Full text of "Byte Magazine Volume 10 Number 02: Computing and the Sciences"

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FEBRUARY 1985 VOL.10, NO. 2

$3.50 IN UNITED STATES

$4.25 in CANADA / £2.10 In U.K.

A MCGRAW-HILL PUBLICATION

0360-5280

THE SMALL SYSTEMS JOURNAL

COMPUTING AND
THE SCIENCES

FEATURES : i v

HP Integral Preview L,

Macintosh Office Preview
Circuit Cellar

EPROM Programmer
C-to-Pascal
Servo Simulation
Image Processing

REVIEWS:

Epson Geneva PX-8

Modula-2 Compilers

Janus/Ada

NewWord

E-Mail

MT 160 Printer

^gi j.

d'i

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
nereis 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 He is small —
under SHOO*

Of course, since the lie 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

Wllh a lie. your kid can do something construct ire after school. Like leant to write stories.
Or learn to fly. Or eren learn something slightly more advanced. Like multirariable calculus.

for preschoolers to SAT 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

p®^» chessi

fg.

MATH MAZE Dc^UJore

E^^thf APPLE 1 1 BASIC HANDBOOK ®i , A

•

S8W*

■

"Enzyme Kinetics."

And the Apple He conies 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.

Ail 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

in its optional canying case, the
Ik can even run away from home

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

an extra disk drive when the time comes.

So while your children's shoe sizes
and appetites continue to grow at an
alarming rate, there's
one thing you know
can keep up with them.
Their Apple lie.

To learn more
about it, visit any
authorized Apple dealer.
Or talk to your own
computer experts^
As soon
sis they get home from school.

* The FIC is concerned about price-fixing. So this is only a Suggested Retail Price. You can pay more if you really want to. © I98i Apple Computer Inc. Apple and the/fiple logo are
mistered trademarks of Apple Computer Inc. Stickybear Shapes is a trademark of Optimum Resource. For an authorized A/pie dealer nearest you call (800) 538-y696. In Canada, call

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

CONTENTS

174

FEATURES

■■■■■HflMMMi

Introduction 96

The HP Integral Personal Computer by Phillip Robinson 98

Hewlett-Packard's new all-in-one system makes UNIX truly portable.

Ciarcias Circuit Cellar: Build a Serial EPROM Programmer

by Steve Garcia 104

Steve devises an affordable version of an essential tool for hackers.

The Macintosh Office by ]ohn Markoff and Phillip Robinson 120

AppleTalk networks the Macintosh and its new laser printer.

C to Pascal by Ted Carnevale 138

This program can make the conversion process less tedious.

Simulate a Servo System by Don Stauffer 147

Model complex engineering problems on personal computers.

Introduction to Image Processing by ]effrey L. Star 163

Manipulate images to make them more informative.

THEMES

Introduction 174

The Birth of a Computer conducted by \ohn G Hash 177

In this interview. James H. Wilkinson discusses the building
of a computer designed by Alan Turing.

A LowCost Data-Acquisition System

by Kiyohisa Okamura and Kamyab Aghatfabriz 199

A compromise between cost and quality, this system is adequate for many research projects.

Fourier Smoothing Without the Fast Fourier Transform

by Eric E. Aubanel and Keith B. Oldham 207

The authors present an in-depth look at a technique for removing noise from your data.

Paranoia: A Floating-Point Benchmark by Richard Karpinski 223

'lest the quality of your software, not just its speed.

Modeling Mass-Action Kinetics by Alan Curtis 239

In the future, microcomputers may have a substantial role in major scientific computations.

Viewing Molecules with the Macintosh by Earl j. Kirkland 251

A BASIC program provides 3-D images of complex molecules.

Laboratory Interfacing by Uncoln E. Ford. M.D 263

A medical researcher examines the capabilities and limitations
of an important laboratory device.

Interfacing for Data Acquisition by Thomas R. Clune 269

Three interfaces are compared.

REVIEWS

Introduction 286

Reviewer's Notebook by Glenn Hartwig 289

NewWord by }ohn Wellborn and Hand Reel 291

A word processor from some of the creators of WordStar.

BYTE (ISSN 0360-52801 is published monthly by McGraw-Hill Inc. Founder lames H. McGraw (1860-1948). Executive, editorial, circulation, and advertis-
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in the United States of America.

2 BYTE • FEBRUARY 1985

COVER ILLUSTRATION BY ROBERT T1NNEY

BUTE

February

VOLUME 10. NUMBER 2, 1985

Janus/Ada by Mark J. Welch 295

A nonstandard subset of Ada for MS-DOS and CP/M-80.

The Epson Geneva PX-8 by Rich Malloy 302

It weighs five pounds and features a CMOS Z80 microprocessor.

Two Modula-2 Compilers for the IBM PC by Kevin Bowyer 311

Price is but one of the differences between these implementations.

E-Mail for the Masses by Wayne Rash Jr. 317

Comparing two electronic-mail services. MCI Mail and EasyLink.

Mannesmann Tally MT 160 by Mark J. Welch 325

A dot-matrix unit with a variety of print modes.

Review Feedback 331

Readers respond to previous reviews.

KERNEL

Introduction 337

Computing at Chaos Manor: Troubles by jerry Pournelle 339

jerry's usual look at a variety of products includes a section
on the proliferation of computer books.

Chaos Manor Mail conducted by ]erry Pournelle 359

Jerry's readers write, and he replies.

BYTE Japan: Disks and Printers by William M. Raike 367

Our correspondent in lapan describes important new peripherals
displayed at the 1984 Data Show.

BYTE West Coast. What Next?

by John Markoff, Phillip Robinson, and Ezra Shapiro 371

Our West Coast editors report on Thunderscan,

the ins and outs of windowing, new workstations, and more.

BYTE U.K.: Realizing a Dream by Dick Pountain 379

The Whitechapel Computer Works MG-1 personal workstation is
almost a dream computer— and it costs less than its competitors.

Computers and Law: Copying Mass-Marketed Software

by Robert Greene Sterne and Perry J. Saidman 387

This column debuts with a look at two Lotus lawsuits settled out of court.

Circuit Cellar Feedback conducted by Steve Garcia 393

Steve answers project-related queries from readers.

EDITORIAL: SERVICE AND SUPPORT 6

MlCROBYTES 9

Letters 14

Fixes and Updates 33

What's New 39,421

Ask BYTE 48

Clubs & Newsletters 59

Book Reviews 65

Event Queue 83

Programming Insight 399

Books Received 409

Unclassified Ads 477

BYTE's Ongoing Monitor Box.
BOMB Results 478

Reader Service 479

Address all editorial correspondence to the Editor. BYTE, POB 372. Hancock. NH 03449. Unacceptable manuscripts 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. Trademark registered in the United States Patent and Trademark 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 Si. 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. $1.50. Copying done for other than personal or internal reference use without the permis-
sion of McGraw-Hill Inc. is prohibited. Requests for special 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 WC1R 4E! England.
Subscription questions or problems should be addressed to: BYTE Subscriber Service. POB 328, Hancock, NH 03449

286

337

SECTION ART BY EUGENE MIHAESCO

FEBRUARY 1985 -BYTE

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BYTE

editor in chief

Philip Lemmons
managing editor

Gene Smarte

CONSULTING EDITORS

Steve Ciarcia

Jerry Pournelle

senior technical editors

G. Michael Vose. Themes

Gregg Williams

technical editors

Thomas R. Clune

Jon R. Edwards

Richard Grehan

Glenn Hartwig. Reviews

Richard Kraiewski

Ken Sheldon

Richard S. Shuford

Jane Morrill Tazelaar

Eva White

Stanley Wszola

Margaret Cook Gurney. Associate

Alan Easton. Drafting

WEST COAST EDITORS

Ezra Shapiro. Bureau Chief. San Francisco
John Markoff, Senior Technical Editor, Palo Alto
Phillip Robinson. Senior Technical Editor. Palo Alto
Donna Osgood. Associate Editor. San Francisco
Brenda McLaughlin. Editorial Assistant. San Francisco

NEW YORK EDITOR

Richard Malloy, Senior Technical Editor

managing editor.

electronic publishing and communications

George Bond
user news editors

Anthony J. Lockwood. What s New
Mark Welch. Microbyles

CONTRIBUTING EDITORS

Dennis Allison, at large

Mark Dahmke. video, operating systems

Mark Haas, at large

Rik Jadrnicek, CAD. graphics, spreadsheets

Mark Klein, communications

Alan Miller, languages and engineering

John C. Nash, scientific computing

Dick Pountain. U.K.

William M. Raike. \apan

Perry Saidman. computers and law

Robert Sterne, computers and law

Bruce Webster, software

COPY EDITORS

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Margaret L. Dagner. Human Resources.
Officers of the Corporation: Harold W. McGraw. Jr.. Chairman: Joseph L. Dionne. President and Chief Executive Officer: Robert N. Landes. Senior
Vice President and Secretary; Ralph J. Webb. Treasurer.

CROMEMCO COMPUTERS*

'E9IWPlEl# III IwlMltJE UNlA 9 191 EM W

EVEN BETTER...

UNIX System V, the new standard In multi-
user microcomputer operating systems, gives you high
performance features along with the portability and
flexibility of a standard

Cromemco computers can make UNIX System
V even better. Because our systems are designed with
UNIX in mind. First of all we offer UNIXBystem V
with Berkeley enhancements. Then, our hardware uses
advanced features like 64K of on-board cache memory
and our high speed STDC controller to speed up disk
operations - very in at wj th UN [X.

More capability and expandability

We have a high-speed, 68000-based CPU that
runs at 10 MHz, coupled with a memory manager that
uses demand-paging and scatter loading to work with
UNIX, not for it

We provide room for expanding RAM to 16
megabytes- with error detection and correction -for
ruiiiiing even the most sophisticated and advanced
microcomputer programs. And the power to accom-
modate up to 16 users -all with plenty of memory.

But we give you even more.

A complete solution

We give you a choice in systems: the System
100 series, expandable up to 4 megabytes of RAM, and
the System 300 series, expandable to 16 mega-
bytes. A high speed 50
megabyte hard disk drive
is standard on the sys-
tems. And you can ex-
pand the hard disk
capacity up to 1200
megabytes using stan-
dard SMD drives. You
can add floating point
processing. High resolution
graphics. Video digitizing and
imaging. Communica rhrough

standard protocols. Mainframe interface.

And software support is here to meet your
needs. We offer major programming languages, data-
base management systems, communis ■ .ware,
including SNA architecture, X.25 protocol, and Ethernet;
even a program to interface to an IBM PC if you need to.
And, of course,, access to the broad range of standard
UNIX applications programs that is growing dramat-
ically every day.

Easy to use.

We also make our systems e; - o use,
because we install the operating syst fore we

ship your computer. No complicated installation pro-
cedures. And the Berkeley enhancements give you
the standard UNIX System V operating system,
but with the added convenience of these widely
acclaimed improvements.

Cromemco's System 100 and - m 300
computers: designed to be the highest performance
UNIX systems available anywhere.

Just call or visit one of our UNIX System V
Official System Centers to see for yourself. They'll
also give you a copy of our new publication, "What
you should know before you buy a UNIX system." '■
Or contact us directly

We'll be glad to show you how to get a
better UNIX system, :

Corporate Headquarters: Cromemco, Inc.,
280 Bernardo Avenue, RO. Box 7400, Mountain
View, CA 94039. (415) 969-4710. In Europe;

■■'..■ Cromemco ■
GmbH, 6236
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Frankfurter Str.
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UNIX is a trademark »f Bell Laboratories.

IBM is a trademark of International Business Machines Corp.

Cromemco

Inquiry 76

FEBRUARY 1985 • BYTE 5

EDITORIAL

Service and Support

When computers are working they
keep us entertained, or at least oc-
cupied. That's why happy customers
seldom praise the retail stores and
mail-order businesses that sold them
their computer equipment, and why
we hear much more criticism of com-
puter dealers. Often retail salespeople
are decried for knowing little about
the computers and software they sell
and mail-order firms for providing less
customer support than retail stores.

But the reality varies from store to
store and transaction to transaction.
I have had nothing but good experi-
ences with mail-order companies, in-
cluding free replacement of 100 flop-
py disks when three of ten in the first
box wouldn't format properly. I've
bought software, a modem, a printer,
and various supplies through phone
orders to mail-order businesses.

My experiences in retail stores have
been mixed. I once heard a salesman
tell a customer that Pickles and TVout
were programming languages (they
actually were two people who pro-
duced a version of CP/M for the Ikndy
Model II). On another occasion the
sales staff of a retail store refused to
go through the bother of taking an
order for VisiCalc or to hold a copy
for me from the next shipment. I went
back several times only to find Visi-
Calc sold out again and no one will-
ing to take my order. (Finally I bought
VisiCalc through mail order and had
no problems.) On the other hand, the
retail salespeople at the computer
store where BYTE made some recent
purchases not only know what they
are doing but also give technical sup-
port when things go wrong.

Street Addresses

There is room for improvement in
both mail-order and retail computer

sales practices. The great concern
with mail-order businesses is well
expressed in a letter we received
from John C. Gunn, director of con-
sumer affairs for Priority One Elec-
tronics of Chatsworth, California:
"Although we are primarily an in-
dustrial distributor, a measurable por-
tion of our revenue comes from our
mail-order' ads. We frequently hear
horror stories about some poor soul
who sent his money to a mail drop or
post office box somewhere. . .and
never saw any product or a dime of
his dough. Incidents such as this hurt
all of us."

Priority One took an interesting
practical step to counteract this prob-
lem. ,,r Tb assist in protecting unwitting
consumers from unscrupulous adver-
tisers," Gunn writes, "we lobbied
strongly for the passage of a bill in-
troduced by California Assemblyman
Jack O'Connell. This law requires all
advertisements in our state to carry
the street address of the company
placing the advertisement." We com-
mend Priority One for its efforts to
protect the interests of customers of
mail-order businesses.

Remote Diagnostics

The convergence of computer and
communications technologies offers
an unprecedented opportunity for im-
proving customer support. When a
personal computer is connected to
the telephone system through a
modem, and if the operating system
and hardware are still capable of tak-
ing input from the serial port, then
someone at the other end of the
telephone line should be able to take
control of the computer and put it
through a series of diagnostic tests.
The availability of such remote
diagnostics would be a great conve-
nience for computer users, retail
stores, mail-order businesses, and

manufacturers. Remote diagnostics
would be much less expensive than
shipping costs and would reduce or
eliminate the problems sometimes
caused by the consumer's inability to
describe a problem in a way meaning-
ful to technicians. Instead of lugging
the machine back to the store or
packing it up for shipment, the con-
sumer could just connect the com-
puter to the telephone and watch the
diagnostics at work. In many in-
stances, the consumer could learn
what was wrong and how much it
might cost to fix before sending out
the equipment. The service or-
ganization would know what type of
repair was coming and be prepared
to fix it. In some cases the machine
wouldn't have to be sent out at all;
there could be a software fix or a
board swap.

Some companies already furnish
diagnostic disks. These disks are valu-
able, but because of a lack of infor-
mation needed to interpret the results
of the tests, they tend to leave the
customer poorly informed. Remote
diagnostics would permit the service
organization to use additional tests to
identify the problem more precisely
and then to tell the customer more
about the extent of the repairs and
potential costs.

Since repair bills can range from
$75 to more than $1000, mystery
breeds distrust. Consumers often
express suspicion about repair costs
of the automobile and other famil-
iar machines. Similar feelings of
distrust about repairs of computer
equipment could become much more
pervasive. Remote diagnostics could
reduce mystery and improve con-
sumer confidence in the computer in-
dustry. We hope the use of remote
diagnostics becomes standard in-
dustry practice.

—Phil lemmons, Editor in Chief

BYTE • FEBRUARY 1985

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Inquiry 201 FEBRUARY 1985 -BYTE 7

Wordstar Wordprocessing and SuperCak3 Integrated Spreadsheet now included Free with all Seequa computers.

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IBM is a registered trademark of International Business Machines Corporation.

8 BYTE • FEBRUARY J985

Inquiry 277

MICROBYTES

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

CP/M for the Macintosh

IQ Software, Fort Worth, TX, is selling a version of CP/M-68K for Apple's 128K-byte Macin-
tosh for $395, including Digital Research's C Compiler and Macro Assembler. CP/M 2.2
emulation is available for $195 extra but runs only on a 512K-byte Macintosh. A 512K-byte
Macintosh is also required to access the mouse and pull-down menus. CP/M-68K disks are
not compatible with other Macintosh disks.

Superex, Micromax Unveil Macintosh Business Software

Superex Business Software, Yonkers, NY, announced 2 5 new products for the Macintosh,
priced from $20 to $800. The least expensive item is also the only hardware product in-
troduced: MacSpeak is a $19.95 external speaker. All products should be available this
month.

Also included are business programs for cost estimating, time billing, inventory, finance,
business letters, sales, and wholesaling. A complete accounting package with Accounts
Payable and Receivable and General Ledger modules is $750. A Home Executive program is
$90.

Four engineering packages— for civil, mechanical, chemical, or electrical engineers— are
$100 each. A MacScience series includes Physics or Chemistry formulas for $100 each.
Statistics and job-hunting programs were also announced.

Micromax, San Diego, CA, introduced Gallery, a business-accounting software series. The
Finance module, which includes General Ledger, Accounts Payable and Receivable, and Cash
Disbursement, is $795; industry-specific vertical applications are also planned.

Conetic Introduces Desktop Management Software

Conetic Systems Inc., San Leandro, CA, introduced Higgins, a specialized relational database
program for the IBM PC XT or PC AT that includes an appointment calendar, telephone/ad-
dress file, expense report, and message features. Information entered into the program is
linked to related files; for example, the telephone directory is checked when an appoint-
ment is made. Information for up to seven people can be tracked on one computer. A local-
area-network version that exchanges nonprivate schedule information is also available. The
single-user version of Higgins is $395.

Lantech Offers UNIX-like Operating System for $129

Lantech Systems Inc., Dallas, TX, announced uNETix 2.0, a multitasking operating system for
the IBM PC that it says is compatible with AT&T's UNIX operating system but costs just
$129. Using optional $100 window-management software, PC users can execute up to 10 ap-
plications concurrently; one of those could be a PC-DOS application running under
Lantech's $50 PC Emulator.

While a hard disk is recommended, Lantech says the operating system can run on a two-
disk system. A separate version of uNETix is available for use in local-area networks.

Smalltalk for PCs

Digitalk, Los Angeles, CA, introduced Methods, a Smalltalk-80 object-oriented development
system for the IBM PC. The $250 system includes a compiler, debugger, and text editor; it
uses a text-based windowing system with pop-up menus. Methods requires an IBM PC with
512K bytes of RAM and two 360K-byte disk drives.

Software Systems, San Francisco, CA, is also developing a Smalltalk for the Apple II, with
later versions planned for 8088- and 68000-based systems.

[continued]
FEBRUARY 1985 -BYTE 9

MICROBYTES

Software Teledelivery Efforts Falter

At last year's Winter Consumer Electronics Show, several companies announced or dis-
cussed plans for electronic delivery of software. Some, including Xante, Romox, and Cumma
Technology, planned to download to erasable programmable read-only memory (EPROM)
cartridges at dealer terminals. Others, including Control Video's GameLine and the Nabu
Network's cable service, downloaded programs directly to computers or video games.

Xante, Romox, and Cumma have all ceased operations, mainly because of poor dealer
response and the general collapse of the cartridge video-game market Nabu's cable-TV-
based software-downloading service continues to operate in Ottawa, Ontario, despite finan-
cial troubles. Control Video Corp., Vienna, VA, said poor distribution and the general video-
game slump led it to cancel its GameLine service for the Atari 2600 VCS.

Control Video is now testing a new service which allows subscribers to play 20 games
available each month as often as they wish for a $14.95 monthly fee, which includes rental
of a 2000-bps modem from BellSouth. MasterLine is now available for Apple II and Com-
modore 64 owners in Atlanta, Los Angeles, Houston, and Washington, DC.

Separately, NBC announced that it would cancel the NBC Teletext service in late January.

NANOBYTES

Intel introduced the 82588 single-chip local-area-network controller. The 82588 can be used
in low-cost baseband or broadband networks— including such IEEE 802.3 protocols as IBM's
PC Network and the developing STARLAN— at speeds up to 2 megabits per second. Initial
pricing will be $45 each in large quantities. . . . Laserstore, Princeton, NJ, plans to sell a
2.5-gigabyte write-once optical streaming-tape drive. The drives should be available in large
quantities in mid-1986 for about $2500. . . . Multi Solutions announced a licensing agree-
ment with Computer Engineering & Consulting of Tokyo, under which CEC will translate
Multi Solutions' SI operating system for Japanese computers. Currently, SI runs on several
68000-based computers and is being translated by MSI for the IBM PC AT. The agreement
guarantees a minimum of $40 million in royalties, according to Multi Solutions. . . . WATCOM
Products Inc. has released two products developed at the University of Waterloo in
Canada. WATFILE is a $295 data-management system for the IBM PC; JANET/2 is network-
ing software for IBM's PC Cluster system. . . . Alphacom announced a 133-character-per-
second printer at $249 that it says is compatible with Epson's RX-80. . . . Corvus and NEC
have agreed to jointly develop a single-chip controller for Corvus's Omninet local-area net-
work. Currently, an Omninet controller requires three chips developed by Corvus. . . . Ad-
vanced Micro Devices now offers a 1 0-MHz version of the 80186 processor. . . . Phoenix
Software, Norwood, MA, has developed an IBM PC XT-compatible ROM BIOS and is
developing software compatible with IBM's PC AT. Phoenix's earlier IBM PC-compatible
ROM BIOS code has already been licensed by AT&T, Kaypro, T&ndy/Radio Shack, Wyse
Technology, and Zaisan. . . . Rumors that Tkndy would begin selling ACT computers in its
Radio Shack stores are apparently false. Instead, the two companies announced a joint ven-
ture to operate a chain of computer stores in Europe, called TA ComputerWorld. The stores
will sell both Tkndy and ACT computer products. . . . AST Research announced RamStak, a
memory-expansion board for the Apple Lisa computer. The board can add up to 2
megabytes of memory to the Lisa; with 512K bytes, it's priced at $1395. . . . Mosaic Elec-
tronics, Oregon City, OR, announced Access-M, an expansion card for the Commodore 64
adding up to I megabyte of memory. The standard $195 card includes 64K bytes of RAM
and RAM-disk software; additional memory is plugged into the card. . . . PortaAPL, a $275
APL interpreter for the Macintosh, was introduced by Portable Software, Cambridge, MA.
PortaAPL adds a full-screen editor and access to many Macintosh ROM toolbox routines to
the standard APL language but requires a 512K-byte Macintosh. . . . C Line Inc., Chicago, IL,
announced a dBASE II-to-cEnglish converter. The $795 program converts standard dBASE II
source code into cEnglish, which is then translated by the $900 cEnglish program into C,
which is in turn compiled into machine language by a C compiler.

10 B YTE • FEBRUARY 1985

TheTI855is

the only printer

with letter quality,

draft sp>eed,

graphics,

plug-in font

modules...

all for under

]

.. ..

Texas Instruments

Finally, the printer for all PC needs.

The TI 855 printer. The
printer for all major PC's.
See for yourself today.
Call 1-800-527-3500
for the dealer
nearest you.

Texas ^^
Instruments

Creating useful products
and services for you.

This printout was not generated by the TI 855.

DPF012BY
2764-08

FEBRUARY 1985 -BYTE II

Slide Cat from kodak introduces:

THE CAT QUICK

SLIDE MAKERS
THAT WILL

YOU GRIN.

"Now you can make presentation-
quality instant slides from CRT
screens, one at a time. Slides that
integrate beautifully into the rest
of your show. It's like having your
own instant slide department. And
you don't have to be an audio-
visual professional to do it.

"Kodak's new cat-
quick slide-makers are
a versatile group of

KODAK

INSTAGRAPHIC
Copy Stand

Use this well-designed unit to make slides of
pictures, printed material, and artwork up to
11" x 17" Or small, three-dimensional objects.
Right in your office. In ordinary room light.

state-of-the-art products designed
to convert computer-generated
material into slides, fast!

"With our new imager, you can
make instant slides (or prints)
from just about any data that
appears on your CRT screen... pie
charts, bar charts, organization
charts, etc. And you can use just
about any size terminal — 9-, 12-,
13-, even 19-inch screens. Direct

Inquiry 345

Turn CRT Data
Into A Slide, Cat-Quick.

KODAK

INSTAGRAPHIC
CRT Slide Imager

Contains KODAK
INSTAGRAPHIC
Camera Back, KODAK
INSTAGRAPHIC Slide
Module, and KODAK
INSTAGRAPHIC CRT
Cone. Just add the
appropriate CRT
adapter to make
instant presentation-
quality slides that
integrate beautifully
into the rest of your
show. There's even an
optional module that lets you make prints.

conversion from CRT to
slide can save you time,
and money! For slides
from hard copy use our
sleek copy

stand. Both methods
are easy and affordable.
Your options are many. You
can buy one product, or the entire
line. Make a single slide or
an entire presentation. Prove
a point, or wow an audience.
Even use our camera back, module,
and film to photograph images
electronically transferred with
many manufacturers' video image
recorders! And get results that
make a grin begin.

Kodak I Kodak

Instagraphic" **-*■ II Instagraphic ^

KODAK CRT Adapters

Make an instant slide or print

from your screen, any screen —

9-, 12-, I3-, even 19-inch — with your

choice of adapter to fit between the imager and

the CRT screen.

KODAK INSTAGRAPHIC
Slide Mounter and Mounts

Last step. Mount your slide quickly and
easily with this simpletouse device.
Eases film into the slide mount auto-
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mount together or touch the image area.

'To learn more
"about these new
state-of-the-art
products, call 1 800 44KODAK,
Ext 233 (1800 445 6325,
Ext 233), or use the coupon below.
Or contact your local dealer in
Kodak audiovisual products, listed
in the Yellow Pages under 'AV
equipment and supplies.' "

New cat-quick slide-makers
from Kodak.

THEY'RE GONNA
MAKE YOU GRIN

Eastman Kodak Company, Dept 412 L

Motitn Picture and Audiovisual Markets Division

Rochester, NY 14650

□ Please have a representative call me. A8071

□ Please send me your informative Slide Cat brochure. A8072

KODAK INSTAGRAPHIC Color Slide Film

Shoot just one slide or an entire presentation. One-
ata-time exposure means you waste no film, waste
no money. If you need instant color prints of CRT
displays, use KODAK INSTAGRAPHIC Color Print
Film and substitute the KODAK INSTAGRAPHIC
Print Module.

FEBRUARY 1985 -BYTE 13

LETTERS

CP/M Plus for the Model 4

Editor's note: \n the following sequence of letters,
reader William F. Crowell addresses Tandy Cor-
poration Chairman ]ohn Roach, BYTE [having
received a copy of Crowell's letter) responds to
Crowell. and David Krebbs of Tandy replies to
Crowell.

Dear Mr. Roach.

I am a longtime computer customer of
'Iandy Corporation. I presently own two
Model Is, a Model 4, and a Model 4 P. For
over 18 months now, since it was first an-
nounced, I have been waiting to receive
a working version of Model 4 CP/M Plus.

First. I had to wait 1 3 months after 'Iandy
announced the product before it was even
released. (However, this didn't stop Iandy
from advertising the product as available
during this entire period of time, presum-
ably to sell more Model 4s to customers
who want to run CP/M Plus.) I immediate-
ly bought a copy. As you know, however,
the original release was full of bugs.

I volunteered to beta-test the new
preliminary version 1.1. which I did. I im-
mediately discovered that random access
failed miserably. Then I observed from the
source code. RANDOM. ASM, that virtual-
ly nothing had been done to implement ran-
dom access on the Model 4 hardware en-
vironment.

Iandy calls this an operating system?
How could the company even release it
in the first place without random access?
Also, the BIOS is supposed to emulate a
DEC VT-52 terminal, but it doesn't. Many
of the VT-52 control codes don't work. Fur-
ther, the promised CBASIC has never been
released, and there is no release date that
I am aware of.

How is it that Tandy is able to release
so much other TRS-DOS software, but it
takes over 17 months now to merely write
a correct BIOS for CP/M Plus? This rather
obviously represents a violation of the
antitrust laws.

Why haven't the popular magazines
reported this irresponsible and reprehen-
sible conduct by Iandy? Are they afraid
of losing your advertising?

You are hereby placed on notice that I
will attempt to file a class-action suit
against Iandy Corporation for consumer

fraud, breach of contract, antitrust, and
possibly other causes of action unless
working versions of CP/M Plus and CBASIC
are available for purchase and the work-
ing version of CP/M Plus is provided to
purchasers of the original version within
30 days of this date.

I am sorry to take such an unfriendly
tone in this letter, but apparently threats
of legal action are the only thing that
iandy understands.

William F. Crowell

A ttorney

Oakland, CA

BYTE replies:

We called Mark Yamagata of Tandy re-
garding CP/M Plus for the Model 4. Mr.
Yamagata quickly admitted that there
were bugs in the product He added that
the new version was almost ready but
that one more bug had to be worked out.
He said the new version would be avail-
able by the end of October. He also said
that all registered users would be advised
of the new version, which will be avail-
able to them at no charge. We hope the
new version solves the problems you've
encountered with CP/M Plus; if not, or if
Tandy fails to ship the new version,
please let us know so we can report on it.

As to magazine policies on publishing
letters to the editor, we receive far more
letters than we can publish We try to
choose those of greatest interest to the
greatest number of readers. When we
receive copies of complaints like yours,
we generally call the company involved
and try to obtain information about how
the problem can be solved. If a solution
appears imminent, we call the author of
the letter and inform him or her. By the
time we could publish the letter, the
reason for the complaint will have dis-
appeared.

In this case, the solution appears to
have been "imminent" for a long time.
We hope that CP/M Plus is now fully func-
tional on the Model 4.

Tandy replies:

Dear Mr. Crowell,

1 regret your problems with Model 4
CP/M Plus, but 1 can do no more than to

repeat some of the points that 1 men-
tioned during our previous telephone
conversations. You are correct in observ-
ing that Model 4 CP/M Plus got onto the
market later than we originally intended
and that the initial release had bugs. This,
as you know, is not at all unusual with
software. Virtually all software packages
do contain bugs when they are first
released, and these bugs are subse-
quently removed as later versions of the
software packages come into the market.

From your letter 1 infer that you do not
regard the version of Model 4 CP/M Plus
that we are now selling as a "working ver-
sion." 1 must respectfully disagree. It is
the position of Tandy Corporation that
our Model 4 CP/M Plus software package
is quite adequate for the purposes for
which it is intended, and retail sales to
date, as well as user feedback, indicate
that the public agrees with us. 1 am sorry
if this particular software package is not
suitable to you in some way or ways, but
you will understand, I trust, that it is not
possible for us to design our products so
that they are perfectly acceptable in
every respect to every single member of
the buying public.

Regarding your comments on the
VT-52, please note that the first release
of the Model 4 CP/M Plus manual did
contain errors on the decimal values
assigned to the VT-52 emulation codes.
The correct codes have been sent to you
by Mr. James Brown, of this office, and
a Publication Change Notice has been
submitted for future editions of the
manual. You will find that the VT-52 con-
trol codes will work correctly with the in-
formation that Mr. Brown sent to you.

[continued]

LETTERS POLICY: To 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, letters
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 • FEBRUARY 1985

Portable

Backup!

Back Up All the Hard Drives in Your Office.

The MaynStream offers fully portable hard drive backup
employing the latest software technology. It is compatible with
IBM, Compaq, and NCR personal computers* and comes with
an industry-leading 1 -year warranty.

; rVJaynaid Electronics

430 E. SEMORAN BLVD., CASSELBERRY, FL 32707

305/331-6402
Inquiry 202

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267359:

LETTERS

Enclosed please find a BASIC program
that utilizes random-access procedures to
retrieve and store data. At this time, we
are not able to duplicate any inherent
flaws with random-access procedures in
CBAS1C under CP/M Plus.

Let me advise you as well, by the way,
that the catalog number for Model 4
CBAS1C is 26-221 7, and it is now available
in our stores at a retail price of $99.95.
In fact, it was released in June of this year.

1 repeat my previous offer to you: if you
wish to have a full refund on the Model
4 CP/M Plus package that you purchased,
just send me the complete package
(media and manual) together with a copy
of your sales receipt 1 shall then see that
a check is cut and sent to you at once.
1 make this offer to you in an effort to re-
tain your goodwill.

1 do not pretend that our position, as
1 have stated it above, will be perfectly
acceptable to you, but 1 trust that at least
you now understand it clearly. We do ap-
preciate your past business, and 1 hope
that we shall be favored with more of it
in the future.

David Krebbs

Radio Shack Computer

Customer Services

A Pirate Confesses

This is an open letter to software vendors
and dealers. It has been prompted by
various letters and articles that I have read
recently concerning why otherwise ethical
people would "pirate" software.

I do not advocate the piracy of software.
It is nothing short of theft. However, I have
been guilty of pirating a package or two
for one reason: I refuse to spend my
money on software that I cannot be sure
will run on my machine. No vendor that
I know of will offer you a money-back
guarantee on its software package. I work
on mainframe computers for a living, and
very few vendors of mainframe software
will not let you have a 30-day trial on one
of their packages.

I understand that the volume of dollars
spent on a mainframe package is con-
siderably more than what personal com-
puter users spend for their software pack-
ages; however, we personal computer
users do not work with the same size
budgets as mainframe users.

Some software vendors do in fact offer
demonstration disks, but the disks that I've
seen flash lots of colors and text describ-
ing the products but do not give you an
opportunity to use the products and

[continued)

16 BYTE • FEBRUARY 1985

Inquiry 56

What every Apple owner
should know about

WORD

juggler:

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 "cut-and-paste' 1 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 arent 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

Wmmmmmm^m incorporated

2525 West Evans, Suite 220
Denver CO 802 19

Inquiry 264

Quark and Word Juggler are trademarks of Quark Incorporated. Apple is a
registered trademark of Apple Computer. Inc.

Ask about our specially-priced educational version.

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AID

Typequick 85 85

ALPHA SOFTWARE

Data Base Manager 295 1 79

ANDERSON-BELL

Abstat 395 267

ASHTON-TATE

D Base II 265

DBase III 363

Framework 363

Friday 169

ATI

Training Word Star 75 45

Training dBase II 75 45

BORLAND INTERNATIONAL

Toolbox 49 40

COEX

Advanced Lotus 1-2-3 70 45

CHANG LABS

Rags to Riches Ledger 99 79

CONDOR

Condor 3 650 249

CONTINENTAL SOFTWARE

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Writers Pak 295 199

Footnote 99 84

Datebookll 295 179

Notebook 150 98

Proofreader 50 38

Grammatik 75 65

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LEXISOFT

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MONOGRAM

Dollars and Sense (IBM) 179 149

Dollars and Sense (Mac) 149 119

OASIS

Word Plus 150 105

Punctuation and Style 150 95

PACIFIC DATA SYSTEMS

Money Track 295 219

PEACHTREE

Peachtext5000 425 185

CalendarManagement 195 165

Decision Manager 625 495

Business Graphics System 295 219

Peachpak 4 395 199

PETER NORTON

Norton Utilities 100 65

PRENTICE-HALL

Execuvision 395 299

SELECT INFORMATION SYSTEMS

SelectWord Processor 295 199

SORCIM

SuperCalc2 295 154

SuperCalc 3 395 199

SOFTWARE PRODUCTS INT'L

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TYLOG

dBase Window 249 155

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The Desk Organizer 195 129

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Move It 150 85

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LETTERS

determine if they will satisfy your needs.
I try to study a product as much as I can
from reviews in the trade publications. I
then select one or two similar packages
and attempt to find people who are using
them. I obtain a copy (or the original) and
the product's documentation, and I try the
package out for a month or so. If I like the
product. I then purchase a "legitimate"
version of it or else I erase my copy or
return it to the lender. In this respect I am
probably more ethical than most in that
I will buy a legitimate copy of any software
that I intend to use on my machine for any
length of time after I have already ob-
tained a pirated version of it.

I seek only to protect my investment,
and I will discontinue this practice when
I can obtain a full-function demonstration
disk of a package that I intend to purchase.
I somehow expect that quite a number of
software vendors would be opposed to a
30-day trial arrangement because their
products wouldn't stand up to head-to-
head competition.

Name and address withheld

No Support from Apple

I would like to confirm the lack of available
Apple documentation noted in Dennis
Doms's letter ('A Call for Better Apple Sup-
port." September 1984. page 14).

After purchasing an Apple Uc in May to
complement my lie while I was traveling,
I was immediately confronted with a lack
of technical details needed to connect my
"non- Apple" peripherals to the lie. What
are the pin connections on the serial
ports? What are the memory locations
that control baud rate, characters per line.
ACIA status, etc?

Since I travel extensively I thought I
could pick up the Apple lie Reference Manual
in one of the many authorized Apple
dealers I visit when out of town. After
visiting over 30 stores in New York. New
Jersey, southern California, and Oregon.
I have been unable to find the reference
manual.

I hope that letters like Dennis's and mine
will stir Apple into getting the publications
into the hands of the thousands of Apple
users who want to know all there is to
know about one of the most revolutionary
products of our times.

George W. Ziegler, Jr.
Mahwah, NJ

I read with interest Dennis Doms's letter
describing his problems obtaining Apple
documentation.

{continued)

18 B YTE • FEBRUARY 1985

Inquiry 110

And you thought there was only
one "Graphics Card?

Now you have a choice for bit-
mapped graphics. Priced at $399—
$100 less than what you'd expect
—AST's Preview! brings high resolu-
tion bit-mapped graphics and clear,
crisp text to your IBM® PC ; XT or AT
monochrome screen. And there's
no standard like AST quality.

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
full-screen high resolution graphics,
an IBM PC-compatible parallel printer
port and Hercules™ bit-mapped
graphics card compatibility.

It works with all kinds of soft-
ware too, no other card offers more.
New generation integrated business
programs, bit-mapped text process-
ing and advanced windowing appli-
cations are specialties.

Then there's the nonstandard fea-
tures AST is famous for— consistent
quality, reliability, comprehen-
sive documentation, service, support
and extra value. We include our

SuperPak™ RAM disk simu-
lator and printer spooler
utility diskette. Judged by PC
WORLD readers as a World
Class Winner for the past two
years, it's worth $45 by itself.

The leadership strength that
makes our consistent quality so
affordable is carried throughout
our complete line of PC enhance-
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graphics products which provide
a variety of features from serial ports
to expansion memory, as well as
multifunction boards, micro-to-
mainframe communications, local
area networks and disk subsystems.

So you can settle for the com-
mon, ordinary graphics card and
hope for the best. Or you can pay
$100 less and know you have the
best— Preview! only from AST. For
more information and dealer loca-
tions call our Customer Information
Center (714) 863-1333, Ext. 5249.
Or write, AST Research, Inc., 2121
Alton Avenue, Irvine, CA 92714
TWX:753699ASTUR.

] 64K Screen Memory

■ llvo Pages of High
Resolution 720 Hori-
zontal PELS by 348
Vertical Line Bit-
Mapped Monochrome
Grapliics

• 80 Cliaracter By
25 Line IBM PC-
Compatible Text
Display

• Standard IBM Charac-
ter Set

• Compatible With
Popular Bit-Mapped
Graphics, Text and
Windowing Applica-
tions Softivare

• Parallel Printer Port

• SuperPak Utility
Diskette

• Hercules Compatible

Prcvietv! and SuperPak trademarks of AST Research,
Inc. IBM trademark of International Business Ma-
chines Corp. Hercules Graphics Card trademark of
Hercules Computer Technology Lotus 1-2-3 and
Symphony trademarks of Lotus Development Corp.
Framework trademark of Ashlon-Tale. Word trade-
mark of Microsoft. Inc. MetaWINDOW trademark
ofMctagraphis.

Inquiry 5 for Dealers.
Inquiry 6 for End-Users.

R€S€flRCH INC.

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

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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"
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Inquiry 33

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NAME

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Expiration Date

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m BORIPOD

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4113Scotts Valley Drive
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TELEX: 172373

LETTERS

After several years of CP/M experience.
I purchased an Apple lie in May. I have
written and phoned Apple in Cupertino,
the Apple distributor in Charlotte, and two
Apple dealers. The response I have got-
ten is difficult to accept. Based on the in-
formation I have to date, the Apple lie
Technical Manual, ProDOS Technical Manual,
ProDOS Users Kit, and Applesoft Technical
Manual volumes 1 and 2 are unavailable
and there is no official date for delivery.

My choice of the He was based on the
promise of true portability by the end of
1984. The present availability of carrying
cases and portable power supplies
coupled with the continued assurance, by
Apple, of the flat-screen display in 1984
will provide the hardware I expected when
I chose the lie. The total lack of technical
information for the He and the operating
system will make software development
almost impossible.

Don Overton
Atlanta. GA

I found the letter by Dennis Doms con-
cerning the lack of technical support by
Apple for its new ProDOS System very
true. I am one of those newcomers to
computers. It is indeed a nightmare try-
ing to make sense out of Apple ProDOS
from the scant instructions supplied with
the Apple lie.

For months I have been trying to buy
several of Apple's manuals on ProDOS.
especially BASIC Programming with ProDOS.
The authorized Apple dealer has no idea
when his shipment will come in.

In my opinion any machine, no matter
how excellent it may be, is no better than
the instructions that teach the operator
how to use it. It seems a pity that a com-
pany that can spit out machines at such
a terrific rate cannot supply the bare tools
the operator needs to operate that
machine. Imagine that same company's
concern if. when its new production line
was ready to roll, it found it had few in-
structions on how to operate it.

David D. Perry
Ridgecrest, CA

Take Back Your Mac

I am outraged. Apple's original descrip-
tions of the Macintosh, as quoted in the
press, made it clear that the Macintosh
was a 5 1 2 K system that was being released
in a temporary 128K version due to
failures on the part of Apple's suppliers.
Now we are told (in defiance of the ex-
perience of any user of the machine) that
the 128K Macintosh is a useful computer

and will continue to be sold at the original
price, while a 512 K version will cost $1000
more. What's more, any purchaser of the
earlier 128K machine who desires to up-
grade to 51 2 K must pay the $1000 dif-
ference in price. This policy is as blatantly
unscrupulous a case of bait-and-switch as
was ever practiced.

As a professional programmer. I was in-
trigued and excited by the concept of the
Macintosh and eagerly awaited the release
of the real, 512K. machine. As a consumer.
I am disgusted by Apple's business prac-
tices and have no intention of throwing
good money after bad. 1 am especially
frustrated by this decision of Apple's, since
I am sure that it will strangle the Macin-
tosh in its cradle, and so my already sub-
stantial investment in the machine will
have been for nothing.

Kirk Rader
Los Angeles, CA

I openly plead for a programmer or pro-
gramming team somewhere to develop
RAM-disk software to use the 512K RAM
on the "fat Mac" as a RAM disk as well
as for memory.

A logical configuration to emulate the
128K Mac would be 128K memory with
a 384K RAM disk. Later, variable options
of more memory and less RAM would be
nice, but they are not essential initially.
Good programs like Microsoft Word can
use disk I/O to make files larger than
memory and would not be limited by the
main-memory constraint, but rather only
by the RAM-disk memory constraint.

Such a RAM disk must permit copying
data to and from it, programs to and from
it. and opening it. So designed, the system
and major programs that use disk overlays
could be loaded into RAM. with conse-
quent lightning-speed operation. I believe
such software is essential for the Mac to
appeal to business. It would also make
software development itself easier and
faster.

