOup 



SoldeHail [Goldl Standard 

Pari Ho. 19 1093 lPOup 



8 pmSG .39 

HpinSG 49 .45 .39 

!6pinSG .55 49 45 

18 pmSG 65 59 .51 

20prnSG .75 .65 ,59 

22pinSG .79 .69 .65 

24p;nSG 79 .69 65 

28pinSG 95 85 75 

36pinSG 1.25 I 15 99 

40 pin SG 1.39 125 115 



1103 
4027 

4H6N-4 

MM5261 
MMS?fi2 
MM5270 

41256 



IB 1024x1 (300ns) 

16 4096x1 [250ns]. . . 

16 16.384x1 (I50rts) . 

16 16.384x1 (2O0ns) 

16 16.384.1 (250nsl 

15 65.536.1 (150nsi 

16 ;»xl (200ns) 
18 1024x1 (300ns) 
22 204S«I " 



P65n5| 



1 39 - 8/10,95 
1.15-8/895 
89 - 8/6 95 
519-8/4095 
.195-8/38 95 
.35 - 8/ 1 95 



18 4096x1 (250ns) MK4096 

22 4096xt (200ns) 2107 

16 8192x1 (200ns) 

16 262,l4.}xl(200nsl 



-STATIC RAMS 



2102-2L 
2111 

TMS4045 

TMS40L47-45 

5101 

?,■'.!!>:< V 

nv^i li.p ;■ 

!".M ll.!l'/ 

li'.t. iiv'-i 
m',Mi-:C i 
HM5116P-4 

>•,;•• urn' ■; 
!*■/■■ :l-.:- ', 
ii!,'>".;-. -u.r i. 1 
nt.".:- ■.!' is 
rtM6264U IS 
27LSO0 
7489 
74C921 
, : ■-■ 
'4S189 



25Gx4 
256x4 
1024x4 



(450ns) 8101 . 

(350ns) 

<250ns) LP (9IL02I 
(450ns) 81 11 
(450ns)"" 
|450ns) 



18 1024x4 |2O0ns) LP . 

18 40%x1 <7Unsl 

18 1024x4 (70ns) . 

18 1024x4 t4S0ns) 



I 29 - 8/995 
195-8/13 95 
139-8/10 95 
t 69 - 8/13 49 



22 256x4 

18 4096x1 

24 2048x8 

24 2048x8 

24 2048x8 



(450ns) 

1450ns) CMOS 

(450ns) 4044 

1 1?0ns) CMOS 

1 120ns) LP CMOS 
. ( I50r»s) CMOS. . 
2048x8 (150ns) L P CMOS 
24 2048x8 r2O0ns> CI^OS . 
24 2048»:8 1200ns) L P CMOS . 
20 8192x8 (120ns) CMOS 
28 8192x8 (120ns) L P CMOS 
28 8192x8 |l50ns)CMOS 

~ HSOnslLPCMOS 

(80ns) LP. 

(50ns) 3101 . 

(250ns) CMOS . . 

(250ns) CMOS 165181 

(35ns) 93405 

(35nsl 3101 



28 8192x8 

16 256x1 

16 16x4 

IB 25fud 

IB 1024x1 

16 16x4 

16 16x4 



37 95 
3995 
- 3495 
3795 



16 1024xt (50ns) OC 193415) 
16 16x4 (50ns) OC (74S269I 



1702A 
2708 
2708-5 
1MS2516 

: 

2716 

27161 
27160-5 
2732 

\ i 
2732A-20 

27C32A30 

2764-20 

2764-25 

27C64 

7(7'./..; 
;'/i;'i:,". 

;'/,".(;.'!, 
AllilWI. 
/IS:';;/ 

/-v;>p 

74S387 

/.;■,.',," 

74S473 

/4S570 
74S571 

82S23 
82S1I5 
82SI23 
82S126 
82SI29 

82SI85 

82SI91 

DMB7S181N 

DM87S184N 

OMB7S185fJ 

OM87S19UJ 



— PROMS/ EPROMS 

24 256x8 (1„s). 3.95 

24 1024x8 (450ns]. .395 

24 1024x8 (550r»s( SM0024C. 3 49 

24 2048x8 t450ns)2716 4.95 

24 4096x8 (450ns)NMC2532 549 

20 8192x8 (450ns) 1095 

24 2048x8 (450ns) 3 voilage. . 795 

24 20-18x8 l450ns) .395 

24 2048x8 CMOS 1495 

24 2048x8 (350ns> . S 49 

24 20-18x8 (550ns) 3.75 

24 4096x8 MMin-.i 495 

24 4096x8 (200ns} 10 95 

24 4096x8 (?0()ns)21V 1149 

24 4096x8 (250ns) 21V . 7 19 

24 4096x8 (450ns) 21V . . . . 6.49 

24 4096x8 (300ns) 21V (CMOSl . 2295 
20 8192x8 1200ns) 21V - 14.95 

28 8192x8 (250ns) 21V ... . . 7.19 

""' ....... 649 

2295 

8192x8 HSOnsl 21V , . 24.95 

28 16.384x8 [250nsj I28K Eprom 21V 21,95 

2B 32,768x8 ::■ s 256K Eprom (14V) 9995 

16 32x8 i'liriMOC ii!:i:v,i li 1 75 

16 256x4 PROM rS S3 II 1.79 

16 32x8 PROM CS, I...... 1,79 

16 256x4 PROM OC. 16300-1) .1.95 

20 256x8 PROMTS (6309-1) ... .4 95 

20 512x8 PROM TS (63490) -1 95 

20 512x8 PROM OC. (6348) . 4.95 

24 512x8 PROM TS (0M87S29GN) 4 95 

24 512x8 PROM C. (6340) 495 

18 1024>:4 PROM IS 6.95 

24 1024x8 PROM TS, 9.95 

16 512x4 PROM OC. (0305) 2 95 

16 512x4 PROM TS (6306). . . 2 95 
18 1024x4 PROMOC (6352). 4.95 

IB 1024x4 PROM TS (82S137) 4 95 

PROMOC,(?7S18) 2.95 

PWMTS P7SI5) ...... 9.95 

PROMTS B7S191 2.95 

PROM C, (27S20) ... 2.95 

PROMTS I27S211 2.95 

(27S12) 



32x8 

24 512x8 

16 32x8 

16 256x4 

16 256x4 

16 512x4 

18 2048x4 

24 2048) " 



AI1C0808 
ADC0809 
ADC08I6 
ADC08I7 
OAC08UG 
OAC0B07 



DAC0B31 
D/iClOOO 
DAC1D0B 
DAC1020 
DAC1022 

OAC1230 
OAC123I 
XV5I013A 



'RDM IS IIUP24S8I) 9.95 

(BOnsI 14.95 

z« 1024x6 PROMTS. (82S 181). . 9.95 

B 2048x4 P«0M OC I82SI84) 9.95 

18 20-18x4 PfliM TS (82SI85) 995 

24 2048x8 PK0MT5.(82SI9I) ... 14.95 

—DATA ACQUISITION 

Mij'dck [IC/DC Cnnvi'!l.:i * !.V lo ~9V 2.95 
A.Htamirler (lMlSlii ... 14.95 

•■ . ,VI)(.!..!M:rh:r I ' V.'lS(i) 4.95 

.-. iiil A/DCiiiivnln ,11 Mil 
28 iiliit A/I) Cunv w/f)-Ch;tiim;l Analrii) 995 
28 ;i lii: A/l) Convert* [8 Gh Mufti.) , 4,49 

40 ;■■; lilt A.'OCiiriv w/IC, t:i,anni:l An.slmi 1495 
40 B-BitAmi ,' L) . . 9.49 

16 fl-ftl O/A Convi:nei |0.78ii> Lin). . . . 1.95 
16 B-BrtD/A )..... 1.49 

16 8-Bil D/A Converter IMC1408-8). . 2.25 

!U D/AC ((]!>'' Lin.) 595 

■ tlpO.'ADiriv ( 10-, Lm) ... 4.49 
24 11)11,1 il.'A Cunv. Mi'irn Ccmp (0 05".! 7 95 
20 UHliI D/ACiiiiv Mn:r.i Cinip. (is 
16 1 ()■ iiil D/A Cpnv (()()!).■„ Lin.) 7.95 

16 iMltDMCom id '() hUa) 5.95 

18 l?-tlil O'A Cunv (I) >'()',■ l.m 1 6.95 

20 I iirui MLi-, i(l!> lm) . 1.1,95 

20 12-Bit Up O/A Cow ( 10= c Lm.) . . 13 95 

40 30X Biud IURT (181602). 3.95 







Wire Wrai 

Sockets 

(Gold) Level 113 

PirlUn. 1-9 10-99 100 up 



8 pin WW .55 .49 

lOpmWW .69 65 

14pi)iWW 75 69 

16p«iWW 79 .72 

IBpmV/W .95 85 

20pm WW 1.19 1 09 

22pm WW 129 119 

24 pmvVW 1 35 119 

28pm WW 1.69 1 55 

36pm WW 1 89 1,79 

40pinWW2.29 1,95 



.59 



179 



CIJMflP Br 
Header Plugs (Gold] 

PirtHo. 19 1099 100 up 



14 pinMP 65 59 

t6 pin HP 69 65 
24pmHP 1.15 .99 



Header Covets 

14|)inHC 15 13 
16 pin IIC 19 17 
24pm HC 29 .25 



22 



$10.00 Minimum Order - U.S. Funds Only 
California Residents Add 6Wo Sales Tax 
Shipping - Add 5% plus $1.50 Insurance 
Send S.A.S.E. for Monthly sales Flyer! 



Spec Sheets - 30c each 
Send $1.00 Postage for your 
FREE 1985 JAMECO CATALOG 
Prices Subject to Change 




nnaE 



ameco 

BEama 

1355 SHOREWAY ROAD, BELMONT, CA 94002 
12/64 PHONE ORDERS WELCOME — (415) 592-80$7 Telex: 176043 




DT1050 — Applications: Teaching aids, 
appliances, clocks, automotive, telecommunica- 
tions, language translations, etc. 

The DT105O is a standard DIGIT ALKEH kit encoded with 137 separate 
and useful words, 2 tones, and 5 different silence durations. The 
words and tones have been assigned discrete addresses, making it 
possible to output single words or words concatenated into phrases 
or even sentences. The "voice'* output ol the DT1050 is a highly in- 
telligible male voice. Female and children's voices can be synthesiz- 
ed. The vocabulary Is chosen so that it is applicable to many pro- 
ducts and markets. 

The OT1050 consists ol a Speech Processor Chip, MMS4104 (40 pin) 
and two (2) Speech ROMs MM52164SSR1 and MM52164SSR2 (24-pin) 
along with a Master Word list and a recommended schematic 
diagram on the application sheet. 

DT1050 Digitalker™ $34.95 ea. 

MM54104 Processor Chip S14.95 ea . 

DT1057- Expands the DT105D vocabulary from 137 to over 260 

words. Includes 2 ROMs and specs. 

Part No. 0T1O57 S24.95 ea. 



DlMinli^nfL 



Pari N 



7045IPI 28 CMOS Precision Timer 

7045EV/KM 28 StoPwalcliChip. XT I (Evaluation Kill 

7106CPL 40 3V;OigilA/0(LCODrive) 

FE02030 3'/: Digit LCD OispUy tor 710617116 

7106Ev7Ki1 40 IC. Circuil Board. Oisplay (Evaluation Kit) 

7I07CPL 40 3',', Digit A/OILED Drive) 

7107EV/Kit 40 IC. Circuit Board. Display (Evaluation Kit) 

7116CPL 40 3V? Digit A/O LCD D)S HLD 

7201IUS Low BalteiyVolt Indicator 

72051PG 24 CMOSLEO Stop watch /Timer 

7205EV Kit 24 S!op*atcr»Criip. XTL lEvauation Kiti 

7206CJPE 16 ToneGenerator 

72D6CEV Kit 16 ToneGeneralor Chip. XTL Evaluation Kit) 

7207AIPD 14 Oscillator Controller 

7207AEV/Kil 14 Fieq Counter Chip, XTL lEvalualion Kil) 