I've checked, and apparently Apple's
own programming philosophy is opposed
to this concept. If someone does do this,
I hope he or she sells it for a reasonable
price ($50 or less) or else releases it ac-
cessibly into the public domain. Without
such a development, my company will
probably never buy a Mac and will prob-
ably never develop software for it.

Don Slaughter

Micro Cost Software

Seattle, WA

Perhaps two of the most often used words
throughout articles dealing with the

Macintosh are "potential" and "wait." The
Macintosh was introduced over nine
months ago, and still there is a lack of
varied and practical software available for
the computer. On the day of its introduc-
tion Apple announced that "hundreds" of
software companies had already had the
Macintosh for up to two years. Software
for the machine would be available in a
torrential flood in a matter of weeks. Nine
months later a real word processor (i.e..
capable of handling more than eight or
nine pages) is still not available, nor can
I find a spelling checker, a true database
manager, or a high-level language. If soft-
ware companies have had over two years
to work on their products and still have
not fully developed what could be con-
sidered "standard" software products, just
how long is the Macintosh software-devel-
opment cycle? Is Apple truly supporting
its software developers?

Added to the problem of third-party
software is the lack of support software
from Apple itself. Nine months after the
computer was introduced, an assembler
has not even been made available, nor is
a communication program like MacTerm
available yet. Neither of these programs
is particularly tricky to write, and. in fact.
Apple must have had a 68000 assembler
in house for quite a while (rehosting an
assembler from the Lisa to the Macintosh
takes over nine months?).

Many trade magazines and journals ap-
parently wonder about these same prob-
lems. Often an attempt is made to ra-
tionalize Apple's tardiness and lack of sup-
port. The most common story is: "The
Macintosh is a radically new computer re-
quiring programmers to adapt to a com-
pletely different kind of style, and besides.
128K of memory makes for a tight
squeeze on programs. When the 512K
Macintosh is available, all kinds of fancy
programs will appear and life will be
wonderful again."

Well, the 512K Macintosh was recently
announced. Now I can easily find several
stores advertising the 128K Macintosh for
$1600 and the 512K Macintosh for $2400.
Yet Apple wants the people who have
already paid $2 500 to fork over another
$995 for the 51 2 K upgrade. The entire
computer obviously costs far less than
$1000 to make, since that is the price the
university consortium schools pay, and
you can be certain that Apple is not so
dedicated to education that it would pass
up this additional source of profit.

If 128K is such a burden on software de-
velopers, why wasn't the computer re-
leased after the expanded memory was

22 BYTE • FEBRUARY 1985

LETTERS

available? This would have given devel-
opers more time to work on their software
as well. If Apple felt it just had to be in
the market with a machine like the 128K
Macintosh, why was it priced so high? At
least Apple could have promised all the
early purchasers a fair price (or even no
cost) on the upgrade.

I truly feel that Apple has treated its
customers unfairly and with a certain
amount of contempt. Prior to owning any
Apple product I had a great deal of trust
and respect for the company. In fact it was
that trust and respect that convinced me
to buy a Macintosh even though I was
aware of its limitations. I felt certain that
Apple would take care of its customers.
However, since buying a Macintosh, that
trust and respect has gone. Even though
1 could recommend no alternative, I would
not advise anybody to buy a Macintosh.
Instead, I would recommend waiting un-
til Apple straightens up or until another
company recognizes the void and fills it.

R.S. LUEBKEMAN

Rancho Cucamonga, CA

Choosing a
Campus Computer

We have recently undertaken a project to
introduce the use of microcomputers in
the junior/senior Physical Chemistry
course at the University of Florida. Al-
though the students are reasonably
mature and mathematically sophisticated,
they have shown a surprising reluctance
to "get their feet wet" via hands-on work
with the microcomputers available for the
course (six Sanyo MBC 55 5 units, chosen
for their low price, reasonably good
graphics, and ability to use the 8087 math
coprocessor).

There are several problems in introduc-
ing a microcomputer course as described
above at a large state institution such as
the University of Florida (35,000 students),
where no requirement exists that students
purchase a microcomputer (not to men-
tion a specific brand of microcomputer).
Even if money were available to fund pur-
chase of sufficient machines to handle ap-
proximately 4000 technical students per
year, along with space to house them,
there remains the possible objection that
the entire enterprise would be at least
"type-specific." Thus we might select MS-
DOS, Microsoft BASIC, and WordStar,
which would slant the situation toward
IBM PCs and/or compatibles. This might
lead to a loud chorus of objections from
Macintosh supporters, for example.

[continued)

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Inquiry 29

FEBRUARY 1985 -BYTE

LETTERS

While some may disagree, 1 feel that the
situation is more acceptable if reasonable
alternate-brand selections do exist such
as the IBM PC Seequa Chameleon, Eagle,
Zenith 1 50, Tava. Tandy 2000, etc. How-
ever, selection of a unique machine such
as the Macintosh is virtually an endorse-
ment of a specific brand rather than type,
to the exclusion of all others.

1 would be interested in hearing from

others concerning this dilemma. Please

write to me at the Chemistry Department,

University of Florida, Gainesville, FL 3261 1.

Robert J. Hanrahan

Gainesville, FL

Icons Are Arcane

Circa 5000 years ago, writing was invented
in ancient Mesopotamia. This earliest

THE INOVION PERSONAL
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known script, cuneiform, was derived from
pictographic symbols that became stylized
and standardized in form. Eventually it
became mixed with phonetic elements un-
til it was almost entirely phonetic. Our
alphabet is most probably ultimately
derived from ancient Egyptian— also
originally a pictographic system. The point
is this: Over thousands of years a phonetic
and finally alphabetic system was devel-
oped. To anyone who has gone through
the painful process of learning cuneiform
or Egyptian, the superiority of the
alphabet is readily apparent. A picto-
graphic system (Apple's "icons") requires
that the user learn many, many symbols.
My contention is that though users may
find icons more "user friendly," ultimate-
ly, as systems and software become more
complex, the icon system will become
more unwieldy and arcane than present
systems.

As a humanist who uses computers ex-
tensively in my work, I would like to see
user interfaces developed for micros that
are faster, more streamlined ("elegant"),
and smarter ("knowledge-based") to aid
in the learning process. It doesn't take the
uninitiated user long to grow impatient
with the Mac.

Ann Marchant
Berkeley, CA

Bravo, Borland!

This is the kind of letter I would like to be
able to write more often. It's about the
people at Borland International, who
distribute TUrbo Pascal and. if we are lucky,
a lot of other programs.

I've already spoken to Borland's pro-
grammers about a problem, and with a
completely satisfactory result. The latest
event was my ordering of the Commodore
64 CP/M version of TUrbo Pascal. When it
arrived, it was an MS-DOS disk, which I
couldn't use. 1 scribbled a note on the in-
voice and mailed the whole package back
the same day, the same way it arrived, at
a cost of about a dollar in postage.

Today the United Parcel Service truck
pulled up and delivered the correct
replacement package— Second Day Air. It
cost Borland $4. That is class.

William T. Powers
Northbrook, IL

Sage Defended

1 wish to respond to Dr. Richard Peskin's
appraisal of Sage computers ("A Second
Opinion on the Sage," September 1984,

[continued]

24 BYTE • FEBRUARY 1985

Inquiry 147

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

r wkv,

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, CA 94710 Ph: 4 1 5 540-6000 lelex: 754063 Trademarks/Owners: Hercules/Hercules Computer lechnology, 1-2-3,
Symphony/Lotus Development; IBM, AT/International Business Machines

Inquiry 135

FEBRUARY 1985 -BYTE 25

LETTERS

page 18) as lacking "many architectural
features needed for multiuser, multitask-
ing applications." This is a gross distortion
of the facts, since, from the beginning,
Sage has supplied an excellent multiuser
BIOS capable of supporting not only
multiple users but multiple operating sys-
tems running simultaneously. 1 know of no
other supermicro that can make this claim.
Even single-user operating systems such
as Softech's UCSD p-System appear to be
multiuser on the Sage as multiple copies
are run in memory partitions isolated by
the Sage MU BIOS. The BIOS allows easy
configuration of each user's time slice and
priority, flexible mapping of RAM disks
(yes, more than one!), memory and disk
partitions, and serial ports and peripheral
devices. Different operating systems may
be allowed access to shared disk space.
At last count, at least 1 1 operating sys-
tems are supported, including CP/M 68K,
Volition's Modula-2 system, HyperFORTH,
and Whitesmiths's UNIX-like multiuser
Idris. The Idris implementation currently
available was ported to the Sage by Rakon,
an Australian company. Rakon's version re-

portedly runs 2. 5 to 5 times faster on the
same hardware as Logos Information Sys-
tems' (Dr. Peskin's firm). In this light, Dr.
Peskin's opinion about Sage can hardly be
characterized as "objective technical
assessment."

The new products announced in
September by Sage (now Stride Micro) will
have a hardware memory-management
option to support UNIX System V with
Berkeley enhancements. They also run
faster (10 MHz standard, 12 MHz optional),
support hardware floating point, utilize the
industry standard VME bus, come stan-
dard with Omninet networking hardware,
and are even lower in cost.

Jai Gopal Singh Khalsa
Millis, MA

Improving the
IBM Keyboard

Where I work we have IBM PCs and X'ls
in abundance. People are always griping
about the poorly designed keyboard, i.e.,
the long reach to the Return key and the
dual-function 10-key pad/cursor controls

that perform only one of their roles at a
time. The complaints peaked around
budget time, when data entry to spread-
sheets became a paramount hassle. We
found a partial remedy, however. Instead
of switching between the 10-key pad and
the cursor controls by using the Num Lock
key, we found it easier to divide the labor
between our two hands by locking in the
10-key pad for data entry and then, to
move to another cell, holding the left shift
key down with our left hands and moving
the cursor with the 10-key pad that then
functions as a cursor control.

Granted, this is not a perfect solution,
but the roar did quiet. Now we'd like to
know how to solve the problem of the
reach to the Return key.

W. Travis Good
Summit, N]

Software Swapping

In response to "Dear Thieves" (August
1984, page 18), William Wright has ex-
pressed the opinion that it is entirely

[continued)

PSpica

The circuit simulator that
brings mainframe advantages
to your micro.

Now the industry-standard Spice, minus Spice's original
"bugs" has been brought to the IBM-PC. With PSpice , the
electrical engineer can try out a circuit right at his or her desk
without having to build it Design and check in 20 minutes
what normally takes four to eight hours and the wiring of two
dozen transitors on a breadboard. Take chances. Explore.
Re-work. Without the worry that someone's waiting for
the mainframe.

• AC, DC and Transient Analysis

• Up to 120 transistors per circuit

• One-fifth the speed of VAX-11/780

• Affordably priced at $950 (Quantity price breaks)

MicroSim's Probe is an interactive, comprehensive graphics post
processor pro gam option that gives outstanding visual enhancement to
your PSpice work.

MicroSim Corporation

14101 Yorba Street • Tustin, CA 92680 • (714) 731-8091

VAX is a trademark of Digital Equipment Corporation.

IBM-PC is a trademark of International Business Machine Corporation.

26 BYTE • FEBRUARY 1985

Inquiry 217 for Dealers. Inquiry 218 for End-Users.

idex

Apple Owners: Increase your Display up to 455% and

Get The Big Picture!

■

I 40-Columns

| 80-Columns » | UltraTerm

You know the importance of "Bottom Line" and cash-flow
management in your daily operations. Original 40-column
spreadsheets were adequate, 80-column spreadsheets
were better, but even with 80-columns you still waste
valuable time scrolling your spreadsheet searching for
data. The Videx UltraTerm will provide you the tool you
need to reduce wasteful searching, and free up your time
to make important business decisions.

Just look at the actual display photo above. The dark
green portion of the spreadsheet represents the amount
of information you get with a standard Apple display. The
medium green area shows you what you get with ordinary
80-column displays. Nice. But not enough. With UltraTerm,
your business "Big Picture" is exploded up to a full
128-columns by 32-lines (as shown by entire photo above),
or 455% more data than you've previously had to work
with.

UltraTerm i s a trademark o f Videx. Inc. Apple i s a trademark o f Apple Computer, Inc ,
Visicalc is a trademark of VisiCorp, Inc.

1. Except colors which were added for illustrative purposes only.

2. Assuming VisiCalc and Apple 40x24 display. Inquiry 324

In addition to the obvious benefits of using the UltraTerm
with your spreadsheet, you can gain depth, breadth, and
power when using the new generation of word processors
that exploit the UltraTerm's vast array of display
capabilities. Word processors that currently use
UltraTerm's expanded display formats include WORD-
STAR, Word Juggler lie, Letter Perfect, Executive
Secretary, Apple Writer II (with Videx Preboot), and Write
Away.

So, contact your local computer dealer today! If they are
out of stock you can call Videx directly. Get THE BIG PIC-
TURE today!

Suggested Retail Price— $379.00

idex

1105 NE Circle Blvd., Corvallis, OR 97330
503-758-0521

NEW from BORLAND!

Jerry Pournelle,
Byte, July 1984

'TURBO PASCAL appears to violate
the laws of thermodynamics.

You won't find a comparable price/
performance package anywhere. It
is simply put, the best software deal
to come along in a long time. If you
have the slightest interest in
Pascal. . .buy it."

Bruce Webster,
Softalk IBM: March 1984

o o o>'

wnfuAL

•ERSION 2.0

j#py*

li£

BORLAND

INTERNATIONAL

GIFT PACK

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A SAVINGS OF $30!

What a gift for you and your friends! The extraordinary TURBO PASCAL
compiler, together with the exciting new TURBO TOOLBOX and new TURBO
TUTOR. All 3 manuals with disks for $99.95.

TURBO PASCAL Version 2.0 (reg. $49.95). The now classic program
development environment still includes the FREE MICROCALC SPREAD SHEET.
Commented source code on disk

• Optional 8087 support available for a small additional charge

NEW! TURBO TOOLBOX (reg. $49.95). A set of three fundamental
utilities that work in conjunction with TURBO PASCAL. Includes:

• TURBO-ISAM FILES USING B + TREES. Commented source code on disk

• QUIKSORT ON DISK. Commented source code on disk

• GINST (General Installation Program)

.Provides those programs written in TURBO PASCAL with a terminal installation module
just like TURBO'S!

• NOW INCLUDES FREE SAMPLE DATABASE . . . right on the disk! Just compile
it, and it's ready to go to work for you. It's a great example of how to use TURBO
TOOLBOX ana, at the same time, it's a working piece of software you can use
right away!

NEW! TURBO TUTOR (reg. $29.95). Teaches step by step how to use the TURBO
PASCAL development environment— an ideal introduction for basic programmers.
Commented source code for all program examples on disk.

30 DAY MONEY BACK GUARANTEE Available at your nearest software dealer.

For VISA and MASTERCARD order call toll free: l-(800)-2 5 5-8008 i-(800)~742-1133

(Lines open 24 hrs., 7 days a week) Dealer and Distributor inquiries welcome (408) 438-8400

CHOOSE ONE (please add $5.00 for handling and shipping U.S. orders)

All Three-Gift Pack $ 99.95 + 5.00 SPECIAL! Ibrbo Toolbox $49.95 + 5.00

All Three & 8087 139.95 + 5.00 SPECIAL! Turbo Tbtor 29.95 + 5.00

Turbo Pascal 2.0 49.95 + 5.00 Ibrbo 8087 89.95 + 5.00

Check_ Money Order. VISA MasterCard

Card #: Exp. date: _

My system is: 8 bit 16 bit

Operating System: CP/M 80 CP/M 86 MS DOS _

Computer: . Disk Format:

Shipped UPS

PC DOS .

Please be sure model number & format are correct.

NAME:

ADDRESS:

CITY/STATE/ZIP:
TELEPHONE: _

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. is

») BORlflflD

D) INTERNATIONAL

4113 Scotts Valley Drive
Scotts Valley, California 95066
TELEX: 172373

Inquiry 34

Inquiry 101

Eco-C Compiler

Release 3.0

We think Rel. 3.0 of the Eco-C Compiler is the
fastest full C available for the Z80 environment.
Consider the evidence:

Benchmarks*

(Seconds)

Benchmark

Eco-C

Aztec

Q/C

Seive

f\b

125

Oeref

CNC

Matmuit

115

N/A

* Times courtesy of Dr. David Clark
CNC - Could Not Compile
N/A - Does not support floating point

We've also expanded the library (120 func-
tions), the user's manual and compile-time
switches (including multiple non-fatal error
messages). The price is still $250.00 and
includes Microsoft's MACRO80. As an option,
we will supply Eco-C with the SLR Systems
assembler - linker - librarian for $295.00 (up to
six times faster than MACRO 80).

For additional information,
call or write: .

^ed« oPTf.Nc . (317) 255-6476
6413 N. College Ave. • Indianapolis, Indiana 46220

■QTiM

W FORTH

Try the professional language offering
the utmost performance in the shortest
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HP-150,

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Wang PC,

Ail CP/M and
MSDOS computers.

Laboratory Microsystems Incorporated

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

LETTERS

32-bit versions. Choose from our wide
selection of programming tools including
native code compilers, cross-compilers,
math coprocessor support, and B-Tree
file managers. All fully supported with
hotline, updates, and newsletters.

wrong and dishonest to copy software,
even for one's own use. He is absolutely
right. But his statement is incomplete.

The software industry, in general, has
shown a total disregard for honesty in its
marketing. A large portion of the available
software is sold without proper testing. It
is tested by us, after we pay a ridiculous
price for it. Customer support just does
not exist, and the documentation is often
a joke. According to the "rules" l must buy
WordStar for each machine in the office.
And I do not have backup protection with
some software. Even after paying their
price I am held ransom!

My complaint is not against all software
publishers. Lotus, for example, has done
a wonderful job of documentation and
service.

Mr. Wright is right. But incomplete. Two
wrongs don't make a right. But as long as
the publishers are so blatant in their dis-
honesty, software swapping will be with us.
Dave Churcher
Rye, NH

Swift Remark

I really got a big laugh out of Paul Bern-
stein's letter ("Computers and Lawyers."
August 1984, page 16) about the "argu-
ment" between him and his fellow lawyer
Robert Wilkins over whether lawyers need
to know "terms such as RAM, bps. . . .
"and other foreign, often unnecessary
technical terms.'" That from lawyers, ". . .a
Society [that] hath a peculiar Cant and
Jargon of their own, that no other mortal
can understand, and wherein all of their
Laws are written, which they take special
Care to multiply; whereby they have
wholly confounded the very Essence of
Truth and Falsehood, of Right and Wrong."
No comment could better be made on
the subject than that by Jonathan Swift in
Gulliver's Travels, Part 4: A Voyage to the
Country of the Houyhnhnms, Chapter 5.
William E. White
Miami, FL

Modula-2: Overrated?

After reading all those pro Modula-2 and
Ada articles in BYTE (August 1984), I at
first feared I was the only one who har-
bors mixed feelings concerning these lan-
guages. I was relieved to find David V. Mof-
fat's "UCSD Pascal vs. Modula-2: A Dis-
senting View" (page 428).

While I don't agree with all of Mr. Mof-
fat's views (e.g., that the lack of publica-
tions on Modula-2 will become less

(continued)

30 B YTE • FEBRUARY 1985

Inquiry 173

from Microcomputer Accessories, Inc.

TOP DRAWER!

Absolutely first class. Our Keyboard
Storage Drawer is tops— it can turn
your narrow credenza or typewriter
return into a perfect work station.
From a reinforced platform on pro-
tective felt pads, the cantilever
drawer extends on industrial
strength ball bearing glides and
locks into working position. The
scratch resistant finish matches
IBM colors. Optionallocking device.
Also available — an under-desktop
suspension model — the bottom
drawer. But still ' 'top drawer!"

u: ^i

5721 Buckingham Parkway
P.O. Box 3725

Culver City, Calif ornia 90231
Telephone 213/641-1800

Inquiry 355.
In Europe: Inquiry 356 for Dealers.

N.V. Microcomputer Accessories Europe S.A; '
Rue de Florence 37
1050 Bruxelles, Belgique
Telephone 02/538.61.73

These and other fine products are available at
Sears Business Systems Centers, Computer-
land, Businessland, IBM Product Centers and
other computer&oftware retail locations.

LETTERS

distinct in the future), I'd like to point out
a couple of items that have escaped men-
tion so far.

The improved readability of Modula-2
source, achieved by the no-longer-needed
BEGIN...END brackets that contain Pascal
compound statements, is obviated be-
cause of the END statement that ter-
minates all control structures apart from
REPEAT. 1 would have preferred a specific

end statement for each control statement,
like ENDDO, ENDWHILE. ENDLOOP.
ENDIF. etc.

Pascal's lamented rigid order in which
declarations have to be made shows its
main advantage when it comes to soft-
ware maintenance. 1 wouldn't want to look
for that doubly defined global variable
that crept in when an existing program
was extended, were it possible to declare

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as a template with Lotus 123 and Symphony. It takes only 10
seconds to recalculate all forms, is easy to use, and is IRS
approved. Federal 1040 and state forms are $95.00, corporate
returns are $195, and annual updates are only $45 to $75. All
programs require Lotus 123 version 1A and 256Kb or more
memory. To order programs or free detailed catalog phone

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Dealer inquiries welcome.

123 and Symphony are trade

nt Corporation.

said variable anywhere near the pro-
cedure that used it first, let alone in some
external module.

I find Modula-2's IF not much of an im-
provement over that of Pascal as far as
nested IFs are concerned, the latter of
which I tend to avoid and use logical ex-
pressions instead, laking Robert J. Paul's
recipe example ("An Introduction to
Modula-2," August 1984, page 195).
wouldn't you agree that

IF (oregano IN recipe[1])
AND
(thyme IN recipe[1])
THEN

WRITELN('Use oregano & thyme')
ELSE
WRITELN( 'Use only thyme');

is easier to understand than what ap-
peared on page 198?

Edmund Ramm
Kaltenkirchen, West Germany

What a shame that you did not include the
article "UCSD Pascal vs. Modula-2: A Dis-
senting View" by David V. Moffat in the
theme section of your August issue; it
would have provided some balance in
what was an informative but rather biased
section.

1 write to support Mr. Moffat's thesis that
Modula-2 has yet to be proved a signifi-
cant improvement over UCSD Pascal. Hav-
ing used UCSD Pascal since 1980. I can
link in assembly-language routines, build
libraries, and write units with hardly a sec-
ond thought. For programmers, the in-
equality of

Benefits of Modula-2 > Cost of

software +
time to re-
learn + time
to rewrite old
routines

must be clearly shown to be true. 1 have
yet to be convinced that the benefits
outweigh the value of Pascal experience.
Could it be that those software companies
that have sold thousands of Pascal com-
pilers in the past few years now fear that
they are beginning to saturate the market
and are promoting Modula-2 as a means
of maintaining company profits?

One small point: Am 1 the only one who
finds that dozens of ENDs. some for IFs.
some for FORs, some for LOOPs, make
Modula-2 programs less easy to read than
Pascal programs?

Stuart A. Bell

Sidmouth, Devon, England

{continued on page 416)

32 BYTE- FEBRUARY 1985

Inquiry 26

FIXES AND UPDATES

BUGS

C Listing Bug

Bob Bonomo picked out a bug in the C
source listing for the quicksort function in
the October BYTE japan. (See "Bits and
Pieces" by William M. Raike. page 369.)
In listing 1 on page 3 74, the third WHILE
statement should read:

while (j > i&&strcmp(base|j|. pivot) >=0)

Our thanks to Mr. Bonomo.

A Case of Misidentification

A caption in our product description of
the landy 1000 incorrectly identifies a
screen display. (See "The landy 1000" by
G. Michael Vose, December, page 98.)

On page 101, the caption identifies the
screen display on the right as being pro-
duced by DeskMate. The photo actually
depicts a screen from IBM's HomeWord,
a word-processing program that also runs
on the landy machine. HomeWord is pro-
duced by IBM's Entry Systems Division in
Boca Raton, Florida.

Penny Wise, Pound Foolish?

A note arrived from Paul Hills of
Launceston in Cornwall. England, telling
us that we misstated the annual subscrip-
tion fee for his club's newsletter. (See
Clubs & Newsletters, August, page 68.)

The 6809 User Group Newsletter is available
for £3 annually. Overseas subscriptions are
$4.70 in the U.S. and $6 in Canada.

Weather Report Incorrect

Charles S. Barnaby. vice president of the
Berkeley Solar Group, sent us a clarifica-
tion concerning the computer service that
his company offers. In Matthew Lesko's
article "Low-Cost On-Line Databases"
(October, page 167). it was incorrectly
stated that the Berkeley Solar Group offers
"the latest weather."

The Berkeley Solar Group has a large
collection of weather data; however, this
data is based on records at least several
years old. The data is suitable for use with
building energy-analysis software. Portions
of this information are available through

interactive inquiry but the bulk of it serves
as input for hour-by-hour building simula-
tion programs.

The weather data is available for users
of the Berkeley Solar Group's building
energy-analysis software, which includes
such programs as DOE-2. CALPAS3, and
FCHART. The data can be used for other
purposes, but its purchase must be
negotiated on a case-by-case basis.

We thank Mr. Barnaby for clarifying this
inaccuracy on our part. The Berkeley Solar
Group can be reached at 3140 Martin
Luther King jr. Way. POB 3289, Berkeley,
CA 94703. (415) 843-7600.

Books Have American Distributor

Jeffrey A. Blackman of the Computer
Science Press in Rockville, Maryland, sent
us some information about five books
mentioned in the November Books
Received section (page 495).

The books, A First Course in Formal lan-
guage Theory, From logic to Computers. LISP Pro-
gramming, Microcomputers and Their Commercial
Applications, and UNIX for Users, are all
published by Blackwell Scientific; however,
they are distributed in North America by
the Computer Science Press.

If you wish to order these books, con-
tact Computer Science Press Inc., 1 1 laft
Court. Rockville, MD 20850. (301)

2 51-9050.

Windy Day Bug

Mark R. Parker of Seattle. Washington, saw
an error in listing 1, the Module Windy-
Day, in Eric Eldred's review "Volition Sys-
tems' Modula-2" (June, page 353).
In the procedure OpenWindow (page

3 56). the line:

Open (wind, 0, 1, 39);

should read:

Open (wind, 0, 0, 1, 39);

because a call to open requires five
parameters. The omitted second zero
places the message at the upper left-hand
corner of the screen.

Also, the comment "Phony" should be
changed to "little busy bee."

New Telephone Number

Microserve in 'fyler, lexas, which was men-
tioned in the October BYTE, has a new
telephone number for its network. (See
'Low-Cost On-Line Databases" by
Matthew Lesko, page 167.)

The new telephone number is (214)
581-3722.

Photo Credits Due

We inadvertently neglected to credit Lee
Wright, a freelance photographer based
in Medford, Massachusetts, for snapping
the photos that accompanied Henry
Brugsch's article in the Guide to the Apple
Personal Computers, a special supplement to
the December BYTE. (See "Apple's New
Modem and Access II." page A 58.)
We apologize for this oversight.

Address Change

Sinclair Research, whose ZX Spectrum-f
was featured in the December BYTE
What's New. has relocated. (See page 435.)
The new address is Sinclair Research.
Berkeley Square House. London WIX 5LB.
England; tel: 01-499 2666; lelex: 265212.

FEEDBACK

More on POPLOG

In the October BYTE U.K.. we inadvertently
listed Aaron Sloman as the distributor for
POP-1 1 and POPLOG. a pair of tools avail-
able to researchers in artificial intelligence.
(See "Pop and Snap" by Dick Pountain,
page 381.)

Mr. Solman informs us that POPLOG is
marketed in the U.S by Systems Designers
Ltd. International, Suite 201, 5203 Lees-
burg TUrnpike, Falls Church, VA 22041,
(703) 820-2700. In the U.K., it's available
from Systems Designers Ltd., Systems
House. I Pembroke Broadway, Camberley,

[continued)

FEBRUARY 1985 -BYTE 33

Inquiry 342

IEEE-488 Interfaces and
Bus Extenders For:

IBM PC, PCjr
& COMPATIBLES

DEC UNIBUS, Q-BUS
& RAINBOW 100

MULTIBUS, VMEbus
STD& S-100

Full IEEE-488 functionality, with the most com-
prehensive language and operating system cover-
age in the industry. It takes experience to make
IEEE-488 systems work with nearly 4000 devices
available from more than 500 different manufac-
turers, and experience is what enables National
Instruments to take the GPIB to the
second power and beyond.

Your personal guarantee of unsurpassed
customer support and satisfaction.
CALL 1-800-531 -GPIB for instant access
to 100 + man-years of GPIB experience.

f7 NATIONAL
K INSTRUMENTS

12109 Technology Blvd.
Austin, TX 78727
1-800-531 -5086 512/250-9119
Telex: 756737 NAT INST AUS

IBM and PCjr are trademarks ot International Business Machines. MULTI-
BUS is a trademaik of Intel. DEC. UNIBUS. Q-BUS. and Rainbow 100 are
trademarks of Digital Equipment Corporation.

FIXES & UPDATES

Surrey. GUI 5 3HX; tel: 0276 62244.

Mr. Sloman has informed us that "POP-
LOG is now the main official AI software
development environment in the U.K. for
Prolog and POP-I I. The existing 'toy LISP
component (suitable for teaching) is being
replaced by COMMON LISP."

POPLOG, according to Mr. Sloman,
comes with a large collection of on-line
help files, teaching files, and libraries of
utilities and demonstration programs.
Mixed languages are supported, and a
multiwindowed screen editor VED can be
used with all three main languages. It runs

Speaking of Least Squares

on VAX computers under VMS and
Berkeley UNIX. It's also available "on a
growing number" of M68000-based UNIX
machines. In North America it's $10,000,
with a ninety-percent (90%) discount for
educational institutions.

"At present." writes Mr. Sloman,
"POPLOG is too big for most personal
computers. Our hope is that it will not be
long before machines with at least 2
megabytes of RAM and 40 to 100 mega-
bytes of backup storage will be cheap
enough to make POPLOG much more
widely available for educational use."

Steven A. Ruzinsky saw a number of
doubtful statements in Marco Caceci and
William Cacheris's article "Fitting Curves
to Data" (May. page 340). He cites these
remarks:

This is called the least-squares criterion. For
random errors randomly generated (usual-
ly a reasonable assumption), this is the best
criterion of all.

"This is simply untrue," says Ruzinsky. "In
order for least squares to be the best
criterion, the errors must have indepen-
dent and identical normal (Gaussian) dis-
tributions. In situations meeting this re-
quirement, least squares can be a max-
imum likelihood estimate of the param-
eters. For situations where the errors are
not Gaussian, least squares is suboptimal.
A good counter example to the authors'
statement is the case where the errors
have a binary distribution, e.g., a random
sequence of Is and -Is. In this case, I

Electronic Yellow Pages in LA

The vice president of Buy-Phone Inc..
David Lappen, sent us information about
his company's database, which was left
out of Matthew Lesko's article "Low-Cost
On-Line Databases." (See October, page
167.)

Buy-Phone is an "electronic yellow
pages" system serving the Los Angeles
area. It has more than 10.000 listings in
2 5.000 search categories, ranging from
current movie listings, restaurant and
department store offerings, to computer
outlets.

Access is free of charge to users. Busi-
nesses pay $ 1 50 for a year's worth of ad-
vertising; ads can be changed daily at no
extra cost. Personal ads, which are also
free, can be posted for two weeks.

At 300 bps, call Buy-Phone at (213) 474-
0270. At 1200 bps, call (213) 470-4679.

believe one will find a minimax fit (also
called "Chebyshev" or "I oo") much more
statistically efficient than least squares."

Mr. Cacheris notes that the first state-
ment was intended to be broad and that
least-squares analyses are often used
under less than optimal conditions since
the results can be checked by various
methods, such as sensitivity analysis.

"Least-squares method is certainly best
when the errors have identical distribu-
tions . . . |which| we mentioned towards
the end of our article when describing
sensitivity analysis. We state that several
synthetic data sets ... are made by add-
ing identical normal distributions to the error-
less curve. Thus, the least-squares fits to
these synthetic data sets are the best fit
to these data sets and the values of the
parameters obtained should approach the
experimental data's values of the param-
eters if the error in the experimental data
has identical normal distributions."

BYTE'S BITS

Public-Domain Software Library

The Houston Area League of PC Users
(HAL-PC), a group of 1000-plus IBM Per-
sonal Computer fans, maintains a library
of public-domain and "shareware" (i.e., pay
if you like it) software. Disks are available
from the library for $2 per disk. For a
listing of titles, send a self-addressed,
stamped envelope to Nelson Ford. HAIr
PC Librarian, c/o The Public Library, POB
61565. Houston, TX 77208.

Software authors wishing to share their
public-domain or shareware programs are
encouraged to contact the group presi-
dent, Duane Hendricks. Other users
groups interested in trades should contact
lack McClure at POB 610001, Houston, TX
77208. ■

34 BYTE- FEBRUARY 1985

THE NCR PC

IS COMPATIBLE WITH
PEOPLEJOO.

Getting along with all kinds of
people is one of the most endearing
qualities of the NCR PC4.

It gets along with bosses, secre-
taries, accountants, engineers, lawyers,
everybody.

Even first-timers take a liking to
this computer the moment they take it
out of the box.

Perhaps its good looks have a lot
to do with this. But its beauty is more
than skin deep.

Its smart, integrated cabinet takes
up precious little space on your desk.

There are no complicated wires or
clumsy boxes to set up. All you have to
do is plug it in.

The keyboard is the same familiar
layout your fingers know and love. Plus
a couple of nice touches. Like separate

cursor keys and a separate numeric
keypad to make it easier to work with
programs that have long lists and lots
of numbers.

The NCR PC even comes with two
special self-teaching programs that
will have you computing in a matter of
minutes. NCR PAL shows you how to
use the computer itself. NCR TUTOR
introduces you to word processing,
spreadsheets and other popular busi-
ness programs.

And if you get lost along the way,
there's a built-in HELP command you
type in to get you back on track.

Add all this up and you start to see
why the NCR PC is so compatible with
people.

Of course, its also compatible with
thousands of programs available at
computer stores everywhere.

And it's compatible with industry
standard hardware. Which means you

can add on all sorts of helpful accesso-
ries. Like a printer, a modem for elec-
tronic mail, a mouse for even easier
operation and all the memory you
need— up to 640K.

If you'd like to meet this terrific
computer, go to your nearest Author-
ized NCR Personal Computer Dealer.

Just ask for the computer every-
body gets along with.

For the name of your nearest
dealer, call toll-free: 1-800-544-3333.
In Nebraska call: 1-800-343-4300.

Inquiry 230

NCR

A BETTER PERSONAL COMPUTER.

IT'S EXACTLY WHAT YOU'D

EXPECT FROM NCR.

^^&rrrw$j

mmM^mm^imf

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

36 BYTE • FEBRUARY 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.

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 .31mm, 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 \s
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 \s 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 255

For more information call

toll-free:

800-221-1490 Ext. 804

P RINCETON

GRAPHIC SYSTEMS

AN INTELLIGENT SYSTEMS COMPANY

170 Wall Street
Princeton NJ 08540
TLX 821402 PGS Prin

Technologically tuned for excellence

FEBRUARY 1985 -BYTE 37

Ft>R PEOPLE WHO

THOUGHT THeYP
NEVER MEET THE

PERFECT IO

We've got one to knock your socks off.
The StarWriter™ Y10 from C. Itoh.

What sets this letter quality daisy
wheel apart is its fabulous figure. Priced at
only $595.

This little beauty prints 22 letter perfect
characters per second. And like the rest of
C. Itoh's fine printers, the StarWriter Y10
acts without acting up.

That's because it has been thoroughly
tested and proven on the job to assure
reliability. And it comes with a full year's
warranty, backed by over 400 authorized
service centers coast to coast.

The Y10 is an awful lot of printer for very
little money. But that's not surprising when
you consider that C. Itoh's been producing
superior printers for over a decade. What's
more, it has the strong backing of our 126-
year-old parent company with over $60
billion in annual sales.

And the StarWriter Y10 is compatible
with most of the popular PCs. It has a 256-
byte buffer. And there is a full line of
accessories available such as a cut sheet
feeder and tractor feed.

Little wonder C. Itoh printers are No. 1
worldwide, with over 2.2 million sold annu-
ally. And with the StarWriter Y10 we're aim-
ing to keep it that way.

To meet your own perfect 10, just see
your local C. Itoh printer dealer. Or for more
information call 1-800-423-0300.

Or write C. Itoh Digital Products, Inc.
19750 South Vermont Avenue, Suite 220,
Torrance, CA 90502.

BaLnmLFo

DIGITAL PRODUCTS

1984 News Group Chicago. Inc.

" StarWriter is a Trademark of C. Itoh Digital Products. Inc.
- 1985 C. Itoh Digital Products, Inc.

38 BYTE • FEBRUARY 1985

Inquiry 38 for Dealers. Inquiry 39 for End-users.

WHAT'S NEW

Tkndy Unveils $999 Notebook Computer

Radio Shack's battery-
powered notebook-size
Model 200 has a flip-up
16-line by 40-column LCD
and a built-in 300-bps auto-
dial modem. The Model 200

comes with 24K bytes of
RAM and 72K bytes of
ROM, and it includes word-
processing, spreadsheet,
telecommunications, and
address-book programs.

Memory can be expanded
with two 24K-byte banks of
RAM. for a total of 72 K, and
a 32K-byte ROM chip.

The system's keyboard has
60 full-travel sculptured keys,
12 special- and general-
purpose function keys, and a
power switch that is auto-
matically depressed when
the LCD/cover is closed. A
cassete interface and
parallel and serial ports are
standard. The Model 200
weighs 4/2 pounds and
measures 11% by 8/2 by 2 3 / 6
inches.

Although the Model 200
uses the same processor as
the Model 100. changes in
ROM will prevent Model 100
machine-language programs
from running on the Model

200; BASIC programs will
work on both. Other dif-
ferences are a modified cur-
sor key cluster, enhanced
word-processing features,
Microsoft's Multiplan spread-
sheet in ROM. calculator
function available from any
program, and optional pulse
or tone dialing. Normal bat-
tery life is 10-16 hours
depending on RAM size, or
you can install rechargeable
nickel cadmium (nicad)
batteries.

The Model 200 will retail
for $999; 24K-byte add-on
modules cost $249.95 each.
Contact Tandy/Radio Shack,
One landy Center, Fort
Worth. TX 76102. or your
local Radio Shack store.
Inquiry 600.

Datavue Portable Includes Disk Drive, 80 by 25 Display

Quadram's Datavue 2 5 is
a 14 -pound portable
computer with a 360K-byte
5^-inch disk drive and a
pivoting 80-character by
2 5-line LCD. It features an
83-key keyboard that com-
municates with the com-
puter through infrared
signals. The Datavue 2 5 has
an 80C88 microprocessor, a
real-time clock, I28K bytes
of memory, and serial and
parallel ports. It is powered
either by an AC adapter/
recharger or by built-in bat-
teries that last up to four
hours.

Monochrome graphics are
available in either 640 by
200 resolution or 320 by
200 resolution with four
levels of gray. An internal
300-bps modem is an op-
tion. Memory can be ex-
panded to 2 56K bytes using
64K-byte chips or to I

megabyte using 2 56K-byte
chips. Quadram also plans
to release an external IBM
PC-compatible bus-
expansion chassis and an
external second floppy-disk
drive.

The Datavue 2 5 should be
available in March for
$2195. Contact Quadram,
43 55 International Blvd.,
Norcross, GA 30093, (404)
923-6666.
Inquiry 601.

Model 1131 Compass
Has 128-column LCD

GRiD Systems' Model
1131 Compass is a port-
able computer with a 2 5-line
by 128-column electro-
luminescent display (ELD).
GRiD says that the durable
1 0-pound computer is built
to stand a shock equal to
130 Gs. The Model 1 131
features 2 56K bytes of RAM
(expandable to 5I2K bytes),
384K bytes of nonvolatile
bubble memory, a 300/1200-
bps auto-dial/auto-answer
modem, and the MS-DOS
operating system in ROM.

The Compass Model 1 1 3 1
costs $6795; with 51 2 K
bytes, it's $7995. The price
of the original Model 1 100
is now $42 50. Contact GRiD
Systems Corp., 2 53 5 Garcia
Ave., Mountain View, CA
94043, (415) 961-4800.
Inquiry 602.

[continued]

FEBRUARY 1985 -BYTE 39

WHAT'S NEW

Visage

Videodisc Software

Development System

Visage has introduced a
series of products for
developing interactive
videodisc software. Using an
IBM PC or compatible per-
sonal computer, a standard
videodisc player, and
Visage's controller card and
software, developers can
create interactive programs
for educational applications
using images from video-
discs overlayed with
computer-generated text and
graphics.

Visage's Vlink 1000 in-
cludes an IBM PC expansion
card and language-interface
software, which together
support NTSC graphics with
2 56 by 192 overlay capabili-
ties. The Vlink 1 500 adds
the ability to switch between
a 2 56 by 192 overlay and a
320 by 200 nonoverlay im-
age, while the V:Link 1550
allows both 2 56 by 192 and
320 by 200 graphics to be
overlayed on videodisc
images. Prices range from
$1150 to $2150.

The VStation 2000 family
all feature IBM PC-com-
patible computers with 2 56K
bytes of RAM. one or two
floppy disks, the V:Link 1550
graphics board, and a
13-inch RGB color monitor.
Some of the V:Station con-
figurations also include
medium- or high-resolution
touchscreens. 10-megabyte
hard disks, and 512K bytes
of memory. Prices range
from $5995 to $10,850.

Visage's products support
the KoalaPad. Bit Pad. and
Microsoft Mouse as graphics
input devices. Optional sup-
port packages allowing the
Visage software and hard-
ware to be used with BASIC,
Pascal. dBASE II. and 8088
assembly language cost
$295 each. V:Paint I and II.
$500 each, use the Micro-
soft Mouse ($125 extra) to
create images. Cables are
available to link the V:Link

NEC Introduces Four-Color Plotter

Britewriter is a four-pen
color plotter that NEC
says is compatible with
Hewlett-Packard plotters. The
Britewriter can plot at a
speed of 60 millimeters per
second (mm/s) in low-speed

mode and 112 mm/s in high-
speed mode. Characters can
be drawn at 4.6 cps in one
color or 2.6 cps in four col-
ors. The plotter comes with
black, blue, green, and red
felt-tip pens; an optional set

of colors includes violet,
orange, brown, and pink
pens. The plotter can be
used with plain paper or
transparencies up to 8/2
inches wide.

The Britewriter is available
with parallel or RS-232C
serial interfaces. It features a
2 56-byte character and in-
struction memory and sup-
ports the ASCII character
set. Because it uses the
same commands as Hewlett-
Packard 7470 and 7550A
plotters, it works with most
graphics programs that
support Hewlett-Packard
plotters.

The Britewriter plotter will
retail for $599. Contact NEC
Information Systems Inc..
1414 Massachusetts Ave.,
Boxborough, MA 01719.
(617) 264-800.
Inquiry 604.

Commodore Announces 128K Computer

Commodore's B128 runs
any program written for
the Commodore 64 and has
a number of additional
capabilities. This sytem has
128K bytes of memory, ex-
pandable to 512K, and it
can display 80 columns by
2 5 lines of text in color on
an optional monitor. In addi-
tion to the 8500 processor.

which is used to run Com-
modore software, the B128
includes a 2-MHz Z80 co-
processor to run most
CP/M-80 programs.

The 92-key keyboard has a
numeric keypad, 4 cursor
keys, 4 numbered shiftable
function keys, and 4 special-
purpose function keys. Like
the 64, the B128 can display

16 colors and 8 indepen-
dently movable sprites and
can generate sound in three
voices each with a range of
eight octaves. The B128
comes with the same serial,
expansion, user, and joystick
ports as the 64; it also in-
cludes video interfaces for a
standard television or an
RGB or NTSC monitor.

Commodore also intro-
duced a faster disk drive for
the Commodore 64 and
B128. It transfers data to the
64 at 320 cps, or to the
B128 at 2000 cps, or. when
running CP/M, 3200 cps.

The Commodore B128 will
sell for less than $400. Con-
tact Commodore. Computer
Systems Division, 1200
Wilson Dr., West Chester, PA
19380, (215) 431-9100.
Inquiry 605.

card to Sony, Pioneer. RCA.
and Hitachi videodisc
players.
Visage supplies its V:EXEC

and V:Draw software and
one language interface with
all V:Link and V:Station
products. Contact Visage

Inc.. 12 Michigan Dr.. Natick.
MA 01760, (617) 655-1503.
Inquiry 603.

{continued)

40 B YTE • FEBRUARY 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, 1 28K 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 simultaneously handle
8" and 5W' 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 1 28K 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!

NEW! SBC 86/87

-mm

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-150 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 310

Yes, ~«*

I'm interested %
in information ^ 4

regarding:
□ Systemaster II
□ SBC 86/87 □ Z-150 MB
□ Evaluation Program
□ Teletek's S-100 Board Line

Name_
Company.
Address

WHAT'S NEW

Modular Robot Kit

Cybot's TUtor is a
modular robot with a
five-axis arm designed for
educational and training
uses. Because the robot can
be dismantled and reassem-
bled many times, it helps
you understand how
robotics work.

The package includes the
robot arm, complete with
five motors and a gripper,
and the Controller module,
which has one free S-100
card slot for custom applica-
tions, a standard RS-232C
serial port, and an interface
for an optional "teach pen-
dant." You can control the
robot arm by sending ASCII
commands from a personal
computer through the
RS-232C port or by directly

manipulating the arm with
the teach pendant.

Also available is an Op-
tical Encoder Set. Since the
set indicates the actual posi-
tion of one of the motors
(five are needed to monitor
all five axis motors), a full
feedback loop can be used
to make sure the robot arm
is precisely where it's sup-
posed to be.

The complete Cybot llitor
robotics kit costs $3395.
The optional teach pendant
is $129.95. Each Optical En-
coder Set is $70. Parts of
the robot kit can be pur-
chased separately. Contact
Cybot Inc., 12 510 128th Ave.
NE, B-5, Kirkland, WA
98034, (206) 823-4156.
Inquiry 606.

Computer Satellite Service

Satellite Broadcast Net-
work has announced a
satellite service that will
transmit financial and news
information to personal
computer owners. SBN plans
to have the service opera-
tional in May. You will need
a 12 -GHz satellite-receive
antenna, a low-noise
amplifier, a solid-state
receiver, and SBN's
demodulator; all are
available from SBN for $695.
SBN will also charge a fee
for access to each type of
information, starting at
about $2 5 per month.
SBN will use multiple
9600-bps channels. Some
channels will broadcast news
and weather information,
others will transmit stock
and commodity prices. One
channel might permit down-
loading of software sample
programs, while another
could include special-interest
database information. A
user could place a request
for special database infor-
mation with modems and
telephone lines, but the
response could be broad-

cast via satellite to avoid
phone charges. A special
header code would ensure
that only one person could
decode the information.

Contact Satellite Business
Network Inc.. 212 West
Superior St., Chicago, IL
60610, (312) 266-9844.
Inquiry 607.

Sord Adds 80 by 25
Display to IS- 11

Sord has released a ver-
sion of its IS- 1 1 Consul-
tant computer with an
80-character by 2 5-line
liquid-crystal display and a
built-in 300-bps modem. The
6 /2-pound IS-11C has 80K
bytes of RAM (expandable
to 144K), 72K bytes of ROM,
a 128K~byte microcassette
tape drive, 62 full-travel
sculptured keys plus 8
special function keys, and a
CMOS Z80A microprocessor
running at a speed of 3.4
MHz. In addition to parallel
and serial ports, the IS-IIC
can interface with a bar-
code reader, a separate
numeric keypad, and op-
tional 64K-byte ROM car-
tridges. Word-processing and
communications software
are standard in ROM.

The IS-IIC should be avail-
able this month for $1495.
For more information, con-
tact Sord Computer of
America Inc.. 645 Fifth Ave..
New York. NY 10022, (212)
759-0140.
Inquiry 608.

[continued)

42 BYTE • FEBRUARY 1985

PERSONALITY
PROBLEM?

UNIX™ and DOS™ At the Same Time!

Looking at an IBM PC/AT? Happy with DOS but want
UNIX? Happy with UNIX but want DOS? Want them
working together?

Get The Connector!™

The Connector is a revolutionary product that allows
DOS applications to run on the IBM PC/AT or XT
under VENIX/86 (the first licensed AT&T UNIX
operating system for the IBM PCs) or PC/IX. That
means you can add one or more terminals to your AT
which run programs using multi- user VENIX/86 to
share the disk and printer. Switch between UNIX and
DOS at the console with a single command. And run
more than one task simultaneously. Like running a
spelling check in the background while you print a
report and run Lotus 1-2-3™ or dBasell™

Get yourself an AT and load it with VENIX. Collect
your DOS and/or UNIX applications. Well supply The
Connector. The right solution to your software per-
sonality problems.

Call for complete details.

Unisource Software Corp., Department 4109,
71 Bent Street, Cambridge, MA 02141.
Telex 92-1401 /COMPUMART CAM.

617-491-1264

Also

available
on the
PC/XT and
compatibles.

* UNIX is a tr:s- Inc. DOS is a trademark of Microsoft, inc. PC/AT and PC/XT are trail ( Sic i on lit ever is .1 trademark

of Uniform Software Systems, Inc. VENJX/86 Implementation by VtmurCnm. Inc. 1 -2-3 unit LOTUS arc trademarks of Lotus Development Corp. dBasell is a
trademark of Ashlon-Tatc.

Inquiry 318

Getting UNIX Software
Down to Business

FEBRUARY 1985 -BYTE 43

WHAT'S NEW

Digital Filtering Chip for Speech Processing

Kurzweil Applied In-
telligence has intro-
duced the KSC 2408 digital
filter chip for use in sound-
processing applications.

Each of the eight filters in
the KSC 2408 processes 24
bits of information (with 48
bits accumulated at a time).
Each of the filters processes

information in a given fre-
quency range; Kurzweil says
that dozens of filters— or
many 2408 chips— would be
needed to divide up the fre-
quency spectrum of the
human voice enough to
make speech recognition
possible.

The 2408 can process
sound up to a sampling fre-
quency of 12 5 kHz (12 5,000
cycles per second) if only
two filters are activated; if
all eight filters are activated,
the maximum sampling rate
is 32 kHz. Since the chip is
programmable, it can be
used for other types of
digital filtering, including
high-pass, band-pass, or low-
pass.

Kurzweil plans to market a

10,000-word vocabulary
speech-recognition system
and is working on develop-
ment of a voice-activated
typewriter. Company
founder Raymond Kurzweil
earlier developed the
Kurzweil Reading Machine,
which can read text for the
blind regardless of the
typeface, and the Kurzweil
2 50 digital keyboard (music
synthesizer).

The Kurzweil 2408 digital
filter chip costs $81 for a
3-MHz version or $101 for a
6-MHz version; quantity dis-
counts are available. Contact
Kurzweil Applied Intelligence
Inc.. 411 Waverley Oaks Rd.,
Waltham, MA 02154, (617)
893-5151.
Inquiry 609.

Twelve Million Instructions per Second

According to Cromemco.
its Maximizer copro-
cessor subsystem executes
an average of 12 million in-
structions per second. The
Maximizer features a
2900-series ECL (emitter-
coupled logic) bit-slice pro-
cessor running at 48 MHz. It
also has I6K bytes of 50-ns
RAM, 16 dual-port registers,
and 4096 48-bit words for
downloaded microcode in-
structions. Cromemco says
the chip's speed is en-
hanced by the use of a
60-ns multiplier chip and a
doubly pipelined instruction
path. Most instructions ex-
ecute in 62.5 ns, though
some may take as long as
125 ns.

The Maximizer comes on
two S-100 (IEEE-696) bus
boards that plug into
Cromemco's microcom-
puters. The system runs
under the company's Cromix
operating system, and it will
soon run under UNIX
System V as well.

The Maximizer supports
FORTRAN. Pascal, and C.
Also available is MAXASM,

a microcode assembler used
to write custom microcode
for applications where ex-
ecution speed is critical.

The Maximizer retails for
$3495; the MAXASM Micro-
code Assember costs $2995.
Contact Cromemco Inc.. 280

Bernardo Ave. POB 7400,
Mountain View, CA 94039,
(415) 964-7400.
Inquiry 610.

Data Access Enhances Database Program

Data Access Corpora-
tion's DataFlex 2.1 is a
1 6-bit version of the com-
pany's multiuser relational
database programming
system. It permits over 16

million records per file, up
to 250 files, each as large as
the operating system will
handle (up to 2 gigabytes,
32 megabytes in MS-DOS),
and use of unlimited RAM.

The package includes a
relational database com-
mand language, a custom
menu system, and an ap-
plication generator. Versions
of the program are available
for such operating systems
as MS-DOS/PC-DOS 1.1
through 3.1. CP/M. CP/M-86,
Concurrent CP/M-86. MP/M,
MP/M-86, and 'IurboDOS.
DataFlex also operates
under a number of network-
ing systems.

Pricing depends on the
computer, operating system,
and number of users; a
single-user IBM PC version
is $995. A separate run-time
version is available. For
details, contact Data Access,
852 5 Southwest 129 Terrace,
Miami, FL 33156-6565. (305)
238-0012.
Inquiry 611.

[continued on page 42 1 )

44 B YTE • FEBRUARY 1985

Need RGB color and
TTL monochrome A
support from a /
single board?

#*-F**'/S

INrELUGENr 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

Iook 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.

Ever/one 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., Paramount, CA 90723
Toll Free Tel: (800)325-2455 Calif. Tel: (213)633-5504 Telex: 509098

Inquiry 150

FEBRUARY 1985 'BYTE 45

STEM

Components are the essence of your computer.
Without the right components, you're restricting
your system's potential for maximum productivity.

CompuPro components enable you to make the
most of your computer's capabilities. Choose from
more than 25 boards to build or expand your system
. . .to any of our ten fully integrated models. You
can add more users to your CompuPro system,
increase its memory, add a hard disk drive— all
with modular components that mesh perfectly
with your existing system.

Since 1973, our design team has been recognized
for creating the highest performing, most reliable
products at the lowest possible price. For the
toughest business, scientific and industrial com-
puting environments— across the country and
around the world— make CompuPro IEEE 696/
S-100 components the essence of your system.

Cpu Boards

Mdrive®/h

512K or 2 Mb disk memory board. Emulates disk drive operation
and runs under CP/M®or MP/M™ Can increase operating speeds
up to 3500%. Expandable up to 4 Mb for even more storage.

46 BYTE • FEBRUARY 1985

CPU 68KI M 68000-based board with sockets for memory
management unit and up to 8Kx16 (16 Kb) of EPROM.

CPU 86/87I M 8086-based board with sockets for 8087 math
processor and 80130 firmware chips. Compatible with 8- and
16-bit memory.

CPU 8085/88I M The original, much imitated dual processor
board delivers 8-bit, 16-bit, or 8- and 16-bit computing capability.

CPU-ZI M Includes all standard Z80B features. Downward compati-
bility with the vast library of 8080 software.

CPU 32016I M A true 32-bit processor for the desktop micro-
computer. Compatible with 8- and 16-bit memory.

CPU 286I M Based on the high-performance iAPX 80286/10 16-bit
processor. 100% software compatible with 8086 and 8088 proces-
sors for unprecedented speed and power.

Cmos Static 12 Mhz Memory Boards

RAM 22™ 256Kx8 or 128Kx16-works automatically with 8- or
16-bit processors. A low-power, high-density RAM board.

RAM 23I M 128Kx8 or 64Kx16-works automatically with 8- or
16-bit processors. A low-power, high-density RAM board.

Dual Fu

isk Subsystem,

Two 8" floppy drives provide up to 2.4 Mb of formatted storage.
With all-metal enclosure, Disk 1A™ controller, rugged power
supply, cables, and software: Digital Research's CP/M-80™ and
CP/M-86®

8" Floppy Hard Disk Subsystem

One or two 8" floppy disk drives and one 20 Mb, 40 Mb or 80 Mb
hard disk drive in all-metal enclosure with controller; rugged power
supply, cables and software. CP/M-80 and CP/M-86.

Disk Controller Boards

Disk 1AI M High-performance, high-speed floppy disk controller
for 8" and 5 1 /4 " drives; reads and writes most popular formats.

Disk 2™/Selector Channel™ A high-performance 8" Winchester
disk controller with high operating speed and flawless DMA.

he Essence Of Computing

System Support T

Clock/calendar; math processor option; RS-232C serial port;
interval timers and interrupt controllers; plus many more useful
features.

Systems

CompuPro's extensive System 816 series of fully integrated single-
and multi-user microcomputers includes eleven IEEE 696/S-100
bus models offering 8-, 16- or 32-bit operation, and our
CompuPro 10 and CompuPro 286 business computers.

All are CP/M or MP/M based, enabling users to access more than
3,000 industry standard application programs.

Desktop Enclosure 2

With shielded/terminated 21-slot motherboard, power supply, fan,
dust filter, rugged all-metal construction.

"Bits, Bytes and Buzzwords" is a primer for those who want to
get started right in business qomfluting. 25 pages.

"CompuPro Product User Manuals" Volume 1. 250-plus pages.

"CompuPro Product User Manuals " Volume 2. 300-plus pages.

"Interfacing to S-100/IEEE 696 Microcomputers" by Mark Garetz
and Sol Libes. 321 pages.

Individual technical manuals also available.

WRANTY

All CompuPro products are backed by a one year limited warranty
with a two year option. We also offer nationwide on-site service by
Xerox Americare™-free with the purchase of designated systems.

Disk 3I M A high-performance Winchester disk controller for 5Va "
hard-disk drives. High speed "burst mode" DMA transfers each
disk sector in a block.

Interface Boards

Interfacer 3™ Eight RS-232C serial ports

(2 synchronous/asynchronous, 6 asynchronous).

Interfacer 4I M Three RS-232C serial ports, one parallel port, one
Centronics parallel port.

Mpx 1

Multi-user system front-end processor with 16K on-board RAM.
Intended for OEM applications only.

High-Performance Motherboards

Quiet, fast and reliable. Shielded with active termination. A variety
of formats (6, 12 or 21 slots) offers maximum flexibility.

Inquiry 58

(ompuPro

3506 Breakwater Court, Hayward, CA 94545

For further information and the location of the participating
Full Service CompuPro System Center nearest you, call
1-800-367-7816. In California call (415) 786-0909 ext. 206.

CP/M and CP/M-86 are registered trademarks and MP/M and CP/M-80 are trademarks of Digital
Research Inc. SuperCalc is a trademark of Sorcim Corp. dBASE II is a registered trademark of Ashton-
Tate. Americare is a trademark of Xerox Corp. MDRIVE is a registered trademark and CPU 68K,
CPU 86/87. CPU 8085/88, CPU-Z. CPU 32016, CPU 286, Disk 1A, Disk 2. Selector Channel, Disk 3,
RAM 22, RAM 23, Interfacer 3, Interfacer 4. System Support 1, MPX-1 and The Essential Computer
are trademarks of CompuPro

FEBRUARY 1985 • BYTE 47

ASK BYTE

Conducted by Steve Garcia

Corona Compatibility

Dear Steve,

I've had my Corona PC for about a year
now, and for the first time I've run into an
incompatibility with the IBM PC The prob-
lem is that the IBM PC has an extra open
socket built into it to add a ROM or
EPROM, and the Corona doesn't. A few
programs on the market make use of this
socket, including a genetics program I am
interested in. Is there a fairly simple way
to add an extra ROM chip?

Another problem is that my BIOS is writ-
ten on a 28-pin 2764, while the chip for
the genetics program is on a 24-pin
2732 A. How can I use the 2732 in my Cor-
ona, and what is the difference between
a 2732 and 2732A anyway?

Yet another problem is the Corona's in-
compatibility with IBM graphics, lb get
graphics on the IBM, you must buy a
graphics color card, which uses memory
locations B800 to BCOO hexadecimal. On
the Corona, different RAM locations are
used for graphics. Is there a way to modify
programs that need the color card (e.g..
Flight Simulator) so that they will work on
the Corona? It may not be that difficult
because there is a graphics driver by HST,
which if loaded before Lotus 1-2-3,
enables 1-2-3 to draw graphs perfectly on
my screen.

Richard Berman
King of Prussia, PA

You should be able to add a ROM to
the Corona by installing it on an expan-
sion board with the proper interfacing
circuitry. This could be built on a PC pro-
totyping board, such as those produced
by Vector Electronic Co., POB 4336,
12460 Gladstone Ave, Sylmar, CA 91342,
(818) 365-9661. Since all 20 address lines
are available in the I/O channel (expan-
sion slots), you can set up the address-
ing as required for the ROMs with your
genetics program. There could be inter-
ference between the Corona's BIOS ROM
and the add-on ROM. IBM uses 40K
bytes out of the 48K bytes of reserved
ROM space, and I suspect that the
Corona uses the same space to preserve
compatibility with IBM.

The 2 732s are programmed at +25 V

while the 2 7 32 As require only 21 V.

A possibility exists that the HST graph-
ics-driver program you mention may
allow you to run the new Microsoft Flight
Simulator on your Corona but not the
original version. The new version can be
loaded from DOS with the command FS,
so a driver can be loaded ahead of the
program. The original version could be
loaded only by rebooting, which of
course wipes out the graphics driver. See
your dealer for a demonstration before
you buy because there may be other in-
compatibilities not fixed by the HST
driver.— Steve

Source Book Needed

Dear Steve,

As a computer counselor, I help clients
with hardware and software purchases,
checking sources and buffering clients
from high-pressure salespeople. Since I
am not affiliated with any computer manu-
facturer or outlet, I do not limit my clients
to the selections of a particular store.
However, this lack of affiliation means that
I do not receive promotional materials,
which limits my effectiveness. Can you
recommend any source book that lists
various computer manufacturers and gives
at least minimal specifications on their
products?

Patricia Selk
Stafford, VA

Many sources of information of the
type you need are available. First, most
computer magazines, including BYTE,
publish reviews of microcomputers, pe-
ripherals, and accessories. These are a
good source of unbiased information.

Second, you can get promotional infor-
mation from manufacturers by writing to
them on your letterhead, explaining your
needs. Their addresses are available in
ads in BYTE and other magazines and are
frequently published in buyers guides
and directories available at most com-
puter stores and many bookstores.

A third source is companies that spe-
cialize in publishing survey reports on this
type of equipment One of these is Data-
pro Research Corporation, 1805 Under-

wood Blvd., Delran, NJ 08075, (800)
257-9406.SX.eve

Drive-Head Problem

Dear Steve,

I bought an Atari 800 and two Atari 810
disk drives three years ago. Some time
ago. one of the drives began to have prob-
lems. Before realizing that it was only a
burned-out 1C, I measured the head's
resistance with a digital tester. Since then,
the drive seems to be able to write but
does not read. I think I've magnetized the
head. I tried to demagnetize it with various
methods (including the use of a commer-
cial head demagnetizer for cassette
recorders), but I haven't had any success.
If you think I must replace the head, could
you tell me where I could buy it?

Odino Ciai
Buenos Aires, Argentina

Digital testers normally do not supply
enough current to damage a disk-drive
read/write head. You did not say whether
you could write to a disk and read it from
the other drive. It is possible that the
alignment of the head was disturbed
when you were making your tests. Try
some cross-checks to see if that is the
case. Also, check the obvious things, such
as dirt on the head and a worn head-load
pad. The head-load pad is a little felt pad
that keeps the disk in contact with the
head. If it is worn, data may not be prop-
erly read or written. Check the continui-
ty of the read head with an ohmmeter
or your digital tester. If the head coil is
open, see if there is a mechanical break
in the wiring.

If you are convinced that the head is
defective, a replacement can be obtained
from Micro Peripherals Inc., 9754 Deer-
ing Ave., Chatsworth, CA 91311, (213)
709-4202.-SX.eve

Sharing Files

Dear Steve,

We have several Eagle PCs in our
analytical laboratory, all of which use two
pieces of software: pfs:File and Lotus

[continued]

48 BYTE- FEBRUARY 1985

WORD PROCESSORS AT THE LEADING EDGE

Ah, the great ones . . .

They organized their ideas, their intui-
tions, their idioms. They set them down,
sorted them out, arranged them and
re-arranged them till they came out right.

They used small scraps of paper to
record huge hunks of Truth; primitive
tools to produce profound prose. But
when the words finally went forth, they

made indelible marks on all who read
them.

The amazing thing is that these mon-
umental processors of words, did it
without the benefit of monumental help.

Like Leading Edge Word Processing:
the easiest to use, yet most potent
piece of software ever created to take
full advantage of all the power inherent,
but until now un-tapped, in today's

most sophisticated personal computer:
(Like the IBM® PC and the even faster
and more powerful Leading Edge"" &
AT&T.)

The heart and soul of it is a 51/4"
floppy disk, elegantly logical instruction
manual and documentation . . . every-
thing. And what you end up with is
word processing at the leading edge.

LEADING EDGE ™ WORD PROCESSING FROM $100

IBM IS A REGISTERED TRADEMARK OF INTERNATIONAL BUSINESS MACHINES CORPORATION.
LEADING EDGE IS A TRADEMARK OF LEADING EDGE PRODUCTS. INCORPORATED.

Inquiry 178

FEBRUARY 1985 "BYTE 49

MINORITY

HI-TECH

INDUSTRIES

CALL TOLL FREE
1-800-428-7979

Call on Other Items Not Listed

PRINTERS • PLOTTERS

Epson Call

Enter

Sweet-P 6 Pen Plotter $739

Inforunner

Riteman Blue Plus 140CPS IBM $272

Riteman Plus 120CPS 229

Riteman 15 160CPS 8K Buffer 490

Riteman Blue Mac 140CPS 383

Riteman L.Q 215

Juki

5500 Call

6100 $400

6300 Call

Legend Can

Okidata Can

Silver Reed

EXP400 P or S $240

EXP500 P or S 303

EXP550 P or S 395

EXP770 P or S 769

MODEMS • MONITORS • DRIVES

Anchor

Mark XII $235

Express 1200 Baud (Hayes Exact) 272

Volksmodem 1200 Baud 1 SO

Hayes

Smartmodem 1200 $469

Smartmodem 1200B (IBM) 405

Novation

Smart Cat Plus 2400 Baud $695

Smart Cat Plus 1200 Baud 299

Access 1-2-3 w/Crosstalk (IBM) 359

Apple Cat II 1 95

Zoom

Netmaster (lie. II + ) $115

Amdek Can

Taxan

Amber 12" 116 $115

Amber 12" 122 (IBM) 131

RGB 12" 425 (IBM) 415

RGB 12" 440 (IBM-ULTRA-RES) 566

Persyst Bob Board (for 440) 390

NEC Call

Team-Mate

1110 Internal 3.3MEG Disk (IBM) $698

COMPUTERS • CARDS

NEC

PC-8401A Computer $839

PC-8201A Computer 299

PC-8201 A-90 Battery Pack 17

PC-8206A 32K Ram 173

PC-8271A AC Adapter 17

Paradise

Modular Graphics Card $269

MGC with A & B Module 526

SOFTWARE • DISKETTES

Enable Call

LotUS 1-2-3 Call

Micropro

WS Pro (IBM) $235

WS 2000 245

WS 2000+ 295

Practicorp

Practiword/Base/Calc III (IBM) $ 1 89

Above each separate 69

Maxell

MD-1 (Oty 100) $172

MD-2 (Qty 100) 220

MF-1 3.5" (Qty 100) HP & MAC 303

Fuji

MD-1 (Qty 100) $159

MD-2 (Qty 100) 1 99

MF1 3.5" (Qty 100) HP & MAC 299

MD2HD (Qty 100) IBM-AT 546

SOFTWARE NON-RETURNABLE

MINORITY HI-TECH INDUSTRIES

5021 N. 20th Street, #10261
Phoenix, Arizona 85064

Other Information: (602) 890-0596

MosterCord

• WE BUY •
SURPLUS GOODS

Sisj

ASK BYTE

Prices reflect3-5% Cash Discount. Shipping on most items
$3.00. Prices and availability subject to change without
notice. Send cashier's check or money order ... All
other checks delay shipping 2 weeks. add #185

1-2-3. Because each computer is produc-
ing data that is eventually compiled into
the same reports, it would be a great time-
saver to have the systems all sharing a
common hard disk containing the basic
software as well as the data files.

Does this type of data-file sharing re-
quire an elaborate LAN (local-area net-
work) setup? It seems that a simple multi-
ple linking of the PCs to a large hard disk
would serve our purpose nicely or are we
greatly oversimplifying the problem?

We are considering moving up to a true
relational database-management system
such as dBASE II (or 111) or Condor but are
still unsure that the file-sharing system we
have in mind will work.

Your advice on just how complicated (or
simple) such a system could be would be
greatly appreciated and would surely help
us out of a real quandary.

Charles Harper
Dallas, TX

Your situation appears to be one that
does not require an LAN— yet! But you
would probably be better off if you did
plan for one, especially if you intend to
move up to a true relational database
system. Even your simple file sharing
could cause some potentially disastrous
problems without the "safety net" of true
LAN software. I am referring to problems
that occur when two individuals access
the same file simultaneously. Under cer-
tain conditions, it is quite probable that
when two people write to the same file
at nearly the same time, the resulting file
will be incorrect from either' s point of
view. Worse yet, a condition called "fatal
embrace'' can essentially hang up the en-
tire system until it is manually reset
Another point to remember is that not
all software is ready for multiple users,
although most LANs provide some
mechanism to make it usable while avoid-
ing the problems I've mentioned.

Two suppliers featuring LAN hardware
and software are Corvus Systems and Or-
chid Technology. Another possibility is to
purchase an IBM PC AT and IBM's net-
working software (when it becomes
available).

Corvus can be reached at 800-4-
CORVUS. Orchid Technology is located
at 47790 Westinghouse Dr., Fremont, CA
94539, (415) 490-8 5 8 6. -Steve

Track Balls Are Better

Dear Steve.

I use my Z-I00 almost exclusively for
word processing and other nonnumerical

data-manipulation tasks. I find the number
pad to the right of the keyboard useless
except for the cursor-control keys, which
I think are tedious and clumsy.

What about this: replace the number
pad with a track ball for cursor control.
Or even better, an upside-down mouse (I
never could understand why they had to
run around on a tabletop— mine is always
too cluttered) with one or two appropriate
function buttons.

Is this possible? Am I the only one who
would use such a gizmo? Where can I go
for information on how this might be
done?

Michael R. Thomas
Port Arthur, TX

Some people who use track balls and
mice claim that they would never go back
to using cursor-control keys again. That
is why several companies are making
these devices for micros. Your idea to in-
corporate such a device into a keyboard
is a good one, but it will have to be done
by keyboard manufacturers. There is no
easy or economical way to modify your
Z-100 keyboard, due to the differing
natures of keyboards and mice and their
interaction with a particular program. A
keyboard sends a unique code to the
computer for each key as it is pressed.
A mouse or track ball does not generate
the same code when it is used, and the
information it does generate usually
enters the computer through a different
port.

Add-on mice are sold with utility soft-
ware that translates the signals from the
mouse into usable information. A word
processor, for example, has been written
to accept the control codes generated by
certain keys (the cursor keys) and always
expects those codes to come from the
keyboard. Most current software is not
written to take advantage of mice or
track balls and would have to be
modified to use these devices. Of course,
Microsoft's Word program was written
specifically for a mouse. Other programs
are appearing that also use mice.— Steve

Power-Line Pollution

Dear Steve.

I greatly appreciated your article "Keep
Power-Line Pollution Out of Your Com-
puter" (December 1983, page 36). A near-
by lightning flash once damaged a tran-
sistor board in my RCA television.

To protect my IBM PC. I am using the
Radio Shack filter strip (cat. #26-1451).

[continued]

50 BYTE* FEBRUARY 1985

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 fonts, 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 352

INTERNATIONAL MICROCOMPUTER SOFTWARE, INC.
633 Fifth Avenue • San Rafael, C A 94901 • 415/454-7101

RUNS ON: IBM PC/ compatibles,
and Corona PC, 192K
RAM. IBM PCjr., and
Mindset, 256K RAM.
HP 150, 320K RAM.
All require DOS 2.0 and
up and 1 drive.

MICE: Summagraphics, Mouse

Systems, Microsoft.

JOYSTICKS: Any IBM compatible.

GRAPHICS Amdek, Hercules, IBM,
CARDS: PCjr., Quadram, Scion,

Tecmar, STB, Paradise.
MON ITOR: Color or black and white.

OUTPUT: Printers: IBM /Epson
graphics, Epson FX-80
and 100, MX 80 and 100,
IDS Non-Color, IDS
Prism Color, NEC 8023,
C-ltoh8510, Okidata8X
or 9X series, Radio
Shack CGP-220, Xerox
1770, PrintaColor
TC1040, Quadram
Quadjet, Transtar Color,
Diablo C1 50, Tektronix
4695, HP Thinkjet, Star
Micronics, Epson JX-80,
Data Products 8050,
IBM Color printer.
Plotters: HP 7475A and
7470A.

PC Paintbrush is a registered trademark of ZSOFTCORP.

FEBRUARY 1 985 • BYTE 51

ASK BYTE

Would you please answer the following
questions?

Is it necessary to connect my IBM PC
Color Display Monitor to the 0.5-A moni-
tor outlet on the filter, as recommended
for Radio Shack monitors?

My PC is connected to the 1.2 5- A pro-
cessor outlet. Is this all right?

I could not determine from your article
where the MOVs are to be soldered on this
unit. Could you tell me where they go?

Is it advisable to remove disks from
drives before turning the main power
switch on?

I also need your help on a different
problem. We have often found that our
telephone bills contain calls we did not
make. The telephone company doesn't
charge us for these calls, but this involves
an examination of each bill and checking
with Ma Bell to determine whether we
made suspect calls.

The computerized telephones being in-
troduced are becoming more sophisti-
cated, but none, as yet. keeps a record of
outgoing calls. Is it possible to modify
such a unit or to inexpensively build a
device that would do this?

I have one Ibuch-Tbne and two rotary-
dial telephones, and I would like the new
unit to be attached to one of them that
would record outgoing calls on all three.
Sidney Belman
Teaneck, NJ

The Radio Shack filter strip was origi-
nally designed for the TRS-80 Model I
computer, and the filters for each outlet
were designed to handle different types
of noise. The outlets have current limita-
tions because the filters have current
limitations. As long as the current ratings
are not exceeded, any socket can be
used.

The IBM PC is rated at 200 W at 120 V
AC This works out to 1.66 A, which is in
excess of the 1.2 5 -A rating of the filter.

It is not necessary to remove disks from
the drives before turning on the PC. It
was a problem on the TRS-80 Model I,
but the PC has an a utoboot feature that
allows the disk to be inserted prior to it
being turned on.

Recording outgoing telephone calls can
be accomplished by a simple pulse-
counter circuit connected to a computer.
The computer would poll the line to see
if a call were being made and then read
and store the output of the pulse counter.
A suitable pulse-counter circuit can be
found in Telephone Accessories You Can
Build by Jules H. Gilder (Hayd en, 1976).

[continued]

52 BYTE • FEBRUARY 1985

Inquiry 194

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

gUEASE

New"

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

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

MEW*

euease

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, otherhosts 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

TRS80MODEL3

149

CP/M-80 HOST

750

APPLE

/PRO UPGRADE

250

TRS 80 MODEL 4

199

APPLE HOST

750

RADIO SHACK

Z (VI EDITOR)

C TUTOR COMPILER

PHACT DATABASE

C GRAFX

SUPERDRAW

UNI-TOOLS 1

125
99

299
99

TRS 80 PRO (3 & 4)

AZTEC C65 C COMPILER

APPLE DOS 3.3
PRODOS
E EDITOR

299

199

CALL

VAX HOST
MACINTOSH

CALL
CALL

COMMODORE 64
MACINTOSH

QUICKC

125

TRS 80 RADIO SHACKTRS DOS

s a trademark of TANDY.

MANX SOFTWARE SYSTEMS
Box 55
Shrewsbury, N J 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 (NJ)

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 1BA - 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 195

FEBRUARY 1 985 • BYTE 53

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 He 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 more functional 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-$437

■ up to 8 independent channels

■ range and offset adjustable
AI02 8-Bit Analog

Input Interface $299

■ 16 input channels

■ 70 microseconds conversion time

Plus the SC14 system for front-
end signal conditioning and
amplification, the UI16 isolation
system for AC or DC power input
or output, and more . . .

(Designed and manufactured in the USA)

AND NOW . . . AMPRIS™

An easy add-on to Applesoft®

BASIC.

With AMPRIS you can:

■ Read and store analog and

digital inputs

■ Send out analog and digital

outputs

■ Set, read and control the DI09

counters

■ Set, read and control the DI09

shift registers

■ Make full use of the DI09 inter-

rupt capability

Using AMPRIS is as easy as in-
serting an ampersand (&) com-
mand where you would normally
insert an Applesoft command. For
more information about the com-
plete line of DAISI peripheral
devices and the full spectrum of
their applications, write or phone:

Interactive Structures, Inc.
146 Montgomery Avenue
Bala Cynwyd, PA 19004
Telephone: (215) 667-1713

ASK BYTE

A simpler circuit not requiring a com-
puter, would consist of a tape recorder
to record the pulses. The tape could then
be played back through the pulse
counter to see what numbers were
dialed. The tape recorder could be con-
trolled by the pulse detector.— Steve

Computerized Home

Dear Steve.

I am planning to build a house and
would like to provide for computer con-
trol in my home. Can you offer any sug-
gestions?

Paul W. Marsh
Urbana, IL

With the almost daily announcement
of some computerized device, it makes
sense to provide a means for installation
in the home. However, it is difficult to
know what devices will ultimately be
required.

I will be presenting a series of three ar-
ticles, beginning in April, covering the
construction of the Circuit Cellar home-
control system.— Steve ■

Between Circuit Cellar Feedback, personal ques-
tions, and Ask BYTE, I receive hundreds of letters
each month. As you might have noticed, at the end
of Ask BYTE I have listed my own paid staff. We
answer many more letters than you see published,
and it often takes a lot of research.

\f you would like to share the knowledge you have
on microcomputer hardware with other BYTE
readers, joining the Circuit Cellar! Ask BYTE staff
would give you the opportunity. Were looking for
additional researchers to answer letters and gather
Circuit Cellar project material.

\f you're interested, let us hear from you. Send
a short letter describing your areas of interest and
qualifications to Steve Garcia. POB 582, Glaston-
bury. CT 06033.

I N 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 Ask BYTE staff includes manager Harv
Weiner and researchers Bill Curlew, \j\rry
Bregoli. Dick Sawyer, and ]eannette Dojan.

54 BYTE • FEBRUARY 1985

Inquiry I5l

> >W:\i

« : ~ipr- ■» i 1 "

INPUT/OUTPUT TECHNOLOGY, INC.

85387 Avenue Stanford, Unit 113, Valencia, CA 91355 • [805] 857-1000

Uncompromising Additions to your S-1QO/IEEE-696 BUS

DUAL GPIB-48B INTERFACE
BOARD

A Stand-Alone, Independently Controlled
Dual Channel IEEE-4BB I/O Processor. In-
terface Activity Modes for Controller-in-
Charge, Controller Assigned or Terminal
Bus Slave, and all Interface Functions are
handled transparent to Host System CPU
through an on-board CPU and DMA con-
troller. User Friendly operation.

AST, P/N 5274B-B00-10B

RGB COLOR GRAPHICS BOARO

Programmable resolution up to 512 x 512
pixels with A local video planes end on-board
graphics processor. Color mapper allows 1 6
colors from a palette of 4D9B. Light pen
input. Plus more ...
AST, P/N 5B74B-300-101

12-BIT A-O-A CONVERTER
BOARO

B Channel A-D: 12 microsec. Conversion,
50KHz Sample Rate, Programmable
Gains, Dffset and Diff. /Single Modes.
B Channel D-A: 2 microsec. Settling,
Bipolar V or Unipolar I Output. Program-
mable Reference levels, Dual-Ported Chan-
nel Refresh RAM. 16/B-Bit Date
Transfers via I/O or Memory Mapped
AST, P/N 5274B-9Q0-101

BAR COOE PROCESSOR BOARO

The BarTender is a stand-alone I/O Pro-
cessor that reads and prints most common
Bar Codes. Includes bi-directional reading,
wand interface, clock/calendar with battery.
Extensive documentation and software.
A&T.BS74B-500-101 Without Wand
AST,Be74B-500-B01 With Wand

PERIPHERAL SUPPORT
BOARO

Two Serial SYNC/ASYNC Ports with
RS-232, TTL or Current Loop Outputs,
three B-Bit Parallel Ports, three Timers.
Real Time Clock/Calendar and Response
Programmable Interrupt Controller. Small
Proto Area with +5 and +12v.
AST, P/N 5E74B-150-101

MULTI-PURPOSE
PROTOTYPING KIT

Industrial Quality with Plated-Thru holes for
Wire-Wrap or Solder projects. Complete
with +5, ±12v Regulators, Bus Bar, Filter
Capacitors, and Manual.

P/N 52748-450 Inquiry I48

ALSO AVAILABLE: MULTI-FUNCTION I/O BOARD, SMART PROTOTYPING KIT, 12BKx8/64Kx16 STATIC RAM MODULE

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

ALOCKEDDOORADEADMAH

AalOIiuucstoaohethcmtmfa:

JUNE

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

■hPI

rffT^'

& ?>*&&«

■ ■ f ■ £

fF '*'* r-

'\ y ^ *~ \ ,

ip>i-..

^^^^HHk- :

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 off er 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 TOTHE 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.

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

with surprising twists, unique
characters (many of whom

possess extraordinarily developed inside a story. Get one from
personalities), and original, logical, Infocom. Because with Infocom's
leave out one essential element- often hilarious puzzles. Communi- interactive fiction, there's room

the main character. And that's
where you enter in.

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

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 -

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 arid III.
*Use the IBM PC version for your 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 145

FEBRUARY 1985 • BYTE 57

Master Piece
puts the power at
your fingertips.

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 of
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 noise
are responsible for 70-90% of all
PC malfunctions. They can wipe out
memory in your PC, taking hours of
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, just 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 169

s lis l 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.

£&fii£HU

CLUBS & NEWSLETTERS

• VISIT WITH APPLE
USERS— Ideas, information,
and the latest computer
news are available to
members of the Arkon Info-
system, a 24-hour 300-bps
bulletin-board system
operating in Toronto,
Canada. Upload, download,
electronic mail, and public
messages are a few of its
features. Also included are
20 conferences; 10 mega-
bytes of storage, and on-line
help. The annual fee for
using the system is $19.95.
but inquirers can log on
under the "Guest" user
function. Questions about
the system can be sent
through the (F)eedback-to-
sysop function of the Arkon
Infosystem at (416) 593-
7460. Other details are
available from David
Fingold. Arkon Infosystem.
409 Queen St. W, Toronto,
Ontario M5V 2A5. Canada.
(416) 593-9653.

• CHAMELEON ADVOCATE
The National Chameleon
Users Group (NACHUG) pro-
duces a newsletter, The
80/88 National Newsletter, that
contains hardware and soft-
ware reviews, updates, and a
users forum. Member dis-
counts are provided on pe-
ripherals and accessories.
Membership is $12 a year.
Contact Steven Bender,
NACHUG. POB 28360.
Queens Village, NY 11428.

• SIG. NEWS FOR PUBLIC-
DOMAIN SOFTWARE

PC-SIG News, a newsletter
from the PC Software In-
terest Group (PC-S1G). is
devoted to public-domain or
user-supported software for
the IBM PC and compatible
computers. It lists the disks
in the library, updates recent

disk arrivals, and encourages
patches and feedback from
users. The members have
compiled a directory with a
subject index and listings.
Contact the PC Software In-.
terest Group, Suite 130.
15 56 Halford Ave., Santa
Clara, CA 95051.

• C-CLUB IN RIVER CITY

The River City Commodore
Club is a nonprofit organiza-
tion that meets twice a
month to promote interest
in all Commodore com-
puters. The group features a
large club library, help
groups, and basic and ad-
vanced tutorials. For details,
write River City Commodore
Club. POB 4298. North Little
Rock, AR 72116.

• COMPUTER AND SOFT-
WARE LAW-The Center for
Computer/Law, a nonprofit
educational institution, pro-
vides research and educa-
tional services in computer
law. The Center produces
Computer Ihxw journal an inter-
national journal on the legal
issues of computers, tele-
communications, and the in-
formation industries. It also
publishes a quarterly law
review, Software haw journal
that contains scholarly ar-
ticles from computer law ex-
perts, as well as a bibliog-
raphy of software law and a
directory of recent cases.
Contact the Center for Com-
puter/Law, POB 3549. Man-
hattan Beach, CA 90266.

• MANY SHARED
BENEFITS-The First
Attache/2001 User Group
(FAUG) produces a monthly
newsletter titled Where It's
Att. Members meet quarter-
ly, have access to public-
domain library disks, and
receive support by tele-
phone and networking. The
club can be reached on
CompuServe at 70346.63.
Annual dues are $3 5. Con-
tact Charles Raisch. FAUG.
1827 Haight. San Francisco.
CA 94117-2791. (415)
221-3415.

• NO TIME LIMITS SET
YET— In northern Idaho a
24-hour bulletin-board
system called I-PACE fea-
tures Atari downloads. Pass-
words are not required, no
time limits are set. and peo-
ple add to it frequently. The
BBS number is (208)
772-9421. Contact Robert
Marshall. POB 5123. Coeur
D'Alene, ID 83814, (208)
772-5922.

• CHRISTIAN COM-
PUTERISTS— Christian pro-
grams, a member's ex-
change, a monthly newslet-
ter, and discounts on com-
puter supplies are available
from the Elect Christian
Computer Club. For details
and a free issue of the
newsletter, £ 3 C Electletter.
write to the Elect Christian
Computer Club, Department
LAI, POB 31022, Chicago. IL
60631-0022.

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. 0/ 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.

• TRIANGLE dBASE USERS
GROUP— Members of a
users group for dBASE II
and III meet at 7:30 p.m. on
the second Wednesday of
each month in the Dreyfus
Auditorium of the Research
Triangle Institute in Research
Iriangle Park, North Caro-
lina. A bimonthly newsletter
is available on CompuServe
(70156.404). and a public-
domain library of applica-
tion disks is planned. An-
nual dues are $10. Send a
self-addressed, stamped
envelope for a sample news-
letter to Rich Slatta, Triangle
dBASE Users Group, 2618
Davis St.. Raleigh. NC
27608. (919) 782-8926.