7215IPG 24 4 Func CMOS Stopwatch CKT 

7215EV/KH 24 4 Func Stopwalch Chip. XTL (Evalu lion Kit| 

7216AUI 28 8 DigilLJn/v Counter C A 

721601PI 28 6 Digil Frerj Counter C C 

72171JI 28 4 Digit LEO UP/Down Counter C A 

7217AlPt 28 4 Oigrt LEO Up/Oown Counter C C 

7224IPL 40 LCD4V? Oigit Up Counter DRI 

7226AEV/Kil 40 5 Funclion Counler Chip. XTL Evaluation Kill 



130009 1983 INTERSIL Data Book (13560) , 



1049 
1495 
4695 
1095 
4695 
1095 



19 49 
31.49 

2149 
1095 



9995 

^ $9,951 



74HC High Speed CMOS 



74HC00 14 

74HC02 14 

74HC03 14 

74HC04 14 

74HCU04 14 

74HC08 )4 

74HC10 14 

74HC1I 14 

74HC14 14 

74HC20 14 

74HC27 14 

74IIC3D 14 

74HC32 14 

74HC42 16 

74HC51 14 

74HC5B 14 

74HC73 14 

74HC74 14 

74HC75 16 

74HC76 16 

74HC85 16 

74HC66 14 

74HC107 14 

74HC109 16 

74HC112 16 

74HC123 16 

74HC125 14 

74HC132 14 

741IC137 16 

74HCI38 16 



74HCI39 16 

74HC147 16 

74HC151 16 

74HC153 16 

74HC154 24 

74HC157 16 

74HC158 16 

74HC160 16 

74HCI61 16 

74HC162 16 

74HC163 16 

74HC164 14 

74HC165 16 

74HC166 16 

74HC173 16 

74HC174 16 

74HC175 16 

74HC190 16 

74HC191 16 

74HC192 16 

74HC193 16 

74HC194 16 

74HC195 16 

74HC221 16 

74HC237 16 

74HC240 20 

74HC241 20 

74HC242 14 

74HC243 14 

74HC244 20 



74C0O 
74C02 
74C04 
74C08 
7.1C10 
74C14 
74C20 
74C30 
74C32 
74C42 
74C48 
74C73 
74C74 
74C85 
74C86 
74C89 
74C90 
74C93 
74C95 



m««,M«' 



74HC245 2C 

74HC25I IE 

74HC253 IE 

74HC257 IE 

74HC259 IE 

74HC266 U 

74UC273 2C 

74HC280 14 

74HC299 2C 

74HC366 IE 

74HC367 IE 

74HC373 20 

74HC374 20 

74HC390 15 

74HC393 14 

74HC533 20 

74HC534 20 

74HC595 16 

74HC688 20 

74HC4Q24 14 

74HC4040 IE 

74HC4060 IE 

74HC4075 14 

74HC4078 14 

74HC4511 IE 

74HC4514 U 

74HC4538 II 

74HC4543 II 

74|ICU04 is un 



74C107 
74C151 
74CI54 
74C157 
74C160 
74C161 
74C162 
74C163 
74C164 
74C165 
74C173 
74C174 
74C175 
74C192 
74C193 
74C195 
74C221 



74C240 

74C244 
74C373 
74C374 
74C901 
74C902 
74C903 
74C906 
74C907 
74C911 
74C912 
74C915 
74C917 
74C922 
74C923 
74C925 
74C925 
80C95 
80C97 



TL071CP 

TL072CP 

TL074CN T 

TL081CP 1 

TL082CP 

TL084CN V 

LMI09K 

LM301CN 

LM302H 

LM304H 

LM305H 

LM307CN 

LM308CN 

LM309K 

LM3I0CN 

LM3I1CN 

LM312H 

LM317T 

LM3I7K 

LM3I8CN I 

LM319N 1 

LM320K-5 

LM320K24 

LM320T-5 

LM320T-I2 

LM320T15 

LM320T-24 

LM322N I' 

LM323K 

LM324N H 

LM3290Z 

LM331N I 

LM3342 

LM335Z 

LM336Z 

LM337MP 

LM337T 

Lt,)338K 

LM339N 1 

LM340K-5 

LM340K12 

LM340K 15 

LM34DK24 

LM340T-5 

LM340T-12 

LM34DT-15 

LM340I-24 

LF347M I- 

LM348N V 

LM350K 

LF351N I 

LF353fl I 



LF355N 6 

LF356M 8 

LM358N 8 

LM359N 14 

LM370N 14 

LM373N 14 

LM377N 14 

IM3B0CN 8 

LM380N 14 

LM361N 14 

LM3B2M 14 

LM384N 14 

LM386N-3 B 

LM387N 8 

LM369N 18 
LM391N-801S 

LM392N I 

LM393N B 

LF398N 8 
LM399H 

LF412CN g 

TL494CN 16 

TL498CP 8 

NE531V 8 

NE544N 14 

NE550A 14 

NE555V 8 

XR-L555 8 

LM556H 14 

NE558N 16 

NE564N 16 

LM565N 14 

LM566CN 8 

IM567V 8 

NE57a>J 16 

NE57IN 16 

NE592N 14 

LM703CN 8 

LM710N 14 

LM711N 14 

Lli4723N 14 

LM733fJ 14 

LM739N 14 

LM741CJJ 8 



LM747N 14 .( 

LM748N 8 ! 

LW76IHC 9! 

LM1456V g 1.5 

LM1456CN g ! 

LM1488N 14 I 

LM1489M 14 .( 

LMI496« 14 ! 

Lr.11605CK 9. 1 

LMI800N 16 2.. 

LM1871N 18 2! 

LM1872M IB 3; 

LM1877N-914 2! 

LM1889N 18 1.! 

LMI896N 14 1! 

LM2002T 1 1 

ULM2003A 16 U 

XR2206 16 3< 

XR2207 14 2< 

XR2208 16 1.1 

XR221I 14 21 

LM2877P 1 < 

LM2B78P 2! 

I.M2901N 14 i 

LM2902N 14 I 

LM2907H 14 2>! 

LW29t7tJ 8 1.5 

LM3900N 14 .5 

LM3905CN 8 11 

LM3909N 8 ( 

LM3914N IB 2: 

LM3915IJ 18 2.: 

LM3916N 18 2 .3 

RC4I36N 14 1.2 

RC4I51N8 8 1.S 

RC4I95TK 5.5 

LM4250CN a 14 

LM4500A 16 29 

NE5532 8 IE 

NE5534 8 1 .3 

79M05AH 1.2 

ICL30388 14 39 

LM130BOH 8 1.1 

LM1360ON 16 1 1 

76477 28 3.5 
MOREAVAIUBLE 



30003 1982Nat. Linear Data Book ii952Dgs) S11.9S 



252 BYTE • JANUARY 1985 



Commodore® Accessories g& HAPPY HOLIDAYS! 



RS232 ADAPTER FOR 
VIC-20 AND COMMODORE 64 




The JE232CM allows connection of standard serial RS232 
printers, modems, etc. to your VIC-20 and C-64. A4-pole 
switch allows the inversion of the 4 control lines. Com- 
plete installation and operation instructions included. 
• Plugs into User Port • Provides Standard RS232 signal 
levels • Uses 6 signals (Transmit. Receive, Clear to Send, 
Request to Send, Data Terminal Ready, Data Set Ready). 

JE232CM $39.95 



VOICE SYNTHESIZER 
FOR APPLE AND COMMODORE 




COMPAQ • COLUMBIA • EAGLE 

These PC compatibles and others use the IBM64K for memory 

expansion. 

IBM64K (Nine 200ns 64K RAMs) $43.95 



APPLE He 

Extended 80-Column/64K RAM Card. Expands memory by 64K to 
give 128K when used with programs like VisiCalc'". Fully assem- 
bled and tested. 
JE864 $99.95 

TRS-80 MODEL I, III 

Each Kit comes com plete with eight MM5290 ( UPD4 1 6/41 16) 16K 
Dynamic RAMsand documentation forconversion. Model 1: 16K 
equipped with Expansion Interface can b e expanded t o 4 8 K with 
2 Kits. Model III: Can be expanded from 16K *o 48K using 2 Kits. 
Each Kit will expand computer by 16K increments. 

TRS-16K3 200ns (Model III) $8.95 

TRS-16K4 250ns (Model 1) $6.95 



TRS-80 MODEL IV 

Easy to install Kit comes complete with 8 ea. 4 1 64N-20 (200ns) 
64K Dynamic RAMs & conversion documentation. 

TRS-64K-2 (Converts from 16Kto64K) $38.95 

TRS-64K-2PAL (8 ea. 4164 w/Speciat PAL Chip 
to expand from 64K to 128K). . . $59.95 

TRS-80 COLOR AND COLOR II 

Easy to install Kit comes complete with 8 each 4 1 64N-20 (200ns) 
64K Dynamic RAMs and documentation for conversion. Converts 
TRS-80 Color Computers with D. E. EI F and NC circuit boards to 
32K. Also converts TRS-80 Color Computer II to 64K. Flex DOS or 
OS-9 required to utilize full 64K RAM on all computers. 
TRS-64K-2 $38.95 




Es Protect Yourself... 

DATASHIELD* 
Surge Protector 



• Eliminates voltage spikes and EMl-RFI noise 
before it can damage your equipment or cause 
data loss ■ 6 month warranty ■ Power dissipa- 
tion (100 microseconds): 1 ,000,000 watts • 6 
sockets ■ 6 foot power cord * Normal line volt- 
age indicator light ■ Brown out/black out reset 

Model 100. . f^f" $69.95 



Protect 
Yourself.., 



l PC 



DATASHIELD 

Back-Up 
Power Source 

| Providesupto30minutesofcontinuous 120 

I VAC 60Hz power to your computer system 

a m (load dependent) when you have a black out 

or voltage sag • Six month warranty • Weight 

(PC200): 24 tbs.-(XT300): 37.5 lbs. 

PC200 (Output rating: 200 watts) $299.95 

XT300 (Output rating: 300 watts) $399.95 



V 



Kj£ Intelligent 300/1 200 Baud 
Prometheus Telephone Modem with 
Real Time Clock/Calendar 

The ProModem*" isa Bell 2 1 2A (300/1 200 baud) intelli- 
gent stand-alone modem ■ Full featured expandable 
modem -Standard features include Auto Answer and 
Auto Dial, Help Commands, Programmable Intelligent 
Dialing, Touch Tone™ and Pulse Dialing & More • Hayes 
command set compatible plus an additional extended 
command set • Shown w/'alphanumeric display option. 

Part No. Description Price 

PM1200 RS-232 Stand Alone Unit $349.95 

PM1200A Apple II, II+ and lie Internal Unit $369.95 

PM1200B IBM PC and Compatible Internal Unit $269.95 

PM1200BS IBM PC & Comp. Int. Unit w/ProCom Software $319.95 

MAC PAC Macintosh Package $399.95 

(Includes PM1200, Cable, & ProCom Software) .__ 

OPTIONS FOR ProModem 1200 

PM-COM (ProCom Communication Software) $79.95 

Please specify Operating System. 

PM-OP (Options Processor) $79.95 

PMO-16K (Options Processor Memory - 16K) $10.95 

PMO-32K (Options Processor Memory - 32K) $20.95 

PMO-64K (Options Processor Memory - 64K) $39.95 

PM-ALP (Alphanumeric Display) $79.95 

PM-CC (Apple lie to PM1200 Cable) $29.95 

PM-MC (Macintosh to PM1200 Cable) $29.95 



KEYBOARDS 



Apple® Accessories 



5 1 /4" APPLE™ 

Direct Plug-In 

Compatible Disk Drive 

and Controller Card 

The ADD-514 Disk Drive uses 
Shugart SA390 mechanics-143K 
formatted storage ■ 35 tracks 
■ Compatible with Apple Control- 
ler & ACC-1 Controller • The drive 
comes complete with connector and cable — just plug 
into your disk controller card * Size: 6"L x 3tt"W x 
8-9/16"D ■ Weight: 4Vfe lbs. 

ADD-514 (Disk Drive) $169.95 

ACC-1 (Controller Card) $ 49.95 

More Apple Compatible Add-Ons... 

APF-1 (Cooling Fan) $39.95 

KHP4007 (Switching Power Supply) $59.95 

JE614 (Numeric/Aux. Keypad for/fe) $59.95 

KB-A68 (Keyboard w/Keypad for II & |[+) $79.95 

MON-12G (12" Green Monitor for ll.ll+./te, lie). . . . $99.95 

JE864 (80 Col. +64K RAM (or//e) $99.95 

ADD-12 (5 V Hall-Height Disk Drive) $179.95 



DISK DRIVES 



JE520AP 



JE520CM 

• Over 250 word vocabulary-affixes allow the formation of more 
than 500 words • Built-in amplifier, speaker, volume control, and 
audio jack • Recreates a clear, natural male voice • Plug-in user 
ready with documentation and sample software • Case size: 
7'/4"L x 3V4"W x 1-3/8"H 

APPLICATIONS: • Security Warning • Telecommunication 

• Teaching • Handicap Aid 

• Instrumentation • Games 

Pari ^No. Dascrlptlon Price 

JE520CM For Commodore 64 & VIC-20 S114.95 

JE52QAP For Aoole II, II+ . and lie S149.95 



Computer Memory Expansion Kits 



IBM PC AND PC XT 

Most ot the popular Memory Boards (e.g. Quad ram™ Expansion 
Boards) allow you to add an add! 64K, 1 28K, 192K or 256K. The 
IBM64K Kit will populate these boards in 64K byte increments, 
The Kit is simple to install-just insert the 9- 64KRAM chips in the 
provided sockets and set the 2 groups of switches. Complete 
conversion documentation included. 
IBM64K (Nine 200ns 64K RAMs) $43.95 



W 



;&»*mvv 



13%"Lx4WWx 3 /<i"H 



New.' 




1 6-9/1 6Tx6 s »'Wx1VH 







Mitsumi 54-Key Unencoded 
All-Purpose Keyboard 

• SPST keyswitches • 20 pin ribbon cable connec- 
tion ■ Low profile keys • Features: cursor controls, 
control, caps (lock), function, enter and shift keys 
•Color (keycaps): grey • Wt.: 1 lb. • Pinout included 

KB54 $14.95 



76-Key Serial ASCII Keyboard 

• Simple serial interface ■ SPSTmechanicaf switch- 
ing • Operates in upper and lower case • Five user 
function keys: F1-F5 ■ Six finger edge card connec- 
tion ■ Color (keys): tan • Weight: 2 lbs. • Data incl. 

KB76 $29.95 



Apple Keyboard and Case 
for Apple II and II+ 

• Keyboard: Direct connection with 1 6-pin ribbon 
connector ■ 26 special functions • Size: 141V'L x 
5 VW x 1 li"H 

• Case: Accommodates KB-A68 ■ Pop-up lid for 
easy access • Size: 15ft"W x 18"D x 4WH 

Price 



New! 



KB-EA1 Keyboard and Case (pictured above) $134.95 

KB-A68 68-Key Apple Keyboard only $ 79.95 

EAEC-1 Expanded Apple Enclosure Case only $ 59.95 



POWER SUPPLIES 



TRANSACTION TECHNOLOGY, INC. 
5VDC @ 1 AMP Regulated Power Supply 

• Output: +5VDC @ 1.0 amp (also +30VDC regulated) • Input: 1 15VAC,60Hz 

• Two-tone (black/beige) self-enclosed case • 6 foot, 3-conductor black 
power cord • Size: 6<V L x 7" W x 2U" H ■ Weight: 3 lbs. 

PS51194 $14.95 




RFD480 (Remex 5 1 A" full-ht.) $129.95 

JA551-2 (Panasonic 5'A" half-ht.) $139.95 

TM100-2 (Tandon 5% " full-ht.) $159.95 

FD55B (Teac 5 V half-ht.) $1 49.95 

SA455 (Shugart 5V* " half-ht.) $159.95 

FDD100-8 (Siemens 8" full-ht.) $139.95 

PCK-5 (5 1/ 4 " Power Cable Kit) $2.95 

PCK-8 (8" Power Cable Kit) $3.95 

UV-EPROM Eraser 



8 Chips -21 Minutes 




1 Chip- 15 Minutes 



Erases all EPROMs. Erases up to 8 chips within 21 minutes (1 chip 
in 1 5 minutes). Maintains constant exposure distance of one inch. 
Special conductive foam liner eliminates static build-up. Built-in 
safety lock to prevent UV exposure. Compact — only 9.00"l. x 
3.70"W x 2.60"H. Complete with holding tray for 8 chips. 

DE-4 UV-EPROM Eraser $74.95 

UVS-11EL Replacement Bulb $16.95 







Power/Mate Corp. REGULATED POWER SUPPLY 

• Input: 105-1 25/210-250 VAC at 47-63 Hz • Line regulation: ±0.05% • Three 
mounting surfaces • Overvollage protection • UL recognized • CSA certified 
Part No. Output Size Weight Price 

EMA5/6B 5V@3A/6V@2.5A AWL x 4"W x 2W'H 2 lbs. $29.95 
EMA5/6C 5V@6A/6V@5A 5WLx WW x 2 ? V'H 4 lbs. $39.95 



POWER PAC INC. REGULATED POWER SUPPLY 

• Perfect forcomputersystems- Output: +5VDC® 11 Amps, -5VDC@ 1 Amp, 
+12VOC @ 2 Amps. -12VDC @ 0.5 Amp and +24VDC @ 3 Amps • Over- 
voltage protection ■ Size: 1 2 VL x 6WW x 4WH • Weight: 1 7 lbs. • Spec incl. 

PS2922. $69.95 



4-CHANNEL SWITCHING POWER SUPPLY 

• M icroprocessor. mini-computer, terminal, medical equipment and process 
control applications • Input: 90-130VAC. 47-440Hz • Output: +5V DC @ 5A, 
-5VDC® 1 A; + 12VDC@1A,-12VDC@ 1A • Line regulations: ±02%- Ripple: 
30mV p-p • Load regulation: =1% ■ Overcurrent protection • Adj: 5V main 
output ±10% ■ Size:6%"l.x 1 VW x 4-1 5/16"H -Weight: US lbs. 

FCS-604A $69.95 



Switching Power Supply for APPLE II, II+ & lie™ 

• Can drive four floppy disk drives and up to eight expansion cards 

• Short circuit and overload protection * Fits inside Apple computer 
•Fully regulated +5V@5A, +12 V@ 1.5A, -5V @ ,5A. -12V @ .5A 

■ Direct plug-in power cord included • Size: 9%"L x 3'/2"W x 2VH 

■ Weight: 2 lbs. 

KHP4007 (SPS-109) $59.95 



$10.00 Minimum Order — U.S. Funds Only 
California Residents Add 6 1 /2% Sales Tax 
Shipping — Add 5% plus $1.50 Insurance 
Send S.A.S.E. for Monthly Sates Flyer! 



Spec Sheets — 30c each 
Send $1.00 Postage for your 
FREE 1985 JAMECO CATALOG 
Prices Subject to Change 




ameco 



ELECTRONICS 



1355 SHOREWAY ROAD, BELMONT. CA 94002 
12/84 PHONE ORDERS WELCOME — (415) 5928097 Telex: 176043 




JE664 EPROM PROGRAMMER 

8K to 64K EPROMS - 24 & 28 Pin Packages 

Completely Sell-Contained - Requires No Additional Systems lor Operation 

• Programs and validates EPROMs • Checks lor properly erased EPROMs 

• Emulates PROMs or EPROMs • RS232C Computer Interface for ediling and 
program loading - Loads date inlo RAM by keyboard - Changes date in RAM 
by keyboard • Loads RAM from an EPROM • Compares EPROMs for conlenl 
differences • Copies EPROMs -Power Input: 1l5VAC.60Hz. less than 10W 
power consumption -Enclosure: Color-coordinated, lighl tan panels with 
molded end pieces in mocha brown ■ Size: 15 VL x 8^ "D x 3'^"H ■ Weighl: 
5*i lbs. 

The JE 664 EPROM Piogramnwi emulates and programs various 8-Bl VWbr d EPROMs Irom 8X to 
MKBil memor/ capacity Data can be entered into the J£ 664s internal 8K x 8-Bit RAM in three 
ways : ( 1 ) froma ROMor£PROM;(2)lroman extemalcomputer viathe optional JE665RS232C 
BUS; (3) Irom ilspanelkeyboard. The JEG64'sRAMs may be accessed foremulation purposes 
from the panels test socket loa n rot ernal microprocessor. In programming and emulation, the 
JE66-1 allows tor e cami nation, chang e and validation Ot program conlenl The JE664°s RAMs 
canbeprogrammedquicWy toaii"i"s(c* any value), allowing unused addresses m the EPROM 
lo be programmed later without necessity ot W W erasing. The JE6M displays ATA and 
ADDRESS in convenient hexadecimal falplianumcnc, lormat. A "DISPLAY EPROM DATA" 
buttonchanges theOATA readout from RAM word toEPROMword and is displayed mboth 
hexadecimal and bma^ code The hont panel leaiures aconv en i e ni operating guide. The JE66J 
Programmer includes °ne JMi 6A Jumper Module (as 'Bled below)- 

JE664-A EPR0M Programmer. $995.00 

Assembled 4 Tested (Includes JM16A Module) 

JE665 - RS232C INTERFACE OPTION - The RS232C interlace Option implemenis 
computer access to the JE664's RAM. This allows the computer to manipulate, sloie arid 
transfer EPROM da la loand from the JEG64. A sample program listing issupplied in MBASIC lor 
CP/M computers. Documentation is provided to adapt the soltware to other computers with an 
RS232 port. 960D Baud. 8-bit word, odd Parity with 2 stop bite 

EPROM Programmer W/JE665 Option 
JE664-ARS $1195.00 

Assembled & Tested (Includes JM16A Module) 
EPROM JUMPER MODULES - The JEWs JUMPER MODULE (Personality Module) is a 
plug -in Module that pre-sets the JE664 for Die proper programming putses 10 the EPROM and 
configures the EPROM socket connections tor that particular EPROM 



JE564 [FROM 

Jumper Mnd Ng 


irtm 


Piajrimmnj 

Vettige 


EFflOM MAKUFHETIKIEH 


PF.FCE 


JM08A 


Mia 


25V 


iwn. M.OTti3.N,il. Intel. II 


. SI495 


JM1W 


2716. TMSM16 fTII 


2SV 


AMD. HrUtfu. MKiefc 


. . SH95 


JMI68 


HBH1S0.WII 


■ v,' -'v - 1:-. 


M«cnWL n . . 


SH.95 


M l?A 


•>»i:sv 


25V 


Motorola, n. MxtK OKI . . 


mm 


JM328 


2733 


:sv 


AMtl. Fill !Su. NEC. KlJClii InW. 


SU95 


JMJ2C 


?/'J2A 


21V 


Fujitsu Intt 


SliK 


JM64A 


MCMsarw. 

MCM6317&* 


21V 


MMortm 


. . S1495 


Mh*B 


27W 


21V 


m . : .r:>- tOM 


-SH95 



3K*Z 1MS2SW 



Inquiry 187 



JANUARY 1985 -BYTE 253 



A B Computers 

THE VALUE LEADER II SINCE 1976 



® SANYO 
® 

Sanyo 550 & 555 PC's. Built-in software 
includes MDOS Version II, Wordstar, Calc- 
Star, Basic, more. Great Prices. 

Computer Ram Drive Price 

550-1 128K' 180K (1 drive) S895. 

550-2 128K' 360K(1 drive) 950. 

555-1 128K" 360K (2 drives) 1075. 

555-2 128K" 720K (2 drives) 1275. 

•EXPANDABLE TO 256 



Ymmth I data 

I systems 



All Zeniths fully software & 
patible with the PC and 
keyboard: 

Computer Ram Drive 

ZF-151-21 128K360 
ZF-151-52 320K 720 (2 drives) 
ZW-151-52 320K10.6MB + 360 
ZF-161-2V 128K360 
ZF-161-52* 320K 720 (2 drives) 
'Portable 



hardware corn- 
XT , .superior 

Ports Price 

1PL/2SER. CALL 
1PL/2 SEP, CALL 
1PL/2 SER. CALL 
1PL/2SER CALL 
1PL/2 SER CALL 



Panasonic. 




PANASONIC 1090 

Friction & tractor, 

excellent correspondence mode, 

Epson code compatible $239. 



OTHER COMPUTER SPECIALS 

IBM PC and PC XT in stock 

available at special prices CALL 

ALSPA 8" CPM Computers. 64K 
memory workhorse at super special 
prices. 

1/SS as low as S500. 

2/SS S700. 2/DS $1,000. 

Franklin Ace — not many left, 

super prices CALL 

Commodore— full line CALL 

DISKS & ACCESSORIES 

Price per 5%" Disk 

3M SS DS AT 

Qty. SS/DD DD/DD 96 TPJ 96 TPI H DENS 

200 $1.55 2.14 3.16 3.49 CALL 

100 1.59 2.19 3.22 3.56 CALL 

10 1.62 2.23 3.29 3.63 CALL 

VERBATIM SS DS AT 

Qty. SS/DD DD/DD 96 TPI 96 TPI H DENS 

200 $1.61 2.17 3.29 3.63 CALL 

100 1.65 2.22 3.36 3.71 CALL 

10 1.68 2.26 3.43 3.78 CALL 

MAXELL SS DS AT 

Qty. SS/DD DD/DD 96 TPI 96 TPI H DENS 

200 $1.93 2.56 2.74 3.43 5.04 

100 1.97 2.61 2.80 3.50 5.15 

10 2.01 2.66 2.86 3.57 5.25 

30 Macintosh 3Va" diskettes in Amaray 
diskbank $135. 




SOFTWARE 

Master Type (Scarborough) $22. 

Math Blaster! (Davidson) 35. 

Typing Tutor III (S&S) 35. 

Alphabet 200 (Spinnaker) 22. 

Success with Math (CBS) 18. 

Typing Tutor II (Microsoft) 18. 

Algebra I (Peachtree) 22. 

Story Machine (Spinnaker) 22. 

Word Attack! (Davidson) 35. 

Get Organized! (Electronic Arts) 159. 

Spotlight (Software Arts) 120. 

Microsoft "Word" (w/Mouse) 325. 

Unix Operating System for PC CALL 

Copy PC 29. 

Flight Simulator II (Sub Logic) 39. 

1-2-3 (Lotus) 299. 

PFS:File {Software Pbshg.) 89. 



HIT PARADE 

Symphony (Lotus) 499. 

PFS:Report (Software Pbshg.) 79. 

PFS:Write (Software Pbshg.) 89. 

dBase III (Ashton-Tate) 489. 

dBase II (Ashton-Tate) 349. 

Framework (Ashton-Tate) 489. 

Multimate (Multimate) 320. 

Chart (Microsoft) 179. 

Multiplan (Microsoft) 129. 

Wordstar (Micropro) 335. 