• NEWSLETTER WITH
FOCUS-Users of Lotus
1-2-3 and Symphony can
focus on applications with
learn Mode, a mbnthly
newsletter from Systems
Consulting. Among its fea-
tures are book reviews, solu-
tions to problems, questions
and answers, and updates
on Lotus products. Article
contributions are welcome.
learn Mode is $30 for 12
issues. Request a com-
plimentary copy of the first
issue from Systems Con-
sulting, POB 982, Palo Alto,
CA 94302, (415) 326-8605.

• FRIENDLY USERS

Business computer users in
the Chicago metropolitan
area form the Tandy Busi-
ness Users Group, which
meets on the third Wednes-
day of each month. The
monthly newsletter. T-BUG.
contains a schedule of com-
ing events, workshops, and
forums, profiles, meeting
notes, news releases, and
product announcements. An-
(continued)

FEBRUARY 1985 • BYTE 59

COMPUTERBANC

GET SERIOUS, STOP PAYING HIGH PRICES NOW!

THOUSANDS OF AVAILABLE ITEMS. CALL FOR COMPLETE PRICING.

SYSTEMS

IBM PC

256K Two 360KB Disk Drives. Color
Graphics/Monochrome Graphics board,
Parallel Printer Port, Monochrome Display
(Amber/Green). DOS 2.1.
LIST PRICE $2950.00 — ONLY $2095.00
SUPER XT 10 Meg Upgrade . . . $2795.00
IBM AT 11% OFF

IBM SOFTWARE

LOTUS 1-2-3 $295.00

LOTUS Symphony 449.99

MICROPRO Wordstar 249.00

ASCII Expro.ForIBM 125.00

Wordstar Professional 359.00

Infostar 249.00

Mulimate 269.00

MICROSOFTWord 229.00

WordW/Mouse 279.00

Multiplan 139.00

Project 159.00

ASHTONTATE Friday 179.00

dBASEII 280.00

dBASEIH 349.00

Framework 359.00

UFETREE SOFTWARE Volkswriter 119.00

Volkswriter Deluxe 169.00

FOX & GELLER Quickcode 139.00

dUtil 59.00

dGraph 149.00

MICRORIM Rbase:4000 295.00

PES Write 89.00

File ..89.00

Report 89.00

Proof 79.00

Access 79.00

ENER6RAFHICS 269.00

NORTON UTHinES 59.00

IBM HARDWARE

AST Six Pack Plus 64K 259.00

MegaPIus II . : 259.00

PC Net 1 Starter Kit 830.00

QUADRAM Quadboard OK 219.00

Quadcolor I or Microfazer 64K 205.00

Quadlink 479.00

MICROSCTENCE

10MB Wnchester 799.00

HERCULES Mono Graphics 329.00

Color Card 199.00

FIANTRONICS Colorplus 389.00

STB Rio plus 64K 249.00

Super Rio 259.00

Graphix +11 NEW 309.00

TEAC 55B 124.00

55F 180.00

TANDON TM100-2 179.00

IBM Floppy 1.2 Meg CALL

TALL GRASS 12MB W/Tape . . . . 2799.00

RAM 64K upgrade 35.00

RAM 256K upgrade 26.00

MOUSE SYSTEMS Optical Mouse ... 189
ALSO • XCOMP, FERSYST. ORCHID,
TITAN AND OTHERS

PRINTERS LETTER QUALITY

BROTHER HR-15 375.00

HR-25 629.00

HR-35 859.00

JUKI 6100 429.00

NEC 2030 659.00

2050 799.00

3530 1229.00

3550 1539.00

PRINTERS DOT MATRIX

STAR MICRONICS Gemini 10X . . . 259.00

Gemini 15X 389.00

EPSONRX-80 F/T 329.00

FX-80 349.00

FX-100 649.00

LQ1500 1299.00

OR3DATA92A 389.00

93A 649.00

B4A 949.00

PANASONIC 1091 CALL

TOSHIBA 1350-P 1399.00

MONITORS

AMDEK 300 129.00

300A 145.00

310A 169.00

CoIorI+ 269.00

Color II 459.00

TAXAN Composite Amber 119.00

121/122 149.00

420 (RGB) 439.00

415 (RGB) 489.00

PRINCETON GRAPHICS HX-12 . . . 469.00

SR-12 625.00

MAX-12 189.00

ZENITB ZVM-122 Amber 95.00

ZVM-123 Green 95.00

NEC 1201 Hi Res Green 125.00

1205 Hi ResAmber 125.00

1206 Green 85.00

JC1215 Composite Color w/audio . .215.00
JC1216 Color RGB 334.00

MODEMS

HAYES 1200 469.00

1200B 389.00

300 199.00

Micromodem //e 219.00

ANCHOR MarkX 109.00

MarkXD 249.00

Volksmodem 59.00

NOVATION Smart Cat Plus CALL

Access 1-2-3 419.00

Apple Cat n 239.00

J-Cat 99.00

U.S. ROBOTICS PC Modem 365.00

Pass word 349.00

PROMETHEUS Promodem 1200 . . 329.00

APPLE PRODUCTS

MICRO SCI AZ drives 179.00

RANA EUIE 1 219.00

TEAC drive 189.00

APPLE Compatible drive 169.00

WESPER Interface 69.00

BUFFERED 16K 139.00

SYSTEM SAVER Fan 69.00

MICROSOFT Premium //e 279.00

Softcard CP/M 29.00

Multiplan 129.00

MAC Muliplan (Macintosh) 129.00

Basic (Macintosh) 109.00

APRICORN Serial Card 69.00

Z-80 Card 59.00

ASCII Express Professional 89.00

MAXELL S/S 19.00

D/S 27.00

KOALA Touch Tablet 79.00

HAYES Mach m JoySick 39.00

THUNDERCLOCK 119.00

MOCRTNGBOARD CALL

APPLEMOUSE H 129.00

VTDEXUltraterm 179.00

80 COLUMN/64K Interf ace //e only 99.00
80 COLUMN Card 11+ only 59.00

WE SUPPORT THESE FINE SYSTEMS:
AppU, Compag, IBM, Sanyo and many
more

TELEX #550757/ ANSWER BACK— COMFUTERBANK UD

Orders Only
800/332-BANC

OUTSIDE CALIFORNIA

COMPUTERBANC

16783 Beach Blvd., Huntington Beach, GA 92647

714/841-6160 Inquiry 70

n factory staled packages We guarantee all items for 30 days Within this period, defect?* merchandise n

Cash or Cashiers check is required o

CLUBS & NEWSLETTERS

nual dues are $3 5 and in-
clude a one-year subscrip-
tion to the newletter. For an
application and further
details, write Carlos Hidalgo,
T-BUG. 311 Long view Rd.,
Waukegan, IL 60087, (312)
623-9661.

• EXCHANGE ATARI NEWS
The Atari Computer Club of
the Palm Beaches produces
a monthly newsletter, The
Pokey Press, that features club
news, pen pals, participating
businesses, news from
shows, and software and
product reviews, and
welcomes the exchange of
newsletters with other Atari
groups. Contact Jim Wood-
ward, Atari Computer Club
of the Palm Beaches, Apt.
B-101, 15993 Southwest 8th
Ave., Delray Beach. FL
33444.

• SPECIALIZED NEWS FOR
ACADEME— Theories in the
field of word processing are
addressed in Research in Word
Processing Newsletter, a nine-
month publication from the
Liberal Arts Department of
the South Dakota School of
Mines and Technology. It
functions as a clearinghouse
of information relevant to
computer-based writing in-
struction at all educational
levels and contains original
research, article abstracts,
bibliographies, and software
evaluations. Article submis-
sions are welcome. Contact
The Editors, Research in Word
Processing Newsletter, Liberal
Arts Department, South
Dakota School of Mines and
Technology, Rapid City, SD
57701-3995.

• FOR NEW VENTURES

A monthly newsletter,
CompuNenture, contains soft-
ware reviews and informa-
tion on how to make money
using your microcomputer.
Subscriptions are $20 a
year. Contact Microcomputer
Software & Consultants, POB
1039, Mount Vernon, NY
10550.

• MORE FOR ENCORE
Encore 100 and 200. two
software-based portable net-
work analyzers that are
designed for data-communi-
cations monitoring, diag-
nostics, and emulations, now
have a users group spon-
sored by its manufacturer,
Digitech Industries. A
newsletter, \Lncore Com-
municator, serves to solve
user problems or print user
programs. Application engi-
neers answer hardware and
software questions and
supply needed information.
To receive a business-reply
registration form, contact
Joseph Luciano, Digitech In-
dustries Inc., 66 Grove St.,
POB 547, Ridgefield, CT
06877, (203) 438-3731.

• COMMODORE IN SILVER
The Silver State Commodore
Users Group of Las Vegas,
Nevada, meets at 7:30 p.m.
Wednesday nights at the
local YMCA. The $4 per
month dues entitle members
to vote and to copy any of
35 public-domain programs.
Though most members use
Commodores, the group is
not limited to a particular
computer. The club offers
ongoing classes in BASIC,
program demonstrations,
and assistance. Contact
Karen Douglas, Silver State
Commodore Users Group,
POB 81075, Las Vegas, NV
89180.

• FOR THE FORTUNE

Users of the multiuser
Fortune 32:16 can join
/u/fortune, a group that
meets in Cambridge, Massa-
chusetts, on the first
Thursday of each month.
Meetings include presenta-
tions of new software, small
group discussions, and user
support. A monthly newslet-
ter is produced. For com-
plete information, contact
Josh Lobel or Mark
Palmerino, /u/fortune. Suite
28, 20A Prescott St.. Cam-
bridge, MA 02138. (617)
876-4763. ■

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 a registered trademark of Dysan Corporation. © 198-1, Dysan 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

Somebody has to be better
than everybody else.

Inquiry 98

Flexible Diskette

Sooner or
later, you'll have

to
this computer

— Nem.

PC MAGAZINE'

»M^

1984

1 Do V oU get "

*ss£SZxg*Z-~

erf

teb

Better sooner.

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Computers don't ever get
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Ericsson, in

Computer-induced
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Eye strain

Back pain

Headaches

Shoulder

Hand/wrist

Neck pain

(Source: "Ergonomic

Principles in Office

Automation" Pub.

1983 by E.I.S. AB,

Sweden.)

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

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its very Swedish
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Inquiry 108

FEBRUARY 1985 -BYTE 63

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64 B YTE • FEBRUARY 1985

BOOK REVIEWS

ALAN TURING:
THE ENIGMA
Andrew Hodges
Simon & Schuster
New York: 1983
600 pages, $24.95

COMPUTER GRAPHICS

PROGRAMMING

Gunter Enderle. Klaus

Kansy, and Giinther Pfaff

Springer-Verlag

New York: 1984

560 pages, $39

DATA STRUCTURES AND
PROGRAM DESIGN
Robert L. Kruse
Prentice-Hall

Englewood Cliffs, NJ: 1984
486 pages, $29.95

ALAN TURING:
THE ENIGMA
Reviewed by
G. Michael Vose

And thus it was that . . .
thinking in his spare
time, an English homo-
sexual atheist mathematician . . . conceived of the com-
puter." This startling claim is at the heart of the first ma-
jor biography of Alan Mathison Hiring (1912-1954), a man
whose legacies include the Hiring machine and the Hiring
test. Andrew Hodges has uncovered the genius of this
complicated man and recorded the evolution of his ideas
within the unique context of the tumultuous times in which
he lived. Hodges's fascinating study adds new informa-
tion to the history of computer science, counters its all-
American bias, and claims a rightful place for the eccen-
tric Alan Hiring.

Revising history is a risky endeavor. The task demands
rigorous scholarship and the courage to successfully
challenge the assumptions of the past. Hodges's Alan
Hiring: The Enigma brims with painstaking research and em-
phatic interpretation. No less an authority than the New

York Times (December 4,
1983, section 7, page 80)
has labeled this volume a
work of major literary
importance.

This praise derives from
the wealth of ideas ex-
posed and illuminated in
the book, from lucid discus-
sions of complex mathe-
matics to revelations about
the secret cryptography
work accomplished by Hir-
ing and others during World
War II. Through this work,
the fortunes of war con-
tributed significantly to the
creation of the British
computer.

In Bletchley Park, a
London suburb, the cryp-
tography group worked to
decipher codes generated
by the German army's
Enigma machine. While
Turing's inventiveness was
instrumental in breaking
these codes, his life was full
of naive contradictions,
similar in nature to the
Nazis' refusal to believe
that the codes of their
cipher machine could ever be broken.

Hodges is sympathetic to the idea that the Allied vic-
tory in WWII hinged on the battle in the Atlantic in which
Hitler's U-boats tried to isolate Britain by cutting off her
sea supply routes to the West. Here, the breaking of the
Enigma codes made the difference between victory and
defeat because deciphering German naval messages
helped transatlantic convoys avoid the U-boat wolf packs.
But it is Hodges's contention that 'Hiring came up with the
major formulations of modern computer science that
makes this biography so significant.

Of course, the Universal machine (now known as the 'Hir-
ing machine) that 'Hiring conceived in 1 93 5 and described
in a 1936 paper called "On Computable Numbers, with
an Application to the Entscheidungsproblem" has rightf ul-

{continued)

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BOOK REVIEWS

ly taken its place as a seminal computer science idea. It
was central to Turing's lifelong inquiry into the idea that
machines could be intelligent. However, his later, little-
publicized ideas about how computing machines might
work form the bulk of the biographer's most interesting
revisions to the historical record.

During his Enigma-deciphering work, Hiring designed
and helped construct a machine called the Bombe, an
electromechanical device that calculated the permutations
of the Enigma's enciphering rotors. It used relays as
switches and was a specialized, high-speed calculating
machine. Turing's work on the Bombe enabled others in
the Bletchley Park group to develop the Colossus, the
machine that some historians consider the first computer.
The Colossus began service in December of 1 943, but Hir-
ing played no part in its design or construction. In con-
ceiving and building the Bombe, however, and later
machines like the Delilah (a telephone-voice enciphering
device), Hiring began fermenting the ideas that he would
later develop to construct a version of his Universal
machine.

The distillation of these ideas appeared in "Proposed
Electronic Calculator." a late- 1 94 5 report prepared in con-
junction with his new responsibilities as senior scientific
officer with the Mathematics Division of the National
Physical Laboratory (NPL) in Bushy Park, 'feddington. In
this report, Hiring laid out plans to construct a machine
later named the ACE (automatic computing engine), a proj-
ect in response to the American scientific community's
efforts to build a digital computing machine. The plan
outlined the construction of a true automatic electronic
digital computer with internal program storage, a fully devel-
oped scheme broader in scope than those conceived by
John von Neumann and others. But to Hiring it was an old
idea.

An Innovator

The stored-program concept was a natural one to Hiring
because it was essentially the same idea that he
developed in connection with the "instructions on paper
tape" idea that was central to his Universal machine. The
ACE report described how the stored-program concept
would apply to a computer. The report's discussion of how
the machine's instruction tables would be created leads
to Hodges's claim that lUring ". . . invented the art of com-
puter programming." This art, in Hiring's words, would find
that "Instruction tables will have to be made up by math-
ematicians with computing experience and perhaps a cer-
tain puzzle-solving ability." Hiring later wrote routines, in
conjunction with J. H. Wilkinson (see the interview on page
177), to perform floating-point arithmetic that enabled pro-
grammers to multiply two numbers without knowing what
was really happening inside the machine, thus presaging
the development of high-level languages. His notes for the
ACE report talk about "subsidiary" routines and about
"burying" and "unburying" an area of memory contain-
ing information vital to a program returning from a sub-

66 BYTE- FEBRUARY 1985

Inquiry 40

BOOK REVIEWS

sidiary routine. (This is known today as "pushing" and
"popping" the stack.) He even envisioned the use of
remote terminals, claiming that "It would be quite possi-
ble to arrange to control a distant computer by means
of a telephone line."

Although he left the NPL before the ACE machine was
built because he was unable to deal with the politics of
bureaucracy, 'Hiring nonetheless walked through the front
door of British computing. Taking up the post of Deputy
Director, Royal Society Computing Laboratory at Man-
chester University, he arrived in time to witness the fru-
ition of the other English attempt to build a computer.
Driven by the efforts of M.H.A. Newman (a former pro-
fessor of 'IUring's and the first reader of "Computable
Numbers") and Cambridge mathematician M.V. Wilkes, the
university assembled a team of wartime electronics engi-
neers and Bletchley Park mathematicians to work on de-
veloping a computing machine. The major difference be-
tween the Manchester machine and IUring's ACE was the
type of memory used. The ACE used acoustic delay lines
made of thin tubes filled with mercury, capped on each
end by piezoelectric crystals. A signal traveling between
crystals through the mercury was "stored" for a microsec-
ond. The Manchester machine used electrostatic tubes,
primarily cathode-ray tubes that stored information as a
charged phosphor, refreshed every millisecond, on the
tube's screen.

Less encumbered by bureaucratic entanglements than
the NPL, the university's computer, later called the Mark
I, executed its first program on June 21, 1948. 'Hiring
became a programmer of the Mark I ; for the rest of his
life, which presumably ended by his own hand a scant six
years later, he worked on research that interested him but
led to no significant discoveries. But during this time he
exchanged ideas with other Manchester faculty members,
including Michael Polyani, whose disdain for the idea of
intelligent machines gave rise to the debate that spurred
'IUring's creation of the test that later carried his name.
The Hiring test was put forth in an article called "Com-
puting Machinery and Intelligence" in the October 1950
issue of Mind. Its now-famous central thesis was that if a
machine's response to interrogation was indistinguishable
from a human's, then the machine exhibited intelligent
behavior.

Hodges's treatment of the intellectual accomplishments
of IUring's life is a major contribution. The book is a foun-
tainhead of stimulating thought— discussing 'IUring's ideas
on the determinism/free-will dialectic, for example— and
historical minutiae. Hodges reveals, for example, that Mark
I program code was written in base 32 arithmetic nota-
tion, a modification of Baudot teleprinter conventions. Hir-
ing found it easy to think in this notation and confused
his colleagues by writing base 32 numbers on the
blackboard when explaining an idea. A slash (/) was the
symbol that represented the number in this notation and
is the likely origin of today's convention of writing 0s with

[continued)

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FEBRUARY 1 985 • BYTE 67

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BOOK REVIEWS

a slash through them (also a good way to differentiate
from the letter M 0"). Hiring was also fascinated throughout
his life by the natural occurrences of flower petals, fir-cone
florets, and sunflower seeds in a Fibonacci number
sequence.

Aside from its contributions to the historical record this
book is a fascinating human story. Turing's disdain of social
conventions, his lack of social graces, and his individuali-
ty brought him both pleasure and pain. Though not a psy-
chological history, Alan Hiring: The Enigma explores the
human side of the man who gave life to some remarkable
ideas. Equally important, the study remains aware of the
role played by the circumstances of a man's life in the
development of his thought. Turing's ideas could have
taken a much different tack were it not for a world war
and a German cipher machine.

The major unanswered question about Alan Hiring is
why he took his life. There was a homosexual scandal,
resulting in a conviction for violation of sexual decency
laws, and a subsequent agonizing year of drug treatment
with female hormones. But his suicide came a full year
after the end of the treatments and probation for his of-
fense. Hodges closes his book with a 1 5-page discussion
of government debates about excluding homosexuals
from sensitive scientific and research posts for fear of their
susceptibility to blackmail and coercion. But he never
satisfactorily answers the question, Why suicide? Turing's
mother never accepted this verdict, claiming that Alan's
death was accidental. If Hodges explored the other
possibilities, he doesn't reveal his findings.

Though minor, there is one flaw in this book: it is
plagued with editing and typographical errors, no doubt
a result of the complexity of the manuscript. Anyone in-
terested in the idea of intelligent machines should have
no problem overlooking these errors. The book is never-
theless a major work in the history of computer science.
Well indexed and containing 28 pages of bibliographic
notes, it is a valuable resource for information about the
people who created the technology and the papers they
wrote describing their ideas.

G. Michael Vose is BYTE's senior technical editor for theme articles.
He can be contacted at POB 372, Hancock, NH 03449.

COMPUTER GRAPHICS

PROGRAMMING

Reviewed by Judith L. Maggiore

The Graphical Kernel System (GKS) is the international
standard for computer-graphics software. Computer
Graphics Programming is an important addition to the stan-
dard document defining GKS because it explains concepts,
examples, and figures that could not be included in the
standard document. Gunter Enderle, Klaus Kansy, and
Gunther Pfaff are in a good position to write about that

[continued]

68 BYTE • FEBRUARY 1985

Inquiry I5 2

WHY INVEST $90 IN MODULA-2?

BECAUSE YOU'RE COMPETING WITH PEOPLE

WHO BELIEVE THE BEST PROGRAMMING METHOD

IS THE ONE THEY ALREADY KNOW.

Whoever decided to make the
switch from Roman Numerals to a
more efficient notation for doing
arithmetic should be a hero. His
friends probably reacted as if he'd
asked them to learn a whole new
language. We think you'll see the
parallel with Modula-2, especially
after you try it.

Niklaus Wirth, creator of Mod-
ula-2, asserts that Modula- 2 is an
abstract tool for the control of com-
puting machinery: "In my opinion,
the term programming language
is ill chosen and misleading. Pro-
gram notation would be eminently
more appropriate."

We're not proposing that you learn
a "new language." That would be like
arguing the merits of English versus
French. But it does make sense to
avail yourself of the most efficient
known technology for controlling
computing machinery -- while your
competition is left in the dark ages.

Compared to Modula-2, whatever
program notation you're now using
is like doing your arithmetic in
Roman Numerals.

In this limited space, we won't try
to prove that Modula-2 is the best
available competitive tool for the
serious computer entrepreneur.
"Such matters," according to Frank
Herbert (DUNE), "can only be
tested in the crucible of survival, not
in the play of symbols."

The question is, for $90, can you
afford not to test our claim? No other
company in history has made it as
easy for you to do business. Our
entire object-program licensing
agreement is on this page.

So put some distance between
yourself and those who believe the
best programming method is the one
they already know.

MODULA-2 COMPILERS FOR IBM PCs,
MACINTOSH, LISA AND APPLE lis - $90

Modula-2 compiler and interpreter with
enhanced, bit-mapped graphics are available
for Apple's Lisa, Macintosh and II computers;
IBM's PC, XT and compatibles (MS-DOS
2.0); and others to be announced.

ABOUT MACMODULA-2™

MacModula-2 is what 128KB Macintosh
users have been waiting for. Over 400 of the
ToolBox ROM routines are supported , includ-
ing pull-down menus,. multiple windows,
multiple fonts, QuickDraw graphics, the
ROM-based serial driver, the sound driver,
mouse support, etc. The M-code interpreter
reduces memory requirements for 128KB
Mac systems, yet executes at up to 75% of
native-mode speeds if extensive use is made
of the ROM routines.

Also included with MacModula-2 is a full-
screen, mouse-driven editor, a Transfer Menu
facility that reduces the need for returning to
the desktop between compiles, links and
edits, and a Resource Maker that allows the
entrepreneur to ship modifiable menus to
customers, without shipping the actual Mac-
Modula-2 source code.

THE IDEAL MODULA-2 ENGINE

We'd love to introduce you to the Lilith. It's
a workstation computer with bit-map graph-
ics, three-button mouse and a bit-slice proc-
essor. The Lilith was designed by the original
Modula-2 team at the Swiss Federal Institute
of Technology (ETH) as the ideal Modula-2
engine. Over 200 have been placed into aca-
demic and research environments. Now
Modula Corporation makes a commercial ver-
sion for your more demanding problems.
Just call 800/UUTH2 to hear about customer
benchmark reports.

SOFTWARE LICENSE

Join us In a commitment to personal integ-
rity. Our prices are fair. Unlike program license
agreements you can't help but violate, we've
tried reTHINKing a few things. Perhaps we
can start a trend that makes violation of
another's intellectual property unfashiona-
ble. Without ali the "whereas" and "herewith"
language, here's our attempt to transfuse
integrity into the entrepreneurial bloodstream:

You agree to treat the information wesendyouas if it were a book,
with the exception that you are granted the right to make backup
copies. Simple, Pournelle logic!

lnthespiritofthe"book"analogy,youarefreetotakeyourbookto
another house (or computer) with you. This, of course, means
someone at your own house (or computer) cannot simultaneously
read it. Similarly, you can loan your book to a friend. But there can be
no possibility you can read it at the same time. You may sell your
book, only if the new owner agrees to these same conditions (which
means a copy of this agreement, signed by the new owner, must be
sent to us). Finally, just as in a book, it lacks integrity to substitute
your name for that of the legitimate author.

As for our warranties: Defective software may be returned within
thirty days for a replacement. But just like any other self-help book,
its value to you is what you make of it. No matter how badly it
damages your life, or that of your customers, we're not obligated to
do anything whatsoever about it.

Now, it's time to play "How'd- you-like-to-
see-something-rea//y -scary?" When you
send us your check or credit card authoriza-
tion, enclose this page (or a copy) with an
original signature. Violate this agreement of
integrity, and you'll get a doozer of a course in
integrity at the claws of our attorneys; and
they'll tell your mother.

MODULA

CORPORATION

reTHINK

1673 West 820 North, Provo, UT 84601
801/375-7400 or 800/ULITH2

In addition to information on the Lilith, please send me the Modula-2 Compiler at $90 for the D IBM PC or XT, or the Apple D lis, □

Lisa or the D Macintosh.

Utah residents include 6% sales tax.

$10 handling and postage for all orders.

$ : Total amount enclosed/authorized.

My signature below, besides being a possible credit card authorization, indicates my agreement to all the above terms.

□ My check is enclosed.

□ Please bill my □ VISA / □ MASTERCARD

Card number

Expiration

Signature

Date

Print/type full name

Title

•

Company

Phone

Address

City

Zip

Inquiry 224

FEBRUARY K

Inquiry 50

ledtecl ormdl Dental

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Apple and MacPaint are trademarks of Apple Computer. Inc
Macintosh is a trademark licensed to Apple Computer. Inc

BOOK REVIEWS

standard because they have been involved in its design
and review for several years.

The history of computer graphics has been one of frag-
mentation and separation. The subject is broad, covering
areas including computer-aided design (CAD), business
graphics, mapping, video games, and more. Each area had
its own preferred hardware for displaying pictures. CAD
applications used vector-refresh devices, while business
graphics used storage tubes and pen plotters. The intro-
duction of raster devices led to even more diversity. Soft-
ware was tailored to take advantage of the capabilities of
a particular device. As well as being device-dependent,
computer-graphics software was also application- and sys-
tem-dependent. There was little relation between the soft-
ware used to design circuits and the software used to draw
histograms. This situation meant that graphics programs
were useful only for the application, operating system, and
device for which they were specifically designed.

As graphics devices became less expensive, more peo-
ple discovered computer graphics. The advantages of be-
ing able to display data as pictures are obvious. Once the
prohibitive cost was removed, computer-graphics users
proliferated. These new users of computer graphics were
not interested in designing whole new systems— they were
interested in using computers to draw pictures.

At this point, the field was ripe for a standard. The de-
velopment of this standard began in the mid 1970s, with
many organizations participating. In the United States,
standardization was initiated in 1974 by the Association
for Computing Machinery's Graphics Standards Planning
Committee, part of the special-interest group on computer
graphics. This work was taken over by ANSI (American Na-
tional Standards Institute) committee X3H3, one of the
major contributors to the review of GKS. The work of all
the committees in various countries was consolidated
under the auspices of the international Standards
Organization (ISO) and eventually led to the development
of GKS. The authors estimate that there were 50 man-years
of effort devoted to the development of the graphics
standard.

Computer Graphics Programming has something for every-
one. The novice to computer graphics will find the defini-
tions of graphical terms and concepts very valuable. Ex-
perienced graphics users and experts will find the book
the best help available for understanding GKS. Applica-
tions programmers who plan to use an implementation
of GKS will probably use this text daily as a reference. Im-
plementors of GKS will find the sections on device and
language interfaces and implementation styles invaluable.
Students and teachers on either the undergraduate or
graduate level can use Computer Graphics Programming as a
text or reference for a course in computer graphics.

Well Organized

The authors have organized this book very well. Section
I contains an overview of the standard's general concepts

[continued)

c . • FEBRUARY 1985

Inquiry 130

The first 3-in-One printer with a good head for
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The Toshiba P1351 is the ultimate 3-in-One
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And it's supported on popular graphics software
like Lotus 1-2-3™

Intelligence that's unlimited. The Toshiba
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It also gives you the ability to down-
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Intelligence that's letter-perfect. Our unique
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Intelligence and speed. You wont have to
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Intelligent and dependable. The Toshiba
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So make the intelligent move. To the

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J^ For more information, call

> 1-800-457-7777, Operator 32.

Lotus and 1-2-3 aie trademarks o1 Lotus Development
Corporation. SPRINT 5 is a trademark of Qume Corporation.

In Touch with Tomorrow

TOSHIBA

TOSHIBA AMERICA. INC.. Information Systems Division

Inquiry 314.

FEBRUARY 1985 -BYTE 71

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72 BYTE • FEBRUARY 1985

Advice. Price.

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Inquiry 211

FEBRUARY 1985 • BYTE 73

Inquiry 293

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BOOK REVIEWS

and vocabulary. The precise and clear definitions of graph-
ical terms and concepts presented in this section should
go a long way toward clarifying the vocabulary we need
to talk about computer graphics. These basic terms and
concepts form the basis of the more formal description
of GKS found later in the book. Included in this section
are chapters on the principles and goals used in the design
of GKS and the interfaces to GKS. Since GKS is designed
to be device- and system-independent, it must be inter-
faced on one side to a specific language and on the other
to the graphical hardware. Chapter 6 is especially useful
because here the authors provide concise definitions of
all the main ideas used in GKS. These definitions are
followed by chapters that supply additional detail and
amplification about each concept.

The second section describes the process of the devel-
opment of the GKS standard. The authors sketch briefly
the history of computer graphics and the events that led
up to the final GKS document. The most interesting part
of this section is chapter 3. which presents some of the
issues the developers of GKS had to resolve. Arguments
pro and con on each issue and the ultimate decision of
the committee are discussed.

Section III, the largest part of the book, is a detailed
description of the functional capabilities of GKS. Enderle,
Kansy, and Pfaff explain all the functions and data struc-
tures relevant to GKS.

The definitions of the functions are presented in two
parts. First is the language-independent version, taken
directly from the GKS standard document. Next is the
FORTRAN definition. Following the function definitions are
examples of programs or program fragments using GKS.
The examples are presented in both Pascal and FORTRAN
and very clearly show typical uses of GKS by applications
programmers. The book also includes some exercises in-
tended to help students and teachers.

Section IV will be most useful to the implementors of
GKS. those people who will write the subroutine package
that makes GKS available to applications programmers.
This section covers methods of implementation, imple-
mentation styles, interfaces to devices, and interfaces to
specific languages. A mapping of the abstract data struc-
tures of GKS to FORTRAN data structures is included.
Other topics in this section are graphics metafiles, valida-
tion of GKS implementations, and three-dimensional ex-
tensions to GKS.

Evaluation

This book clarifies an area that is often confusing and
obscure. Tferms and concepts are excellently presented.
Anyone seriously involved in the use of GKS will find this
book invaluable.

More pictures and illustrations should have been in-
cluded. A book on computer graphics needs lots of pic-
tures. The second problem is minor. The use of the English
language seems awkward at times.

[continued)

74 BYTE- FEBRUARY 1985

Inquiry 335

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

"86 I in
aJ a t

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 S
tern from Mark Williams Company

MWC86

MWC86 is the most highly optimized
C compiler available anywhere for the
DOS and 8086 environment.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 World, June, 1984, summed it up:

*Unix is a Trademark of Bell Laboratories.

"Of all the compilers reviewed, MWC86
would be my first choice for product
development. It compiles quickly, prop
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." W^

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-

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

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 Company

Windows (or C

Creative Solutions

Halo

Media Cybernetics

PHACT

PHACT Associates

The Greenleaf Functions

Greenleaf Software

Btrieve

SoftCraft

SIEVE

Time in Seconds
M Large Mode!
■ Small Model
Size in Bytes
D Large Model
Small Model
1.2

The C Programming System
from Mark Williams

The C Programming System from
Mark Williams delivers not only the
best C compiler for the 8086 but also
the only C source level debugger. That's
why it does for C programming what C
did for programming. The Mark Wil-
liams C Programming System gives the
programmer the MWC86 C compiler
and the csd C Source Debugger for
only $495. Order today by calling
1-800-MWC-1700. Major credit cards
accepted.

Technical support for The Mark Wil-
liams C Programming System is pro-
vided free of charge by the team that
developed it.

Mark Williams Company

1430 W. Wrightwood Ave.
Chicago, IL 60614

Inquiry 197

FEBRUARY 1985 -BYTE 75

Inquiry 349 for Dealers. Inquiry 350 for End-Users.

Powerful Single Board Computer
Includes CP/M Plus™ on Disk

$599

New Items:

• MSDOS Coprocessor

• 68000 Copioa;ssof

• 80X24 LCD Driver

• H;ird/f?AM Disk

• 3Vi Single Board

Z80 CPU

MSC-ICO uses the most popular microprocessor, the
280. as its mam CPU. MSC-ICO runs at 4 MHZ without
any wait States Tne wnolesystem is incorporated intoa
high quality four layer PC board measuring only 145mm
X 250mm f JO* x t"). The system requires only 12 Amps
at + SVolisandOIAmpsat + 12 Volts.

Banked CP/M Plus Included
CP/M Plus 13 banked) is included on disk with all
manuals CP/M Plus is upwardly compatible with CP;M
2 2 and includes the SO debugger, the MAC and RMAC
macro assemblers and the LINK-BO loader. MSC-ICO's
custom BIOS provides suppoit lor multiple disk formats
and I/O device control. System specific software for dtsk
formatting, disk copying, defining function keys and
modifying screen attributes is also included.

I2BK0RAM
One *4K bank of memory is devoted to CP/M and its
disk cache blocks, while the other 64K bank is devoted
to applications programs. This arrangement not only
provides more memory for programs, but it significantly
increases the speed of disk I/O.

Internal Floppy Disk Controller
MSC-ICO handles Shugart/ANSI standard floppy disk
drives in a variety of sizes and formats:

• 8 - SSSD, 243Kb
•B-DSDD, 1.2Mb

• 5-1/4" DSDD. 320Kb

• S-1/4" DSQD. 800Kb

• S-1/4" QHD, 1.2Mb

Up to four drives of any density or sue can be con-
nected to MSC-ICO. Both S t/4and8inchconnectors are
on-board to make disk drive connections easy.

High Speed CRT Controller
MSC-ICOcontams an 80 x 24linememorymappedCRr
controller. Video output is composite or separate to
match any monitor. Attributes such as insert and delete
line, reverse video, and semigraphics are supported.
Cursor escape sequences are »n extension of DECS
VTS2 and can be easily reprogrammed to emulate most
standard terminals.

CP/M fins'" ill Dq.ui Reie.wcn. inc

Mountain 8lde Oomputer

Video, 128Kb, CP/M Plus™, and more

Two RS232C Ports

MSC-ICO communicates with printers, modems, plot-
ters, and other s.tandaid RS232C devices through its
two serial ports. These ports are independently pro-
grammable for baud rates, stop bits, data format and
parity. Synchronous communication on Port A is
jumper selectable.

Centronics Parallel Port
A standard Centronics parallel port allows MSC-ICO to
communicate with printers and other parallel devices

Parallel Keyboard Port
MSC-ICO connects to any ASCII parallel keyboard of
positive or negative polarity with a negative strobe. A
type-ahead buffer and programmable function keys are
provided by MSC-ICO's custom BIOS.

Ifi Bit TTL I/O Port
This poit allows you to access printers, relnys, LED's.
DAC's, ADC's, switches, EPROM programmers and
many other devices,

Clock Calendar
The battery backed up clock calendar provides ume and
date information to CP/M for Me stamping The clock
can also be accessed from applications programs

External Bus
MSC-ICO's 50 pin bus connector provides expansion for
a hard disk controller. RAM disk, graphics or a 68000
system. Please call or write for more information on
these options.

MSC-ICO Saves Time and Money
With MSC-ICO's low cost and quality worksmanship,
why spend time, energy and money to design, debug
and test your own system Whether you require single
units or targe volume quantities we can meet your
needs. Order your evaluation unit today!

TIME

Time is money! Moore
helps you save both
with the most complete
catalog selection of
computer supplies
and the kind of old
fashioned service only
modern technology
can provide.

Request your FREE catalog today!

Mail this coupon to:

Moore Computer Supplies Catalog

P.O. Box 20, Wheeling, IL 60090

Or call toll-free:

1-800-323-6230

YOURNAME

TITLE

BUSINESS PHONE

COMPANY NAME

ADDRESS

CITY

STATE

ZIP CODE

COMPUTER MAKE AND MODEL

TYPE OF BUSINESS

NO. OF EMPLOYEES

Depl. 164921

BOOK REVIEWS

It's too early to tell what effect GKS will have on the
computer-graphics industry. It will be interesting to see
how GKS stands up in light of recent developments. What-
ever the future of GKS, it is a very important development
now, and Computer Graphics Programming is indispensable to
anyone wishing to understand and use GKS.

}udith L. Maggiore programmed graphics for three years prior to
teaching computer science classes and computer-graphics seminars at
Keene State College (Mathematics DepL Keene, NH 0343 1).

DATA STRUCTURES
AND PROGRAM DESIGN
Reviewed by Edward Brent

The boundary between writing programs that merely
get by and designing programs that perform complex
tasks efficiently is one that many programmers never cross.
Yet it is a boundary that is fundamental to the develop-
ment of programming as a discipline. People who program
by the seat of their pants and hold their programs together
with the electronic equivalent of spit and baling wire must
give way to trained programmers who develop finely
crafted, efficient, and maintainable programming solutions
to difficult problems. The selection and design of ap-
propriate data structures and algorithms is a crucial ele-
ment of professional-quality programming. The central
role of data structures in professional programming is in-
sightfully examined by Robert L. Kruse in Data Structures
and Program Design.

Audience

In the preface Kruse indicates this book includes all the
topics of specific courses recommended and offered by
ACM (Association for Computing Machinery) Curriculum
78. The prerequisite for the book is a first course in pro-
gramming, or equivalent experience, and elementary ex-
perience with Pascal.

I find the book suitable for a second course in computer
programming. However, it could also be of value to pro-
grammers not enrolled in a computer science course but
interested in upgrading their programming skills.

But the issues of selecting appropriate data structures
should not be relegated to a second course on computing.
Because the selection of data structures is such an im-
portant aspect of quality programming, it should not be
left for more advanced books.

Kruse consistently highlights the distinction between
abstract structures and their implementations. He begins
by addressing the programming principles of top-down
refinement, program design, and review and testing; he
illustrates these principles with extended examples.

In chapters 2 and 5, Kruse discusses the more impor-
tant structures: stacks, queues, and other lists in both con-
tiguous and linked representations and binary trees. He

(continued)

76 BYTE • FEBRUARY 1985

Inquiry 225

1 COMPUTERS

IBM SYSTEM SPEC

IALS

256K, 2 Drives

>rall

256K. 2 Drives, color graphics, printer

adaptor & PGS HX-12 monitor $2499

256K. 1 Drive & 10 MB Hard Disk ...... $2459

TWO USER SYSTEM (incl. 10 MB, Advanced

Digital PC Bd & Terminal) $3859

COLUMBIA

MPC 4220 (256K, 2 Drives)

)Ca!l

PROFESSIONAL (10 MB, w/tape backup) . . .

>Cal)

VP 2220 (Portable w/256K)

>Call

COMPUPRO 10 (10 MB, Multi-user)

SCall

CORONA PC-22 (256K. 2 Drives) (

Call

Portable PC-22(256K, MS-DOS 2.0) ..... 1

Call

FUJITSU MICRO 16s (8086/Z80A) $1995

MORROW DESIGNS Pivot, M02, MD3.

MD5, MDII <

Tall

NEC

PC-8801A (Z80A, 64K, 2 Drives, 12" Monitor,

WordStar, MailMerge, Multiplan.NBASIC). $1 1 49

APC-1II Specials w/ printer & Software .... J

Call

SANYO

MBC 550-2 (8088, 128K. 1 DSDD Drive (320K),

WordStar, CalcStar, EasyWriter) SCall

MBC 555-2 (550-2 Plus 1 Add. Drive,

Mailmerge, Spellstar&lnfostar) SCall

SEEQUA Chameleon/Plus (8088/Z80) .... SCall

SWP Micro Computer Products

Co-Power-88 Board (8088 w/ 256K, 1 MB)

For KAYPRO 2, 4 & 10

SCall

TELEVIDEO

1605 (8088. 128K, 2 Drives, DOS 2.0) SCall

TPC-II (Portable Version of Above) SCall

ZENITH Z-151-52 (8088. 2 Dr, 320K RAM) . . SCall

ZW 151-52 (1 Dr, 10 MB Hard Disk)

SCall

FOR IBM PC/XT/ AT & COMPAQ

ADVANCED DIGITAL Multi User Bd (8086) . $

Call

AST RESEARCH INC.

ADVANTAGE!! (Multi FtnBd for AT) $

Call

MEGA PLUS II (64K,Ser&Clk) $

279

SIX PACK PLUS (64K. Ser/Par. Clk) $

259

MONO GRAPH PLUS Card $

Call

QUADRAM

EXPANDED OUADBOARD (S. P, Clock, Game)

64K $259 384K S

429

QUAD 512+ (Serial Port, Maximum 512K)

64K $229 256K $

349

OUADCDLDR I (Video Board) $

iqq

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339

Color Card (RGB, Composite, Parallel) . . . . $

169

INTEL 8087/80287 Math Co-Processor. ... J

Call

KEYTRONIC Deluxe IBM Keyboard (5151). . . $

199

MA SYSTEMS PC Peacock (RGB & Composite.

Parallel Port) $

?nq

MICROLOG Baby Blue II (Z80B, 64K, Parallel &

Serial Ports, Clock/Calendar) $

529

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Call

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299

Modular Graphics Card $

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Module A/B $

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STBSYSTEMS Graphix Plus 11 <

319

Super Rio w/64K $

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179

TEAC FO-55B (DSDD Thinline Drive) $

159

TECMAR Graphics Master (640x400 RGB) . . $

489

The Captain (w/DK) <

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1st Mate (w/ OKI i

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TSENG LABS Ultra

3 ak <

489

GenTech

1 HARD DISK

APPLE MACINTOSH HARD DISKS NOW AVAILABLE!

CORVUS, DAVONG & TECMAR . . . CALL FOR PRICES!

AMPEX20MBW/25MBTapeBack-Up . . . SCall

EVEREX 10 MB Internal for IBM. . .

$795

MITAC 10 MB Internal for IBM . . .

$699

CORVUS

Dmnidrive (11 MB)

. . . $2079

Transporter . . . $399 The Bank

. . . $1779

DATAMAC Trustor 10

. . . $1129

DAVONG

Universal External: 10/21 MB ... .

S1875/S2595

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. . , , SCall

MAYNARDELECTRONICS 10/20/30 MB . . . SCall

PEGASUS-GREAT LAKES

10 MB Internal For IBM

.... $959

23 MB External (w/ Controller) . . .

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SYSGEN

10/20 MB w/TapeBack-Up

S2295/S2849

Image/Oic-File

$799/$1199

TALLGRASS

12 MB External w/20 MB Tape Back-Up . $2399

20 MB External w/20 MB Tape Back-Up . $2499

TECMAR

Remov. Cartridge Winchester in PC (5 MB) $1569

10 MB w/ 5 MB Cartridge in Chassis

. . . $3119

XCOMP 16MB External (For IBM, Apple,

Kaypro & Morrow Designs). . . ,

. , . $1749

DOT MATRIX PRINTERS

C-ITOHProwriter18510AP

$329

I DATA PRODUCTS All Models

SCall

EPSON JX-80: Color Printer

$585

LQ-1500 $1109 RX-100 . . .