"Personal Pearl (pearlsoft)— Database 
filing/reporting system for personal 
productivity. Manipulate database thru 
simple English sentence commands. Great 
for beginner or pro. Super business aid. 
Includes functions for bookkeeping, general 
ledger, billings management, mail list, sales 
analysis, budget planning, more $235. 



We carny full software lines by Electronic Arts, Scholastic, Scarborough, 
PFS, Spinnaker, Batteries Included, Others. If you don't see it here, CALL. 



' AB's OWN DISKETTES-top disk quality 
atalowjowprice. . .buy 100(DS/DD) and 
pay only $1.50 per disk. 
Plus, before February 28, get a free Amaray 
Mediamate 5 disk file in the bargain! 

ABcarrys all major brands. . . 3M, Verbatim, 
Maxell, Wabash, BASF, Sentinel, Dysan. . .in all 
popular sizes and configurations. CALL for super 
prices. 

DISK STORAGE 

Mini Flip 'N File (50 5" disks) $17.45 

Rolltop 100 (100 disks. 

10 dividers) 28.99 

Mini Kas-ette/10 (for 5" disks) 

1/2.25 10/2.05 ea. 

*Amaray Mediamate 5 11.99 

Innovative Concepts— fold out style for 5" 
disks: 

Flip 'N File/25 16.50 

Flip 'N File/50 22.95 

Smith & Bellows Wooden Storage 
Boxes for 5" disks. Natural or dark finish. 

For 50 disks 18. 

For 70 disks 21. 

For 100 disks 24. 

PLUS— "HEAD" disk cleaning kit 

(w/2 disks) 11.99 

IBM drive analyzer (Verbatim) 22.50 



MONITORS 

USI-20 Mhz band width, 1000 lines 
resolution. Easily capable of 80 character 
display. 

• 1200G (Pl-2)p12" green phosphor 
SPECIAL $85. 

• 1200A (Pi-3)-12" amber phosphor 

SPECIAL 89. 

AMDEK 

Video 310A-12" amber, 18 meg. 

TTL-IBM $155. 

ZENITH 

ZVM-124-12" amber-22 MHz, TTL 

for IBM $150. 

ZVM-135-High res. RGB + composite 

monitor 470. 

ZVM-135-1 -Cable for RGB 

monitor 23. 

PANASONIC 

12" Green 20 MHz (Sound) $137. 

12" Amber 20 MHz (Sound) 145. 

ELECTROHOME 

ECM 1226-12" Green $95. 

ECM 1302-1-13" Color RGB 195. 

ECM 1302-2-13" Color (Hi Res.) 330. 

POWER DEVICES 

Datashield back-up power source 

200 PC-200 watt $265. 

300 XT-300 watt 390. 

"BITS" Power back-up-250W 695. 

True uninterruplable 

Brooks 6 Outlet— Surge Supres- 
sor/Noise Filter 54. 

Computer Power lnc-500 VA 1320. 

Tripp Lite 425 VA 390. 



'Ordering Information: Order by check. MasterCard or VISA 
Personal checks take 15 days to clear, no waiting on certified 
checks or money orders Add 3% shipping and handling on all 
orders (minimum S2 00}. Mail AP0/FP0 Aif may require addi- 
tional charges PA residents add 6% sales tax. MA residents 
add 5% All items subject to availability Prices subject to 
change Additional discounts available to qualified educational 
institutions Requests for bid on volume requirements invited 



OUTPUT DEVICES 

Printers by Star, Epson, C. Itoh, Amdek, 
Panasonic, Okidata, Diablo, Brother: 

Star Micronics Gemini 10X 

-10" carnage, F/T 120 CPS $258. 

Epson LQ-1500-NEW 24-pin 

letter quality dot matrix CALL 

Epson RX-80-Tractor Feed, 
Graftrax+ 289. 

Okidata 92 CALL 

Amdek Printers 

5025-25 CPS Oaisywheel, 2K Buffer CALL 

5040-40 CPS Daisywheel, 2K Buffer CALL 

5055-55 CPS Daisywheel, 2K Buffer CALL 

Brother HR-35 Daisywheel- 
25 CPS Bi-Directional 889. 

Brother HR-25 Daisywheel- 
23 CPS Bi-Directional 649. 

Brother HR-15 Daisywheel- 
13 CPS Bi-Directional 389. 

Star Radix 10 600. 

Star Radix 15 695. 

C. Itoh 

Prowriter I (Parallel) CALL 

Starwriter (40 CPS) CALL 

Diablo 620 (Daisywheel) CALL 

IBM Parallel Printer Cable 19. 

COMMUNICATIONS 

Mark X Auto Dial/Auto Answer $119. 

Anchor Mark XII Smart modem 265. 

Hayes Smartmodem 1200B 459. 

(includes Smartcom II software) 

Hayes SmartModem 1200/300 529. 

"Crosstalk" software 135. 

• Voad keyboard-phone software for 
IBM PC and compatibles. Features 
mail merge, call reporting, "Note 
Pad" and more CALL 



FREE CATALOG! 

This ad space can accommodate only a 
few of the exceptional values available 
from AB. Our latest catalog is packed with 
fantastic buys, top brands, thousands of 
items. For a free copy call or write. 



commodore 
I commodore 

C 6420 AutO Modem (also available lor Atari & 
Apple at slightly higher price) $ 65 

iTech Sketch Light Pen & Micro 

'illustrator 44. 

MSD Superdrives, single and dual CALL 

CBC 4/12 Analog to Digital 

4 Chan/12 Bit 179. 

Typing Tutor III w/Letter Invaders 35. 

(Also for Apple & IBM) 

Paper Clip Word Processor 
CBM/C64 60. 

80 Column Display Card 
by "Batteries Included" 149. 

Oracle (Consultant) Data Base 
by "Batteries Included" 89 

BusCard II 
by "Batteries Included" 149. 

Cable from BusCard to Parallel Printer 25. 

All other "Batteries Included" items 
in stock CALL 

FORTH for PET/C 64 

(Full Fig. Model) by Cargile/Riley 50. 

Ditto Disk 64 (copy discs even if original is 
copy protected) 36. 

STAT for PET/CBM/C64 95. 

Comprehensive Statistical Analysis Routines 

• AB's C64 Upgrade Kit: Includes BusCard ll 
IEEE Cable & MSD Superdrive 319. 

KMMM PASCAL IV.1 (C64/PET) 95. 

NEW64 + PASCAL CALL 

FLEX-FILE II - User friendly. Set-up and 
maintain data base. Includes report writer 
& mail label routines 59. 

Petscan— Connect up to 37 CBM/PET compu- 
ters as networked cluster to shared drives 
& printers CALL 

C-Scan— Connect up to 8 computers (C 64, 
VIC 20, or similar buss) to shareddrivesand 
printers..... 125, 



/ETC. 

Panasonic, Amdek, Hitachi & Other — V2 
height, double side drives from $149. 

• Data Technology TeamMate Drive-super 
new system. Puis 3.3 MB on 5%" floppy. Formats 
to 2.8. For PC XT owners, an allernative to hard disk 
4 disks back-up 10 megabytes CALL 

• Winchester Drives (10 MB) 799. 

Quadram Quadboard-Parallel port, serial port, 
ciock/calendar. 

No RAM-S299, w/64K-$379. w/384K-$499 

• AMDEK MAI graphics card for 
IBM PC 200. 

Hercules graphics board 359. 

Votrax speech synthesizers- 
Personal Speech System 249. 

AST— full line of IBM cards & boards .CALL 

Keytronics 5150 keyboard 179. 

Hewlett Packard calculators, all models: 

LOW, LOW PRICES ...CALL 

Koala Pad (w/software) 98. 

4164 Chip-Memory expansion for 

IBM, 64K..... 39. 

Interface Cables— 6, 10, 12 ft, all 

popular connectors CALL 

(Dealer inquiries invited) 



ORDER LINE, 9 AM-6 PM EST 

800-882-1211 

(IN PA., 215-822-7727) 

CUSTOMER SERVICE 

215-822-7727 



GZ>, 



A B Computers 

252 BETHLEHEM PIKE 
COLMAR, PA 18915 



254 BYTE • JANUARY 1985 



Inquiry 5 



by Charles Bigelow 



Font Design 
for Personal 
Workstations 



Better fonts mean 
greater legibility 
and productivity 



Business users are increasingly 
suspicious about the auto- 
mated office. It has not provid- 
ed the increase in productivity that 
system vendors promised. One 
reason for its failure is that the fonts 
on business systems have not been as 
legible as the traditional typefaces 
familiar to the office worker. 

When a vendor claims that the fonts 
on a system are "pretty good" or 
'close enough" or "almost cor- 
respondence quality" this is the same 
as saying that the fonts are less than 
optimum and that the vendor has 
short-changed the reader on legibili- 
ty. Considering the amount of time of- 
fice workers spend reading digital 
fonts, anything less than the highest 
possible quality is counterproductive. 
Until recently, few remedies were 
available for the problems caused by 
poor font designs for personal com- 
puters. The character-generator tech- 
nology still used to produce letter- 










forms on most computer terminals 
usually provides a single size of a 
single style of coarse-resolution dot- 
matrix letters. Character-generator 
technology usually does not let the 
user modify the fonts because the 
character images are contained in 
hardware or firmware. 

Moreover, the designs of such fonts 
are often the work of people un- 
trained in letterform design, while 
traditional lettering artists have re- 
jected computers because the tools 
and output media of digital typo- 
graphy have been so clumsy and 
crude. The result is that most existing 
workstation fonts are not designed for 
optimum legibility even within the 
limitations of the technology. 

Computer literacy has therefore 
been a good deal less pleasant and 
productive for the reader than tradi- 
tional scribal and typographic literacy. 
The hackerish look of dot-matrix fonts 
on screens and printers has partially 
prevented full acceptance of com- 
puters as tools for a literate public. 

Today, however, the look of com- 
puter fonts is undergoing a major 
change. The newer raster-based tech- 
nologies of bit-mapped display and 
nonimpact printing offer potential 
solutions to many of the technical and 
aesthetic problems with digital fonts. 
These technologies can produce 
digital font images that more closely 

[continued) 

Charles Bigelow is Assistant Professor of 
Computer Science and Art at Stanford 
University. A MacArthur Foundation Prize 
Fellow, he organized the international seminar 
"The Computer and the Hand in Type 
Design' at Stanford in 1983. You can write 
to him at Stanford University, Department 
of Computer Science, Stanford. CA 94305. 



JANUARY 1985 • BYTE 255 



FONT DESIGN 



resemble traditional analog typefaces. 
The secret of designing digital fonts 
is to adhere to the principles of read- 
ability found in traditional letter- 
form designs, while tuning the fea- 
tures and details of the design to the 
digital medium (for an example, see 
photo 1). 

Readability 

The resolutions of common bit- 
mapped screen displays range from 
60 to 100 lines per inch, with an 
average of approximately 72 lines per 
inch. This is about one-tenth the 
resolution of average-quality digital 
typesetters used in the graphic arts 
and publishing industry. 

It is a truism that communication of 
information is most effective and 
economical when the characteristics 
of the transmitter match those of the 
receiver. In literate communication, 
the transmitter is the system that pro- 
duces the text image, and the receiver 
is the human visual system. The digital 
text image must contain as much res- 
olution as the eye and brain can 



receive and interpret but need not 
contain more information than that. 

There is a way to estimate the 
theoretical minimum resolution for 
good-quality digital text. Experiments 
by psychophysicists and perceptual 
psychologists suggest that the visual 
system cannot detect spatial frequen- 
cies greater than 60 cycles per degree 
of visual angle. That is. the visual 
system perceives a bar grating of 
regularly spaced black and white lines 
as solid gray if the spacing is so fine 
that more than 60 black and white 
line pairs are imaged in one degree 
of visual angle as measured at the 
retina. This provides a measure of the 
upper limits of the visual system's 
ability to resolve the kind of detail 
produced by a digital raster. At a 
reading distance of approximately 12 
inches. 60 cycles per degree of visual 
angle is equal to a resolution of 300 
cycles per inch at the screen. 

We can now estimate the minimum 
resolution necessary for good-quality 
digital text by using a principle of 
digital signal-processing theory devel- 




Photo I : Display screen of the VAXstation 1 00, a workstation made by Digital Equip- 
ment Corporation. The proportionally spaced screen fonts on the VAXstation are members of 
the Pellucida family, a set of original typeface designs optimized for legibility and clarity on 
bit-mapped computer displays. The characteristics of the Pellucida digital letterforms were 
developed by Charles Bigelow and Kris Holmes. 



oped by Harry Nyquist at Bell Labora- 
tories in the 1920s. It states that a 
signal can be digitally sampled and 
reconstructed without loss or distor- 
tion if the sampling rate is at least 
twice the rate of the highest frequen- 
cy in the original signal. This minimum 
sampling rate is known as the Nyquist 
limit or Nyquist rate. Sampling below 
the Nyquist limit introduces aliasing, 
in which the high-frequency com- 
ponents of the original signal are er- 
roneously reproduced as spurious 
lower-frequency components of the 
reconstructed signal. In digital typo- 
graphy, one form of these aliases is 
the jaggies— the jagged stair-step pat- 
terns that fringe the edges of digital 
type. 

To faithfully sample and reconstruct 
a signal of 300 cycles per inch, you 
need a minimum sampling rate of 600 
lines per inch. In fact, resolutions in 
the range of 600 to 720 lines per inch 
were used for many common digital 
typesetting devices developed during 
the late 1960s and the 1970s. A 
decade of experience with these ma- 
chines showed that this resolution 
range was adequate for low- and 
medium-quality printing such as 
newspapers, telephone books, and 
magazines, but not for the highest- 
quality typesetting and printing, 
which required digital resolutions of 
1200 or more lines per inch. 

The Nyquist limit is only a 
theoretical minimum, and for high- 
quality letter images, real-world 
sampling rates often have to be 
higher. The practical evidence sug- 
gests that today's screen resolutions 
of 72 lines per inch are at least one 
or two decimal orders of magnitude 
too low to produce text of optimum 
visual quality. 

The lesson here is that traditional 
analog typefaces cannot be imitated 
and jaggies cannot be eliminated on 
today's display screens. The only prac- 
tical solution is to design screen fonts 
within the limitations of the available 
raster system, to optimize the font's 
features to the mechanisms of the 
human visual system, and to make 
sure these features conform to the 

{continued) 



256 BYTE • JANUARY 1985 









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FONT DESIGN 



familiar historical principles of letter 
design. 

Size 

'type size is an important factor in 
legibility. Up to about 18 point (a 
printer's point is approximately J/72 
inch), the larger sizes are easier to 
read than the smaller. This article is 
set in 10-point type. 

Most users view the screens of com- 
puter workstations at a somewhat 
greater distance than they do books 
and printed documents because para- 
phernalia such as a keyboard, mouse, 
or graphics tablet tend to intervene 
between reader and screen. Some 
ergonomic guidelines recommend a 
viewing-distance range of 16 to 28 
inches; other guidelines recommend 
a range of 13 to 20 inches. At this 
distance, screen fonts should be 
about 1.2 to 2 times as large as 
printed text fonts. 



This measure must be corrected for 
the fact that the apparent size of text 
in English (and other languages that 
use the Latin alphabet) is more 
dependent on the size of lowercase 
letters than on the body size of the 
whole font. Lowercase is measured by 
its "x-height." which is the vertical 
distance from the baseline (on which 
all the letters appear to sit or stand) 
to the top of the lowercase x. The 
body size of a font is the vertical 
distance from the bottom of a 
descender, such as the stem of a p, 
to the top of an ascender, such as the 
stem of a b. 

The x-heights of common text types 
range from about 40 percent to 60 
percent of the type's body size. A 
type with an x-height of 50 percent of 
the body is a face of medium-large 
appearance. A popular 10-point book 
face might have an x-height of about 
5 points. If we assume a display 



screen with resolution of 72 lines per 
inch (one pixel per printer's point), 
then a screen font should have an x- 
height of 7 to 10 pixels to adjust for 
the greater average reading distance. 

Weight 

The weight of a typeface is its relative 
density, or proportion of black image 
to white background. Weight can be 
measured as the ratio between the 
thickness of a straight vertical stem 
(such as the stem of an 1) and the x- 
height. The greater the stem thickness 
in proportion to the x-height, the 
heavier the weight, and the darker the 
text image appears. For printed mat- 
ter, the optimum weight ratio ranges 
from 5 to 6 stems per x-height (5:1- 
6:1). 

This presents a difficult problem for 
the screen font designer. For example, 
given an x-height of 7 pixels, a stem 

{continued) 



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FONT DESIGN 



weight of one pixel is too light, but a 
stem weight of two pixels is too heavy. 
The digital raster cannot permit non- 
integer stem weights, and thus an op- 
timum ratio seems impossible. 

However, on a computer screen the 
perceived stem thickness is almost 
always different from the nominal 
thickness computed from the speci- 
fied raster resolution. Physical factors 
that influence perceived stem weight 
include the size and intensity of the 
writing spot, the amount of spot over- 
lap, the speed with which the writing 
beam turns from on to off versus the 
speed from off to on, the character- 
istics of the phosphor, and the bright- 
ness and contrast of the display. 

When the letterforms are black and 
the screen background is white, these 
factors usually combine to erode a 
significant portion of the perceived 
stem weight. If this erosion is around 
20 percent total (not an unusual 
amount), the perceived weight ratio of 
a font with x-height of 7 pixels and 
stems of 2 pixels would be approxi- 
mately 4.4: 1. While rather dark, this 
is preferable to a one-pixel stem, 
which would produce a weight ratio 
of 8.7:1— far too light and spindly. A 
larger x-height of 9 pixels with a stem 
of 2 pixels would, under the same 
conditions, yield a perceived weight 
ratio of 5.6:1, within the optimum 
range. 

Thus, an interaction occurs between 
font size, as measured by x-height, 
and stem thickness that makes some 
size/stem combinations significantly 
more legible than others. A font de- 
signer has to filter the matrix of all 
possible low-resolution digital fonts to 
pass only those of acceptable weight 
ratios. 

Contrast 

In traditional text typefaces and let- 
tering based on the Latin alphabet, 
vertical letter elements are thicker 
than horizontal elements. The stems 
of an n are thicker than the serifs or 
the connecting arch; the vertical 
bowls of an o are thicker than the 
horizontal hairlines. This difference 
between vertical and horizontal fea- 
tures is called contrast. Faces with 



high contrast have a brilliant, glittery 
look, and faces with low contrast have 
a stolid, monotonous look. 

For screen fonts to have some of the 
legibility of traditional typefaces, the 
traditional contrast must be pre- 
served. Fonts in which the vertical and 
horizontal elements are the same 
thickness have an unfamiliar texture; 
this unfamiliarity impairs legibility. 

When both horizontals and verticals 
are only one pixel in thickness on a 
CRT display and the letters are black 
on an illuminated background, the 
legibility problem is exacerbated by 
the erosion of vertical stems, which 
become even thinner than horizon- 
tals, contrary to the reader's visual ex- 
pectations. Such fonts not only ap- 
pear weak and spindly, they seem 
unclear and ill-defined, as though the 
reader's vision is blurred or some- 
thing is misadjusted on the display 
screen. What is actually blurred and 
misadjusted is the font's design. 
However, thicker stems require a 
larger x-height to maintain the proper 
font weight, so there is a lower limit 
to the size at which contrast can be 
implemented on a screen font. 

Spatial Frequency 

I have discussed visual spatial fre- 
quency as a means of estimating the 
visual system's limits of sensitivity, but 
the lower spatial frequencies in text 
are even more important. Many psy- 
chophysical experiments suggest that 
the human visual system is most sen- 
sitive to spatial frequencies in the 
range from 2 to 6 cycles per degree 
of visual angle. A line of text contains 
multiple spatial frequencies; the fun- 
damental one is the regular alterna- 
tion of black vertical stems with inter- 
vening white counters (the space in- 
side a letter like n or o) or inter-letter 
spaces. 

Estimates of the fundamental 
spatial frequencies of printing types 
at text sizes show a range from 4 to 
6 cycles per degree of visual angle, 
which is within the range of the visual 
system's peak sensitivity. When large 
text sizes (such as those used in lux- 
ury books where typographic econ- 

[continued) 



260 BYTE • JANUARY 1985 



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Ordering Information: Check, Money Order (payable to MOUNTAIN VIEW PRESS, 
INC.), VISA, MasterCard, American Express. COD's $5 extra. Minimum order $15. 
No billing or unpaid PO's. California residents add sales tax. Shipping costs in US 
included in price. Foreign orders, pay in US funds on US bank, include for handling 
and shipping by Air: $5 for each item under $25. $1 for each item between $25 and 
$99 and $20 for each item over $100. All prices and products subject to change or 
withdrawal without notice. Single system and/or single user license agreement 
required on some products. 






MOUNTAIN VIEW PRESS, INC. 

MOUNTAIN VIEW, CA 94040 (415) 961-4103 



PO BOX 4656 



Inquiry 246 



JANUARY 1985 • BYTE 261 



FONT DESIGN 



omy is not a factor) are included in the 
estimates, the range expands to in- 
clude 2 and 3 cycles per degree, the 
remaining area of peak sensitivity. 
Type size and spacing are not ar- 
bitrary; they have been carefully 
tuned to the mechanisms of the visual 
system by centuries, even millennia, 
of careful experimentation. Screen 



fonts should also be tuned to this 
band of fundamental frequencies. 

A failing common to many screen 
fonts is spacing between letters that 
is too tight in some combinations, too 
loose in others, and generally ir- 
regular. Irregular spacing between let- 
ters is faddish in advertising typo- 
graphy, where it serves to attract at- 



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C Productivity Series— 






The Professional's Edge 




"V 


Blaise Computing has a ♦ C VIEW MANAGER'" is 

range of programming aids for our display screen manage- 
the most popular C compilers in ment system that makes 
the IBM environment that no screen development and doc- 
serious system developer should umentation much faster. It 
be without. These packages help comes with a complete 
you to easily access advanced 1 ibrary of C functions which 
capabilities of the hardware and use the screensyouhavede- 


>• 


V 


operating system, and to finish veloped to recall and display 
your projects with a substantial information, capture and 
saving of time and effort. With validate field data entry, and 
software development costs and provide context-relevant 
pressures as great as they are, help files. $275 
can you afford not to take advan- ♦ AS YNCH MANAGER'" is a 
tageofthe finest tools available? library of interrupt-driven 
♦ C TOOLS'" puts advanced routines providing a general 
string handling functions at interface to both COM ports 


V 


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your disposal and provides a for your asynchronous corn- 
high-level interface to all munications applications. 
BIOS functions from your C Introductory price of $175 
program. Complete screen includes all source, 
handling, graphics primi- All of these products may be 
tives, and a substantial group used by developers with no 
of useful, general-purpose royalty payments to Blaise Corn- 
functions are also featured . $125 puting. Source code either 


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♦ C TOOLS 2 ,M lets your pro- comes with the package, or is 
gram perform all the ad- available. We support Lattice, 
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interrupt handling, and dy- dite your order or to obtain fur- 
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all done "right." Buffer and directly, 
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BLAISE COMPUTING INC. 




2034 Blake Street Berkeley, CA 94704 






(415) 540-5441 




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tention to sales pitches that the 
reader would otherwise ignore, but 
analysis of several centuries of typo- 
graphic texts demonstrates that open, 
rhythmic spacing is the most read- 
able. 

Proportion 

Because the alphabet is a system, the 
proportions of the letters must be 
tuned to each other and to the overall 
proportions of the alphabet design. 
The widths of the letters must con- 
form to three main criteria: the x- 
height of the alphabet design, the op- 
timum spatial frequency of the text, 
and the historically evolved letter 
shapes. 

The average width of the letters in 
relation to the size of the font deter- 
mines the fundamental spatial fre- 
quency of the font at a particular 
reading distance. This frequency 
should be within a certain range, as 
discussed earlier. Moreover, the dif- 
ferent widths of the letters in relation 
to each other help the reader dis- 
criminate their forms and permit a 
rhythmic spacing pattern. 

Proportionally spaced fonts are 
more legible than monospaced fonts 
because of the more finely tuned pat- 
tern of the text. When monospaced 
fonts are necessary, a font designer 
should compensate for the irregular 
rhythm and distorted proportions, but 
such compensation is possible only 
up to a point. The limitations of 
mechanical typewriter technology 
created a need for monospaced fonts, 
but these limitations are not neces- 
sary in digital typography. The less 
legible monospaced fonts can now be 
retired from most applications. 

Differentiation 

Serifs act as flags on character shapes 
to aid in differentiation. Note that in 
a sans serif (i.e., without serifs) font, 
an r followed by n is easy to confuse 
with an m whereas the same com- 
bination in a serifed font is less easy 
to confuse with m. Similar demonstra- 
tions are possible for other letter 
combinations. Therefore, while sans 
serif fonts might seem more modern, 

{continued) 



262 BYTE- JANUARY 1985 



Inquiry 41 



.- •* 



/ 



i 



LURKING 



That power cord may look 
innocent. But it could suddenly turn 
against your PC 

It could, for example, hurl a 
power spike from static or lightning into its delicate 
circuitry. Wiping out its memory. Or destroying a defense- 
less component. 

Don't risk it. Get a 
6-outlet Wire Tree Plus™ surge 
protector from NETWORX™ It 
guards against spikes. Filters 
out RF interference And it's i 
the only device with two jnl ^ 

phone jacks to protect 
modems against surges. 

Other unique features in- 
clude separate switches for 
the CPU and peripherals 
and a bracket that 
mounts under the front of the workstation. 
The illuminated switches are easy to reach, and yet 
recessed, so you can't accidentally shut down power 
and lose data. 

If you don't need 6 outlets, pick up our 4-outlet 
WireTreeT M Or our single-outlet Wire Cube™ 
that's ideal for portable computers. 