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RX-80/80F/T SCall FX-80/100.

■mwMii— milium— it — m

• SCall

*& a ,

MANNESMANN TALLY

MT160L SCall MT180L.

Spirit-80 $249 MT1602.

$789

SCall

MPI Sprinter/SX (Portable, 300 cps)

.... SCall

NEC

P2 Pinwriter (180 CPS, 10" Carriage)

.... $649

P3 Pinwriter (180 CPS, 15" Carriage)

.... $869

OKIDATA

Ask for NEW Apple Imagewriter Co

mpatible

ML 92 SCall ML 93 .

.... SCall

ML 84(P) . . , . SCall Pacemark

SCall

PANASONIC KX-P1091/1093

. $299/$Call

STARMICRONICS

Gemini I0X. . . . $249 Gemini 15

X . . . . $349

Delta 15 $459 Radix 10.

$489

TEXAS INSTRUMENTS

850 RD $489 855 RO .

.... $759

TOSHIBA

P1340 SCall P1351 .

. . . . $1289

LETTER DUALITY PRINTE

ABATILO-20 (18 CPS. 15" Carriage)

.... $359

AMDEK 5040 (40 CPS)

. . . $1299

BROTHER/DYNAX

HR-15 XL (20 cps, Diablo Compat.)

$379

HR-25/HR-35

. $619/8869

CORONA Laser Printer faster than HP

. . . $2699

DIABLO

620APL $779 630 ECS/I

BM. . $1979

JUKI 6100 (17CPS. Diablo Compat.)

.... SCall

6300(40 CPS, Diablo Compat, 3KBu

.) . . . SCall

NEC

2030 $659 3510 . .

. . . $1269

3550. $Call 8850 . .

■ - ■ $1879

OLYMPIA Compact RO/2

$349/3419

QUADRAM Ouadjet (Ink Jet Printer)

.... $759

QUME Sprint 1140/1155

$1299/51479

Letterpro 20

.... SCall

SILVER-REED EXP 500 (parallel or se

ial) . . $369

EXP 550 (p or s, 15" carriage) . . .

.... $449

STAR MICRONICS Power Type (18 CP

S) . . . $339

TRANSTART120/T130

. $409/8569

■jwimu;i

NEW!! POLAROID PALETTE!! $Call

AMDEK DXY-100/Amplot II $599/$749

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

OT-114 Digitizer (4-Button Cursor) $739

PANASONIC VP-6801A $1449

ROLAND DXY-101/800/880 SCall

STROBE Model 200/Model 260 $519/8729

AMDEK

Video 300/300A/31OA $135/145(165

Color 300 .... $259 Color 500 $389

Color 600 ... . $459 Color 700 $529

DYNAX Fortis FC10 (13" RGB) SCall

MONITECH 12" Green/Amber $80

PRINCETON GRAPHICS HX-12 $469

SR-12 (690x480) $609

Max-12 (12" Amber, TTL) $179

QUADRAM Ouadchrome $489

Ouadchrome II $459

ROLAND

MB-121G .... $135 MB-122G $155

CB-141 $269 CC-141 $559

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

MMM

ESPRIT

Esprit I SCall Esprit II $479

Esprit III SCall ESP-6310 $559

OUME102/102A 8469/8489

103/108 (Green) 8849/8519

TELEVIDEO 914/924 8519/8675

950/970 SCall

Personal Terminal $419

w/300 Baud Modem $528

VISUAL 50/55/60 $559/8689/ Call

102/300 $Call

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 IDM

BLUE LYNX 3278 SCall

DCA Irma/lrmaline/lrmaKey SCall

IDEAcomm3278 SCall

ANCHOR

Mark VI $179 Mark XII $249

HAYES

Smartmodem 300/1200 $1 99/SCall

Smartmodem 1200B w/SmartCom II $399

NOVATION

Smart Cat Plus 300/1200 w/ Mite $329

PRENTICE POPCDM C100/X100 8289/8299

PROMETHEUS Promodem 1200 SCall

QUADRAM Quadmoderu SCall

TRANSEND PC Modem Card 1200 $419

VEN-TEL 300/1200 Haif Card $439

SOFTWARE

ASHTON-TATE dBase Ill/Framework .

. . . SCall

PRENTICE HALL VCN ExecuVision . .

. . . SCall

REAL WORLD MBSI Accounting . . .

. . . SCall

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$319/$Call

MICROPRO WordStar 2000/Pro pack.

. . . SCall

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8285/SCall

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. . . $129

SAMNA Word III.

. . $375

SATELLITE SOFTWARE WordPerfect .

. . . SCall

SOFTWARE PUBLISHING PFS Write .

... $97

CENTRAL POINT Copy II PC/PLUS . .

... $29

FOR APPLE ll/lle

APPLE Maclntosh/lle SYSTEMS. . .

. . . SCall

ALSCP/MCard . .*

. . . $279

Smarterm II (80 Column Card) . . .

. . . $129

AST RESEARCH INC. Multi I/O Card .

. . , SCall

DIGITAL RESEARCH CP/M Gold Card w/64K . $339

FOURTH DIMENSION 16K RAM Card . .

... $55

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. . . $129

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Micromodem He w/SmartCom 1 . .

. . . $239

Smartmodem 300/1200

8199/8479

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. . $125

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. . . SCall

Softcard (Apple/Franklin)

. . . $229

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... $69

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J-Cat (Auto Drig/Answer. 300 Baud)

$99

Apple Cat II (300 Baud)

. . . $209

212 Apple Cat II (1200 Baud) ....

. . . $389

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. . . $389

ORANGE MICRO Grapples

. . . $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(10boxmin)...$12"

3M $30

Maxell $30

PRINT BUFFERS
QUADRAM Microfazer

Parallel/Parallel

16K . . $139 64K.

Serial/Serial, Serial/Parl, Parl/Serial

BK. . . $145 16K. . . $155 64K , . $209
INTERACTIVE STRUCT. Shuff leBuffer 32K . . . $269
PRACTICAL PERIPHERALS Microbuffer 32K. . $209

Dysan $31

Verbatim $30

$185 128K. $239

^ ATARI
RANA 1000.. $245

SURGE PROTECTORS

EPD/CURTIS All models SCall

NETWDRX Wire Tree/Wire Tree Plus. . 845/860

ULTIMA SF-600 839

EMERGENCY POWER SYSTEMS

TrippLite BC200-10 (battery incl) $270

TrippLite BC425-FC (425 Watts) $429

SOLA ELECTRIC Mini UPS SCall

CUSTOMER SERVICE

401-781-0020

ORDERS ONLY

800-843-4302

150 Broadway, Suite 2212, N.Y., NY 10038

HOURS 9-8 ECT/MON-SAT

Money Order. Cashier's Ck. Personal Ck (2 Weeks To Clear).

APO Orders Add 6% (minimum S7). Add 3% For Net Terms.

All Returned Non-Defective Merchandise Are Subject To

20% Restocking Charge.

GenTech Reserves the Right to Change Advertised Prices.

tXPttESS,

Inquiry 120

Inquiry 131

HARM NY VIDEO & COMPUTERS

2357CONEYISLANDAVE.,BROOKLYN,NY 11223

TO ORDER CALL TOLL FREE

800VIDEO84 OR 718-627-1000 OR 800-441-1144

IBM PC W/DRIVE

APPLE 2C

$1299.95

$869.95

OKIDATA92

GEMINI 10X

^SZ > ^ r

$349.95

$226.95

"PRINTER SPECIALS

Okidata92

350

Radix 15

567

Panasonic KXP 1091

259

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551

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481

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201

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291

Powertype

280

Silver Reed EXP 550

382

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229

Daisywriter

•774

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286

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387

BrolherHR15

339

Silver Reed EXP 770

742

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392

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572

Nee 3550

1299

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598

Brother HR35

784

Nee 2050

847

Epson LQ1500

1039

Keyboard

122

OlympiaRO

312

Toshiba 1351

1208

Riteman Blue +

279

Nee 7730

1843

Delta 10

329

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684

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1843

Delta 15

456

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233

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836

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227

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530

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567

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339

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371

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382

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678

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509

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546

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1431

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350

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138

Quadjet

721

MNNSMN 180L

742

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233

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1034

NEC 8850

1754

HP Laser Jet

3021

Epson QX10

1712

Pinwriter P3

848

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350^^

WOW!

APPLE

2E w/Disk Drive

859

Macintosh

1689

Apple 2C

869

Imagewriter

486

Addt. Drives from 114

COMMODORE

Commodore64

177

1541 Disk Drive

204

1702 Monitor

208

MPS801 Printer

179

1526 Printer

215

ATARI

800 XL

107

1027 Printer

219

1050 Drive

159

Indus. Drive

279

1025 Printer

169

SANYO

550S.S.

648

550D.S.

659

555 D.S.

949 ■

555S.S.

839

CRT30

99 |

IBM

PCw/Drive

PC XT

PC Portable w/Drive

PCjr.

Color Card

Monocrome Card

IBM Monitor (GRNh

Tecmar Captain 64K

AST Six Pack

Tallgrass20 Meg

Quad Board

Paradise

Keytronics

Hercules Color

Hercules Monochrome

Plantronics

STBGraphix

PC w/10 Meg Hard Dr.

Bemoult Box

10 Meg Drive

Teac 1/2 Ht

Shugarl 1/2 Ht

1/2 Ht

1299
2499
1499
459
144
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224

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Amdek 300 Green 114

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Color 700

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Zenith Green

Taxan210

PrlnctonHX12

Taxan122A

Taxan 420

MODEMS

Hayes 1200
Hayes 1200B
Hayes 300
Micromodem 2E
Access 123
Novation J-cat

229
324
384

139
369

435
382

FRIENDLY SERVICE AT A FRIENDLY PRICE

Friendly Computer Center, Inc.

1381 Coney Island Avenue. Brooklyn. New York 11230

EPSON

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FOR IBM

AST Six Pack Plus 64K . . . 249.00
Ouadram Expanded Ouadboard

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 Mouse w/Mouse
w/P.C. Paint and Menue . . 159.00
Hayden Saragon III Chess. 34.90
Microsoft Flight Simulator 1137.90
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Friendly Computer Center, Inc. <

BOOK REVIEWS

covers more advanced applications of trees, including AVL
(Adelson-Velskii and Landis) trees, contiguous represen-
tation of binary trees, lexicographic search trees, and ex-
ternal searching. There is no discussion of graphs.

Kruse examines algorithms for searching, looking up
tables, accessing hash tables, and sorting. He presents an
in-depth study of recursion. The author works out large,
complex programs in detail, and he develops programs
to index text and to evaluate mathematical expressions.

In the appendixes, Kruse discusses techniques from
combinatorial mathematics for assessing algorithms
analytically. He also covers methods for manually remov-
ing recursion and presents standard syntax diagrams and
tables for Pascal.

Pascal and Clear Examples

Kruse illustrates principles using Pascal programs that have
been tested on several compilers. I endorse this strategy;
others have used pseudolanguages. For people using
Pascal, the book is eminently useful and educational. You
can enter the programs and try your own modifications.

The book contains many in-depth examples of applica-
tions of data structures to programming problems.
Realistic examples include Conway's game of Life, a text-
indexing program, and a program that evaluates mathe-
matic expressions.

I lost count of the number of times I came across
valuable nuggets of information or explanations that
clarified concepts I had read about in other books but
failed to understand. Where other authors simply use
pointers, Kruse discusses how pointers can be created
even in languages in which they are not implemented.

It is apparent that much of Kruse's time preparing this
text was spent trying it out on students, polishing the
prose, and clarifying important points. This book stands
head and shoulders above others in making difficult con-
cepts understandable.

Unfortunately, while Kruse covers most of the fundamen-
tal data structures I expected, he does not include a
chapter on graphs. Graphs are an important data struc-
ture different enough from other data structures so as to
require individual consideration. They have significant
practical applications for scheduling programs, flow pro-
grams, and trip planning.

Data Structures and Program Design excellently covers data
structures and algorithms for operating on them. Kruse
is readable, covers topics in great depth, and does so
without losing the reader. I recommend the book for a
second course in any formal computer curriculum or as
a resource and reference book for programmers who seek
to improve their programming skills on their own. ■

Edward Brent, an associate professor of sociology and family and com-
munity medicine (108 Sociology, University of Missouri. Columbia.
MO 65211), has recently completed a post-doctorate fellowship in
which he studied the role of data structures in artificial-intelligence
programming.

78 BYTE • FEBRUARY 1985

Inquiry 115

et the Picture with

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 specif ications, pricing,
availability and much more.

Customers, distributors and sales
personnel can quickly search data
and viewthe 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 bltathe
©JHOTOBASE menu. Capture
images of text, photos, artwork an$
3-dimensional objects with an
ordinary video camera and our
high resolution PC-EYE™ video
digitizer. Pop back into your data
&as& system an® add the picture
ngme to your data base like you
would any other piece of
information. The full functionality of
the data base; system is preserved,
brut 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 320 x 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 li is a trademark of Ashton-Tate; R-Base
4000 is a trademark of Microhm, Inc.; IBM Filing
Assistant is a trademark of International Business
Machines Corporation.

Inquiry 49

CHORUS Data Systems, Inc., 6 Continental Blvd., P.O. Box 370, Merrimack, New Hampshire 03054

SHE'S TEMPORARY

THE DAMAGE IS PERMANENT.

One wrong key.

The slightest slip.

And your accounts receivable
are accounts irretrievable.

It can happen to you-because
a leading cause of data loss is
human error. If you employ people
and computers, youre vulnerable.

Unless you backup your data.

Every day.

No matter what.

The smartest way to do that
is with a Tallgrass HardFile"
Mass Storage System.

Shownabove, the 20 megabyte HardFile
with 20 megabyte tape for $2,995.

TALLGRASS SELLS MORE
HARD DISK STORAGE WITH
CARTRIDGE TAPE BACKUP
THAN ANYONE IN THE WORLD.

Tallgrass took the industry's
most reliable medium— magnetic
tape— and perfected a format
that's become the standard for
personal computers.

We used a removable tape
cartridge to store data out of

80 BYTE • FEBRUARY 1985

harm's way. And made two ver-
sions. Our 3000 Series HardFiles
combine tape's accuracy with
the enormous capacities of hard
disk, providing 12, 20, 35 or 70
megabytes storage with a remov-
able cartridge tape for backup.
Our 4060 tape storage system,
for personal computers with
hard disks built in, supplies 60
megabytes of backup capacity.

Result: the world's best selling
mass storage systems with the
most reliable data protection.

The only kind to have when
facing a permanent problem.

For a free brochure, your
nearest dealer, and more
good reasons to backup,
call 1-800-228-DISK. And
solve your problems
permanently.

TALLGRASS
TECHNOLOGIES

COMMITTED TO MEMORY

Inquiry 307

HardFile' - and Tallgrass** are trademarks of

Tallgrass Technologies Corporation. c 1984 Tallgrass Technologies.

X PROFESSIONAL'S CHOICE

Lotus
1-2-3

<899

Software

Word Processing Editors

EASYWRITER II

SYSTEM
FANCY FONT
FINAL WORD
MICROSOFT WORD
MICROSOFT WORD

W/MOUSE
MULTIMATE
PFS: WRITE
SAMNA WORD III
VOLKSWRITER

DELUXE
VOLKSWRITER

SCIENTIFIC
THE WORD PLUS

(OASIS)
WORDPERFECT
WORDPLUS W/BOSS
WORDSTAR
WORDSTAR 2000
WORDSTAR 2000+
WORDSTAR

PROFESSIONAL
XYWRITEIK

Spreadsheets/
integrated Packages

ELECTRIC DESK

ENABLE

FRAMEWORK

LOTUS t-2-3

MULTIPLAN

OPEN ACCESS

SMART SYSTEM

SPREADSHEET
AUDITOR

SUPERCALC3

SYMPHONY

TKl SOLVER

Lotus
Symphony

<419

dBase III

$339

Framework

$339

MultiMate

<859

WordStar
2000+

<319

$219
$139
$189
$239

$289
$259
$95
$Call

$159

$309

$105
$249
$319
$199
$269
$319

$259
$229

$209
$459
$339
$299
$135
$299
$559

$ 79
$199
$419
$269

Desktop
Environments

DESK ORGANIZER
GET ORGANIZED
SIDEKICK
SPOTLIGHT

Communications/
Productivity Tools

CROSSTALK
PROKEY
RELAY
SMARTCOM II

Samna
Word III.

'CALL

$129
$159
$ 45
$109

$105
$ 89
$ 99
$109

Database Systems

ALPHA DATA BASE

MANAGER II
CLOUT V 2.0
CONDOR III
DBASE II
DBASE III
INFOSTAR+
KNOWLEDGEMAN
PFS: FILE/PFS:

REPORT
POWERBASE
QUICKCODE III
R BASE 4000

Languages/Utilities

CONCURRENT DOS

C86C COMPILER

DIGITAL RESEARCH
C COMPILER

DR FORTRAN 77

LATTICE C COMPILER

MICROSOFT C
COMPILER

MS BASIC COMPILER

MS FORTRAN

NORTON UTILITIES-
NEW

TURBO PASCAL

Project
Management

HARVARD PROJECT

MANAGER
HARVARD TOTAL

PROJECT MANAGER
MICROSOFT

PROJECT
SCITOR PROJECT

5000 W/GRAPHICS

Professional
Development

MANAGEMENT EDGE
SALES EDGE
THINK TANK

Home/Personal
Finance

DOLLARS AND

SENSE
FINANCIER II
HOWARD TAX

PREPARER 85
MICROTAX
MANAGING YOUR

MONEY

$179
$139
$299
$269
$339
$319
$269

$169
$219
$169
$259

$189
$299

$219
$219
$Call

$309
$249
$239

$CaII
$45

$219
$299
$159
$289

$159
$159
$119

$119
$119

$195
$Call

$129

Graphics/Statistics

ABSTAT $279

AUTOCAD $Cail
BPS BUSINESS

GRAPHICS $229

CHARTMASTER $239

CHARTSTAR $209

DR DRAW $199
ENERGR APHICS W/

PLOTTER $279

EXECUVISION $259
GRAPHWRITER

COMBO $389

MS CHART $159
OVERHEAD

EXPRESS $139

PC DRAW $259

PC PAINTBRUSH $ 89

PFS: GRAPH $ 95

SIGNMASTER $179

STATPRO $Call

STATPAK-NWA $329

STATPAC-WALONICK $299

Accounting Modules

BPI $329

GREAT PLAINS $479

IUS EASYBUSINESS $309

MBA $369

OPEN SYSTEMS $399

PEACHTREE $299

REAL WORLD $469

STATE OF THE ART $389
STAR ACCOUNTING

PARTNER $249
STAR ACCOUNTING

PARTNER II $599

Hardware *

Multifunction Boards

AST ADVANTAGE $C*II

AST 6 PAK PLUS (64K) $249
AST 6 PAK PLUS

(384K) $449

AST MEGAPLUS II (64K) $269

AST MEGAPAK (256K) $349

QUADBOARD (64K) $269

QUADBOARD (256K) $399
QUADBOARD EXP.

(64K) $269
QUADBOARD EXP.

(384K) $469

QUAD 512 + (64K) $269

ORCHID BLOSSOM $Call

PERSYST $CaN

TECMAR CAPTAIN(64K) $279

TECMAR WAVE (64K) $209

Display Boards

AST MONOGRAPH PLUS $Call
EVEREX GRAPHICS

EDGE $419

HERCULES GRAPHICS

CARD $329

HERCULES COLOR

CARD $179

PARADISE MODULAR

GRAPHICS CARD $285

PARADISE

MULTIDISPLAY CARD $285
PERSYST $Call

PLANTRONICS

COLORPLUS $419

PRINCETON SCAN

DOUBLER $Call

STB GRAPHICS

PLUS II $309

TECMAR GRAPHICS

MASTER $489

TECMAR VIDEO VAN

GOGH $259

TSENG ULTRA PAK $449

Displays

AMDEK 300G/300A $139/149

AMDEK 310A $179

AMDEK COLOR II + $459

PRINCETON HX-12 $469

PRINCETON MAX-12 $179

PRINCETON SR-12 $CaH
QUADRAM

AMBERCHROME $179

ZENITH 124 AMBER $145

ZENITH 135 COLOR $Call

Modems

AST REACH 1200 $Call

HAYES 1200 $459

HAYES 1200B $399

HAYES 2400 $Call
VENTEL1200

HALF CARD $Csl

Accessories

CURTIS SURGE

PROTECTORS $Cnll
EPD SURGE

PROTECTORS $Call
GILTRONIX A/B SWITCH $Call
MICROBUFFER INLINE

(64K) $264
MICROFAZER INLINE

(64K) $219

64K RAM SET $40

256K RAM SET $Cafl

8087 MATH $150

Printers/Plotters

AMPLOT II
C. ITOH
COMWRITER II
COMWRITER420
DIABLO 620/630
EPSON FX-100+
EPSON LQ-1500
EPSON JX-80
JUKI 6100
NECP3
NEC 2050
NEC 3550
OKIDATA84P
OKIDATA 93P
QUME SPRINT 1155
TOSHIBA P1351
SWEET P 6 PEN
PLOTTER

Emulation Boards

ASTPCOX
AST 3780
ASTSNA
ASTBSC
BLUE LYNX
CXI 3278/9
IRMA
IRMALINE
IRMAPRINT
QUAD 3278

Input Devices

KEYTRONIC5151
MICROSOFT

MOUSE
PC MOUSE W/ PAINT

Mass Storage

ALLOY PC-BACKUP

20MB
ALLOY PC-DISC

20MB
IOMEGA 10+10 MB
MAYNARDWS-1 10MB
SIGMA

SYSGEN IMAGE
TALLGRASS HARDFILE

+ TAPE
TEAC H&JLfcHEIGHT

Networks

AST PC NET $Call

CORVUS NET $Call
DIGITAL RESEARCH

STARLINK $1199

ORCHID PC NET $Cafl

•CALL FOR SHIPPING COSTS

$859
$Cafl
$CaU
$Call
$Catt
$Ca»
$CaU
$Call
$419
$899
$769
$1399
$729
$619
$1569
$1279

$899

$949
$609
$689
$ 29

$Ca!l
$Call
$869
$999
$Cal
$949

$139
$159

$1649

$1769
$2895
$CaH
$Ca*
$CaH

$Caii
$159

Chart-Master

*239

AST6Pak
Plus

<849

Quad Board I Smartmodem I Smartmodem
Expanded64K| 1200B 1200

<869 <399 <459

LOWEST PRICE
GUARANTEE!!

We will match current

nationally advertised

prices on most products.

Gall and compare.

fie

Diskette

Library

Case

with your order

TERMS:

Checks— allow 14 days to clear. 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.

In New York State call (718) 438-6057

€ ml '' r: ~''

MON.-THURS. 9:00AM-8:00PM
SUN. & FRI. 9:00AM-4:00PM

Softline Corporation
P.O. Box 729, Brooklyn, NY. 11230
TELEX: 421 047 ATLNUI

82 BYTE • FEBRUARY 1985

Inquiry 283

EVENT QUEUE

February 1985

• AI. EXPERT SYSTEM
BRIEFING-Artificial In-
telligence and Expert Sys-
tems: What Business Must
Know Today to Reap the
Benefits Tomorrow, Marriott
Copley Place. Boston. MA. A
one-day executive briefing.
The fee is $790. Contact Lee
Burgess, Professional
Development Programs.
Rensselaer Polytechnic In-
stitute. Troy Building. New
York. NY 12180-3 590. (518)
266-6589. February 11

• 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. The
cost is $730. Contact Stod
Cortelyou. Continuing
Engineering Education.
George Washington Univer-
sity. Washington. DC 20052.
(800) 424-9773; in the
District of Columbia. (202)
676-8520. February 11-13

• NETWORK COMPO-
NENTS EXPLAINED-Data

Communications Network
Components. Atlanta. GA. 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

lowers 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
Education Association. Hyatt
Regency Hotel. Austin. TX.
The theme is "New Direc-
tions for Education Using
Modern Day Technology."
Contact TCEA Conference.
POB 2 573. Austin. TX
78768. February 13-16

• PC SYMPOSIUM
The 1984 UNM Personal
Computer Symposium. Uni-
versity of New Mexico. Albu-
querque. Exhibits, seminars,
and demonstrations of per-
sonal computer systems for
business, education, and
professional offices. Contact
the Tau Beta Pi Honor Soci-
ety, c/o Dr. Randy Truman.
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

• MICROS FOR EDU-
CATORS— Association of

Teacher Educators National
Conference. Riviera Conven-
tion and Resort Hotel. Las
Vegas. NV. Exhibits and
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 60115,
(815) 753-1241.
February 18-19

• MANAGE YOUR COM-
PUTER— Managing Com-
puter Resources. Winter-
green Learning Institute.
Wintergreen. VA. Focuses on
networking, system design,
performance evaluation, and
operational difficulties en-
countered by managers and
executives. Rates vary from
$570 to $769, depending on
accommodations. Contact
Dr. M. D Corcoran. Winter-
green Learning Institute,
POB 7. Wintergreen. VA
22958. (800) 325-2200; in
Virginia. (804) 325-1107.
February 18-22

• COMMUNICATIONS FOR

EXECS-Info/Central. O'Hare
Exposition Center, Chicago.
IL. A computer and commu-
nications show and con-
ference for executives and
data-processing managers.
Topics: mainframes, micro-
computers, telecommunica-
tions systems, and micro-
graphics. Contact the Show
Manager. Info/Central. 999
Summer St.. Stamford. CT
06905. (203) 964-8287.
February 20-22

1 F YOU WANT your organization's 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.

• MODULA-2 ENGI-
NEERING-Software

Engineering with Modula-2,
Atlanta. GA. A course
emphasizing methods for
building large-scale software
systems in Modula-2. Pre-
requisite: knowledge of Ada
or Pascal. The fee is $495.
Contact Elaine Hadden
Nicholas. Department of
Continuing Education.
Georgia Institute of Tech-
nology Atlanta. GA 30332-
0385. (404) 894-2 547.
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 FAIRE

The Fourth Annual IEEE
Computer Faire. Huntsville.
AL. Sponsored by the In-
stitute of Electrical and Elec-
tronics Engineers. Contact
Terry Mizell. POB 5188.
Huntsville. AL 3 5805. (205)
532-2036. February 22-23

• COMPUTERS IN MEXICO

The First International Com-
puter and Communications
Exposition and Conference:
MexCom '85. Mexico City.

[continued)

FEBRUARY 1985 • BYTE 83

Inquiry 309

ERGO® 4000 is the ASCII Terminal featuring
80-column by 66-line format for full-page dis-
play capability. Features include: 15 down-
loadable function keys, four video attributes,
pass-through printer port, screen saver,
alternate character generator, settable tabs,
24-line display, and user-definable custom
mode. (Compatible with VT100 codes.) Most
popular word processing packages are
already modified to run on the ERGO® 4000.

micRo-TGRm, inc.

Call toll-free 1-800-325-9056

512 Rudder Road
Fenton (St. Louis County), Missouri 63026

COMPETITIVE EDGE

P.O. Box 556 • Plymouth, MI 48170 • (313) 451-0665
THUNDER 186™ SYSTEM $1995.

Includes 256K RAM, 2-5" Floppys and concurrent DOS®
expandable to 10 or 40 MB hard disk & up to 4 users.
TELETEK SYSTEM ASTER II® SYSTEM ..$5895.

With 2 Hi-speed 128K banked slaves, 10MB hard disk and two
Qume 102 terminals.

Includes fastest Z80 slaves available.

WE INTEGRA TE S YSTEMS
WITH THE FOLLOWING COMPONENTS

CompuPro® Lomas Data Products
Teletek

Sample Component Prices

CompuPro 286 with 287 chip CPU $1199.

Disk 1A . . .$459. RAM 22 . . .$995. I/O 4 . . .$297.

CPUZ™ . . .$215. 85/88 . . .$327. RAM 23-64™ . . .$309.
LDP 286 . . .$1116. LDP Hi-speed 5 12K . . .$899.

Color Magic™ . . .$496. Thunder 186™ . . .$1195.

Teletek Systemaster II® 8MHZZ80 $899.

Teletek HDCTC® Hard Disk Controller $525.

QUME 102 GR . . .$450. C. ITOH 8510 PTR . . .$350.

DRI FORTRAN . . .$250. COMP. Inovation C . . .$299.

All prices subject to change and

stock on hand shipping extra min. $3.

ALL PRICES CASH PRICES

Concurrent DOS is registered treademark of Digital Research Inc. RAM 23, CPU
286/287, CPU Z, RAM 22, are trademarks of CompuPro a Godbout Company.
Thunder 186, Color Magic trademarks of LDP Inc. Systemaster II & HDCTC are
registered trademarks of Teletek Enterprises Inc.

EVENT QUEUE

Mexico. This show features
mini- and microcomputers,
software, office automation
equipment, and communica-
tions exhibits. Contact Mex-
Com, Suite 219, 3421 M St.
NW, Washington, DC 20007,
(703) 685-0600.
February 25-28

• 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 2 5-28

• DYNAMIC COMPUTING

Dynamics on Microcom-
puters, University of Michi-
gan, Dearborn. A course
and workshop for engineers.
Contact Professor R. E.
Little, University of
Michigan, 4901 Evergreen
Rd., Dearborn, MI 48128,
(313) 593-5241.
February 25-March 1

• HIGH-TECH IN FOCUS

High-lech '85 Exhibit and
Seminar, Thunderbird Motel,
Bloomington, MN. More
than 100 manufacturers will
exhibit terminals, periph-
erals, data-communications
equipment, and digital test
instruments. Admission is
free. Contact John Bastys or
Barb Mueller, Countryman
Associates Co., 1821 Univer-
sity Ave., St. Paul, MN
55104, (612) 645-9151.
February 26-27

• MICRO-AIDED MANAGE-
MENT— Microcomputer-
aided Maintenance Manage-
ment System, Ramada Inn,
Airport, Milwaukee, WI. This
course shows how com-
puters can help improve the
maintenance functions of
any organization. The fee is
$60. Contact Unik Asso-
ciates, 12 545 West Burleigh,
Brookfield. WI 53005, (414)
782-5030. February 27

March 1985

• DISCOVER UNIX

Discover UNIX, various sites
throughout the U.S. A two-
day seminar exploring such
topics as the UNIX file
system, shell interpreter, text
editors, programming lan-
guages, and system tools.
The fee is $595. Contact
Data-lech Institute, 57 Lake-
view Plaza, POB 2429, Clif-
ton, NJ 07015, (201)
478-5400. March

• COMPUTERS FOR SALE

Computer Supermarket, San
Mateo County Fairgrounds,
San Mateo, CA. A gathering
of retailers, manufacturers,
distributors, and potential
consumers of a wide variety
of computer-related prod-
ucts. Contact Microshows,
Suite 203, 1209 Donnelly
Ave., Burlingame, CA 94010,
(415) 340-9113. March 2-3

• FOSE SOFTWARE SHOW

Federal Office Systems Ex-
position (FOSE) Software
'85, Convention Center,
Washington, DC. Workshops,
symposia, and exhibits of
software. Contact Rosalind
Boesch, National Trade Pro-
ductions Inc., Suite 400,
2111 Eisenhower Ave., Alex-
andria, VA 22314, (800)
638-8510; in Virginia, (703)
683-8500. March 4-7

• MINI/MICRO

Mini/Micro Southeast-85,
Georgia World Congress
Center, Atlanta. A con-
ference and exposition. Con-
tact Electronic Conventions
Management, 8110 Airport
Blvd., Los Angeles, CA
90045, (213) 772-2965.
March 5-7

• 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. Contact the Show
Manager, National Design

84 BYTE • FEBRUARY 1985

Inquiry 54

EVENT QUEUE

Engineering Show, 999 Sum-
mer St., Stamford, CT 06905,
(203) 964-0000. March 11-14

• DATACOMM FROM ALL
ANGLES— Data Communica-
tions: Technology, Tech-
niques, and Applications.
Tarry town Hilton, Tarry town,
NY. This seminar covers
existing and emerging
technologies, data compres-
sion techniques and applica-
tions, multiplexers, protocol
conversion, data security,
and local-area networks. The
fee is $150. Contact Glasgal
Communications Inc., 207
Washington St., Northvale,
NJ 07647. (201) 768-8082.
March 12

• ACM COMPUTER
CONFERENCE-The Thir-
teenth Annual ACM Com-
puter Science Conference:
CSC '85, New Orleans Mar-
riott, LA. An employment
register, social events,
technical programs, award
presentations, and exhibits
are highlights of this show.
Contact Delia T. Bonnette,
Conference Chair, Com-
puting and Information Ser-
vices, University of South-
western Louisiana, Lafayette,
LA 70504, (318) 231-6306.
March 12-14

• EDUCATIONAL
CONFERENCE-The 1985
Microcomputers in Educa-
tion Conference. Arizona
State University. Tempe. The
theme for this conference is
"Tomorrow's Technology."
Emphasis will be placed on
integrating computer tech-
nology and languages into
the educational environ-
ment. Exhibits will be
featured. Contact Donna
Craighead, Payne B47,
Arizona State University,
College of Education,
Tempe, AZ 85287, (602)
965-7363. March 13-15

• SIMULATION IN
SUNSHINE-The Eighteenth
Annual Simulation Sym-
posium! Tampa, FL. A forum

for the interchange of ideas,
techniques, and applications
among those working in
simulation. Contact Alex-
ander Kran, IBM Corp., East
Fishkill Facility, Hopewell
Junction, NY 12533.
March 13-15

• INTERFACING
WORKSHOP-Personal Com-
puter and STD Computer In-
terfacing for Scientific Instru-
ment Automation, Virginia
Tech, Blacksburg. A hands-
on workshop with partici-
pants wiring and testing in-
terfaces. The fee is $450.
Contact Dr. Linda Leffel,
C.E.C., Virginia Polytechnic
Institute and State Univer-
sity, Blacksburg, VA 24061,
(703) 961-4848. March 14-16

• SHOW IN DELAWARE
The Seventh Annual
Delaware Computer Faire,
Delaware State College,
Dover. Current technology
for use in the classroom, of-
fice, and home will be dis-
played. Workshops, demon-
strations, and sessions on
the use of computers in the
classroom are planned. Con-
tact Dr. William J. Geppert,
State Supervisor. Mathe-
matics. Department of
Public Instruction. Townsend
Building. POB 1402, Dover,
DE 19903, (302) 736-4885.
March 16

• CLASSROOM
COMPUTING TECHNIQUES

Instructional Strategies for
Integrating the Microcom-
puter into the Classroom,
University of Wisconsin,
Madison. A special em-
phasis is placed on strate-
gies that have already
proved successful. Hands-on
sessions will be offered.
Contact Dr. Judith Roderv
stein or Dr. Roger Lambert,
University of Wisconsin, 964
Educational Sciences Build-
ing, 1025 West Johnson St.,
Madison, WI 53706, (608)
263-4367 or 263-2704.
March 18-19

{continued)

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.

Inquiry 323

FEBRUARY 1985 'BYTE 85

Inquiry 22

The Little Board ... $349*

The world's simplest and least expensive CP/M computer

$5*

CP/M 2.2

INCLUDED

»*

rf*

"UNDER $200 IN
OEM QUANTITIES

Z80A is a registered trademark of Zilog, Inc
CP/M is a registered trademark of Digital Research

• 4 MHz Z80A CPU, 64K RAM, Z80A CTC, 2732 Boot ROM

• Mini/Micro Floppy controller (1-4 Drives, Single/Double Density, 1-2 sided, 40/80 track)

• Onfy 5.75 x 7.75 Inches, mounts directly to a 5 1/4" floppy drive

• 2 RS232C Serial Ports (75-9600 baud & 75-38,400 baud), 1 Centronics Printer Port

• Power Requirement: +5VDC at .75A; +12VDC at ,0SA/On-board -12V converter

• CP/M 2.2 BDOS • ZCPR3 CCP • Enhanced AMPRO BIOS

• AMPRO Utilities Included:

• read/write to more than 2 dozen other formats (Kaypro, Televideo, IBM CP/M86....)

• format disks for more than a dozen other computers

• menu-based system customization

• BIOS and Utilities Source Code Available

• SCSI/PLUS Adapter :

• Mounts directly to Little Board

• Slave I/O board control • Full ANSC X3T9.2

• 16 bidirectional I/O lines • $99/Quantity 1

COMPUTERS. INCORPORATED

DISTRIBUTORS

Argentina-Factorial, S.A 1-41-0018

Australia-ASP Microcomputers 613-500-0628

Belgium-Centre Electronique Lempereur . . 041-23-45-41

Canada-Electronic Sales Assoc (604) 986-5447

Denmaifc-Danbit 03-66-20-20

England-Quant Systems 01-534-3158

Finland-Symmetric OY 358-0-585-322

France-Alain Lequeux 1-525-6960

Israel-Alpha Terminals 03-491695

Spain-Xenios Inf ormatica 3-593-0822

Sweden-AB AKTA 08-54-20-20

USA: Digital Distributors (CA> 408-423-1556

Peripheral BusinessSystems(WA) ... 206-823-6661
Dorado Business Systems (NY/NJ) . . 609-429-2243

v (-.ljivk-^lj i ci-ia. u\JL^i_ii— it-^LJi— (*-\ i cu uoraao business systems iny/nj; .. ouy*4uy-¥¥4.

XS67 East Evelyn Ave. . Mountain View, CA 94041 . (415)962-0230 . TELEX 4940302 i

When Vour
Chips Are Down.

Bank on BVT€K's

(€)PROM MultiProgrammer System S15-G

With Less Restrictions & o FR€€ KCVBOnRD

For Only $995.

Stand Alone or Hook Up to your Terminal,

3 Voltage Devices, Simulation Module,

Supports Bipolar, PALs, 40 Pin Chips.

Also Available: S5 Basic (E)PROM

Programmer, $690. UV Erasers from $67.

(@DD@E)*COMPUT€R SVST€MS CORPORATION

4089 South Rogers Circle, Boca Raton, FL 33431

CALL TO ORD€R(305) 994-3520, Telex 4310073 MGVBTC
Distributor Inquiries Welcome

EVENT QUEUE

• EXPOSING THE MYTH
OF MICROS— Public Aware-
ness Seminars, Hyatt Regen-
cy Los Angeles, CA. A
seminar that shows nontech-
nical businesspeople how a
microcomputer could be
used to increase productivi-
ty. Contact International
Microcomputer Industries
Association, Suite 17 5, 21
Tamal Vista Blvd., Corte
Madera, CA 94925, (415)
924-1194. March 18-19

• COMPUTERS AND
TELECOMMUNICATIONS

COMTEL '85: International
Computer and Telecommuni-
cations Conference, Info-
mart, 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-
nual Conference on Technol-
ogies in Education, Univer-
sity of Arizona, TUcson. This
conference will focus on the
effective implementation of
research in educational
technology. Contact Steve
Louie, NACC1S, Suite 12 5,
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, MI.
More than 2 5 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

• AI FOR ROBOT'S

Aircon 2: The Second An-
nual International Con-
ference on Artificial In-
telligence for Robots, Stouf-
fers Concourse in Crystal
City, Arlington, VA. A con-

ference 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, 1IT Research Institute,
10 West 3 5th St., Chicago, IL
60616, (312) 567-4024.
March 21-22

• EDUCATION AND

COMPUTING-Educational
Computing Today, Westin
Hotel, Renaissance Center,
Detroit, Ml. Kindergarten,
elementary, high school, and
college educators will share
educational computing ex-
periences. Contact Michigan
Association for Computer
Users in Learning,
MACUL/ICCE Conference,
POB 628, Westland, MI
48185, (313) 595-2493.
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 of age.
Contact Dr. Richard B.
Fischer, Division of Continu-
ing Education, University of
Delaware, Newark, DE
19716, (302) 451-8838.
March 21-22

• WINTER COMDEX

COMDEX/Winter, Convention
Center, Anaheim, CA. One
of the largest shows in the
microcomputer industry.
Contact The Interface Group,
300 First Ave, Needham,
MA 02194, (800) 325-3330:
in Massachusetts, (617)
449-6660. March 21-24

• DATABASE SYMPOSIUM
The Fourth Annual ACM
SIGACT/SIGMOD Symposium
on Principles of Database
Systems, Portland, OR. This
conference covers develop-
ments in the theoretical and
practical aspects of database

{continued)

86 BYTE • FEBRUARY 1985

Inquiry 37

Introducing the Most Powerful
Business Software Ever!

TRS-80™ (Model I, II, III, or 16) • APPLE™ • IBM™ • OSBORNE™ • CP/M™ • XEROX™

The VersaBusiness" Series

Each VERSABUSINESS module can be purchased and used independently,
or can be linked in any combination to form a complete, coordinated business system.

VeRSAReCEIVABLES™ $99.95

VersaReCEIVABLES"* is a complete menu-driven accounts receivable, invoicing, and
monthly statement-generating system. It keeps track of all information related to who
owes you or your company money, and can provide automatic billing for past due ac-
counts. VERSARECEIVABLES™ prints all necessary statements, invoices, and summary
repo-.-ts and can be linked with VERSALEDGER 11™ and VERSAlNVENTORY™.

VERSAPAYABLES™ $99.95

VERSA PAYABLES™ is designed to keep track of current and aged payables, keeping you
in touch with all information regarding how much money your company owes, and to
whom. VERSA PAYABLES™ maintains a complete record on each vendor, prints checks,
check registers, vouchers, transaction reports, aged payables reports, vendor reports,
and more. With VERSAPAYABLES™. you can even let your computer automatically select
which vouchers are to be paid.

VERSAPAYROLL™ $99.95

VERSA PAYROLL™ is a powerful and sophisticated, but easy to use payroll system that
keeps track of all government-required payroll information. Complete employee records
are maintained, and all necessary payroll calculations are performed automatically, with
totals displayed on screen for operator approval. A payroll can be run totally, automati-
cally, or the operator can intervene to prevent a check from being printed, or to alter
information on it. If desired, totals may be posted to the VERSALEDGER II™ system.

VERSAlNVENTORY™ $99.95

VersaNventory™ is a complete inventory control system that gives you instant access
to data on any item. VERSA INVENTORY" keeps track of all information related to what
items are in stock, out of stock, on backorder, etc., stores sales and pricing data, alerts
you when an item falls below a preset reorder point, and allows you to enter and print
invoices directly or to link with the VERSA RECEIVABLES™ system. VERSAlNVENTORY™ prints
all needed inventory listings, reports of items below reorder point, inventory value re-
ports, period and year-to-date sales reports, price lists, inventory checklists, etc.

•CQMPUTRQnHICS?

50 N. PASCAGK ROAD, SPRING VALLEY, N.Y. 10977

VERSALEDGER H™ $149.95

VersaI^EDGER II™ is a complete accounting system that grows as your business
grows. VERSAI.EDGER II™ can be used as a simple personal checkbook register,
expanded to a small business bookkeeping system or developed into a large
corporate general ledger system without any additional software.

• VERSALEDGER II™ gives you almost unlimited storage capacity

(300 to 10,000 entries per month, depending on the system),

• stores all check and general ledger information forever,

• prints tractor-feed checks,

• handles multiple checkbooks and general ledgers,

• prints 17 customized accounting reports including check registers,
balance sheets, income statements, transaction reports, account
listings, etc.