That'll take care of power surges. But what if 
your foot gets tangled in a power cord? Prevent 
this potential disaster with the Wire Away™ It 
stores up to four 18-gauge wires and ends the 
hazardous mess of dangling cords. 



BEHIND EVERY 
COMPUTER 

ISTHE POWER 

TO DESTROY 

ITSELE 






NETWORX computer station accessories. And 
don't go home without them. 







C3C3 




Computer Station Accessories 



Inquiry 2 56 









^F? 



JUL I I J 1.1 1 1 I 1 t 1 .1 i 
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COMPAQ' is a registered trademark and COMPAQ DESKPRO" is a trademark of COMPAQ Computer Corporation. IBM' is a registered trademark of International Business Machines Corporation. 
UNIX is a trademark of AT&T Bell Labs. "'1984 COMPAQ Computer Corporation. All rights reserved. 



264 BYTE • JANUARY 1985 



■■■■■■■■ ■■■ ■■■■■■ 




mmmmm 




^T't i ) ■ j r i" t tiii 
// / // i ' i" r r r-r" i i i i i . 



Now you don't have to compromise to 
have it all in a personal computer. 

Pick the new COMPAQ DESKPRO ' 
over the IBM* PC or XT and you get a 
lot more computer for your investment. 

One that runs thousands of the most 
popular programs right of f the shelf— 
at speeds two to three times faster. One 
with a dual-mode monitor (amber or 
green) to display text and graphics. One 
with exclusives like internal tape backup 
and shock-mounted storage system. 

Pick the COMPAQ DESKPRO over 
the IBM AT and you get comparable 
performance without sacrificing any 
PC or XT compatibility. . . but for a lot 
less investment. 

And, of course, you can start having it 
all with your COMPAQ DESKPRO 
today It's available now 

In short, COMPAQ DESKPRO is 
the only personal computer that can 
grow from a PC to XT to AT level 
of functionality —easily, affordable 
compatibly 



It simply works better. 



Conf igure it the way you want: With 
one or two diskette drives. One or two 
fixed disk drives. Or new options like 
a 30M-byte high-performance fixed disk, 
high-speed 8087-2 co-processor and 
internal tape backup for either the 
lOM-byte or 30M-byte fixed disk. 

UNIX -based operating systems? We 
run them today PC DOS Version 3.0? 
That, too. Networking? Can do. Multi- 
users? No problem. Multi-tasking? Easy 
Tape backup? It's inside. High-resolution 
text and graphics? Standard Two speeds? 
Exclusive. 

When you pick the COMPAQ 
DESKPRO, you do have it all— from 
the company that makes the best-selling 
portable business computer in the world. 
For a free brochure and the location 
of your nearest Authorized COMPAQ 
Dealer call 1-800-231-0900, Operator 2 or 
Telex 795437 COMPAQCOMP HOU. 
In Canada, call 416-449-8741. 



co mPAa 



JANUARY 1985 • BYTE 265 



Every option you'll ever need. 

You're looking at ULTRAFRAME?" 
a powerful 8/16 bit multiprocessor 
you can configure to handle any 
application. 

It's the one system that can tackle 
your toughest jobs today with the 
capacity to grow up to 32 users or 
tasks — within the same chassis- 
Get 5" & 8" Winchester drives from 
10-120MB (formatted). Also, 14" 
models from 145MB to 1,160MB. And 
backup systems appropriate to any 
system you design. 

Now run both MS-DOS 
and CP/M software. 

Our system lets you network IBM 
PC's, compatibles or other popular 
PC's into a serious multiuser business 
system. Tie PC's into the speed of an 



S-100 buss with inexpensive boards 
and a coaxial cable. 

Each PC can tap network resources 
including hard disks (10-300MB) and 
system printers with spooling. 

The PC's gain the proven network 

FRONT 

I n ~ n — i 



BACK 




management capablilties of 
TurboDOS™. Run MS-DOS™ and 
CP/M 86 software plus true multiuser 
accounting and data base applications. 

The industry's longest warranty. 

We've built the ULTRAFRAME to 
last — and backed it with a full three 
year warranty. Plus, we give a level 
of old-fashioned factory support you 
won't get from anyone else. And on- 
site maintenance is available nation- 
wide through 45 service centers. 



ULTRAFRAME 




INDEPENDENT BUSINESS SYSTEMS 

Call collect (415) 443-3131 TWX: 910-386-6003 IBSNET 
5915 Graham Court, Livermore, CA 94550 



The multiuser system 

that also networks 

IBM PCs. 



■ MAINFRAME-LIKE 
CHASSIS & POWER 
SUPPLY ENGINEERING. 

Continuous-duty cooling 
capacity. Solid state power 
supply circuitry for max. 
reliability. 




H FAST, HIGH CAPA- 
CITY HARD DISKS. Full 
range of 5", 8" and 14" 
Winchester models from 
10 to 1160 MB, including 
new high-capacity 5" 
drives. 



■ UP TO 32 USERS - 
IN PARALLEL. Add 8 or 

•16 bit SLAVENET™ pro- 
cessor boards — each a 
complete Z80 or 80186 
computer — to maintain 
fast, multi-user perform- 
ance. Both 12 and 20 slot 
S-100 models available. 



■ LOW COST PER 
USER. Higher perform- 
ance and lower cost per 
user than any micro net 
work. True multi-user, 
multitasking operation 
plus shared resources. 



TurboDOS w 
' 2000. 



i registered trademark of Software 



■ CHOICE OF BACKUP 
SYSTEMS. Integral 5" or 
8" floppies to 1.2 MB. 
BACKSTOP™ video ar- 
chiving; BACKSTOP II™ 

■ FAST, MULTIPRO- start/stop tape. 

CESSOR OPERATING 

SYSTEMS. IBS p-NET™ 

and TurboDOS — access 

to all UCSD Pascal™ and 

CP/M™ software. 

IBM PC is a registered trademark of IBM. ULTRAFRAME is a registered trademark of IBS, Inc. 

CP/M and CP/M 86 are registered trademarks of Digital MS-DOS is a registered trademark of Digital Resean 
Research. 



FONT DESIGN 



they are less legible because they lack 
these significant distinguishing 
elements. 

The construction of Latin-based 
alphabetic characters also aids in dif- 
ferentiation. These characters are like 
molecules constructed from simpler 
atoms. The primitive atomic elements 
are called strokes because they were 
originally a single motion of a pen or 
brush. The various kinds of strokes in- 
clude verticals, horizontals, curves, 
and diagonals. The alphabet can be 
subdivided into groups of letters 
made up of particular primitive 
elements. 

For example, in the lowercase, the 
letters n, m, h, r form one group 
based on the vertical straight stem 
and arch; o, c. e form a group based 
on the curved bowl; b, d, p, q form 
a related group based on the curve 
plus straight; and v, w, x, y form a 
group based on the diagonal. These 
groups help the reader to distinguish 
the letterforms. 

Faced with the problem of screen 
jaggies, which are worst on curved 
and diagonal strokes, some font de- 
signers have reduced the letter 
shapes to straight vertical and hori- 
zontal elements. While this technique 
reduces the effect of the jaggies, it 
also destroys the legibility of the font 
by eliminating two of the four primi- 
tive elements and collapsing the form 
groups together. 

When every letter in the alphabet 
resembles every other letter, the basic 
principle of discrimination is lost. 
While the jaggies are a problem, it is 
preferable to maintain the traditional 
shape primitives and keep the letter- 
forms unambiguous, even if the diag- 
onals and curves show jaggies. 

Gray Scaling 

Low-resolution screen fonts are 
another problem for the designer. 
One technical response to this prob- 
lem is to increase the display informa- 
tion from one bit per pixel (the black 
and white bit-mapped display of cur- 
rent workstations) to several bits per 
pixel (the gray-scaled display of some 
> experimental and color workstations). 

[continued] 







.TM 



The Quick Silver Fox 
Jumps Over The Big Blue Dog. 



We really hate to pick on the 
big guys but compared to the 
Silver Fox your basic IBM-PC™ 
is an overpriced dog. 

156k RAM 

Why? Well, for starters, your 
basicSilver Fox comes with 256k 
of RAM which acts like a disk 
drive so that more of your soft- 
ware is accessed at the speed of 
light rather than the speed of a 
mechanical drive head. 

1.6 Megabytes 

Youalso have more than twice 
as much software to access be- 
cause the Silver Fox comes with 
dual 800k disk drives for a total 
of 1.6 Megabytes. Yet the Silver 
Fox can read and write to all 
popular PC formats. 

Free Silverware 

1. MS-DOS 

2. HAGEN-DOS 

3. M-DISK 

4. WordStar™ 

5. EasyWriter 

6. DataStar 

7. ReportStar 

8. FILEBASE 

9. CalcStar 

10. Color Graphics Basic 

11. MailMerge 

12. SpellStar 

13. 25 Games, graphics 
and utilities 

The best free software bundle 
in the business, and the Fox will 
run some programs written for 
the IBM-PC like dBase II and 
Multiplan, and programs written 
for Sanyo's new MBC-550 series. 

Reliability 

Because the Silver Fox is 
born on a totally automated 
production line in Japan it is 
inherently more reliable than 



systems built by hand. The Fox 
is burned and tested for 14 days 
in Japan, and further tested after 
final assembly here in the good 
old U.S.ofA. 

One Year Warranty 

The Silver Fox is built better 
so we can back it with a limited, 
one-year warranty, four times 
longer than IBM. We're Scotts- 
dale Systems and since 1980 
we've shipped over $10,000,000 
of microcomputer equipment 
directly to microcomputer users. 

Because we deal directly with 
users, we think we have a better 
idea of what you want. So the 
Silver Fox includes graphics 
with twice IBM's resolution, a 
printer port, a keyboard with a 
big return key, and a 12", high- 
resolution monitor as standard 
equipment. 

Of course, you could spend 
$4729 at Computerland for an 
IBM-PC that will perform almost 
as well as a Silver Fox. But why 
bother when you can call 

1 C*02) 941-5856 

and get your 

$1398 

to perform like $4729? 

For additional information call 1 (602) 941-5856, or write 

Scottsdale Systems. 617 N Scottsdale Road #B, Scottsdale, 
AZ 85257 

IBM PC pru e is based on a phone quote from the 
MeSH A* Computerland on July 30 1984 Price included 
256k RAM dual 360K drives (800K s weren t available), 
software and a graphics monitor 

Trademarks Silver Fox and Hagen DOS. Scottsdale 
Systems Ltd IBM PC International Business Machines 
Corporation Wordstar Calcsiar, Mailmerge. Spellstar 
rintl Inlosior Micropro International MS-DOS Multiplan 
Microsoft Corpotanon Filebase FJWDP Software Inc 
dBASE II Ashton Tate 

Ordering Telemarketing only, all prices arefor cash. 
FOB Scottsdale, price subject to change, product 
subject to limited supply Visa Mastercard add 3V AZ 
residents add 6"c. Returned merchandise sub|eci tc a 
20"p restocking fee Personal company checks take up to 
3 weeks to clear No C D s or A P s 



FONT DESIGN 



Because they contain more informa- 
tion, gray-scaled fonts can better 
depict traditional letterforms, at least 
when viewed in isolated words and 
phrases. Also, the low-contrast edges 
of curves and diagonals reduce the 
visual effect of the jaggies. The letter- 
forms appear smoother. 

Some researchers have hypothe- 
sized that gray-scaled text would be 
more readable than bit-mapped text. 
Other evidence suggests that the eye 
relies upon high-contrast edges to 
focus the text image during reading. 
The soft, low-contrast edges of gray- 
scaled fonts might actually reduce 
legibility by preventing the focusing 
mechanism from finding a sharp 
edge. It is not yet certain whether the 
conservative eyes of readers will ac- 
cept gray-scaled text, nor whether it 
is physiologically more difficult to 
read despite its less jagged 
appearance. 



Gray-scaled fonts are also more ex- 
pensive to display and more difficult 
to design. They require more bits of 
memory to store the gray value at 
each pixel, and more elaborate and 
stable display electronics. The shapes 
of gray-scaled letters are more depen- 
dent on precise control of brightness 
and contrast on the display. 

Screen and Printer 

The foregoing principles have concen- 
trated on designing screen fonts for 
optimum readability (for more infor- 
mation, see "Digital T/pography" by 
Charles Bigelow and Donald Bay, 
Scientific American, August 1983). 
However, text is also read as printer 
output on paper. The relation be- 
tween screen text and printer text is 
the subject of intensive research, with 
many recent efforts attempting to 
integrate screen and printer in what 
are called "what you see is what you 



get" (WYSIWYG) editing and layout 
systems. 

The WYSIWYG principle is that the 
screen should show exactly how the 
printed document will look. 
WYSIWYG text editors and document 
formatters usually attempt to show 
different typeface styles in different 
sizes, spacings. and page organiza- 
tions. 

The usual model for WYSIWYG sys- 
tems is traditional typography, which 
offers so vast and complex a range of 
possibilities that present WYSIWYG 
systems can offer only a reduced 
subset. This is true because 72-line- 
per-inch screens have only one-fourth 
the resolution of 300-line-per-inch 
printers, and one-tenth the resolution 
of 720-line-per-inch typesetters. 

Usual WYSIWYG implementations 
fall into one of two categories: 
bottom-up or top-down. Bottom-up 

[continued] 



New 64K SBC 

Requires no terminal. 
Includes Video Controller 
and CP/M2.2 - 
Only 

s 375. 

Single board computer runs 
with any size floppy drive- 




Hardware 

• 6 MHz CPU 

• Graphics/Alpha 
Video Controller 

• 2 Serial Ports 

• 4 Parallel Ports 

• I/O Expansion 

• 64K RAM . 

CP / M is a registered trademark 
of Digital Research 

Substantial OEM 



Software 

• Alpha Terminal Driver 

• Floppy Disk Driver 

• Source Code Provided 

• CP/M® 2.2 

Call our Toronto Office today: 
(416) 745-7214 Megatel 
For information write: 
1051 Clinton St., 
Buffalo, NY. 14206 

Discounts Available 



Other SBC models available include 
hard disk controller and more RAM 



Subscription Problems? 



^USWILj^ 




We want to help! 



// you have a problem with your BYTE 

subscription, write us with the details. We'll 

do our best to set it right. But we must 

have the name, address, and zip of the 

subscription (new and old address, if it's a 

change of address). If the problem involves 

a payment, be sure to include copies of the 

credit card statement, or front and back of 

cancelled checks. Include a "business 

hours" phone number if possible. 

BYTE 
Subscriber Service 

P.O. Box 328 
Hancock, NH 03458 



268 BYTE • JANUARY I985 



Inquiry 405 



The only Modula-2 native code compiler 

for 8086/8088-based machines 

and \AX systems. 



All (he strengths of Pascal, plus 
improvements in every respect. 

Modula-2 is Niklaus Wirth's second 
generation programming solution. All 
the best features of his Pascal language 
plus major features f or true modularity, 
support for multi-tasking, type check- 
ing between program modules, syntax 
improvements, and features for in- 
creased portability (to name just a few). 

A complete program development 
system. 

LOGITECH MODULA-2 includes a com- 
plete implementation of Wirth's design, 
plus 8086 large model support and ad- 
ditional LOGITECH modules (including 
display handling and dynamic string 
handling). 

A complement of powerful debug- 
ging tools— including compile-time er- 
ror checks and symbolic debugging— is 
included. 



Professional support from the 
people who wrote LOGITECH 
MODULA-2. 

LOGITECH'S Modula-2 is a professional 
development tool, backed by the most 
professional support available for Mod- 
ula users. 

LOGITECH'S complete Moclula 
family: 

- MODULA-2/86™ native code 8086/ 
8088 compiler 

■ M0DULA-2/VMS ,M VAX-resident 
compiler 

■ M0DULA-2/VX86™ VAX to 8086/8088 
cross compiler 



Don't start another project 
without considering 
LOGITECH MODULA-2. 

Trademarks: M0DULA-2/-86. MODUIA-2/VX86WODULA-2/VMS— LOGITECH. Inc 
Registered Trademarks: VAX— Digital Equipment Corporation 

Inquiry 208 




mw™M<m 



W/i ' — -af* -^m aflMrrm»tfff%\»^ 


5g^5y— — ■ lb order, or lor more inlormation, |t 

^r3p_ J rail or write: R t ";. -■■ ■- — ■■ ■■■ ■■ . 

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=£3 S Redwood City, CA 94063 Ssj Jp - 

E "^[. — In huroperoiUarl: Willy Slri^cr. ~ ~ 

i=sl&~ _ ::= LOGITECH SA, Switzerland. -—-•--- ~~—— — ^— — i— 
^3* — - (021)77 45 45 g 

ggfr^^affl LOGITECH:— — 



Inquiry 214 



magnum 
p.c. 



800-544-4354 




GA Residents OS 
(404)441-3112 IVJ^/ 



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FONT DESIGN 



WYSIWYG systems start with screen 
resolution and force the printer to 
conform to the limitations of the 
screen. In the simplest case, each 
screen pixel is mapped one-to-one 
onto the paper output by the printer. 

While this provides a certain Carte- 
sian satisfaction, since it can be 
logically demonstrated that the 
printer page is exactly like the screen 
display, the two images will actually 
appear very different. As I discussed 
earlier, the screen characters are 
eroded by the characteristics of the 
display technology. However, the 
printed characters are either em- 
boldened, as by ribbon-spread on a 
dot-matrix printer or by toner effects 
on a black-writing laser printer, or not 
eroded to the same degree as the 
screen fonts, as by a white-writing 
laser printer. 

Thus, if a font is tuned to the op- 
timum weight and contrast on the 
screen, it will appear too dark and too 
low in contrast on the printout. Con- 
versely, if the fonts are tuned to the 
printer, they will appear too light and 
too high in contrast on the screen. 
This is unavoidable. What you see is 
not what you will get at the present 
level of display and printer tech- 
nology. 

A second problem with bottom-up 
WYSIWYG is exaggeration of jaggies 
on the printout. Aliasing on the 
screen is somewhat ameliorated by 
the soft intensity contour of the CRT 
writing spot. The spot does not have 
sharp edges, nor is it square or rec- 
tangular; instead it is blurry and 
round. The low-contrast edges of the 
pixels tend to soften the apparent jag- 
gies. Printers, however,, produce a 
high-contrast spot that clearly renders 
the edges of the jaggies. The jaggies 
become even more apparent to the 
reader, since the human visual system 
tends to enhance edges. 

On a laser printer that has several 
times the screen's resolution, several 
printer pixels render a single screen 
pixel. This emphasizes the rec- 
tangularly of the raster and further 
enhances the jagginess of the digital 
artifacts. Printer fonts that simulate 
screen resolutions look noticeably in- 



ferior to printer fonts that are opti- 
mized to the full resolution and imag- 
ing characteristics of the printer. 

Top-down WYSIWYG systems store 
fonts as high-resolution master 
images. These are usually outlines 
that can be scan-converted to raster 
images to represent arbitrary sizes at 
arbitrary resolutions on screens, 
printers, or typesetters. This device- 
independent method is intellectually 
appealing, since the same design pro- 
duces all characters at the writing 
resolution of each target device. 

However, low-resolution and high- 
resolution fonts will not be truly the 
same. In top-down systems, the fonts 
on low-resolution devices become the 
inferior ones, both in comparison to 
high-resolution versions and to op- 
timized low-resolution designs. The 
current generation of master-image 
data structures and associated scan- 
conversion algorithms can do good 
automatic rasterization at bit-mapped 
resolutions of around 1200 lines per 
inch, and an acceptable job at 600 
lines per inch, but only a mediocre to 
inadequate job at 300 lines per inch, 
an incompetent job at 1 50 lines per 
inch, and a hopelessly botched hash 
at 75 lines per inch. 

Conclusion 

The personal workstation offers 
powerful tools to the worker, but 
these tools are dependent upon typo- 
graphy: legible fonts in effective ar- 
rangements. Unfortunately, traditional 
typefaces cannot be successfully re- 
produced at current display screen 
and printer resolutions. To optimize 
legibility, new fonts must be designed 
for the digital media. 

These fonts will be most effective if 
they take into account the nature of 
the human visual system, the logical 
and historical principles that shaped 
present-day alphabets, the character- 
istics of current digital imaging 
devices, and the conceptual structures 
underlying typographic variations and 
arrangements. The new technology 
requires a new typography that pre- 
serves the fundamental features of 
literacy but expresses them with new 
clarity in a new medium. ■ 



270 BYTE • JANUARY 1985 



The PC Plotter: 

It will change the way 

business looks at graphics. 



The lowest-priced professional plotter on the 
market today is Houston Instrument's new four- 
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Price — A multi-pen, compact, single-sheet 
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For the name of your closest PC Plotter 
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(512)835-0900. Outside Texas call 800-531-5205. 
In Europe, contact Houston Instrument, Belgium 
NV., Rochesterlaan 6, 8240 Gistel, Belgium. 
Tel. 059-27-74-45, Tlx. 846-81399. 

Inquiry 164 




_ DdoddsSodq 

£ instrument 

*U.S. suggested list price. 




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JANUARY 1985 -BYTE 273 



SuperSoft Languages 

When Performance Counts 



A programmer's most 
important software tool is 
the language compiler or 
interpreter he uses. He has 
to depend on it to work 
and work well. 

At SuperSoft, we believe it. 
That's why we offer three 
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SuperSoft FORTRAN, 
SuperSoft C, and SuperSoft 
BASIC. They answer the 
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SuperSoft 
FORTRAN 

With large code and data. 

SuperSoft FORTRAN version 2.0 
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and PC DOS. It gives you the 
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It allows double precision and 
complex numbers, full IEEE float- 
ing point, and a full range of other 
important features for the serious 
FORTRAN programmer. Both 
8087 support and a RATFOR pre- 
processor are optionally available. 
FORTRAN (CP/M-80 & 86, MS 

DOS, PC DOS): $325 
8087 support $50 RATFOR: $100 



SuperSoft A 

A true Ada* subset 

SuperSoft A is a completely standard 
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porating approximately 63% of the 
standard Ada syntax and including 
such important features as packages 
and separate compilation. For CP/ 
M- 80 microcomputers: $300. 

SuperSoft C 

SuperSoft C is a high-powered, full- 
featured C compiler designed for 
serious C applications. It is fast- 
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and it is packed with more than 135 
library functions (all delivered in 
source code form). SuperSoft C 
produces optimized assembly code, 
and object code can be ROMed. 

SuperSoft C (for CP/M-80, CP/M-86, 
MS DOS, PC DOS): $350 





SuperSoft 
BASIC 

The SuperSoft BASIC compiler lets 
you get serious with business and 
financial programs. It uses BCD 
math to give you highly accurate 
results for demanding applications. 
SuperSoft BASIC is a true native 
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interpreter. And an additional 
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SuperSoft BASIC Compiler (for 
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$300 

Also available for programmers: 

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To order call: 800-762-6629 

In Illinois call 217-359-2112 



In conjunction with SuperSoft, Supersoft FORTRAN was developed by Small Systems Seivices, 
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Japanese Distributor: ASR Corporation International, TBL Building, 7th Floor, 1-19-9 Toranomon, 
Minato-Ku, Tokyo 105, Japan Tel. 035025550. Telex 222-5650 ASRTYO J. 

•Ada is a trademark of the Department of Defense 
PC DOS is a trademark of International Business Machines. 
MS DOS is a trademark of Microsoft. 
CP/M-80 and CP/M-86 are trademarks of Digital Research, Inc. 

274 BYTE • JANUARY 1985 



SuperS ft 

SuperSoft, Inc., 1713 S. Neil St., 
P.O. Box 1628, Champaign, 1L 61820 



Inquiry 339 



by Bruce D'Ambrosio 



Expert Systems- 
Myth or Reality ? 



The Department of Defense has 
identified artificial intelligence 
(AI) as one of the 10 most 
critical technologies to pursue in the 
remainder of this century. The 
Japanese have launched an ambitious 
fifth-generation computer project with 
AI's application, "expert systems," as 
one of its cornerstone technologies. 
The British and the French have re- 
sponded with major national projects 
of their own. And the United States, 
currently the leader in this area, 
recently increased funding for basic 
research in AI. But what are expert 
systems, what is all the hoopla about, 
and is it justified? 

A Short History of AI 

In the beginning there was the com- 
puter—and it was very difficult to pro- 
gram. Then John Backus et al. in- 

Artificial intelligence 
is being applied 



vented FORTRAN and the world of 
numeric programming was born. 
Shortly afterward, John McCarthy in- 
vented LISP and, with it, symbolic 
programming came into existence. In 
the same way that FORTRAN was an 
outgrowth of numerical analysis, LISP 
was basically an outgrowth of abstract 
mathematics, in particular Alonzo 
Church's lambda calculus. The result 
of this was that early users of LISP 
spent most of their time in search of 
those things that abstract mathemati- 
cians seem to love best— elegant and 
terse solutions to broad classes of 
problems. During the 1960s computer 
scientists developed a number of 
general problem-solving mechanisms, 
and in the late 1960s and early 1970s 
they tried to apply these mechanisms 
to "real" problems. For the most part, 
these attempts resulted in dismal 




failure. In fact, the results were so 
disappointing that one country, Great 
Britain, completely abandoned its AI 
research and development effort. 

What was the problem? Consider 
one particular case— that of determin- 
ing the molecular structure of a com- 
pund when given its chemical formula 
and other information. This can be 
formulated as a "generate and test" 
problem. The system consecutively 
generates each of the possible struc- 
tures the compound can have, based 
on its formula. It then tests the can- 
didate structures against the other 
evidence to determine which one is 
correct. This algorithm works fine for 
a compound with few possible struc- 
tures. However, the number of possi- 
ble structures for any compound of in- 
terest to a chemist runs into the 
millions, and all hope of ever finding 
a solution vanishes, even on the 
fastest computers. The solution to this 
problem is not faster computers. Add- 
ing a single atom to a compound can 
increase the number of possible struc- 
tures by a factor of hundreds, and 
computers are only getting faster by 
a factor of 10 or so each decade. 