Versa LEDGER Ir"" comes with a professionally-written 160 page manual de-
signed for first-time users. The VERSALEDGER II™ manual will help you become
quickly familiar with VersaI^EDGER II™, using complete sample data files
supplied on diskette and more than 50 pages of sample printouts.

SATISFACTION GUARANTEED!

Every VERSABUSINESS™ module is guaranteed to outperform all other competitive systems,
and at a fraction of theircost. If you are not satisfied with any VERSABUSINESS™ module, you
may retum it within 30 days for a refund. Manuals for any VERSABUSINESS" module maybe
purchased for $25 each, credited toward a later purchase of that module.

To Order:

Write or call Toll-free (800) 43 1-2818

(N.Y.S. residents call 914-425-1535)

* add $5 to CANADA or MEXICO

* add proper postage elsewhere

* add 53 for shipping in UPS areas

* add $4 for C.O.D. or non-UPS areas

Inquiry 127

DEALER INQUIRIES WELCOME

All prices and specifications subject to change / Delivery subject to availability.

* TRS-80 is a trademark of the Radio Shack Division of Tandy Ccrp. - * APPLE is a trademark of Apple Corp. • *IBM is a trademark of IBM Corp.

*CP/M is a trademark of Digital Research - *XEROX is a trademark of Xerox Corp.

*OSBORNE is a trademark of Osborne Corp.

T£ m W

A black border may appear around the Palette slide image,
which will be imperceptible when projected.

Nowlast 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 or XT,

DEC Rainbow or PRO, Apple He

or 11+ and AT&T 6300.

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 254

"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 CRE
Think of it as an artist's 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.
I : 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.

Company-
Address —

Cicv-

_Zip_

Telephone-!

PC make and model-

a Polaroid

B-2/85
•Suggested list price. Polaroid*

FEBRUARY 1985 -BYTE 89

\pple It, fle f ///and Apple compatible

Universal for virtually all standard parallel

printers.

Famous for Graphics (LoRes, HIRes, SuperRes)

(logo Compatible)

Terrific tor text (even rotates spreadsheets to

print sidewards)
One set of commands for all printers. One
command changes character sizes. Create
your own printing fonts, alphabets and sym-
bols . . . bold face, underline, italics, subscript
and superscript, HIRes Zooming.

PUS:

FREE Utility and Demon-
stration Software Disk.
CLEAR, comprehensive
user documentation.
PKASO/U ... for all the
reasons you need an
Interface.

«s

Interactive Structures, Inc.
146 Montgomery Avenue
Bala Cynwyd, PA 19004
Telephone: (215) 667-1713

EVENT QUEUE

systems. 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. Con-
tact lechnology Opportunity
Conference. POB 14817. San
Francisco. CA 94114-0817.
(415) 626-1133. March 25-27

• CAI INVESTIGATED
The Twenty-Sixth Interna-
tional Conference of the
Association for the Develop-
ment of Computer-based In-
structional Systems.
Philadelphia. PA. Presenta-
tions and panel discussions
will explore the research
and use of computers for
direct instruction. Interest
groups for educators. Con-
tact ADCIS International
Headquarters. Miller Hall
409. Western Washington
University. Bellingham. WA
98225. March 25-28

• INTEGRATION. COMMU-
NICATIONS. COMPUTERS
IEEE INFOCOM '85.
Washington. DC. Papers will
address such issues as archi-
tecture, protocols, gateways,
and support. Contact lorn
Stack. IEEE INFOCOM '85.
POB 639. Silver Spring. MD
20901. (301) 589-8142.
March 25-28

• MACHINE VISION EYED
The Applied Machine Vision
Conference and Vision '85
Exposition. Cobo Hall.
Detroit. MI. Contact Society
of Manufacturing Engineers.
One SME Dr.. POB 930.
Dearborn. MI 48121. (313)
271-0777. March 25-28

• JOINT CONFERENCE IN
MINNESOTA-Updata '85:
The Seventh Annual Minne-
sota Joint Computer Con-
ference. Radisson South

Hotel. Bloomington. MN. A
conference for data-pro-
cessing professionals. The
theme is "Meeting Ibmor-
row's Challenge loday!"
Contact Mick Williams. Stan-
dard Iron. 4990 North Coun-
ty Rd. 18. New Hope. MN
55428. (612) 533-1110.
March 28-29

• WESTERN EDUCATORS
MEET— Western Educational
Computing Workshops. Uni-
versity of California. Santa
Cruz. A series of workshops
and demonstrations that
give educators hands-on ex-
perience with computer ap-
plication packages and com-
puter hardware. Contact Hal
Roach. Computer Services.
Mount San Antonio College.
1100 North Grand Ave.
Walnut. CA 94542.

March 28-29

• WEST COAST FAIRE

The Tenth Annual West
Coast Computer Faire.
Moscone Center. San Fran-
cisco. 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 Massa-
chusetts. (617) 965-8350.
March 30- April 2

• COMPUTERFEST

The 1985 Greater Baltimore
Hamboree and Computer-
fest. Maryland State Fair-
grounds. Timonium. Exhibits,
flea market, and forums
highlight this annual event.
Admission is $4. and the
gates open at 8 a.m. Con-
tact Baltimore Amateur
Radio Club Inc.. POB 95.
Timonium. MD 21093-0095.
(301) 561-1282. March 31

• FOCUS ON SOFTWARE

Softcon. Georgia World Con-
gress Center. Atlanta. The
Spring and Fall Softcons
have been merged into this
event. Nearly 3000 software
vendors are expected to
participate. Seminars, panel
discussions, forums, and

90 BYTE • FEBRUARY 1985

Inquiry 153

EVENT QUEUE

workshops are planned.
Registration is $35 for
exhibits-only admission or
$195 for a four-day con-
ference and exhibits badge.
Contact Softcon, Northeast
Expositions, 822 Boylston
St., Chestnut Hill, MA 02167,
(617) 739-2000.
March 3\ -April 3

• TELECONFERENCING

SEMINAR— leleconferencing
in the Marketplace, Interna-
tional Congress Centre RAI,
Amsterdam, The Nether-
lands. A seminar for users
and suppliers of telecon-
ferencing services and
facilities. For further informa-
tion, contact International
Congress and Convention
Association, POB 5343,
1007 AH Amsterdam, The
Netherlands.
March 31 -April 3

• MICROPROCESSOR IDEA
EXCHANGE-The 1985
Microprocessor Forum,
Bally's Park Place Casino
Hotel, Atlantic City, NJ.
Tutorials, forums, and ex-
hibits will be held. A robotic
maze contest will be held.
On April 1 and 2, the 1985
IEEE VLSI Test Workshop
will be held. Contact IEEE
Computer Society, Suite 300,
1109 Spring St., Silver
Spring, MD 20910, (301)
589-8142. March 31 -April 4

April 1985

• GULF COAST SHOW

The Second Annual Gulf
Computer & Office Show,
Rivergate Convention
Center, New Orleans, LA.
Seminars, workshops, and
product displays. Contact
Gulf Computer & Office
Show Management, c/o 119
Avant Garde, Kenner, LA
70065, (504) 467-9949.
April 2-4

• MEET SOME NETWORKS
Introduction to Network
Architectures, Atlanta, GA.
This course provides an

understanding of the role of
network architectures and
explains their many forms.
The fee is $795. Contact
Elaine Hadden Nicholas,
Department of Continuing
Education, Georgia Institute
of Technology, Atlanta, GA
30332-0385, (404) 894-2547.
April 2-4

• ENGINEERING WITH

MODULA-2— Software Engi-
neering with Modula-2,
Atlanta, GA. See February
20-22 for details. April 3-5

• COMMUNICATIONS
TECHNOLOGY FOR THE

NONVERBAL-The Fourth
Annual Conference on Com-
munication Technology:
Technology and Nonspeak-
ing Children, Joseph Stokes
Auditorium, Children's
Hospital of Philadelphia, PA.
Up-to-the-minute information
on the use of technology
with nonverbal children will
be presented. Concurrent
sessions will address on-
going research, computers,
and treatment strategies.
The registration fee is $95.
Contact loan Bruno,
Children's Seashore House,
4100 Atlantic Ave., POB
4111, Atlantic City, NJ
08404, (609) 345-5191, ext.
278. April 12-13

• GRAPHICS

Computer Graphics '85,
Dallas, TX. Tutorials and
technical sessions on archi-
tectural and engineering
computer graphics, artificial
intelligence, business graph-
ics, and CAD/CAM. Contact
National Computer Graphics
Association, Suite 601, 8401
Arlington Blvd., Fairfax, VA
22031, (703) 698-9600.
April 14-18

• OPTICAL STORAGE
INVESTIGATED-The 1985
Materials Research Society:
Symposium D, Golden Gate-
way Holiday Inn, San Fran-
cisco, CA. A mass-storage
technologies symposium in-

[continued)

High performance to cost ratio,..

Programming Chips?

Projects develop profitably with development hardware /software from GTEK.

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 2764A &
27128A chips. It will also program
single chip processors.

EPROM

PROGRAMMERS

— Tliese features are standard from GTEK—
Compatible with all RS232 saial Interfax ports • Auto select baud rate • With or without hand-
shaking • Bidirectional XanOCoff • CISTJTR supports • Read pmcompatibte ROMS • No per-
sonality modules • Intel, Motoola, MCS86 Hex formats • Split fadhty for 16 bit data paths •
Read, program, formatted list commands • Interrupt drivm — program and vwify real time while
sending data • Program single byte, block, or whole EPROM • Intelligent diagnostics discern bad
and/or erasable EPROM • Verify erasure and compare commands • Busy light • CcKnplete with
Textool aoo insertion force socket and integral 120 VAC power (240 VAO50Hz available) •

MODEL 7228 - $599
This model has all the features
of Model 7128, plus Intelligent
Programming Algorithims. It
supports the newest devices
available through 512Kbits; 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.

&PAL

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

MODEL 7316 Pal Programmer $ 599

Programs Series 20 PALs. Built-in PALASM compiler.

DEVICES SUPPORTED

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.

by GTEK's EPROM Programmers

NMOS

2758 2764A 2508 68764

2716 27128 2516 8755

2732 27128A 2532 5133

2732A 27256 2564 5143

2764 27512 68766

CMOS

27C16

27C16H

27C32H

27C64

27C256

EEPROM

MPU'S

5213 I2816A 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- $ 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.

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

Inquiry 126

FEBRUARY 1985 -BYTE 91

Inquiry 228

When You Want The Best, Call.

National Business Software and Supplies

Macintosh

NIULTIMATE
PFS FILE
PFS REPORT
PFS WRITE
SYMPHONY
LOTUS 1-2*3
TURBO GIFT PACK
WORDSTAR
SIDEKICK

$285 FLIGHT SIMULATOR $ 35

89 WIULTIPLAN 125

79 DESK ORGANIZER CALL

89 BANKSTREET WRITER CALL

CALL MacFORTH 98

CALL PRO KEY 59

72 PRO KEY 3.0 82

229 NORTON UTILITIES 55

35 R BASE 4000 268

TEAC#55-B DRIVES FOR IBM PC
& COMPATIBLES DS/DD S139

Ribbons and Printwheels

EPSON-OKIDATA-NEC-DIABLO, ETC.

call for prices

(602)967-5681 I visa I Mon-Fri
500 W. Broadway, Ste, 116 n A 8AM-5PM

_„ MasterCard

Tempe, AZ 85282 I I

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
i with manufacturer s warranty. Software not warranted for suitability of pur-
pose. Shipping and handling add $5 per order. Minimum order $50.

EVENT QUEUE

vestigating optical data
storage. Contact D. H.
Davies, Symposium Co-Chair,
3M, 420 North Bernardo
Ave., Mountain View, CA
94043. April 15— 18

• INDUSTRIAL SOFTWARE

EXPO— The Second
CIMCOM: Industrial Soft-
ware Conference & Exposi-
tion, Disneyland Hotel,
Anaheim, CA. Contact Com-
puter and Automated Sys-
tems Association of the
Society of Manufacturing
Engineers, One SME Dr.,
POB 930, Dearborn, Ml
48121, (313) 271-1500.
April 16-18

• TRAINING AND
TECHNOLOGY-The Third
Annual Technology in Train-
ing and Education (TITE)
Conference, Antler's Hotel,
Colorado Springs, CO. A
conference designed to
facilitate the interchange of
ideas and to explore ways
that computers and tech-
nology can be applied to
education and training.
Contact Lt. Colonel McCann,
1985 TITE Conference,
USAFA/DFSR, USAF
Academy, Colorado Springs,
CO 80840-5751, (303)
472-4195. April 16-19

• NETWORK CONTROL

AND MANAGEMENT-Net-
work Management/Technical
Control, Marriott Copley
Place, Boston, MA. Diag-
nostic and test instruments
will be among the products
displayed. Contact Louise
Myerow, CW/Conference
Management Group, 375
Cochituate Rd., POB 880,
Framingham, MA 01701,
(800) 22 5-4698; in Massa-
chusetts, (617) 879-0700.
April 18-19

• PATIENT CARE AND
COMPUTERS-The Second
Annual Physicians and Com-
puters: Applications in Pa-
tient Care, Las Vegas Hilton,
NV. This conference ad-
dresses the concerns of

doctors, nurses, dietitians,
pharmacists, administrators,
and medical record adminis-
trators. Contact Beverly J.
Johnson, University of
Southern California School
of Medicine, Postgraduate
Division, 202 5 Zonal Ave.
KAM 318, Los Angeles, CA
90033, (213) 224-7051.
April 19-21

• COMPUTER FESTIVAL

The Tenth Annual Trenton
Computer Festival, Trenton
State College, Trenton, NJ.
Highlights talks, tutorials,
user-group activities, ex-
hibits, computer-graphics
theater, games, and a
50-acre outdoor electronics
flea market. Contact Ms.
Marilyn Hughes, Trenton
State College, Hillwood
Lakes CN 5 50, Trenton. Nl
0862 5, (609) 771-2487.
April 20-21

• AIDS FOR EDUCATORS

AEDS/ECOO '85: The
Twenty-Third Annual Con-
vention of the Association
for Educational Data Sys-
tems (AEDS), Hilton Har-
bour Castle, Toronto,
Ontario. The theme is
"Computing Knows No
Borders." Contact AEDS/
ECOO '85, c/o OlSE, 2 52
Bloor St. W, Toronto,
Ontario M5S 1V6, Canada.
In the U.S., AEDS/ECOO
'85, 1201 16th St. NW,
Washington, DC 20036.
April 21-27

• SPEECH IN FOCUS

Speech Tech '85, Vista In-
ternational Hotel, World
Trade Center, New York
City. Speakers and ex-
hibitors will focus on voice
synthesis and recognition.
Registration is $195. Contact
Media Dimensions Inc., POB
1121 Gracie Station, New
York, NY 10028, (212)
77 2-7068 or 680-6451.
April 2 2-24

• PUBLIC NETWORK
OPERATIONS-X.25 and

[continued)

92 BYTE • FEBRUARY 1985

Inquiry 200

pOWBtRu

NEVADA

FORTRAN

DISKETTE & MANUAL

1 $29.95

WARE

Nevada FORTRAN is based upon
the ANSI-66 standards
(FORTRAN IV) with some
1977 level features. Advanced features include: IF . . . THEN . . . ELSE
statement; COPY (Include); CHAINing with COMMON; and TRACE
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

1 $29.95

With the built-in, full-screen
text editor, you can easily

develop, programs for 1/10 the cost .__ .^- ._ ..- =—■«■*

of a comparable BASIC interpreter. What's more, Nevada BASIC has
full Matrix operations, Single* and Multi-Line functions, and BCD
math (no round-off errors). You get a diskette and a 220-page manual.
Requires 48K RAM,

V*.

NEVADA

Pi-OT

DISKETTE & MANUAL

\ $29.95

Nevada PILOT, written by Prof.
John Starkweather, the language's
creator, meets and exceeds all
PILOT-73 standards. See the review in January 1983 MICROCOMPU-
TING. This package includes a diskette, 131-page manual, and 10
useful sampie programs.

WHY WAIT? ORDER YOURS TODAY!

Satisfaction guaranteed— or your money back. If for any reason
you're not completely satisfied, just return the package— in good
condition— with the sealed diskette unopened, within 15 days and
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

$4.00.

WE WELCOME C.O.D.'s

^^|^Since1977
ELUS COMPUTING^

(415)753-0186

ELLIS COMPUTING, INC.
391 7 Noriega Street
San Francisco, CA 94122

NEVADA

COBOL

DISKETTE & MANUAL

I $29.95

Nevada COBOL, based upon the

ANSI-74 standards, has all the

popular features. Powerful level 2

features include: compound conditionals and full CALL CANCEL

This software package includes a diskette, 165-page manual, plenty

of examples and 16 complete COBOL source code programs.

NEVADA

PASCAL

DISKETTE & MANUAL

I $29.95

Advanced features include:

14-Digit precision; BCD math (no

round-off errors); Floating point

+ 63 -64; TRACE debugging; Arrays up to 8 dimensions; 64K strings;

External procedures; and Dynamic Module loading. You get a

diskette and a 184-page manual. Requires 60K RAM and one disk

drive with at least 90K storage, -

NEVADA

EDIT

DISKETTE & MANUAL

I $29.95

Nevada EDIT, a full-screen,
video-display text editor, is
designed specifically for computer
program text preparation. Nevada EDIT is completely user-change-
able, can be configured to almost any terminal and takes up only
12K of disk space. This package includes a diskette and 59-page
manual.
ALSO AVAILABLE:

• EXTRA MANUALS $14.95

• COBOL Application Packages, Book 1 $ 9.95

• 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 stated above.

WHEN YOU ORDER, PLEASE SPECIFY
FOLLOWING DISKETTE FORMATS:

D 8" SSSD (Standard CP/M IBM 3740)
5V4" Diskettes for:
D Access/Actrix

□ Apple CP/M

□ DEC VT 180

□ DEC Rainbow
D Epson QX-10

D Heath Hard Sector (Z-89)

□ Heath Soft Sector

(Z-90.Z-100)
D IBM-PC (Requires Z-80,
Baby Blue II Card)

ONE OF THE

D Kaypro Double Density (NCR)

D Micropolis Mod II

D NEC PC 8001

D North Star Double Density

D North Star Single Density

□ Osborne Single Density
D Sanyo 1000, 1050

D Superbrain DD DOS3.X
(512 byte sec)

□ . Televideo

D TRS-80 Model 1 (Base O Mapper)
D Xerox 820 Single Density

CP/M is a registered trademark of Digital Research, Inc. Microsoft is a registered trademark of Microsoft
Corp, TRS-80 is a registered trademark of Tandy Corp. Apple II is a trademark- of Apple Computer, Inc.
Osborne is a registered trademark of Osborne Computer Corp, Xerox 820 is a trademark of Xerox Corp.
Kaypro is a trademark of Non-linear Sys. Heath/Zenith is a trademark of Heath Corp. IBM is a registered
trademark of Internationa! Business Machines, Corp. Nevada BASIC, Nevada COBOL, NevadaFOR-
TRAN. Nevada PILOT, Nevada EDIT, Nevada PASCAL, and Ellis Computing are trademarks of Eflis Com-
puting, Inc. © 1984 Ellis Computing, Inc.

FEBRUARY 1985 • BYTE 93

Inquiry 85 for Dealers. Inquiry 86 for End-Users.

BEFORE YOU BUY
CABLE ASSEMBLIES,

Heavy guage

underhood

shield

P.D.T.

underhood

Gold plated pins

22AWG
twisted conductors

2mm PVC cover

CHECK UNDER THE HOOD!

DATA SPEC™ cable assemblies are the very best. Each
cable Is fully shielded to exceed FCC EMI/RFI emission
requirements. The unique P.D.T. technique, introduced by
DATA SPEC™ and employed beneath the hood shield,
insures maximum integrity under the most adverse
conditions. DATA SPEC™ has interface cables for all your
requirements: Printers, Modems, Monitors, Disk Drives,
and much more. And all DATA SPEC™ cable assemblies
carry a lifetime warranty. Insist on DATA SPEC™ cables in
the bright orange package. Available at better computer
dealers everywhere. For more information, call or write:

MjaorjaeoocL.

A Division of Alliance Research Corporation

20120 Plummer Street • Chatsworth, CA 91311 • (818) 993-1202

dBASEn

with 65,000 memory variables,
arrays, 8087 support, high-speed

math functions, windows,
animation, full syntax checking!

Impossible?

Not anymore!

. . . with GRYPHON

Microproducts' dBASE II

"add-ins". For PC/MS-DOS.

Write or call for details.

mictopVoducts

P.O. BOX 65^13 SILVER SPRING, MD. 20306
C301 ) 346-2585

EVENT QUEUE

Packet Switching Networks,
Atlanta, GA. This course
covers the internal opera-
tions of a packet-switching
network and its implementa-
tion. The fee is $795. Con-
tact Elaine Hadden
Nicholas, Department of
Continuing Education,
Georgia Institute of Tech-
nology, Atlanta, GA 30332-
0385, (404) 894-2547.
April 23-25

• TRADE SHOW,
CONFERENCE-Electro/8 5

and Mini/Micro North-
east-85, New York City.
Topics: artificial intelligence,
communications and net-
works, consumer electronics,
high-density data storage,
and personal computing.
Contact Electronic Conven-
tions Management 81 10
Airport Blvd., Los Angeles,
CA 90045, (213) 772-2965.
April 23-25

• COMPUTER APPLI-
CATIONS EXPLORED

Perscomp '85, Sofia,
Bulgaria. An international
conference on the applica-
tions of personal computers
and the problems en-
countered in using them.
Contact Dr. Marcel Israel,
Bulgarian Academy of
Sciences, Institute of In-
dustrial Cybernetics and
Robotics, 1113 Sofia, Acad.
G. Bonchev St., Bl. 12,
Bulgaria; tel: 72-46-98;
Telex; 22836 ITKR BG.
April 23-26

• MICROS IN EMPIRE

STATE— The Fourth Annual
New York Computer Show
and Software Exposition,
Nassau County Coliseum,
Uniondale, NY. Contact Ann
Katcef, CompuShows, POB
3315, Annapolis, MD 21403.
(800) 368-2066; in Annap-
olis. (301) 263-8044; in
Baltimore. (301) 269-7694;
in the District of Columbia,
(202) 261-1047. April 25-28

• VIRGINIA COMPUTING

The Fourth Annual Virginia

Computer Show and Soft-
ware Exposition. Pavilion,
Virginia Beach. VA. Contact
Ann Katcef. CompuShows.
POB 3315. Annapolis. MD
21403. (800) 368-2066; in
Annapolis. (301) 263-8044;
in Baltimore. (301) 269-
7694; in the District of
Columbia. (202) 261-1047.
April 2 5-28

• EQUIPMENT SALE

Produx 2000: Wholesale
Expo '85. Civic Center.
Philadelphia, PA. Contact
Vertical Marketing Corp.,
POB 5 57, Bala Cynwyd, PA
19004, (800) 523-3882; in
Pennsylvania, (215)
457-2303. April 26-28

• C FOR ENGINEERS

C Programming for Engi-
neers, University of
Michigan, Dearborn. A short
course and workshop. Con-
tact Professor R. E. Little,
University of Michigan, 4901
Evergreen Rd., Dearborn, Ml
48128, (313) 593-5241.
April 29-May 3

• COMMERCIAL AI.
HIGH-TECH CONFERENCE

AI '85: Artificial Intelligence
and Advanced Computer
Technology Conference/Ex-
hibition, Convention Center,
Long Beach, CA. Technical
sessions, panel discussions,
and product displays are
planned. Contact Tower Con-
ference Management Co.,
331 West Wesley St.,
Wheaton, IL 60187, (312)
668-8100. April 30-May 2

• MEETING ON LINE

National Online Meeting,
Sheraton Centre Hotel, New
York City. Formal paper pre-
sentations, product review
sessions, exhibits, and
special workshops and
seminars transmitted via
satellite. Contact Thomas
Hogan, National Online
Meeting, Learned Informa-
tion Inc., 143 Old Marlton
Pike, Medford, NJ 08055,
(609) 654-6266.
April 30-May 2B

94 BYTE • FEBRUARY 1985

INSTANT LAN

WITH STANDARD MICROSYSTEMS' NEW ARCNET-PC, ARCNET-S100 OR
ARCNET-LINK, 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-LINK

ARCNET-I

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* local area network.

All three products incorporate SMC's industry-standard MOSA/LSI local area
network chip set to give you a totally integrated and cost-effective LAN solution.
Software 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.

Inquiry 297

FEBRUARY 1985 • BYTE 95

■

L L

' -■ -r. fv\*, La.

BYTE

Features

The HP Integral Personal Computer THIS MONTH BYTE presents a variety of features including two product

by Phillip Robinson 98 previews.

Oarcia's Circuit Cellar: Developed under the name 'Pisces," Hewlett-Packard's Integral Personal

Build a Serial EPROM Programmer Computer includes UNIX System III in a transportable package. This product

by Steve Garcia 104 pre view by Phillip Robinson, technical editor on our West Coast staff, takes

The Macintosh Office an introductory look at the Integral, its major subassemblies, and its capabilities

by )ohn Marfoff and Phillip Robinson .... 120 anc j limitations. The Integral uses a built-in electroluminescent flat screen and
C to Pascal ink-jet printer, but the big news is its incorporation of UNIX in ROM.

by Ted Camevale 138 y^ e Macintosh continues to provoke lots of love/hate feelings. To bolster

Simulate a Servo System its attractiveness to business environments, Apple introduced Apptelklk, a

by Don stauffer 147 ] cal-area network, and the first two in a series of peripherals designed to

Introduction to Image Processing be networked. Apptetelk, previewed this month by John Markoff and Phillip

by Jeffrey L. Star 163 Robinson, is a departure from what we often consider fundamental to a local-

^^^^^^^^^^^^^^^^^^^ area network concept. With only a printer and file server currently available,

Appld^lk is an interesting approach.

It you are ready to commit your code to EPROM but don't have access to
an EPROM programmer, or if you would like to learn more about the pro-
cess, read Ciarcia's Circuit Cellar. This month, Steve shows us how to build
an EPROM programmer inexpensively. This unit attaches to your computer's
serial port and uses your computer's intelligence. It is also fully documented
and is easily expandable to work with future EPROM designs.

Translating programs among various languages (or even between two
languages) is a wonderful concept but generally difficult to implement. In "C
to Pascal." 'fed Carnevale describes some of the conventional approaches and
problems he discovered while trying to move a graphics subroutine library
in C to a Pascal environment. He also provides us with a program that makes
the process less tedious.

The theme of the March 1984 BYTE was simulation, an intriguing topic once
relegated only to rooms full of computers. While microcomputers really can't
compete with the fast, large-scale simulations that run on the CRAY-1 and other
supercomputers, Don Stauffer uses a microcomputer to "Simulate a Servo
System," using an electronic weighing scale as an example of servo-system
simulation.

Jeffrey L. Star also capitalizes on the power of the microcomputer in his
article "Introduction to Image Processing." While commercial broadcast televi-
sion limits gray-scale reproduction to about 12 levels and human vision covers
a restricted spectrum, image-processing systems usually can deal with at least
32 gray levels and over 16 million unique colors. And, interestingly, there are
a couple of image-processing programs available for microcomputers.

— Gene Smarte, Managing Editor

FEBRUARY 1985 • BYTE 97

PRODUi
REVIEW

THE HP INTEGRAL
PERSONAL COMPUTER

BY PHILLIP ROBINSON

The Hewlett-Packard In-
tegral Personal Computer
is a complete transport-
able computer system
designed around UNIX (System III).
(See photo 1.) With the UNIX kernel
in ROM (read-only memory), an elec-
troluminescent (EL) flat screen,
a 3 /2-inch floppy-disk drive, a built-in ink-jet printer, and
Hewlett-Packard's Personal Applications Manager (RAM),
the Integral is a marvel of advanced personal computing
technology.

History

A big team worked on the Integral, which, during devel-
opment, was known by the name "Pisces." Some of the
team's members I met were Jon Brewster (user interface),
Ray Fajardo (software), Tim Williams (section manager),
Doug Collins (hardware manager), and Andy Rood (oper-
ating system).

While the hardware development of the Integral began
in the fall of 1982, the software development had begun
a year earlier. In fact, several projects were merged to
come up with the Integral. The original design called for
desktop functions in a transportable box: 80 characters
by 2 5 lines on the display a full-size printer (not ther-
mal), and a real keyboard. When the project began, many
of the elements that would meet those requirements
didn't exist, lb assure that those devices would be ready
in time, Hewlett-Packard (HP) had to get intimately in-
volved in the particular technologies. For example, HP
decided early on to use an EL screen and an ink-jet
printer. At the time, EL technology was in its infancy and
HP had to become a major factor in the EL marketplace.

A new alMn-one
system makes

UNIX
truly portable

Brass Tacks

The Integral's logic board is a generic
68000 8-MHz system supplemented
by a few special fillips: a memory
mapper for UNIX and a proprietary
graphics chip. The 684 51 MMU (mem-
ory-management unit) chip wasn't

Editor's note: The following is a BYTE
product preview, it is not a review. We
provide an advance look at this new
product because we feel it is signifi-
cant. A complete review will follow in
a subsequent issue

used for memory mapping because
it slows the memory cycle quite a
bit— it would reside between the pro-
cessor and RAM (random-access
read/write memory). Instead, only the
top address bits are mapped, and
while that mapping is going on, the
lower-half addressing of the RAM also
is proceeding. This leaves the RAM's speed unaffected
while still giving reasonable page sizes.

The RAM comes as a standard 512K bytes (with 32K
more for the display) made up of 25 6K by I bit DRAMs
(dynamic RAMs) with no parity chips. You can purchase
2 56K and 5 1 2 K RAM boards separately and insert them
into the Integral's two internal slots. By using extender
boxes (which plug into one of the slots, sit underneath
the Integral, and provide five slots) you can have up to
5.5 megabytes of RAM. When the 1-megabyte RAM cards
become available (soon after introduction) you'll be able
to use the full logical RAM space of 7.5 megabytes. The
Integral also has 2 56K bytes of ROM, which holds the
operating system. I'll discuss the Integral's ROM a little
more in the UNIX section that follows.

The custom graphics processing unit (GPU) chip was
designed and made by HP in Corvallis, Oregon. Accord-
ing to Jon Brewster, a lot of effort went into the chip,
which handles window scrolling, window moves, line
drawing, and soft character fonts. The GPU is a big chip:
it has a 16-bit ALU (arithmetic logic unit), a 16-bit data
path, and a barrel shifter.

The engineering and a nearly silent fan enable the

Integral to work in some severe environments— up to

40 degrees centigrade and 80 percent humidity. (The

humidity limit is 95 percent without the disks, which

are the most susceptible to moisture

1 problems.) According to HP. some of

the humidity testing involved just tak-
ing the machine outside— remember,

(continued)
Phillip Robinson is a senior technical editor
at BYTE. He may be contact at 1000 Elwell
Court. Palo Alto. CA 94303.

98 BYTE- FEBRUARY 1985

PHOTOGRAPHED BY PAUL AVIS

FEBRUARY 1985 • BYTE 99

Photo 2:
HP's Personal Applications Manager (RAM) and Calculator.

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this was all done in moist Oregon.

No Featherweight

HP says that the Integral is the only

complete product around (i.e., with

both a full screen and a printer) that

you can really carry and that will fit

under airline seats or in overhead

racks. Regardless, this machine definitely remains in the

transportable category. It is smaller than other transport-

ables— such as the Kaypro— but still weighs 27 pounds.

Reliability

I asked what sort of reliability the Integral will have when
it is actually carted around. "You'd be amazed." replied
an HP spokesperson, who recited numerous tests with
glee. For instance, in one test they dropped the system
from a meter up: it sustained some cosmetic damage
but still ran (although that isn't guaranteed). When some-
thing did break during testing. HP made the necessary
changes to the components or case. Further testing in-
cluded vibrating the system, checking for condensation,
and giving prototypes to marketing people.

Another ramification of this reliability obsession is that
HP won't soon introduce a hard-disk version of the In-
tegral. Though HP engineers admittedly had considered
the possibility, it seems they don't trust the ruggedness
of the hard disks they've seen. Beyond that, the design
team believes that RAM disks and ROM-based operat-
ing systems give hard-disk performance without the
problems.

Service

Service for the Integral will be available through dealers
or HP, with the standard 90-day warranty offered in the
US. Because of different legal requirements, the warranty
period will be one year in Europe. You will also be able
to purchase extended service agreements.

I/O Capabilities

The Integral has only a single port on
the back, an HPIB (Hewlett-Packard In-

\n one test

HP dropped the

Integral from a meter

up. \t still ran.

terface Bus) socket. If you need more
I/O (input/output) capabilities you
have to put I/O boards in the slots (for
example, an RS-232C card, which
should be immediately available).

Another form of I/O is provided by
the keyboard and mouse sockets.
These sockets are called Human Inter-
face Loop (HIL) ports and can handle other devices, such
as graphics tablets. Hewlett-Packard has standardized the
protocol for these ports throughout many of its wide
range of products.

Display

The Integral's electroluminescent, flat-screen display is
a centerpiece. Although the display isn't manufactured
at HP. the HP engineers worked closely with the vendor
to assure readability and reliability. In fact, each time I
talked to an HP engineer I was assured that the "slight
shadowing" on the prototype screen had been corrected.
Unfortunately, I never saw the shadow. Maybe eyes
trained on LCDs (liquid-crystal displays) aren't yet ready
to analyze an EL flat-screen critically. The screen is also
fast— with no phosphors to fade, it could be faster than
a CRT (cathode-ray tube). The only color choice is amber.

With 512 by 255 pixels in an area 8 inches wide and
4 inches tall, the Integral screen is twice the size of the
Grid Compass screen— the only other well-known exam-
ple of an EL on a microcomputer. Because the screen
is so thin, the Integral could probably be the shallowest
system you have ever put on a desk. While transportables
of the Osborne and Kaypro variety have to be unbut-
toned and then tilted over, taking up much of the depth
of a desk, the Integral retains its standing position, with
only the keyboard folding down to occupy writing space.

An EL display is clearer than a CRT because there's
no focus problem. As project manager Tim Williams
noted dryly "If a dot lights up. a dot lights up."

The Integral has a variety of fonts and a font editor
that lets you create your own. An antireflective coating
and a circular polarizer for glare
reduction combine to improve your

100 BYTE • FEBRUARY 1985

Photo 3:
PAM, with HP's MernoMaker.

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view of the already crisp images.

TAe Iwte^ra/ PC's

electroluminescent

flat-screen display is

its centerpiece.

Keyboard

The Integral's low-profile keyboard
(photo 4) is a compact adaptation of
a new HP standard keyboard that will
be used with portables, desktops, and
terminals. The keyboard has com-
pletely soft mapping because it will be used in a number
of countries: the Corvallis division of HP gets half of its
business from outside the United States, so German,
French. Spanish, and British versions of the Integral also
were set for introduction in January. Another effect of
European sales is that the arrangement of the keyboard
(and of other system elements such as the display and
fonts) had to meet European ergonomic standards.

The keyboard consists of a full-size QWERTY layout
with sculpted keys surrounded by special function keys.
My first impression is that the keyboard is not especial-
ly quiet but is fast and easy to type with. The numeric
keypad on the right side is closer to the alphabetic keys
than on many other HP keyboards: the engineers had
to squeeze it inward because of the requirements of por-
tability. The cursor keys are below the numeric keypad.

Several of the numeric keys also have special functions,
which are printed on the keys, such as Insert Line and
Delete Character. The Integral also has: a Select key, used
to shift the active window on the screen: Extend keys,
which, in conjunction with the alphabetic keys, produce
special characters: a Reset/Break key and a Stop key,
placed in the extreme top left to prevent frustrating ac-
cidents; and eight programmable function keys, part of
the standard HP user interface. The bottom lines of the
Integral's screen display the changing definitions of the
function keys.

Mass Storage

The mass-storage capacity of the Integral consists of one
HP-standard, 3 /2-inch floppy-disk drive with hard-shell
disks that hold 71 OK bytes each. One of my first reac-
tions to the machine was, "Why is
there only one floppy-disk drive?"

"One disk is cheaper than two," says
HP's Andy Rood. "So the question is:
'Why two?'"

Normally manufacturers include two
disk drives to provide enough total
storage, separate storage devices
for programs and data, and backup
capability.

According to HP, the Integral's single floppy-disk drive,
RAM, and ROM meet these needs: the very high den-
sity of the floppy-disk drive provides enough total
storage; the separation of programs and data is ac-
complished partly by the ROM and partly by the RAM
disk; and because the operating system is in ROM in-
stead of on a disk and the RAM of the Integral auto-
matically includes a RAM-disk function, you can put pro-
grams on the RAM disk and data files on the floppy. As
an added benefit, RAM-disk programs run faster than
those on a floppy disk. Finally, the development team
felt that the high-density floppy and the RAM disk made
up a perfectly capable pair of devices for backing up
files. For those reasons, and to save on space and power,
the team decided to leave out a second disk drive.

The use of ROM for the operating system was a big
challenge: UNIX likes to have a disk drive at its disposal.
The HP team had to "tune" their UNIX so that it didn't
do that. The ROM solution provides that the root file
is on the RAM disk, so when UNIX comes up, the only
file system it presumes to exist is the RAM disk.

You can have more mass storage (externally) if you
want it. Through the Integral's I/O interface you can use
any of HP's many storage peripherals. All of the software
drivers— such as for a hard disk— are already built in.

ThinkJet Printer

One of the features that makes the Integral unusually
"integrated" is the built-in ink-jet printer (see "The
Hewlett-Packard ThinkJet Printer" by Mark Haas in the
January BYTE, page 337). The ThinkJet is also a product
of the Corvallis division of Hewlett-Packard and the
Integral team was intimately asso-

[continued)

FEBRUARY 1985 • BYTE 101

Photo 4:

The Integral Personal Computer's keyboard.

ciated with its development.

As an ink-jet printer, the Thinkjet is
quiet and fast. The characters it pro-
duces are near letter quality. The
Thinkjet can print in a number of dif-
ferent fonts and can also handle
black-and-white graphics. The In-
tegral's keyboard has a Print key that
immediately cues a dump of the screen's contents to the
Thinkjet.

One small drawback of the printer's placement is that
there is no good place to put the paper— that is, if you
put the pile of blank paper just behind the computer,
the system takes up a lot more room.

The Thinklet is generally simple to load and use but
doesn't have a platen knob. Therefore, you have to be
careful not to overrun when using the line-feed and form-
feed buttons.

Mouse

The Integral's optional mouse is HP's standard two-
button, mechanical contraption that uses a steel ball
beneath a circular palm grip. The plug-in position (on
the left side of the unit) is slightly awkward for a right-
handed user because the cable must run behind the
keyboard. The mouse's left button is called the "click-
ing" button (for selection) and the right is called the
"right" button (for mode changing).

Software

The Integral runs HP-UX 2.1, which HP calls a "vanilla"
UNIX environment, and the Personal Applications Man-
ager (photos 2 and 3), HP's operating-environment shell
(see "The HP 1 50" by Phil Lemmons and Barbara Robert-
son in the October 1983 BYTE, page 36, and "The HP
1 10" in the June 1984 BYTE, page 1 11). The Integral's win-
dows emulate terminals that report back at 9600 bits per
second, have 80 characters by 24 lines, and use normal
escape sequences. As Tim Williams puts it, "We think
the UNIX wave is just beginning. And as the UNIX wave
rolls along we want to roll with it and
help it to grow." Ray Fajardo noted

Although the Integral

is compatible with

UNIX System III, it

emulates other versions

that a lot of development time was
devoted to making the Integral run
most UNIX software without modi-
fication. The primary goal was System
111 compatibility: a secondary goal was
flexibility. The system can dynamical-
ly configure drivers and make oper-
ating-system patches on the fly so the
environment is standard yet can be specialized by in-
dependent software vendors. According to HP. HP-UX's
flexibility enables it to emulate Venix, System V, and
other UNIX derivatives. Over 50 utilities, commands, and
standard applications are included with the system.

How hard was it to put UNIX in ROM? "We first did
it the same way we do a disk operating system," says
Andy Rood. "We just took what would have been our
200K boot image, put it in ROM, and put a little power-
on preamble that copied it to RAM just as a bootstrap
up for disk." They then embellished the first version by
making the code execute directly from the ROM and
made some flexibility modifications by linking ROM
through RAM jump tables. Any bugs that turn up in the
ROM now can be masked by intercepting and isolating
ROM routines. The kernel is in the ROM and is treated
as another disk device. At the time the machine is
started, the ROM disk— which has both the PAM shell and
the traditional UNIX init process— is configured. The ROM
looks like shared memory for user libraries and pro-
grams. There also is a demon in the background to do
the disk handling. The HP-UX system is supported by
real-time extensions (BCD |binary coded decimal|, HPIL
IHewlett-Packard Interface Loop|, HPIB, RS-232C and in-
strumentation I/O) and device-independent libraries, as
well as HP Technical BASIC.

User Interface

The Integral's user interface (windows, graphics, function
keys, and optional mouse) were Jon Brewster's respon-
sibility. He explained that the original reason for windows
was to provide users with more than one interface to
the product. HP had discovered that
even novice users use multitasking

102 BYTE- FEBRUARY 1985

Photo 5:

The Integral PC with keyboard in place.

and keep multiple programs on the
display. The windowing system, then,
had to allow novices to do multitask-
ing without worrying about fore-
ground, background, priorities, and
scheduling. Because the mouse was
to be (and is) optional the windows
had to work well with and without it.
Also, unlike the Macintosh, the Integral allows you to
move windows while they are being updated: windows
are moved by animating a sprite (which resembles a cor-
ner of the window) and positioning it— rather than mov-
ing the entire window. Thus, you can hide windows (they
appear as title lines in the lower left of the display),
stretch them (by choosing a new bottom right corner with
a sprite), move them (by choosing a new top left corner
with a sprite), and shuffle them (the top window being
the only one with which you can interface directly,
although the others can still be active).

Applications

According to HP, a variety of software packages will be
available within 60 days of the Integral's introduction.
These include Microsoft's Multiplan, Officeware's Script
and Plan, Ashton-T&te's dBASE III, HP's MemoMaker, Data
and Calculator, HP-UX software development tools, and
others.

More software is being developed both at HP's per-
sonal software division and by independent vendors who
have already been alerted to the Integral's introduction.
Also, because of the compatibility of HP 'technical BASIC,
many programs for other HP systems, such as Series 200
and 500 products, will immediately run on the Integral.

Documentation

Although the documentation I viewed was only in the
draft stage, HP has given plenty of attention to the litera-
ture explaining its system. The documentation is clear
and thorough. Beginners will spend the most time with
the Personal TUtor disk and booklet, a tutorial that takes
an estimated eight hours to fully ab-
sorb. Lessons include use of the

The Integral's user

interface lets you

move, hide, stretch,

and shuffle windows,

mouse, windows, and the organiza-
tion, viewing, printing, and creating of
files. The Integral's documentation
also includes a cartoon booklet that
explains how to set up and start up
the system, and a reference guide. HP
claims that the documentation, user
interface, and PAM will have novices
working on the system within 30 minutes.

Price and Conclusions

The Integral Personal Computer is priced at $4990 (with
HP-UX, PAM, and HP Windows). Although the price is
high for a single-disk-drive system, the perceived price/
value ratio depends on what class of computer you com-
pare the Integral to. HP would like it to be compared
to the higher-performance (and higher-priced) UNIX
machines, rather than MS-DOS transportables such as
the Compaq.

The big question is, who will buy the Integral? Perhaps
business and technical professionals whose require-
ments push the limitations of today's 16-bit MS-DOS
machines. Certainly computer science students and engi-
neers will see many advantages to a complete UNIX
system they can take home. And with the benefits of
multitasking, HP may pull in more people: imagine hav-
ing several data-communications cards, each hooked to
a different electronic information service, and all com-
municating while you work on a spreadsheet and a word
processor.

The HP Integral Personal Computer's advantages in-
clude: state-of-the-art technology; the "everything you
need in one box" design: engineering that looks ab-
solutely solid, and a multitasking environment— all from
a company with a great engineering track record. On the
minus side: the list of software available for the Integral
PC is short, and the price may be too high. But for those
who need advanced computing power and who want to
cast their votes against the IBM PC and its various com-
patibles, the HP Integral Personal Computer may be the
best argument yet for biting the bullet
and switching to UNIX. ■

FEBRUARY 1985 -BYTE 103

104 BYTE • FEBRUARY 1985

PHOTOGRAPHED BY PAUL AVIS.

CIARCIA'S CIRCUIT CELLAR

BUILD A
SERIAL EPROM
PROGRAMMER

by Steve Ciarcia

An inexpensive way to put
your programs on a chip

Over the years, many ar-
ticles have been pub-
lished on programming
EPROMs (erasable pro-
grammable read-only
memories). The number
of articles alone indicates
the value of an EPROM programmer and
the interest expressed in the subject. True-
blooded computer experimenters consider
an EPROM programmer as essential a tool
as a soldering iron and a DVM (digital
voltmeter).

Most EPROM programmers designed for
personal computers are implemented as
bus-dependent I/O (input/output) peripheral
cards that use computer-specific, machine-
language driver programs. By eliminating
the need for an enclosure and using the
system power supply, a relatively cost-
effective unit can be produced. Unfor-
tunately, if I designed such a unit, it prob-
ably wouldn't be for the computer you own.
For computer users who don't have ex-
pansion buses or who want their EPROM
programmer to be transportable between
systems, the only alternative is a stand-
alone EPROM programmer attached to a
serial port (much like a modem). Making it
a separate peripheral device, however,
necessarily increases its cost. In fact, exter-
nal serial-port EPROM programmers are fre-
quently two or three times the cost of

board-level units.

A certain portion of the cost is due to its
separate power supply and enclosure, but
most of the expense is attributed to the
features that manufacturers generally incor-
porate in the devices. The majority of stand-
alone serial-connected programmers are, in
fact, designed as intelligent EPROM pro-
grammers that have the basic processing
power and memory of whole computers. I
have taken this approach on previous
designs. Such devices perform well and re-
quire little assistance from the host system
beyond the data to be programmed.

This time I'm approaching the problem
differently. I've decided to keep it simple
and design the most universally applicable
and cost-effective programmer that I can.

The latest Circuit Cellar EPROM program-
mer is a serial-port programmer that has the
speed of a turtle, the intelligence of the
mightiest computer (that is, it has absolutely
no smarts of its own), and is as functional
as a doorstop between uses. On the posi-
tive side, it's fully documented, universally
applicable, and easily expandable to ac-

[continued]

Steve Garcia (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.

FEBRUARY 1985 -BYTE 105

commodate future EPROM types.

The serial-port programmer can be
operated from almost any system with
a serial port. The driver software is
written completely in BASIC with no
machine-language routines. The
serial-port programmer offers all the
hardware features to program 2716,
2732, 2732A, 2764, and 27128
EPROMS through a serial port, in-
cluding: RS-232C compatibility, no
handshaking necessary, internal
power supplies, jumper-selectable
EPROM types, and jumper-selectable
data rates.

The BASIC-language driver program
included offers features such as:

• menu-driven operation using single
keystrokes

• a help routine that can be called at
any time

• single-byte or burst-write modes

• read or copy EPROM

• optional programming from a disk
file

• verify after write

• verify EPROM erasure

• screen-dump routines by page or
byte

• single-stepping mode

• software-controlled read/write
mode select

• BASIC driver that can be user-
modified

Reviewing EPROM Basics

A personal computer, even in- its
minimum configuration, always con-
tains some user-programmable mem-

ory or RAM (random-access read/
write memory), usually in the form of
semiconductor-memory integrated
circuits. This memory can contain
both programs and data and can be
read or modified as needed.

Any of several kinds of electronic
components can function as bit-
storage elements in this kind of mem-
ory. TTL (transistor-transistor logic)
type-7474 flip-flops, bistable relays, or
tiny f errite toroids (memory cores) are
suitable, but they all cost too much,
are hard to use, and have other dis-
advantages.

In personal computer and other
microprocessor-based applications,
the most cost-effective memory is
made from MOS (metal-oxide semi-
conductor) ICs (integrated circuits).
Unfortunately, data stored in these
semiconductor RAMs is volatile.
When the power is turned off, the
data is lost. Many ways of dealing with
this problem have been devised, with
essential programs and data usually
stored in some nonvolatile medium.

In most computer systems, some
data or programs are stored in non-
volatile ROM (read-only memory). A
semiconductor ROM can be random-
ly accessed for reading in the same
manner as the volatile memory, but
the data in the ROM is permanent. In
a mask-programmed ROM, the data
that can be read is determined dur-
ing the manufacturing process. When-
ever power is supplied to the ROM,
this permanent data (or program) is
available. In small computer systems,

a? |T

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Figure I: Pinouts of the 2716 and 2764 EPROMs.

ROM is chiefly used to contain
operating systems and/or BASIC
interpreters— programs that don't
need to be changed.

Another type of ROM is the PROM
(programmable read-only memory). A
PROM component is delivered con-
taining no data. The user decides
what data it should contain and per-
manently programs it with a special
programming device. Once initially
programmed, PROMs exhibit the
characteristics of mask-programmed
ROMs. You might label such PROMs
as write-once memories.

The EPROM, which is ultraviolet-
light-erasable, is a compromise be-
tween the write-once kind of PROM
and the volatile memory. You can
think of the EPROM as a read-mostly
memory, used in read-only mode
most of the time but occasionally
erased and reprogrammed as neces-
sary. The EPROM is erased by expos-
ing the silicon chip to ultraviolet light
at a wavelength of 2 53 7 angstroms.
Conveniently, most EPROM chips are
packaged in an enclosure with a trans-
parent quartz window.

How an EPROM Works

EPROMs store data bits in cells
formed from stored-charge FAMOS
(floating-gate avalanche-injection
metal-oxide semiconductor) tran-
sistors. Such transistors are similar to
positive-channel silicon-gate field-
effect transistors, but they have two
gates. The lower or floating gate is com-
pletely surrounded by an insulator
layer of silicon dioxide; the upper con-
trol or select gate is connected to ex-
ternal circuitry.

The amount of electric charge
stored on the floating gate determines
whether the bit cell contains a I or a
0. Charged cells are read as 0s; un-
charged cells are read as Is. When the
EPROM chip comes from the factory,
all bit locations are cleared of charge
and are read as logic Is; each byte
contains hexadecimal FF.

When a given bit cell is to be
burned from a I to a 0, a current is
passed through the transistor's chan-
nel from the source to the gate. (The
electrons, of course, move the op-
posite way.) At the same time, a
relatively high voltage potential is
placed on the transistor's upper select
gate, creating a strong electric field
within the layers of semiconductor

(continued)

106 B YTE • FEBRUARY 1985

Figure 2: The serial-port EPROM programmer.

FEBRUARY 1985 'BYTE 107

material. (This is the function of the
+ 21- or + 25-volt |V| V pp charging
potential applied to the EPROM.) In
the presence of this strong electric
field, some of the electrons passing
through the source-drain channel gain
enough energy to tunnel through the
insulating layer that normally isolates
the floating gate. As the tunneling
electrons accumulate on the floating
gate, the gate takes on a negative
charge, which makes the cell contain
aO.

When data is to be erased from the
chip, it is exposed to ultraviolet light,
which contains photons of relatively
high energy. The incident photons ex-

cite the electrons on the floating gate
to sufficiently high energy states that
they can tunnel back through the in-
sulating layer, removing the charge
from the gate and returning the cell
to the 1 state.

The 2700 family of EPROMs con-
tains bit-storage cells configured as in-
dividually addressable bytes. This
organization is often called "2K by 8"
for a 2716 or "8K by 8" for a 2764.
Figure 1 shows the 2716 and 2764.
The completely static operation of
these devices requires no clock
signals. The primary operating modes
include read, standby, and program
(program-inhibit and program-verify

T&ble I : Power supply and grounc

pin numbers for figures 2 and 3.

IC Number

Type

Ground

12 V

-12 V

IC1

AY3-1015

pin 3

pin 1

IC2

74LS175

pin 8

pin 16

IC3.4.5

74LS374

pin 10

pin 20

IC6

74LS00

pin 7

pin 14

IC7

74LS14

pin 7

pin 14

IC8

NE555

pin 1

pin 8

IC9

74LS02

pin 7

pin 14

IC10

MC1488

pin 7

pin 14

pin 1

IC11

MC1489

pin 7

pin 14

IC12

74LS04

pin 7

pin 14

IC13

CD74HC4040

pin 8

pin 16

4.9152MHz

1.8K
-Wr-

RS-232C CONNECTOR
IC11
MC1489

1.8K
— vs/v

IC12
74LS04

£>

ICl-20

IC10

MC1488

IC13
CD74HC4040

IC1-25

tin in

o X) o o o o o

IC8-3

(OPTIONAL)

J s. CLOCK

1 * IC1-17. 40

DATA -RATE GENERATOR

Figure 3 : Serial interface and data-rate generator.

modes are important primarily in
high-volume applications).

Control inputs are used to select the
chip and configure it for one of these
operating modes. In the program
mode, particular bit cells are induced
to contain values. Both Is and 0s are
present in the data word presented
on the data lines, but only the
presence of a causes action to take
place, Tb program the 2716 EPROM,
the V pp input is made + 2 5 V and the
OE input is at a high TTL level. Then,
the TTLrlevel data to be programmed
for a specific address is set up on the
271 6's data lines, and the address is
set up on address lines A0 through
A 10. After a setup time of at least 2
microseconds (/*s). a high TTLrlevel
programming pulse 50 milliseconds
(ms) long is applied to the CE/PGM in-
put. Addresses to be programmed
may be specified in any order.

The 50-ms programming pulse must
be applied once for each location to
be programmed (under no circum-
stances should a^constant high level
be applied to the CE/PGM input in the
program mode). Repeated 50-ms
pulses to the same location are ac-
ceptable, but any pulse width greater
than 55 ms might destroy the chip.
The minimum pulse width is 45 ms.

Circuit Description

Figures 2, 3, and 4 show the sche-
matic drawings for the serial-port
EPROM programmer, the RS-232C in-
terface, and the four-voltage power
supply. T&ble 1 shows the power-
supply connections for the sche-
matics. The main element in figure 2
is the AY-3-101 5 UART (universal asyn-
chronous receiver/transmitter). The
UART converts serial information sent
from the computer into parallel infor-
mation used in the programmer. This
parallel data appears on pins 5
through 1 2 of the UART receiver bus.
The UART can also pass information
back to the computer by converting
any parallel information present on
pins 2 6 through 3 3 of the transmitter
bus into serial information. The serial
information is received from the com-
puter on pin 20 and transmitted to the
computer on pin 2 5.

A logic high level on pin 21 resets
and initializes the UART This level is
generated as a power-on reset (PWR)
every time the power to the program-
mer is turned on or the manual reset
button pressed. This PWR also clears

108 BYTE • FEBRUARY 1985

the receiver character counter, IC2.

UART pins 35 through 39 set the
format of the serial transmission be-
tween the computer and the program-
mer. (I chose to hard-wire these op-
tions rather than provide option
switches that are rarely used.) As
shown, the UART is configured for an
8-bit character length with I stop bit
and parity checking inhibited. If your
computer requires 2 stop bits, con-
nect pin 36 to + 5 V instead of ground.
The programmer will operate at any
desired data rate up to and including
9600 bits per second (bps). A soft-
ware delay loop keeps the program-
mer from being swamped.

The programmer requires 4 bytes to
be sent from the computer for each
location read from or written to in the
EPROM. This 4-byte protocol elimi-
nates the need for incremental
counters and sophisticated decision
logic in the programmer, [t does,
however, reduce the speed of read
and erasure-verification operations.

The first 3 bytes received are
latched a byte at a time into latches
1C3, 1C4, and IC5. The latching pulses
are generated by IC2, which is con-
figured as a 4-bit byte counter. Each
time a byte is received by the UART,
an RDA (received data available) pulse
is generated at pin 19 of the UART.
This pulse is used to clock IC2 and is
gated back to the RDAV (reset data
available) line, pin 18, to clear the
receiver section of the UART. As the
counter clocks, the leading edges of
its output latch the data from the
UART into 1C3, IC4, or IC5. The
counter is reset by the PWR line or
when the fourth byte is received.

The first byte received by the pro-
grammer contains the most significant
3 to 6 bits of the EPROM address
(depending upon the EPROM type)
and I bit to select either the read or
write mode of operation. A logic I in
bit 7 sets the write mode; a logic
sets the read mode.

The second byte contains the lower
8 bits of the EPROM address.

The third byte contains the data to
be programmed into the addressed
location when it is in the write mode
or a dummy character when in -the
read mode.

The fourth byte contains dummy
data in both the read and write
modes. When the counter increments
with the reception of the fourth byte,
it causes IC2 to reset. The time be-

tween setting this output bit and
clearing the counter is about 100
nanoseconds (ns). This short pulse
concluding the setup of the address
and data is used to trigger the actual
programming pulse to the EPROM.

The programming pulse to the
EPROM is generated by IC8. which is
configured as a 50-ms one-shot (trig-
gered by the reception of the fourth
byte). The programming pulse is fed
to the EPROM at several different
locations, depending on which
EPROM is being programmed and
how the EPROM selection jumper
block (see figure 5) is configured.

The one-shot is functional only
when the mode select line (R/W,
read/not write) IC3 pin 2 is a logic 0,
setting the write mode. The mode
select line is also used to select the
programming voltage ranges of the
various EPROMs. When configured
for a 2732 or a 2716 EPROM, a low
on the mode select line sets the V pp
supply to a 25-V level. For all other
EPROM types, the V pp supply is set to
a 21-V level.

Depending on the configuration of
the jumper block, the mode select
line sets the proper TTL levels at the
CE and OE pins to place the various
EPROMs in the read or write mode.
A logic high on the mode select line
causes the V pp supply to drop to V
for the 2732 and 2 73 2 A EPROMs and
to 5 V for the other types.

The mode select line also functions
as the output enable line of data latch

IC5. When the programmer is in the
write mode, data from the UART is
latched and directed to the EPROM
data bus for programming. When the
programmer is in the read mode, IC5's
output is disabled, and the EPROM
data-bus contents are transmitted
back to the computer.

LEDs (light-emitting diodes) I. 2,
and 3 indicate when power is on and
when read and write pulses occur.
They are not necessary to the opera-
tion of the programmer and are mere-
ly included as visual aids.

Figure 3 shows the serial-interface
connections and the data-rate
generator. ICIOand 1C1I are standard
RS-232C transmitter and receiver
chips that conform to the E1A (Elec-
tronic Industries Association) stan-
dard for RS-232C transmission. (If
your computer needs a handshaking
signal, the 50-ms write pulse can be
connected to the clear-to-send line. It
is not used with the software pre-
sented in this article.) The serial-com-
munication rate between the pro-
grammer and the computer is jumper-
selectable. A 4.9152-MHz oscillator
is divided down through a
CD74HC4040 (it must include the HC
designation to accommodate the high
frequency) to produce the appropri-
ate clock rate for the UART.

Figure 4 shows the power supply
used with the programmer. The power
transformer 1 chose was 22 V CT
(center tap), but any transformer from

{continued)

Figure 4: Power supply.

FEBRUARY 1985 • BYTE 109

22 to 25.6V CT is adequate. The
secondary output of the transformer
is full-wave rectified, filtered, and then
regulated to + 12 V, + 5 V, and - 12 V.
Only the + 5-V supply needs an actual
1C regulator; less stringent zener
regulation is adequate for the 12-V

supplies to the RS-232C drivers.

The 3 5-V output consists of com-
ponents C4, C5, D3, and D4 con-
nected as a cascade voltage doubler
with half-wave rectification. This con-
figuration produces an input of ap-
proximately 32 to 34 V to the LM3 1 7/

Jl !

2716

2764

J2 i
J3 <

■

I
3<

>22

J4 •

t
»20

4 \

>21

J5 '

J6 <

i
'18

■
'16

J7 '
J8 i
J9 i

■

9 '

'15

'13

Jll i
J12<

i i

i
12 <

1 1
"13

i i

2732 A

2732

'24

i i

'24

' 23

6 |

6
8

i <

i
'17

i i

i
'17

9 !

'16

<
12

>13

'13

i
3'
4'

27128

(

9 <

(

i i

11<
12*

i •

Figure 5 : Configuration jumpers.

338 regulator. The minimum accept-
able voltage at the input is 28.5 V (for
a 2 5-V output). If you use a higher-
output transformer than 2 2 V CT, be
careful that the input to the V pp
regulator doesn't exceed 35 V. Jf it
does, additional preregulation may be
necessary to use this circuit.

Figure 6 shows the programmable
V pp supply. The 27 32 A EPROM re-
quires the programming voltage to be
pulsed between and 2 1 V, while a
2716 requires a pulse between 5 and
2 5 V. The supply is controlled by the
jumper connections and the mode
select line. With jumper #1 across R6,
the supply is configured for a max-
imum V pp level of 21V When it is
removed, the supply has a maximum
voltage of 2 5 V.

The minimum V pp level is set by two
jumper-selectable programming cir-
cuits, which are also connected to the
regulator's output set point-adjust
line. When jumper #2 is installed, a
two-transistor circuit is enabled, which
applies - 1.2 V to the adjust line. The
result is a 0-V output from the
regulator. When jumper #3 is in-
stalled, the reference-adjust line is set
to allow a + 5-V regulator output.

Interacting with Hardware

The operation of the serial program-
mer should become clear by follow-
ing an example of a write operation
followed by a read operation. This is
the sequence that would necessarily
occur during a standard write-and-
verify cycle.

First, the EPROM programmer is
cleared and set to the read mode by
the power-on reset pulse (which can
be generated by pressing a button or
by turning the programmer on) so
that it is ready to receive the first
character. If we plan a write cycle, the
first character must contain a logic 1
in bit 8 to activate the write mode. The
upper 3 to 6 bits of the EPROM ad-
dress (the page address that depends
on the size of the EPROM) must also
appear in the first 3 to 6 bits (bit
through bit 5) of this first character.
Each character of data to be pro-
grammed into the EPROM is sent to
the programmer as a 4-byte transmis-
sion with the programming address
specified each time.

Tkble 2 indicates the allowable bit
patterns for this first character re-
ceived by the programmer.

For our example, assume that the

110 BYTE • FEBRUARY 1985

data byte C3 (hexadecimal) is to be
written into the first byte of page 4 in
the EPROM. In this case, the first
character received by the program-
mer should be 1x000100. The receipt
of this character pulses IC2 and
latches the page address and mode
select bit into the page/mode latch,
1C3. The mode select bit selects the
EPROM for a write cycle, turns on the

V pp supply to the EPROM, releases
the reset line on the timer, activates
the output enable line of the data
latch, and shuts off the transmission
gate of the UART.

The second character sent contains
the lower 8 address bits for the
EPROM. lb program the first location
in page 4, the rest of the address must
then be 00000000. This character sets

Tkble 2: Allowable bit patterns.

Page

Write Mode

Read Mode

1x000000

0x000000

1x000001

0x000001

1x000010

0x000010

1 X00001 1

0x00001 1

1x000100

0x000100

1x000101

0x000101

1x000110

0x000110

1x000111

0x000111

•

1x111111

0x1 1 1 1 1 1

the second stage of the counter and
latches the lower address location
into the lower address latch, IC4.

The third character, 11000011 (C3
hexadecimal), contains data to be pro-
grammed into the EPROM. When this
character is received, the counter
latches the data into the data latch,
IC5.

The fourth character sent is a
dummy character that may contain
any value. This fourth and last char-
acter simply clocks 1C2 and triggers
the 50-ms programming pulse. When
the one-shot times out, the program-
mer is still in the write mode. It has
to be set to the read mode by ini-
tiating a read cycle.

The four characters sent in our pres-
ent example of a write sequence are
1 xOOOIOO, which sets the write mode
and upper address; 00000000, which
sets the lower address; 110000II,
which sets the data byte (C3 hexadec-
imal); and xxxxxxxx, dummy data.

The read sequence is similar to the
write sequence. The first character

{continued)

32-35 VOLTS '

LM317/LM338

IN OUT

ADJ

4.7K

-wv—

Ql
2N2222

470il
<\ WS* n

IN4732

-12V

Q3
2N2905

"^7

R7
510A

-Ov P

R4
150&

R5
2.4K

R5 + R6 SETS 25V
R5 SETS 21V

R6 | ,, (INSTALLED FOR

470& J A DEVICES)

/
*U

:470&

470&

Q2
2N2222

25V

2716

(2732) JJ2 JJ3 (2716.2764.27128)

25V
0V

2732

R/W | >»-

2732A

v C c

READ
WRITE

21V

2764
27128

Figure 6: Close-up of the programmable V pp supply.

FEBRUARY 1985 -BYTE 111

sent again contains the upper bits of
the address, but bit 8 is now set to
logic to put the mode select line
high (read mode). A logic I on the
read/write line deactivates the pro-
gramming one-shot and tristates the
data latch, 1C5.

Again, the first character is latched
into the page/mode latch, and the sec-
ond character is latched into the lower
address latch. With 1C5 tristated. the
EPROM's data output is placed on the
UART transmitter bus. The third char-
acter is a dummy character that is
used to clock IC2. This signal causes
the UART to transmit the data on the
transmitter bus to the computer. The

fourth character is then sent to the
programmer to reset the counter.

The four characters that must be
sent in the verify sequence of our ex-
ample are 0x000100, which sets the
read mode and upper page address;
00000000, which sets the lower
address; xxxxxxxx, which gets the
data byte from the EPROM (C3 hexa-
decimal); and xxxxxxxx, which resets
the programmer.

Programmer Software

The driver program shown in listing
I could have been written in any lan-
guage that supports input and output
ports. [This program is available for down-

loading from BYTEnet Listings at (603)
924-9820. You can also receive it by send-
ing an IBM PC-formatted disk and return
postage to Steve Garcia] BASIC was
chosen because it has wide appeal in
the personal computer field and
because most systems with serial I/O
ports support BASIC. The software
(flow-diagramed in figure 7) was writ-
ten specifically for the IBM PC but can
be easily modified to conform to most
other systems that also support
Microsoft BASIC. The program was
written with a short MAIN program
module that calls a number of subrou-
tine modules. This modular approach
makes modifying, debugging, or ex-

READ EPROM

INTO

ARRAY

(BEGIN "\
EPROM J

INITIALIZE
VARIABLES

SELECT DATA
RATE

SELECT

EPROM

SIZE

SELECT

EPROM

ERASED OR

EPROM

PARTIALLY

PROGRAMMED

GET INPUT
BYTE

EPROM
ERASED

YES

SET ARRAY
TO ALL
FF (HEX)

DIM ARRAY

AND

OPEN "C0M1"

PORT

YES

VERIFY
EPROM
ERASED

YES

DISPLAY

BYTE

DISPLAY

BYTE

YES

BURN EPROM
AND EXIT

f END J

INITIALIZE
BASE ADDRESS
OF EPROM

DISPLAY
PRESENT
ADDRESS AND
BYTE IN
ARRAY

SET NEW

OFFSET

LOCATION

YES

WRITE TO
ARRAY AND
RETURN

Figure 7: A flowchart of the driver program.

112 BYTE • FEBRUARY 1985

panding the software a much easier
task. Examining the driver software
should provide enough understand-
ing so that any additions or changes
desired can be easily implemented.

The program modules that access
the serial port are labeled READ A
BYTE and WRITE A BYTE in listing I.
These sections contain the only soft-
ware modules that are hardware-de-
pendent and that need to be con-
figured to your particular system.

The WRITE module performs the
actual program burn of the data into
the EPROM. The first statement sends
the page address to the serial port
with the value of bit 8 set to I . This

is accomplished by combining the
page address with the value 128
(10000000 binary). The page address
is calculated elsewhere in the pro-
gram before entering this module.
The next statement sends the lower
address contained in the variable
BYTE to the serial port. This value is
also calculated by the program prior
to entering the WRITE module.

The statement "PRINT #3.DATUM"
sends the data to be written into the
EPROM to the serial port. The last
statement in the WRITE module is a
timing loop that causes the program
to pause while the 50-ms timer in the
serial-port programmer times out.

YES

BURN EPROM

AND

RETURN

YES

DISPLAY ONE
PAGE OF
EPROM

YES

INITIALIZE
BASE ADDRESS
OF EPROM

YES

LOAD ARRAY
FROM DISK

YES

SAVE ARRAY
TO DISK

YES

DISPLAY

HELP

YES

The READ module requests a data
byte from the programmer and
receives the byte from the serial port.
It accomplishes this by sending a
page address and byte address to the
serial port as in the WRITE module.
In this case, bit 8 of the page address
is set to to inform the programmer
that a read cycle is being performed.
The next two lines send a dummy
data value and a strobe to the serial
port to complete the read sequence.
The values of DUMMY and STROBE
are set in the INITIALIZATION
module. The data sent by the serial-
port programmer is received in the
variable RDATA.

Once these modules have been
configured to your system, it is a sim-
ple matter to write and read data from
the programmer. Simply define the
PAGE and BYTE address variables
along with the DATUM value and send
them to your serial port by calling the
appropriate module. The rest of the
program in listing I shows methods
for doing this.

The approach used in the program
is to place any data to be pro-
grammed into the EPROM in an array
so that it can be reviewed and edited
prior to burning it permanently into
the EPROM. The array name is appro-
priately called ARRAYf ). The high-
order byte of every element in AR-
RAYf) stores a flag bit indicating that
the lower-order byte of the element
is data to be programmed. This
method allows the program to write
to only those locations in the EPROM
where a valid data value has been
entered in ARRAYf).

Each time a data value is put into
ARRAYf). the value is combined with
2 56 to set the flag. When it is time to
send all the data to the EPROM. the
flag is checked in each element, and
only those elements with the flag bit
set are sent to the EPROM. This pro-
cess is repeated until all the flagged
elements have been programmed.
The initial values for ARRAYf) are
taken directly from the EPROM by
reading each location and storing the
values in ARRAYf).

Several methods of entering data
into ARRAYf) are used in the program.
One method is to enter each data
value directly from the keyboard; an-
other method is to fill ARRAYf) by
reading an already-programmed
EPROM. Finally, a disk file previously

(continued)

FEBRUARY 1985 •BYTE 113

Listing I : EPROM programmer routines.

1010 REM SERIAL EPROM PROGRAMMER

1020 REM written in

1030 REM MICROSOFT BASIC for the IBM PC

1 060 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

1070 REM INITIALIZATION ROUTINE

1090 KEY OFF

1100 LINE25$ = "BAUD RATE =\ \EPROM=\ \BASEPAGE=\ \"

1110 BR$ = "0000":EP$ = BR$:BP$ = BR$

1120 DEFINT A-Z:ON ERROR GOTO 4600

1 1 30 STROBE = 255:DUMM Y = 255PAGE = 0:BYTE = 0:DATUM = 255

1140 K$ = "VPNEOWHDIBSL":FORMAT$ = "PAGE=\\ BYTE=\\ DATA=\\"

1150 MIMAGE = 0:MCRADDR = &H3FC:DELAY=100

1160 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

1170 REM MAIN BODY OF PROGRAM - KEYBOARD SEQUENCE

1190 GOSUB2250

1200 PRINT" = = = = = = = = = = SERIAL EPROM PROGRAMMER ========

1210 PRINT" BAUD-RATE SELECTION"

1230 PRINT'The SERIAL PORT programmer can operate at several different baud"

1240 PRINT"rates. Select the baud rate for your system from the list below:"

1260 PRINT" (1)300 baud"

1270 PRINT" (2) 600 baud"

1280 PRINT" (3)1200 baud"

1290 PRINT" (4) 2400 baud"

1300 PRINT" (5) 4800 baud"

1310 PRINT" (6) 9600 baud"

1330 PRINT"Enter the number of your selection — > ";:BAUD$ = INPUT$(1)

1340 PRINT BAUD$:BAUD = VAL(BAUD$):IF BAUD>0 AND BAUD<7 THEN 1360

1350 PRINT"<<<<< BAUD-RATE SELECTION ERROR >>>>>": GOTO 1330

1360 BR$ = STR$(300*2'(BAUD-1))

1370 GOSUB2250

1380 PRINT" = = = = = = = = = = SERIAL EPROM PROGRAMMER = = = = = = = = ;

1390 PRINT" EPROM-TYPE SELECTION"

1410 PRINT'The SERIAL EPROM programmer has the ability to program several"

1420 PRINT"different EPROMS. Select the type of EPROM from the list below:"

1440 PRINT" (1) 2716"

1450 PRINT" (2) 2732/2732A"

1460 PRINT" (3)2764"

1470 PRINT" (4)27128"

1490 PRINT"Enter the number of your selection — > ";:ESIZE$ = INPUT$(1)

1500 PRINT ESIZE$:ESIZE = VAL(ESIZE$):IF ESIZE>0 AND ESIZE<5 THEN 1520

1510 PRINT "<<<<< EPROM-TYPE ERROR >>>>>":GOTO 1490

1 520 DSIZE = 1 024 * 2 " ESIZE:PAGES = DSIZE/256

1530 EP1$ = STR$(16*2~(ESIZE-1))

1540 EP$ = "27" + RIGHT$(EP1$,LEN(EP1$)-1)

1550 DIM ARRAY(DSIZE)

1560 GOSUB 2250:GOSUB 4790:GOSUB 2250

1570 PRINT "= = = = = = = = = = SERIAL EPROM PROGRAMMER ========

1580 PRINT " CONDITION OF EPROM"

1600 PRINT"lf the EPROM you are programming is fully erased then select"

1610 PRINT'"EPROM ERASED' from the selection list below. This will save"

1620 PRINT"the time required to read the EPROM into memory. If the EPROM"

1630 PRINT"has been partially programmed then select 'PARTIALLY PROGRAMMED"'

1640 PRINT"and the EPROM will be read into memory prior to programming."

1660 PRINT" (1) EPROM ERASED"

1670 PRINT" (2) EPROM PARTIALLY PROGRAMMED"

1690 PRINT"Enter the number of your selection — > ";:ERA$ = INPUT$(1)

1700 PRINT ERA$:PRINT:ERA = VAL(ERA$):IF ERA = 2 THEN 1740

1710 IF ERAo 1 THEN PRINT" <<<<< SELECTION ERROR >>>>>":GOTO 1C

1720 PRINT"<<<<< INITIALIZING MEMORY - PLEASE WAIT >>>>>"

1730 FOR l = 0TODSIZE-1:ARRAY(l) = 255:NEXTI

1740 ON BAUD GOTO 1750,1760,1770,1780,1790,1800

1750 OPEN "COM1:300 ( n ( 8 l 1,rs l cs,ds" AS #3:GOTO 1810

1760 OPEN "COM1:600,n l 8 l 1 l rs l cs l ds" AS#3:GOTO 1810

1770 OPEN "COMI^OO.n.S.l.rs.cs.ds" AS #3:GOTO 1810

1780 OPEN "COM1: :2400,n,8 l 1,rs,cs,ds" AS #3:GOTO 1810

1790 OPEN "COM1:4800 l n,8 l 1 l rs l cs l ds" AS#3:GOTO 1810

1800 OPEN "COM1:9600 I n l 8,1 l rs I cs l ds" AS#3

1810 GOSUB 2250

1 820 PRINT "= = = = = = = = = = SERIAL EPROM PROGRAMMER = = = = = = = = :

1830 PRINT " BASE-PAGE INITIALIZATION"

1850 PRINT'The SERIAL EPROM programmer is driven by a keystroke-oriented"

1860 PRINT"program. The keys are defined in a HELP menu. This help menu"

1870 PRINT"can be displayed at any time by typing the letter (H) after"

1880 PRINT"the program has been initialized."

1890 PRINTPRINT

1900 PRINT'To initialize the program you must enter the base page"

1910 PRINT"address of the EPROM. This address is generally a HEXADECIMAL value"

1920 PRINT"corresponding to the beginning page of an even 2K-byte boundary."

114 BYTE • FEBRUARY 1985

1930 PRINTFor example 00,08,60,88, etc."

1950 GOSUB 3770:REM SET BASE ADDRESS

1960 IFHFLAG = 1 THEN HFLAG = 0:GOTO 1950

1970 IF ERA = 1 THEN 2000

1980 PRINT'A MEMORY IMAGE OF YOUR EPROM IS BEING MADE"

1990 GOSUB 3890:REM MAKE MEMORY IMAGE

2000 GOSUB 2880:REM DISPLAY HELP MENU

2010 PRINTPRINT

2020 PRINT"YOUR PRESENT LOCATION IS:"

2030 GOSUB 2320:REM READ AND DISPLAY DATA

2040 PRINT"COMMAND — >";

2050 IKEY$ = INPUT$(1)

2060 IF IKEY$> = "a" AND 1KEY$< = "z" THEN IKEY$ = CHR$(ASC(IKEY$) AND 95)

2070 K = INSTR(K$,IKEY$):IF K = THEN PRINT "WHAT ?";:GOTO 2050

2080 HFLAG=0

2090 ON K GOSUB 3430,2380,2440,2160,2500,2660,2880,3550,3760,3980,4240,4400

2100 REM VPNEOWHDIBSL

2110 IF HFLAG = 1 THEN GOSUB 2880

2120 IF HFLAG = 1 OR IKEY$ = "H" THEN 2010 ELSE 2030

2130 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2140 REM BURN EPROM AND END OPTION

2160 GOSUB 3980

2170 IF IKEY$o"N" THEN RETURN

2180 CLOSE:END

2190 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2200 REM MAIN BODY ENDS HERE - SUBROUTINE MODULES FOLLOW

2220 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2230 REM DISPLAY STATUS LINE

2250 CLS:LOCATE 25,1 PRINT USING LINE25$;BR$,EP$,BP$;

2260 PRINT "COMMANDS: ";K$

2270 LOCATE 3, 1,1:RETURN

2280 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2300 REM DISPLAY LOCATION AND DATA

2320 RDATA = ARRAY(PAGE* 256+ BYTE) AND 255:REM GET DATUM FROM ARRAY

2330 PRINT USING FORMAT$;HEX$(BIAS + PAGE),HEX$(BYTE),HEX$(RDATA)

2340 RETURN

2350 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2360 REM DECREMENT ADDRESS

2380 IF PAGE = AND BYTE = THEN RETURN ELSE BYTE = BYTE -1

2390 IFBYTE=-1 THEN PAGE = PAGE - 1:BYTE = 255

2400 RETURN

2410 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2420 REM INCREMENT ADDRESS

2440 IF PAGE = PAGES -1 AND BYTE = 255 THEN RETURN ELSE BYTE = BYTE +1

2450 IF BYTE = 256 THEN PAGE = PAG E+ 1:BYTE =

2460 RETURN

2480 REM OFFSET TO NEW STARTING ADDRESS

2500 ADD$=" ":PRINT:PRINT"ENTER NEW LOCATION IN HEXADECIMAL (hhhh) -> ";

2510 L$ = INPUT$(1):PRINTL$;

2520 IFL$>= "a" AND L$< = "z" THEN L$ = CHR$(ASC(L$) AND 95)

2530 IF L$ = "H" THEN HFLAG = 1:RETURN

2540 IF L$ = "Q" THEN PRINT:RETURN

2550 ADDS = ADDS + L$:IF LEN(ADD$) = 4 THEN PRINT ELSE 2510

2560 PAGES = LEFT$(ADD$,2):BYTE$ = RIGHT$(ADD$,2)

2570 CONS = PAGE$:GOSUB 311 0:IFSUM=-1 THEN 2500

2580 PAGE = SUM -BIAS

2590 IF PAGE > PAGES -1 OR PAGE <0 THEN PRINT"<<<<< OUT OF RANGE > >> > >":GOTO 2500

2600 CON$ = BYTE$:GOSUB 3110:IF SUM= -1 THEN 2500

2610 BYTE = SUM

2620 RETURN

2630 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2640 REM WRITE TO ARRAY - BYTE BY BYTE

2660 XFLAG=0:DATUM$ = " M :PRINT"<<< WRITE MODE >>> ENTER DATA IN HEXADECIMAL (hh) -> ";

2670 D$=INPUT$(1):PRINT D$;

2680 IF D$> = "a" AND D$< ="z" THEN D$ = CHR$(ASC(D$) AND 95)

2690 IF D$ = "H" THEN HFLAG = 1:RETURN

2700 IF D$="Q" THEN PRINT:RETURN

2710 IF D$="X" THENXFLAG=1:DATUM$=" ":GOTO 2670

2720 DATUM$ = DATUM$ + D$:IF LEN(DATUM$)< >2 THEN 2670

2730 PRINT:CON$ = DATUM$:GOSUB 3110:DATUM=SUM

2740 IF SUM= -1 THEN 2660

2750 IF (ARRAY(PAGE* 256 + BYTE) AND 255)< >255 AND XFLAG = THEN 2830

2760 DATUM = DATUM OR 256:REM TAG LOCATION AS WRITTEN TO

2770 ARRAY(PAGE*256 + BYTE) = DATUM:REM WRITE DATUM TO ARRAY

2780 GOSUB 2320.REM DISPLAY WRITE TO ARRAY

2790 IF BYTE = 255 AND PAGE = PAGES -1 THEN RETURN

2800 GOSUB 2440:REM INCREMENT ADDRESS

2810 GOSUB 2320:REM DISPLAY NEXT LOCATION

2820 GOTO 2660

{continued)

FEBRUARY I985 -BYTE 115

2830 PRINT:PRINT"<<<<<< ILLEGAL WRITE TO PREVIOUSLY PROGRAMMED LOCATION >>>>>>

2840 RETURN

2850 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

2860 REM HELP ROUTINE

2880 GOSUB 2250:REM CLEAR SCREEN

2890 PRINT'To initialize the program you should enter the beginning page"

2900 PRINT"address of the EPROM to be programmed. This value is used when"

2910 PRINT"printing to the screen and as a bias value in the write modes."

2920 PRINT'The following single-letter commands are used to control the"

2930 PRINT'modes of the EPROM programmer:":PRINT

2940 PRINT" (I) INITIALIZE BASE-PAGE ADDRESS - base address is ";BIAS$;"00"

2950 PRINT" (V) VERIFY ERASURE"

2960 PRINT" (N) DISPLAY NEXT BYTE"

2970 PRINT" (P) DISPLAY PREVIOUS BYTE"

2980 PRINT" (O) OFFSET TO NEW PAGE AND BYTE"

2990 PRINT" (L) LOAD ARRAY FROM DISK"

3000 PRINT" (S) SAVE ARRAY ON DISK"

3010 PRINT" (W) ENTER BYTE WRITE MODE (use Q or H to exit, X to edit)"

3020 PRINT" (D) HEXADECIMAL DUMP TO SCREEN"

3030 PRINT" (B) ENTER 'BURN EPROM' MODE"

3040 PRINT" (H) ENTER HELP MODE (from any input statement)"

3050 PRINT" (E) EXIT PROGRAM"

3060 RETURN

3070 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3080 REM ***** CONVERT HEXADECIMAL TO DECIMAL *****

3090 REM ENTER WITH HEXADECIMAL STRING IN CONS, EXIT WITH DECIMAL VALUE IN SUM

3110 SUM =

3120 FOR 1 = 1 TO LEN(CONS)

3130 X = ASC(MID$(CON$,(LEN(CON$)+1 -l),1))

3140 IF X<48 OR X>70 THEN SUM= -1:l = LEN(CON$):GOTO 3190

3150 IFX>57 AND X<65 THEN SUM= - 1:1 = LEN(CON$):GOTO 3190

3160 IF X<64 THEN X = X-48 ELSE X = X-55

3170 SUM = SUM + (X*16~(I-1))

3180 IF SUM>255 OR SUM<0 THEN SUM- -1

3190 IF SUM=-1 THEN PRINT"<<<<< INPUT ERROR >>>>>"

3200 NEXT LRETURN

3210 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3220 REM WRITE A BYTE

3240 WPAGE = PAGE OR 1 28:REM SET WRITE PAGE (W/R = 1 )

3250 PRINT #3,CHR$(WPAGE);:REM SEND WRITE PAGE

3260 PRINT #3,CHR$(BYTE);:REM SET WRITE BYTE

3270 PRINT #3,CHR$(DATUM);:REM DATA TO WRITE

3280 PRINT #3,CHR$(STROBE);:REM WRITE STROBE

3290 FOR DEL = 1 TO DELAY:NEXT DELREM WRITE DELAY

3300 RETURN

3310 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3320 REM READ A BYTE

3340 PRINT #3,CHR$(PAGE);:REM SET READ PAGE (W/R = 0)

3350 PRINT #3,CHR$(BYTE);:REM SET READ BYTE

3360 PRINT #3,CHR$(DUMMY);:REM DUMMY DATA SENT

3370 PRINT #3,CHR$(STROBE);:REM READ STROBE

3380 RDATA = ASC(INPUT$(1,#3)):REM INPUT DATA

3390 RETURN

3400 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3410 REM VERIFY ERASURE

3430 PRINT:PRINT"VERIFYING THAT EPROM IS ERASED":PRINT

3440 BYTE = 0:PAGE=0

3450 FOR PAGE = TO PAGES- 1:V$= " OK"

3460 FOR BYTE = TO 255

3470 IF (ARRAY(PAGE*256 + BYTE) AND 255) = 255 THEN 3490

3480 V$ = "<<<<<< NOTERASED >>>>>>"

3490 NEXT BYTE:PRINT"PAGE";PAGE;V$

3500 NEXT PAGE

3510 BYTE = 0:PAGE = 0:RETURN

3520 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3530 REM DUMP TO SCREEN

3550 GOSUB 2250

3560 FOR LN = 1 TO 16

3570 DPAGES = RIGHT$("0" + HEXADECIMAL$(BIAS + PAGE),2)

3580 DBYTE$ = RIGHT$("0" + HEXADECIMAL$(BYTE),2)

3590 PRINT USING"\\";DPAGE$;DBYTE$;": ";

3600 FOR D = 1 TO 16

3610 DDATA$ = RIGHT$("0" + HEXADECIMAL$((ARRAY(PAGE*256 + BYTE) AND 255)),2)

3620 PRINT USING'\\";DDATA$;

3630 IF PAGE = PAGES -1 AND BYTE = 255 THEN D = 16:LN = 16

3640 GOSUB 2440:IF BYTE MOD 16 = THEN PRINT:D = 16

3650 NEXT D

3660 NEXT LN:PRINT:PRINT

3670 IF PAGE = PAGES-1 AND BYTE = 255 THEN PRINT"<<<<<< END OF EPROM >>>>>":RETURN

3680 PRINT"ENTER (C) TO CONTINUE OR (Q) TO EXIT DUMP -> ";:IKEY$ = INPUT$(1)

3690 IF IKEY$> = "a" AND IKEY$< ="z" THEN IKEY$ = CHR$(ASC(IKEY$) AND 95)

116 BYTE • FEBRUARY 1985

3700 PRINT IKEY$:PRINT:IF IKEY$ = "C" THEN 3560

3710 IF IKEY$ = "H" THEN HFLAG = 1:RETURN

3720 IF 1KEY$ = "Q" THEN RETURN ELSE 3680

3730 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3740 REM SET BIAS ADDRESS