Researchers realized that what was 
needed was knowledge— enough in- 
formation to understand the subject 
at hand. If, instead of generating all 
possible structures, the program only 
generated those that were physically 
realizable, the number of candidate 
structures would drop from millions 
to thousands. It would then become 

(continued) 
Bruce D'Ambrosio (2156 Word St.. #4, 
Berkeley, CA 94705) has a B.S.E.E. and 
M.S. from the University of California at 
Berkeley and is still there working toward his 
Ph.D. He lists motorcycles as his hobby. 



ILLUSTRATED BY CHRIS SPOLLEN 



JANUARY 1985 • BYTE 275 



EXPERT SYSTEMS 



possible to test all candidates against 
the evidence to determine which 
would be the correct one. This is the 
approach that was taken in Dendral. 



a landmark AI system for elucidating 
chemical structure when chemical for- 
mula and mass spectrograph evi- 
dence are known. 



Personal Computers 
and Expert Systems 



Many people assume that A I and 
large computers are synony- 
mous. This is less true today than it was 
in the past. For expert systems in par- 
ticular, one of the promises is inexpen- 
sive distribution of expertise. 

Much of the expert-systems develop- 
ment now taking place follows a fairly 
standard model. First, a production- 
rule interpreter is written in LISP, then 
the actual rules for an expert system 
are written. This has two impacts on 
the development environment. First. 
LISP itself is usually interpreted That 
means that the final production rules 
are interpreted by a program that is 
also executed interpretively. and things 
run slowly. For this reason AI re- 
searchers like fast central processing 
units. Also, even if the production-rule 
interpreter is fairly small, the LISP in- 
terpreter must be in memory simulta- 
neously (as well as all of the produc- 
tion rules themselves), and most 
serious LISP systems require at least 
I megabyte of main memory to run 
well, lb my knowledge the only LISP 
systems available for computers with 
64K bytes (or smaller) of address space 
are toys. Recently, however. Gold Hill 
Computer announced a LISP imple- 
mentation for IBM PCs with memories 
of at least 2 56K bytes. While details 
about this system are still sketchy, this 
seems like it might be a product for 
building real systems. Still, interpreted 
LISP on a 5-MHz 8088 processor is 
almost useless because of its slowness. 
However. Gold Hill also says it will 
release a LISP compiler in the near 
future, and the system would then 
become a viable development tool. 

More useful, but also more expen- 
sive, are the major research LISP sys- 
tems that have been ported to several 
of the 68000-based UNIX systems cur- 
rently available. However, with ade- 
quate memory (2 megabytes) and a 
hard disk, these cost $15,000 and up. 

Another alternative is to abandon 



LISP. A major reason for building ex- 
pert systems in LISP is that writing in- 
terpreters in it is easy. However, if 
you're more concerned with building 
rule-based systems than with experi- 
menting with rule interpreters, you 
should be able to implement a rule in- 
terpreter in a language that makes 
more modest demands on computer 
resources. Several research projects 
have been conducted in which the sys- 
tem was designed in a LISP-based en- 
vironment and then ported to either 
BASIC (Puff— a pulmonary diagnostic 
program developed by Stanford and 
UCSF) or FORTH (Delta/Cats-a loco- 
motive diagnostic program developed 
at General Electric research). Both sys- 
tems now run on a small PDP-11 and 
I have heard that Delta/Cats is being 
ported to an IBM PC. Also, rumor has 
it that IBM is developing an expert- 
system shell (rule interpreter and 
associated utilities) in Pascal for opera- 
tion on a variety of their computers. 
Taking this approach, you should be 
able to develop a consultation-style ex- 
pert system on a computer with from 
1 28K bytes to 2 56K bytes of memory. 
Backward-chaining interpreters of the 
Mycin sort can be written so that their 
computation demands are also rather 
modest. In fact, consultation-style 
systems usually spend most of their 
time waiting for user input, rather than 
computing. 

Disk facilities are not crucial, since 
many expert systems load all data and 
rules into memory before they begin 
operation. Again, 5I2K bytes to I 
megabyte of on-line storage should be 
adequate for both the rule interpreter 
and the text of several hundred rules. 
Most expert systems seem to require 
from 500 to 2000 rules. In fact, some 
of the new expert-systems producers 
have taken this approach. These start- 
up companies usually target IBM PCs 
as the hardware for their developed ex- 
pert systems. 



A second dominant theme in AI. 
"pattern-directed inference." was de- 
veloped in the early 1970s. During 
this period. AI returned to its roots, 
so to speak, to pick up a technique 
for higher-level symbolic-program 
organization. This technique is alter- 
nately called pattern-directed in- 
ference or "production rules." Once 
the need for extensive domain- 
specific knowledge was recognized, 
pattern-directed inference seemed to 
provide an answer to the dual ques- 
tions of how to represent this knowl- 
edge inside the computer and how to 
use it. 

The twin themes, then, of extensive 
domain-specific knowledge and pat- 
tern-directed inference dominate ex- 
pert systems work today. 

Knowledge 

It is all very well to say that a system 
needs knowledge, but. by itself, this 
statement is of little use in system 
design. Specifically, it raises two ques- 
tions. First, what kinds of knowledge 
are needed? Second, how will this 
knowledge be used? In some sense, 
a house's furnace thermostat can be 
said to contain knowledge about 
heating houses, but no one would call 
it an expert system. At least three 
kinds of knowledge have been iden- 
tified as useful for symbolic problem 
solving. These are simple domain facts, 
relations between these facts, and 
methods for using these relations in 
problem solving. (Other systems-de- 
velopment-related questions are 
addressed in the text box "Personal 
Computers and Expert Systems" at 
left.) 

To make this taxonomy concrete, 
let's look at an example problem of 
determining where to invest some 
money. (A system that seriously ad- 
dresses this question is far beyond the 
scope of this article. The following 
only suggests how you might use 
expert-systems technology to address 
this problem. Do not judge it for its 
financial acumen.) To simplify the 
problem, consider only three alter- 
natives: a "safe" investment (e.g., 
Treasury bills or certificates of 

[continued) 



276 BYTE* JANUARY 1985 




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Inquiry 18 



JANUARY 1985 -BYTE 277 



EXPERT SYSTEMS 



deposit), blue-chip stocks, and growth 
stocks. Simple facts in this domain will 
include the age of the investor, the 
amount to be invested, and the 
amount already in each of the three 
categories mentioned above. These 
are formalized in figure 1 . In addition, 
you will meet some simple relations 
between these facts to build your sys- 
tem, such as relations between the in- 
vestor's age and the desired amount 
of money in each category Some rela- 
tions that might be in such a system 
are shown in figure 2. Finally there is 
knowledge about how to solve prob- 
lems, given facts and relations. For 
your sample problem, at least two 
strategies are possible. You could ask 
the user for all applicable information 
and use the known relations to 
deduce which investments are appro- 
priate. Or you could try to prove that 
each possible form of investment is the 
proper one and ask the user ques- 
tions as they come up in the course 



of the attempted proofs. 

The first technique is called forward 
reasoning, and the second is back- 
ward reasoning or "backward chain- 
ing." A third possibility often used in 
more complex problems, is a mixed 
strategy, in which both forward and 
backward reasoning are used where 
appropriate. For example, in attempt- 
ing a medical diagnosis, you might 
want to gather initial data first, then 
establish plausible hypotheses to ex- 
plain this data (forward reasoning 
from facts to conclusions), then 
predict unobserved symptoms (back- 
ward reasoning from conclusions to 
facts that would support them) and 
order tests to check for the presence 
of these unobserved symptoms (back- 
ward reasoning again), and finally use 
the test results to confirm or rule out 
the hypothesized diagnosis (forward 
reasoning again). 

Now that you know what kinds of 
knowledge you need to solve the in- 



age The client's age in years 

amount-to-invest Amount the client wishes to add to his investment portfolio 
safe-cash-amount Amount the client has already placed in "safe" investments (e.g., 

T-billsorCDs) 
blue-chip-amount Amount the client has already tied up in "blue-chip" investments 
growth-amount Amount the client has already invested in "growth stocks" 
safe-cash-target Target amount the client should have in "safe" investments 
blue-chip-target Target amount the client should have in "blue-chip" investments 
growth-target Target amount the client should have in "growth stocks" 

enough-safe The truth of the statement "the client has enough cash in safe 

investments" 
enough-blue-chip The truth of the statement "the client has enough cash in 

blue-chip investments" 



Figure 1: Simple facts for the toy investment advisory. 



The client should have a reasonable amount of money in "safe"* investments 
before entering the stock market. 

The client should have a reasonable amount of money in blue-chip stocks 
before venturing into high-risk "growth" stocks. 



Age 


Amount in "safe" 


Amount in "blue-chip" 


< 30 


$1000 


$1000 


30 — 40 


$3000 


$3000 


40 — 50 


$6000 


$4000 


50 — 60 


$9000 


$8000 


>60 


$9000 


$20000 



Figure 2: The informal statement of rules for the toy investment advisory. 



vestment problem, you have to con- 
sider one additional factor. What 
would you like to accomplish with this 
knowledge? Initially, you want to use 
it to recommend an investment, but 
expert systems typically have addi- 
tional goals. Often, expert systems are 
expected to be able to use their 
knowledge to explain why questions 
are being asked and to justify conclu- 
sions once they are reached. They can 
do this because the relationships be- 
tween data items are represented ex- 
plicitly within the system as further 
data, rather than as procedures or 
pieces of code (e.g., Pascal if state- 
ments). Usually you should represent 
these relationships as rules, using a 
technique called pattern-directed 
inference. 

Pattern-Directed Inference 

Pattern-directed inference is actually 
a rather simple technique. The basic 
idea is that you can express knowl- 
edge, especially relational and 
methodological knowledge, as a set 
of "condition/action" pairs. That is, if 
you can prove the condition part of 
a pair, then you get to perform the ac- 
tion part. The condition is a simple 
conjunction of elementary queries; it 
can be thought of as the if part of an 
if... then statement. I hope that the 
word "query" will make you think of 
database queries, which are similar. 
That is, the condition need not be a 
simple test as in the usual 
programming-language if statement. 
Rather, the condition can be more 
general, as in database-query lan- 
guage. For example: 

IF (safe-cash-amount > safe- 
cash-target) and (blue-chip- 
amount > blue-chip-target) 

THEN (invest growth-stocks 
amount-to-invest) 

One difference between this example 
and a standard programming-lan- 
guage if statement is that both the 
"safe-cash-amount" and "safe-cash- 
target" may be unknown when the 
rule is first tested. Additionally, there 
may be several rules that can make 
conclusions about "safe-cash-target." 

[continued] 



278 BYTE • JANUARY 1985 




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Inquiry 351 



JANUARY 1985 • BYTE 279 



EXPERT SYSTEMS 



After you encode knowledge as a 
condition statement, the next step is 
to use it. The most common way to 
do this is to check each rule in turn 
until you find one whose condition 
part is satisfied. Then the action part 
of that rule is executed, and the cy- 
cle starts over. An alternative is to find 
all rules whose condition parts are 
satisfied before you execute any of 
their action parts. When execution 
begins, you choose a starting point by 
using a "conflict resolution" strategy. 
In either case, a production-rule inter- 
preter must implement a two-part 
"recognize/act" cycle. The production- 
rule interpreter must first recognize 
which rules apply and then act (i.e., 
apply the relevant rule or rules). A I 
programmers have implemented 
many variations of this scheme, but 
you have to remember that this style 
of execution couples the rules loose- 
ly. In other words, it generally does 
not matter where you insert a rule in 
a production system. If you want to 
handle a new condition, you simply 
insert the appropriate rule, thus ex- 
panding system capability as in figure 
3. This is in marked contrast to the 
usual "rat's nest" of if statements in 
a typical program. Normal if state- 
ments can be hard to update because 
their control information (that is. when 
they should be used) often is repre- 



sented implicitly by each statement's 
location. 

A variation of this scheme was used 
in Mycin, a medical diagnostic pro- 
gram developed at Stanford. Mycin 
has a built-in back-chaining rule inter- 
preter. That is, if the needed values 
are unknown when Mycin evaluates 
the condition part of a rule, it at- 
tempts to establish them. Mycin does 
this by looking for rules that make 
some assertion in their action parts 
about the unknown values in the con- 
dition part of the original rule. Then 
it looks to see if these rules are ex- 
ecutable. This might, of course, result 
in back-chaining to yet another level. 
Consider the following example. Sup- 
pose you want to show that blue-chip 
stocks are the appropriate investment 
for someone. You might have a rule 
that says: If the amount already in- 
vested in safe 'Ireasury-note-type in- 
struments is greater than the safe- 
investment-target amount, take some 
of that money out of those instru- 
ments and put it into blue-chip stocks. 
Through backward chaining, the sys- 
tem looks for rules that will first 
establish the safe-amount-invested, 
and then the safe-investment-target 
amount. There are no rules that draw 
any conclusions about the safe- 
amount-invested, so the system sim- 
ply asks how much is tied up in "safe" 



IF (enough-s