3760 GOSUB 2250

3770 BIAS$=" ":PRINT:PRINT"ENTER BASE-PAGE ADDRESS IN HEXADECIMAL (hh) -> ";

3780 B$=INPUT$(1):PRINT B$;

3790 IF B$> ="a" AND B$< ="z" THEN B$ = CHR$(ASC(B$) AND 95)

3800 IF B$ = "H" THEN HFLAG = 1:RETURN

3810 IF B$ = "Q" THEN PRINT:RETURN

3820 BIAS$ = BIAS$ + B$:IF LEN(BIAS$)<>2 THEN 3780

3830 PRINT

3840 CON$ = BIAS$:GOSUB3110:BIAS = SUM:PRINT:PRINT:IFSUM=-1 THEN 3770

3850 PAGE = 0:BYTE = 0:BP$=BIAS$ + "00":GOSUB 2250:RETURN

3860 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3870 REM READ EPROM TO ARRAY

3890 PAGE = 0:BYTE = 0:GOSUB 2250

3900 GOSUB 3340

3910 ARRAY(PAGE*256 + BYTE) = RDATA:IF BYTE = 0THEN PRINT"READING PAGE";PAGE

3920 BYTE = BYTE + 1:IF BYTE = 256 THEN PAGE = PAG E+ 1:BYTE =

3930 IF PAGE< = PAGES - 1 THEN 3900

3940 PRINT:PAGE = 0.BYTE = O:RETURN

3950 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

3960 REM WRITE ARRAY TO EPROM

3980 GOSUB 2250

3990 PRINT"<<<<<< BURN ALL PROGRAMMED BYTES?? >>>>>>"

4010 PRINT'TYPE (Y) TO PROGRAM EPROM"

4020 PRINT"(Q) TO RETURN TO PROGRAM"

4030 PRINT"(H) TO DISPLAY HELP MENU"

4040 PRINT"(N) TO RETURN TO PROGRAM FROM 'BURN' MODE"

4050 PRINT'TO ABORT PROGRAM IN 'EXIT' MODE."

4060 PRINT:PRINT"ENTER SELECTION -> ";:IKEY$ = INPUT$(1)

4070 PRINT IKEY$

4080 IF IKEY$> = "a" AND IKEY$< ="z" THEN IKEY$ = CHR$(ASC(IKEY$) AND 95)

4090 IF IKEY$="N" THEN RETURN

4100 IF IKEY$ = "H" THEN HFLAG = 1:RETURN

4110 IF IKEY$ = "Q" THEN PRINT:RETURN

4120 IF IKEY$o"Y" THEN 3990

4130 FOR ADD = TO DSIZE

4140 DATUM = ARRAY(ADD):IF DATUM <256 THEN 4190

4150 DATUM = DATUM AND 255:BYTE = ADD MOD 256:PAGE = (ADD - BYTE)/256

4160 PRINT "BURNING ";:GOSUB 2320

4170 GOSUB 3240:GOSUB 3340

4180 IF RDATA< >DATUM THEN PRINT "<<<<<< DATA NOTVERIFIED >>>>>>"

4190 NEXT ADD

4200 PRINT:BYTE = 0:PAGE = 0:RETURN

4210 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

4220 REM SAVE ARRAY IN DISK FILE

4240 GOSUB 2250:PRINT"THE DISK FILE CREATED HERE WILL CONTAIN ALL THE DATA"

4250 PRINT'PRESENTLY CONTAINED IN YOUR EPROM MEMORY IMAGE AND"

4260 PRINT'WILL BE ASSIGNED THE FILE EXTENSION 'PRM'."

4270 PRINT'THE FOLLOWING IS A LIST OF EXISTING DISK FILES WITH"

4280 PRINT'THE FILE EXTENSION ' PRM'.":PRINT:PRINT

4290 FILES "*.PRM":PRINT:PRINT

4300 INPUT"ENTER THE FILENAME OF YOUR NEW DISK FILE -> ".FILENAMES

4310 IF FILENAME$ = "H" OR FILENAME$ = "h" THEN HFLAG = 1:RETURN

4320 IFFILENAME$="Q" OR FILENAME$ = "q" THEN RETURN

4330 OPEN "0",#1,FILENAME$+".PRM"

4340 FOR l=0TO DSIZE- 1 PRINT #1,(ARRAY(I) AND 255);

4350 IF I MOD 256 = THEN PRINT "SAVING PAGE";l/256

4360 NEXT l:CLOSE #1:RETURN

4370 REM = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

4380 REM LOAD ARRAY FROM DISK

4400 GOSUB 2250:PRINT:PRINT"THE FOLLOWING IS A LIST OF FILENAMES WITH THE FILE"

4410 PRINT"EXTENSION \PRM"':PRINT:PRINT

4420 FILES "\PRM":PR!NT:PRINT

4430 INPUT"ENTER A FILENAME FROM THE LIST ABOVE ->", FILENAMES

4440 IF FILENAMES = "H" OR FILENAME$ = "h" THEN HFLAG = 1:RETURN

4450 IF FILENAME$="Q" OR FILENAME$= "q" THEN RETURN

4460 OPEN "l",#1,FILENAME$+".PRM"

4470 FOR l = 0TO DSIZE- 1:INPUT #1, DATUM

4480 IF I MOD 256 = THEN PRINT "LOADING PAGE";l/256

4490 IF DATUM = 255 OR DATUM = (ARRAY(I) AND 255) THEN 4560

4500 IF ARRAY(I)< >255 THEN 4520

451 ARRAY(I) = DATUM OR 256:GOTO 4560

4520 PRINT"<<<<<< ILLEGAL INPUT DATA FROM FILE >>>>>>"

4530 PRINT" <<<<< < ATTEMPT TO WRITE OVER PROGRAMMED LOCATION >>>>>>"

4540 PRINT"<<<<<< PROGRAM HAS BEEN ABORTED >>>>>>"

(continued)

FEBRUARY 1985 -BYTE 117

4550
4560
4570
4580
4600
4610
4620
4630
4640
4650
4660
4670
4680
4690
4700
4710
4720
4730
4750
4760
4770
4780
4790
4800
4810
4820
4830
4840
4850
4860
4870
4880
4890
4900
4910
4920
4930
4940
4950
4960
4970
4980
4990

CLOSE#1:END
NEXT l:CLOSE#1:RETURN
REM = = = = = = = = = =

REM DISK-ERROR ROUTINE

IF ERR = 53 AND ERL=4290 THEN PRINT"NO PRM FILES":RESUME 4300

IF ERR = 53 AND ERL = 4420 THEN PRINT"NO PRM FILES":GOTO 4670

IF ERR = 53 AND ERL=4460 THEN PRINT"UNKNOWN FILE":GOTO 4670

IF ERR = 61 THEN PRINT "DISK FULL":GOTO 4670

IF ERR = 57 THEN PRINT"RESET EPROM PROGRAMMER":GOTO 4670

IF ERR = 67 THEN PRINT"UNKNOWN FILENAME, DON'T TYPE '.PRM'":GOTO 4670

CLOSE#1:PRINT "UNKNOWN ERROR #";ERR;"IN LINE #";ERL

PRINT"PRESS ANY KEY TO CONTINUE -> ";:IKEY$ = INPUT$(1):PRINT

IF ERR = 57THEN RESUME

HFLAG = 1

RESUME 2110

ON ERROR GOTO

REM ====================================

REM CONFIGURATION ROUTINE

DATA 255,255,196,255,196,255,196,255,255,196,255,196

DATA 026,196,255,255,255,196,255,196,196,255,255,196

DATA 1 96,255,1 96,1 96,255,255, 1 96,255,1 96,255,255,255

DATA 196,255,196,196,255,255,196,255,196,255,196,255

IF ESIZE = 1 THEN RESTORE 4750

IF ESIZE = 2 THEN RESTORE 4760

IF ESIZE = 3 THEN RESTORE 4770

IF ESIZE = 4 THEN RESTORE 4780

LOCATE 1,22:PRINT "JUMPER CONFIGURATION"

LOCATE 3,30:PRINT CHR$(201);CHR$(205);CHR$(205);CHR$(187)

FOR l = 4TO 15

LOCATE l,30:PRINT CHR$(199);" ";CHR$(182);"J";l-3
NEXT I

LOCATE 16,30:PRINT CHR$(200);CHR$(205);CHR$(205);CHR$(188)
FOR l = 4TO 15

READ JUMPER

LOCATE 1,31 PRINT CHR$(JUMPER);CHR$(JUMPER)
NEXT I

LOCATE 4,38

IF ESIZE = 2 THEN PRINT" NOTE: INSTALL J1 FOR 2732A EPROMs"
LOCATE 18,20:PRINT "If jumpers are not properly configured"
LOCATE 19,20:PRINT "shut off programmer and set jumpers,"
LOCATE 20,20:PRINT "then turn programmer back on."
LOCATE 22,20:PRINT "Press any key to continue — > ";
A$ = INPUT$(1):RETURN

created with a SAVE command in the
program can also be used to enter the
data.

A help routine is provided in the
program to assist the user during the
operation of the programmer. It con-
sists of a menu that contains all the
choices available in the driver pro-
gram. The routine can be entered
from any location in the program by
typing the letter H. A screen-dump
routine and an EPROM erasure-veri-
fication routine are also provided.

In Conclusion

The serial-port EPROM programmer
isn't designed for volume program-
ming. It's intended to be a cost-

effective, transportable programmer
that doesn't become outmoded with
each new computer and system bus.
You'll also find, cleverly embedded in
every programming cycle, enough
time for you to take a well-deserved
coffee break.

Circuit Cellar Feedback

This month's feedback begins
page 393.

Next Month

I've always been intrigued by home
control and electronic messaging. In
March, I'll tackle the subject in
earnest, beginning with a Touch-Ibne
Interactive Message System. ■

Special thanks to Larry Bregoli for his software
expertise.

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 08250.

Ciarcia's Circuit Cellar, Volume I covers articles
that appeared in BYTE from September 1977
through November 1978. Volume 11 covers
December 1978 through June 1980. Volume
111 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.

118 BYTE • FEBRUARY 1985

Your Gateway to Artificial Intelligence

Golden

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| Gold Hill Computers
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163 Harvard Street
Cambridge, MA 02139

B10-84

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□ Enclosed is a check to Gold Hill
Computers for GCLisp.

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163 Harvard Street, Cambridge, Massachusetts 02139

Golden Common Lisp is a registered trademark of Gold Hill Computers. GCLisp is a trademark of Gold Hill Computers. The Lisp Explorer is a trademark of San

Marco Associates. Lisp is copyrighted by Addison-Wesley Publishing Company, Inc. The Common Lisp Reference Manual is copyrighted by Digital Equipment

Corporation. Rainbow is a trademark of Digital Equipment Corporation. IBM is a registered trademark of International Business Machines.

Inquiry 123

120 BYTE* FEBRUARY 1985

PREVIEW

THE

MACINTOSH

OFFICE

by John Markoff and Phillip Robinson

Editor's note: The following is a BYTE prod-
uct preview. \t is not a review. We provide this
advance look at this new product because we
feel it is significant.

ON THE FIRST ANNIVERSARY of the
introduction of the Macintosh. Apple
Computer has introduced AppleTalk,
which is a new local-area network
(LAN), and a series of intelligent net-
worked peripherals, including a laser
printer and file server. The company
hopes these products will make the
"Macintosh office" a popular choice
for work groups in large and small
corporations.

AppleTalk and the laser printer are
scheduled to be shipped in March.

The network was developed to
serve as a small-work-group intercon-
nect system, as a tributary to larger
high-speed local-area and long-haul
networks, and. in its most basic form,
as a peripheral bus between an Apple
computer and dedicated peripheral
devices.

The new Apple LAN concept is a
radical departure from common in-
dustry thinking about LAN design (for

(continued)
}ohn Markoff and Phillip Robinson (1000
Elwell CL Palo Alto. CA 94393) are BYTE
senior technical editors.

ILLUSTRATED BY JOAN HALL

FEBRUARY 1985 • BYTE 121

THE MAC OFFICE

AppleTalk networks
the Macintosh and
a new laser printer.

more information on Apple's plans for
the future see the text box "Steve
Drops By" on page 124). Instead of
providing a high-bandwidth channel
to link personal computers to each
other and to larger remote computers.
Apple designed its LAN to be a low-
speed, low-cost network for small
work groups.

The AppleTalk architecture relies on
the distribution of "intelligence" in
network peripherals and on the clever
use of the network's limited speed.
Apple is betting that the principal bar-
rier to networking office microcom-
puters has until now been cost. By
focusing on an LAN that is optimized
to share resources among small
groups, the company hopes to
achieve a better match to the organi-
zation of the typical office.

Since the introduction of the Macin-
tosh. Apple has changed the name of
its LAN from AppleBus to AppleTalk.
When Apple first described the LAN.
the company emphasized the net-
work's role in providing the Macintosh
with "virtual" serial slots for periph-
erals as an alternative to the open
hardware architecture of the Apple II.
As it is released. AppleTalk goes
beyond this. However, you may still be
able to daisy-chain peripherals by
adding a smart network controller.
But for now, Apple has decided to
leave this option to third parties. One
manufacturer. Tfecmar Inc. has already
demonstrated the ability of its 68000-
based hard-disk system to control
both an ImageWriter and an Apple
modem.

Apple is moving toward putting
microprocessors in all or most of its
peripherals. This design philosophy,
plus the standardization on the Zilog
SCC (serial-communications con-
troller) chip that is now used in the
Lisa, Macintosh, and Apple He com-
puters, will make the task of network-

ing peripherals simpler.

At the time of AppleTalk's introduc-
tion, Apple is only demonstrating the
LAN with a prototype 20-megabyte in-
telligent file-server hard-disk system,
which you will need for network ap-
plications such as electronic mail and
print spooling. However, we were told
that -the hard disk will be announced
in August 1985 and it will cost $3 500.
An electronic-mail communications
package for AppleTalk is also
scheduled to be announced at the
same time.

The company is also discussing a
variety of future network products
such as a bridge to link individual
AppleTalk networks, an interface to
the recently announced IBM PC LAN,
communication servers, network data-
bases, and as many as 50 third-party
hardware and software development
projects based on AppleTalk. Details
of these products aren't yet available;
therefore, it is difficult to assess
AppleTalk at present. But after several
false starts at developing a LAN.
Apple is moving toward making it
possible to link its products in office
and other workplace settings.

AppleTalk

The heart of AppleTalk is the Macin-
tosh serial-communications chip, a
two-channel Zilog 8530 SCC that pro-
vides synchronous and asynchronous
data communications at up to 230.4K
bits per second (bps) using a self-
clocking data format. (The 8530 will
provide data communications at
speeds as high as 1 megabit per sec-
ond, using an external clock. Corvus
Systems Inc. has also used this higher-
speed scheme in its Macintosh imple-
mentation of the Omninet LAN.)

At the physical level. AppleTalk con-
sists of a shielded twisted-pair trunk
cable with modules that are passive-
ly connected to computer and periph-
eral nodes via a short drop cable. An
individual AppleTalk network can
have up to 32 nodes and has a packet-
switching protocol and a data rate of
230.4K bps using FM modulation (a
bit-encoding technique that provides
self-clocking) over a maximum
distance of 300 meters.

Externally, AppleTalk is simple, con-
sisting of the connection modules,
each of which has two miniature DIN
three-pin connectors, and a DB-9 port
that connects to the printer port on
the Macintosh via a 2 -meter cable. In-
side each connection module are
resistors, a capacitor, and a small
transformer, designed so that the link
is transformer-isolated and not
susceptible to any kind of radio-
frequency interference (RFI) or static
discharge.

Apple calls the connector modules
self-terminating, which keeps you
from worrying about line termination
and. in combination with the trans-
former, lets you add nodes to the net-
work and remove them without dis-
rupting network functions. A 100-ohm
terminating resistor is included in
each connector box. and there are
two switch connections that are
opened when the miniature DIN con-
nectors are inserted. If both connec-
tors are used, the switches are open,
but if one of the connectors is not
used, the terminating resistor is con-
nected across the line.

AppleTalk uses a dynamic-address-
ing scheme that ensures that each
node on the network has a unique
8-bit address (there is also a
mechanism for internet communica-
tions across bridges and through
gateways). The AppleTalk destination
address is used to "filter" frames at
the data-link layer. Frames are not ac-
cepted unless their destination ad-
dress matches the address of the
receiving node. The SCC chip
facilitates this process by performing
the address-recognition function in
hardware.

AppleTalk doesn't require that a
particular node's address be per-
manently recorded or set with
jumpers. The advantage of this is that
you can move computers and periph-
erals between networks and install
them by simply attaching them to the
network. For example, Apple claims
you can bring your Macintosh to the
network, plug it in, insert a disk, and
turn it on. No special network con-
figuration is necessary. Setting of the
node address takes place when the

122 BYTE- FEBRUARY 1985

THE MAC OFFICE

computer first looks at some non-
volatile memory to find a previous ad-
dress it has saved, or when it com-
putes a new address based on the

generation of a pseudorandom num-
ber. The computer then tests the ad-
dress to see if it already exists on the
network by sending a special packet

to the address. If the address is
already in use, the node there will
answer and a new guess must be gen-

[continued)

We met Burrell Smith and Bud
TVibble and the rest of the
Macintosh office design crew in the
Macintosh headquarters, one of the
many Apple buildings in Cupertino,
California. After moving beyond the
lobby, we heard someone play a pret-
ty piece of music on a grand piano in
the center of a large open area that
also had sofas and a Ping-Pong table.
On the left was the Matisse room; we
used the Picasso room on the right.
During the introduction, someone
mentioned that Steve would drop by
later. When Steve Jobs did drop by, he
had some interesting things to say
about Apple's plans and strategy

"We hope to be able to offer people
two things based on the Macintosh
technology. The first, using the graphics
and the power of that box, is radical
ease of use. That was the first benefit
of the Macintosh and that's the one
we've really been trumpeting this last
year.

"We are just now beginning to dem-
onstrate the second great benefit of
that graphic user interface— capabilities
that you can't do on any other com-
puter. You can't do the kind of project
management you can do on Mac, you
can't do stuff you can do with Mac-
Draw, you can't print out entire forms
or create forms on other computers. It
will take something like the LaserWriter
to really drive that home. As we roll out
the next pieces that complement the
workstation, I think it's going to
become very clear to people why the
graphic user interface is so important.

"Ultimately we think that these prod-
ucts are going to be used to help peo-
ple communicate with each other. Not
analysis, not computationally intensive
things for their own sake, but things to
help people communicate much as the
telephone did. And in terms of com-
munication, look at middle-manager
productivity in particular. Yes, we col-
lect information, we analyze it, but then
we draw conclusions from it and we
need to communicate those conclu-
sions to people around us.

Steve Drops By

"We communicate in two ways.. One,
with paper, and the paperless office,
which generates more paper than the
traditional office; we've all found that
out because we give people tools that
generate the paper. So we've got to im-
prove the quality of visual communica-
tion, improve the ability to communi-
cate via paper. That includes overhead
transparencies, which I think are going
to be a big use for the printer. We can
do that through the software tools on
the Mac and through the ability to print
them.

"The next way that we can radically
improve communication is to elec-
tronically link up people. We can start
to do things like mail, electronic
scheduling, and a variety of things that
will improve how we communicate with
each other. The result of improving
those two ways of communication, I
think, is going to be startling, when
coupled with the fact that you can
learn how to use the system in a half
hour.

"I also think we're holding true to our
vision of trying to remove the service
and support requirements from the
equation of success so that we don't
have to send out a person at a thou-
sand dollars per half day to help you
install your computer system.

"AppleTalk plugs together and you
don't have a chance to forget to hook
up the terminator plugs because there
aren't any, and you don't have to set
the thumb-wheel switches because
there aren't any, and you don't have to
run the network master-configuration
program because there isn't any. You
just plug it together like a telephone
or stereo and it works. And its very,
very difficult to do wrong. Those little
things are what keep you from having
to go out and hold people's hands, run
them through half-day training courses,
and things like that.

"We think that networking is going to
start from the bottom up in small work
groups. If you've got four people on
the network, which is a typical number
to start with, it will cost $150 per per-

son for the head end. So you've got to
have about $1000 to hook up a com-
puter to the net. It may be worth it
someday when there's a lot of great
software. But, right now not many are
going to pay a thousand bucks to hook
up a $2000 computer to a network.

"And that's what AppleTalk is all
about. Nobody's hooking up to nets
because there isn't enough software
that makes it worthwhile. There isn't
enough software that runs in nets
because if you write software to run in
a net, there's nobody to sell it to
because there aren't any nets. So it's
a circular problem. No nets, no soft-
ware; no software, no nets. We want to
break through that logjam with Apple-
Talk costing 50 bucks a computer.

"We just wish the whole world would
standardize on a net. We'd all be happy
Just give us the jacks in the walls every-
where; we'd have no problem calling
it the IBM net or the AT&T net, but it's
not coming together. Ultimately we
feel that (the standard| network in the
office is going to be the digital phone
switch and not something that Apple
or IBM comes up with. It turns out that
the rates at which the digital-phone-
switch standards are emerging (the
CCITT jComite Consultatif International
Telephonique et Telegraphique] stan-
dards) are very close to AppleTalk
rates. They're about anywhere from 64
kilobits per second up to maybe 192
kilobits per second.

"So the rates we have chosen will
probably map well to the ultimate rates
of what will be the office network. And
that's how the voice-data integration
will take place, through a digital CBX,
not through our network or IBM's net-
work. The decision that we made was
fundamental: put intelligence in the pe-
ripherals. The really interesting thing
that's happening isn't the products
themselves, it's the software standards
that are being set. As an example, Post-
Script is more important, in a way than
the printer |the LaserWriter!. "Though
we think that particular printer is what's
going to make PostScript a standard."

FEBRUARY 1985 • BYTE 123

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Amber, MAX- 12 (tor Mono Board) $249 $ 199

QUADRAM. Quadchrome 12"RGBCoior $695 $495

Quadscreen 17"968x512w/cable $1995 $1595

Quadchrome II, 14" RGB Color $ 650 $ 450

Amberchrome, 12" Amber $250 $165

•ZENITH. 12" Amber, ZVM122 $159 $ 95

12" Green. ZVM123 $200 $ 89

12" Amber, ZVM124 $200 $ 139

12"Cokx. ZVM135 $599 $ 469

PRINTERS

DOT MATRIX:

PRINTER INTERFACES
& BUFFERS ust our

UST

EPSON. JX80-Cokx Printer, 160cps

LQ15fJQ200&67cps $1395

RX80~100cps $ 269

RX80-F J\ $ 369

RX100— 100cps,136coi,pinar. $ 499

FX80-160CPS $ 699

FX100— 160cps $ 895

•MANNESMANN Sort -80 col, 80cps $ 399

TALLY. 160-80 cd,l60cps $798

180-132COL, I60cps $1098

OKIDATA.82A-80COJ. 120 c para. $349

83A-132cd., 120c para. $ 749

84-136001, 200cps, para. $1395

92— 8OC0I., 160 cps, para. $499

93-136 col., 160 cps, para. $799

2410P— Pacemark,35Qcps,para $2995

QUADRAM, Quadjet, Inkjet Cokx Printer $895

•STAR MKX, Gemini 10"X, 120cps, 18" $ 499

GemirM 15"X, 120cps, 15" $ 549

TOSHIBA.

1340-144 cps(LQ) & 54cps(DQ) NEW $ 995

1351— lOOcps $1895

TTX, TTXpress. portab(e/t)andhe)d l 40cps $ 229

LETTER QUALITY:

•JUKI. 6300--40cps, para 5 gj

•JUKI, 6100— 18cps, para. 3 pitch $ 599

•TTX 1014-13cps,para.&Ser.pin«/rict3p. $ 499

1114-€ameas 1014w/T/F, 2crJ.*rop- $ 599

OUR

InStock
InStock
InStock
InStock
InStock
InStock
$ 299
$ 568
$ 778
$ 319
$ 599
$1095
$ 399
$ 649
$1995
$795
$ 269
$ 419

$ 795
$1375
$ 129

$ 795
$ 449
$ 365
$ 439

ARBO, IBM-PC to Para Printer Cable $

EPSON. Parallel Interface for LQ1500 $

Serial Interface Board $

MKXAppleill/f&bUeforEr2on&r>miri $

OWOATA,r\jg'nRav,Trar*rs;0ksjapKea. $

ORANGE MKRO,GrarjrJBrr\s for Apple $

Buffered &appterFV;16K $

PRACTICAL, Mbroojff Inline 64K,para $

Microbuff In Line 64K,ser. $

SUADRAM, Ail expandable (w/copy to 512K)

icrofaaer, w/Copy. PP, 8K, f*MP8w/PS $

Microfazer, w/Copy, PP, 64K. #MP64w/PS $

Microfazer, w/€opy, PP, 128K, w/?S $

Microfazer, Snap-on, 8K. PP, Epson w/PS $

Microfazer, Snap-on, 64K, PP, Epson w/PS $

STAR MICRO, Serial Interf a & Cable $

$ 30
$ 79
$ 105
$ 59
$ 42
$ 99
$ 159
$ 259
$ 259
(Snarx>n to 64K)
179 $ 139
$229
$ 345
$ 129
$ 229
$ 79

60
100
130
95
50
149
239
349
349

299
375
169
299

PLOTTERS:

AMDEK, Amplot II, 6 pen, 10 x 14 Bod $1089 $ 899

PRINTER SUPPLIES:

Tractor Feed Paper, Ribbons, Daisy Wheels. CALL

CABLES

ARBO, IBMPCto Modem Cable $ 31 $

IBM-PC to Para Printer Cable $ 60 $

ASTAR.RF Modulator for T.V.(Apple) $ 35 $

CURTIS, Monitor Extension Cable (IBM) $ 50 $

3'-9' Keyboard Extens. Cable (IBM) $ 40 $

RCA, Monitor Cable $ 15 $

ST AR MICRO. Serial Interla & Cable $ 92 $

ACCESSORIES

Curbs, Diamond, 6out)ets, switched $ 50 $ 29

Emerald, 6 outlets, 6' cord $ 60 $ 35

Ruby, 6ouHets, 6'cord,ftter $ 90 $ 52

Sapphire, 3 outlets, w /Titter $ 80 $ 46

EPD, Lemon $ 60 $ 29

Ume $ 90 $ 45

Orange $140 $ 66

Peach $ 98 $ 39

INNOVATIVE, firxvffe 10 pcWfe holder) $ 7 $ 4

Rip n-Frte 50 (diskette holder) $ 22 $ 15

Ksms^tDri.MzfBrpiK£nBM) $140 $ 95

rcSaver™UneCwdw/Tler(lBM) $ 50 $ 35

Remote Control (IBM) $180 $115

System Saver Fan (Apple) $ 90 $ 69

NETWOfOL Wn*rtMoufetw/»r& wg> $ 70 $ 35

PERFECTDATA.HEadOOTTgtgt $ 16 $ 12

I CREDIT CARD
I APPLICATION FORM

IPtease send me a Corroy-
LaPdinte aedrt card <*
I application form. I under- m
I stand mere b no 3%charge
I on ConroyUPointe credit

I card purchases. Mmimum
initial purchase B $400

CITY STATE ZIP

. — ^£°30 SVV Q*rd*n Pttc^Pprtlwti. OR 9722^ j

ORDERING INFORMATION & TERMS:

MAIL TO: 12060 SW Garden ftaoa, Portland, OR 97223 Include your telephone number

double check your figures for Shipping Insurance and Handling (SIH). All items usuaMy in stock.
NO COD. Cashiers checks, money orders, Fortune 1000 checks and pvemmert checks— we immediately honor. Personal and other company checks —allow 20 days to dear.
Prices reflect 3% cash dtscourrt, so ADD 3% to above prices for VISA, MasterCard or American Express. Add SiH CHARGES: US. Mainland, 3% ($5 minimum) for standard UPS
ground; UPS Blue, 6% ($10 minimum); for U.S Postal, APO or FPO, 12% ($15 minimum). Hawaii— UPS Blua For Alaska or Canada— UPS in some areas only, alt others Postal— caH
or write, or specify Postal. Foreign orders except Canada, 18% ($25 minimum). Monitors by Postal or to foreign countries, 30% ($50 minimum). Orders received with insufficient SIH
charges will be refunded. All prices, avaNabirty and specifications subject to errors or change without notice, so call to verify. All goods are new, include warranty and are guaranteed
to work. Due to our low prices and our assurance that you will get new, unused products— ALL SALES ARE FINAL Call before returning goods for repair or replacement
ORD€RD€SKrK)URS-«Mlo€PMr^T,Mono>ytr«ouBh
EconoRAir, Fadnfc", and Caw*" 1 an tr ad a wU of CcmX fciponbdn. PC HetiaCanTMid SotWtn tradwria of Bagium Computer.

124 BYTE • FEBRUARY 1985

LOW PRICES TO PROFESSIONALS WHO KNOW WHAT THEY WANT AND KNOW HOW TO USE 171

FOR YOUR IIM-PC or XT

WE BUY
EXCESS

COMPUTER
SYSTEMS

— Call for Details —

256K ISm- PC

360K

Disk Drives

by CDC

90 Day

Limited Warranty

By Us

Portable,

256K, 2 360K Disk Drives

CALL

® SANYO^

256K, 2 320K Disk Drive.; CALL

Tel^/ideo K .

256K. 2 360K Disk Drives, 8088 Chip

Jfr#m *

Z150,

256K, 2 320K Disk Drives,

MS DOS 2.1, 8088 Chip, 2 S/P

CALL

DRIVES m

ACCESSORIES

for the IBM-PC or XT

LIST
PRICE

OUR
PRICE

AmdskV, » height internal, 320/360K $ 658 $ 498!
Am disk III, 3" Dual Floppies, 5O0K $ 299 $ 249

CONTROL

DATA

DISK DRIVES

320K/360K

DS/DD

SSS $169 FULL HEIGHT
$149 HALF HEIGHT

30 Day Limited Warranty by Factory Authorized Distributor
CDC, feHi Dual Drive Installation Kit $ 30 $ 16

MAYNARD. Floppy ConL (w/Para.Port) $ 300 $ 239
Interface w/Para Port. $300 $ 185
Interlace w/Ser. Port $ 310 $ 195

PERFECT DATA, Head Cleaning Kit $ 16 $ 12

QUADtWI

Quaddisk Internal Hard Disks w/Controller IN STOCK

HARD DISKS

Convert your PC to 10 meg and to be XT compatible with
one of the following INTERNAL HARD DISK SYSTEMS. 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, Controller
Card and Instructions.

KKmiamari
Late

♦Megaflighf 1 00. 1 mbyte Hard Disk Kit $ 799

MAYNARD

10 meg Hard Disk Kit WSlSandstar

Controller will accept 3 Sandstar modules $1395 $1150

+ MEANS A BEST BUY

LIST
ADVANTAGE MuHJf.Bd for AT
SixPakRus,64K,S/P/CC+S/W $ 395
SKPakRus^.S/P/CC+SW $ 695
SxPakP*JS,384K^/CC+S/W $895
Game Port for SxPak $ 50

1/0 Pus II, S/P/CC $ 215

l/0Pluslt, S/P/CCA3 $265

I/O Pus II, 2S/P/CC/G $ 315

Morw&3c*f^'P/TC(fortitus} $ 495
PCNet, Starter Kit, PC002 $1490
PCIH Circuit Board.PC001 $695
ComboPus Products
MegaPus Products
Al ibtio UNHMonitorttt&swiveibase $ 50
LUKIIO 3to 9 Keyboard Exten Cable $ 40
Vertical CPU "System Stand" $ 25
Monochrome Ext Cable Pair $ 50
HAUPPAGE 8087 Chip $ 175

(HUW) 8087 Software Pak $ 180

8087 Macro Pak $245

Uf-cvoi II re Cotor Card w /pan $245
HfcKLULbb Graphics Card, Mono $499
KAMERMAN. External Power Supply
KENSINGTON, Masterpiece

PC Saver " Line Cord w /Fitter
KwTmnir KB5150. Std keyboard
™ iramC KB5151,Std keyboard
KB5151 jr, keyboard

■ ^ Koala Pad '"w /PC Design

Programmer's Guide
II A VM A BR Multifunction (6) Card, MFC
Hft? nKKU Memory Card no RAM
»Hy Memory Card 256K

?LW_. HardDisk l/F Module (HDM) $ 499

$ 30

$395
$140
$ 50
$209
$255
$255
$150
$ 15
$ 69
$199
$495

TAR
SERIES HardDisk Cable

Para Port Module (PPM) $ 59

Serial Port Module (SPM) $ 95

Dock Cal. Module (CCM) $ 55

Game Adapter Module (GPM| $ 49

Memory Module "0"K(MM0) $122

Memory Module 256K (MM256) $ 422

XT10 meg Hard Disk&l/FWSl $1395

OUR

CALL

245

395

465

150

185

215

375

795

365

CALL

159

235

138

195

169

329

295

159

199

169

395

399

357

1150

MICRON. 4164 Chips, 200 ns

UST
$ 12

PC jr Booster with Mouse $ 495
System Card, 64K $ 395

OUR
$ 4

$ 450
$ 139
$ 329
$ 275

MOUSE SYSTEMS PC Mouse w/PC Pamt $ 295 $ 189

PARADISE, Modular Graphics Card $ 395

PLANTRONICS

Color Board & Cobrnv»gic,,16 cotor.w/Para $ 559
Color Board & Draftsman, 16 color, w/Para $ 559

QUADRAM

* Quadboard, no RAM expand to 384K $ 295

* Quadboard 64K, expand to 384KS/P/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,expand to 256K2SCC $ 395
Quadboard II, 256K. 2S/CC $595
Quad 512 + 64K plus serial port $325
Quad 512 + 256K plus serial port $ 550
Quad 512 + 512K plus serial port
Quadcolor I, board, 16 colors

* Upgrade Quadcolor I to II kit
Quadvue, board, Mono/S/P/CC

* Quadchrome, 12" RGB Color Monitor
Quadchrome II, 14" RGB Color Monitor $ 650
Amberchrome, 12" Amber Monitor $ 250
Quad 3278 $1195
Quadnet VI $2295
Quadnet IX $1995

* QuacHink $ 680

TG PRODUCTS. Joystick $ 45

Titan Accelerator PC (8086+ 128K) $ 995

$895
$295
$275

$795

$ 285

$ 395
$ 395

$225
$ 245
$475
$ 525
$ 215
$ 265
$ 395
$ 265
$ 420
$ 625
$ 195
$ 199
CALL
$ 495
$ 450
$ 165
$1090
$1545
$1745
$ 449

$ 29
$ 750

Memory
* Chip Kit

9Each, 4164, 200 ns
90 Day Warranty by us

• ComX
EconoRAM™384K BOARD

$350

Wrth Fastrak n> RAM Otsk Emulator and Spooler Software
Fully Compatible, 1 Year Limited Warranty by ComX

Works on DOS 1.1, 2.0or 2.1
Prices and availability subject to change. CaH.

SOFTWARE for IBM-PC or XT

BUSINESS 8t

UST OUR

APPUEOSOFT..Versaform $389 $249

ARKTRONICS, Jane $295 $ 189

♦ASHTON TATE, Framework $ 695 $ 349

* dBase III $695 $ 369

* dBase II, free, PC-DOS & 128K) $495 $289

* dBase II to III upgrade $200 $ 119
Everyman's OB Primer (Book) $ 15 $ 12
Friday! $295 $ 159

ATI. Training Programs— Large Inventory $ 75 $ 50

BM. Job Cost Accounting $795 $495

Gen'l Acctg, AR, AP or PR, each $ 595 $ 375

Personal Accounting $195 $ 125

♦BROOERBUND, Bank Street Writer $ 80 $ 50

COEX Training Programs -Large Inventory $ 70 $ 45

•CONTINENTAL, Lltrafite $ 195 $ 125

TaxAdvarrtage $ 70 $ 45

Home Accountant Pus $ 150 $ 90

FCM (Filing, Cataloging Mating] $125 $ 79

Property Management $ 495 $ 329

DILiTHWMPRESSPCtoMAC&Back $ 100 $ 65

DO W JONES, Investment Evafuator $ 139 $ 99

Market Manager $300 $ 189

Market Analyzer $350 $ 219

Market Mkroscrjpe $ 350 $ 219

FOX*GEUER,dU«tMS-DOSorCP/M89 $ 99 $ 65

Quickcode or dGraph, each $295 $ 165

HARVARD, Total Project Manager NEW $495 $ 315

Harvard Project Manager $ 395 $ 250

HA YDEN, Pie Writer $ 200 $ 125

Re SpeRer or Sargon III, each $ 50 $ 30

HOWAROSOfT, Tax Preparer $ 250 $ 200

Real Estate Analyzer $250 $ 170

HUMANEDG£toTmjnb^EdpNEW$195 $119

Mind Prober NEW $ 50 $ 32

MartagenentSate or Nepteation Edgeea. $250 $ 159

IUS. EasyWnter I System $ 350 $ 250

EasySpeltef It $ 85 $ 125

GLARAP.OEorlNV.each $595 $375

Business System : GL+AR+AP $1495 $ 995

*INSOfT.GraF0RTH(aiHmated 3D graphics) $125 $ 65

♦KENSINGTON.Easy Link Mail Manager $ 95 $ 65

KNOW ARE, Knoware (reg. graphics) $ 95 $ 64

UFETREE, VWkswriter Deluxe $395 $ 159

Voikswriter $ 195 $ 105

LIVING VIDEOTEXT, Think Tank $ 195 $ 105

LOTUS. 1-2 3 $495 $309

Symphony $ 695 $ 465

MDBS. Knowfedgeman $ 500 $ 300

MECA, Managing Your Money $195 $125

MICROPRO. WordStar* $ 350 $ 189

WordStar 2000 $ 495 $ 295

WordStar 2000 Pus $595 $ 325

WordStar Professional Pus $ 695 $ 395

WordStar Professional, 4 Pak $ 495 $ 265

BUSINESS & TRAINING

UTILITY & SYSTEM

♦MICROPRO. ConectStar

$145

$ 77

$ 315

infoStar Pus (+ Star burst)

$595

MailMerge. SpelStar or Star Index, ea.

$ 99

$ 54

Preoption Pak (MM/SS/SI)

$195

$ 105

*MfCROMM, RBase Series 4000

$495

$ 269

Extended Report Writer

$150

$ 95

RBase Clout

$195

$ 125

MICROSOFT, Spell NEW $ 50

$ 32
$ 125

Multiplan

$195

Chart or Project, each

$250

$ 159

Word

$375

$235

Word with Mouse

$475

$ 289
$ 105

MONOGRAM, Dollars & Janse w/f orecast $180

MULTIMATE Mulbmate

$495

$ 295

OPEN SYS. GLARAP.PRINVor POeacI

$695

$ 429

•OS30RNE/C0MX. (Book & Busin, Stat & Math

Programs on OS/DO Disks)

Some Common Basic Programs (70 ea.) $ 100

$ 69

Practical Basic Programs
PEACHTREE. Peach Pak

$100

$ 69

$395

$ 239

Peach Text 5000

$395

$ 239

PERFECT/THORN. Perfect Writer

$349

$ 179

Perfect Wr iter & Speller Combo

$399

$ 199
$ 25

PROFESSIONAL Trivia Fever

$ 40

QUADRAM. Tax Strategy

$395

$295

Investment Strategy

$395

$ 295

C^Usr«l-2-3al-2-3frjrBusi«s(BDOks) $ 15

$ 12

ROSESOFT, Prokey

$130

$ 87

SOFTWARE ARTS.

TK SorverfMS DOS or PC DOS, spec)
SOFTWARE DIM. Accounting Pus

$399

$ 269

$495

$ 295

SOFTWARE INTL. Open Access

$695

$ 395

SOFTWARE PUBUSHINaPFSReoort $125

$ 79

PFSffle,PFSWrite,PFSCraph,PFSf , lan

$140

$ 89
$ 59

PfSfroof

$ 95

SORCJM, SuperCak: III

$395

$245

SSt/SATELUTE WordPerfect

$495

$ 235

Personal WordPerfect

$195

$ 99

STONEWARE. Advanced D.B. Master

$595

$ 395

SUMMA Traders Forecast

$250

$ 159

Trader's Data Manager

$200

$ 129
$219

Trader's Accountant

$350

Complete System

$700

§445

$ 159

VJStCORP, VtsiCalc 4

$250

DIGITAL RES., CBASIC 86™ (CP/M86) $200
C8A^Comp^(CP/W-86orPCDOSe3) $600

$750
$200
$100
$ 60
$149

PL/1 (PC DOS)

PL/1 (CP/M-86)

Speed Prog. Pkg. (CP/M-86)

DRL0GO-86(CP/M86)
FUNK SOFTWARE. Sideways
HAYES. Smartcom II (Data Com.)
wfNSGfT, GraFORTH (animated 3D graph) $ 125
LIFEBOAT, Lattice C, NEW $ 500

MICROSTUF. Crosstalk XVI (Data Com.) $ 195
MICROSOFT. muMath/muSimp

Business BASIC Compiler

Pascal Compiler

C Compiler

BASIC Compiler

FORTRAN Compiler

COBOL Compiler
MOUSE SYSTEMS. PC Paint
NORTON, Utilities 2.0. 14 programs $
OPEN SYS. BASIC Interpreter NEW $ 195
ROSESOFT. Prokey $130

& EDUCATIONAL

•ARMONK. Ex ecutrve Suite $ 40

BLUE CHIP, Millionaire or Tycoon.each $ 60
BPI SYSTEMS. Persanaf Accounting $ 99
CBS. Large Inventory in Stock
COMPREHEN..rcTutDr(l.lor2.aea.)$ 60
CONTINENTAL Home Accountant Plus $ 150
DAVIDSON. The Stteed Reader II $ 75

Word Attack! or Mattibiasterl each $ 50
DOW JONES, Home Budget $139

HARCOURT. Computer SAT $ 80

MICROSOFT, Right Simulator II $ 50

MONOGRAM, Dollars 4 *nse $ 165

PBL CORP., Personal Investor $ 145

SCARBOROUGH. MasterType $ 50

SIMON fc SCHUSTER, TypingTulorlll $ 50

UTILITY & SYSTEM

$ 03

$ 85
$ 55
$ 40

JilueKlCK

Sidekick (Copiabie)
Turbo Pascal or Toolbox, ea.
♦CENTRAL POINT, Copy II PC
♦COMX, Fastrak™, RAM/Disk emulator
and printer spooler program. Works on any
PC/DOS version or RAMCard.Menu Driven $ 100
DIGITAL RES.. CP/M-86™ (PC/XT) $ 80
Concurrent CP/M- 86™ w /windows $835

GAMES

ATARI, Centipede, PacMan or Oonkey,each $ 35
♦BROCCRSUNO, Large Inventory m Stock
ELECTRONIC ARTS, Full Une in Stock

EPYX, Auto Sim or Tempfe of Apshai $ 40

$ 35 HA YDEN, Sargon 111 (Chess) $ 50

$ 55 INFOCOM, Deadline or Suspended, ea. $ 50

$ 35 Zork I or Zor k If or Zork III, each $ 40

$ 30 *iNSOFT, Mystrix r Wordtrix or Quotrix,ea $ 35

MICROSOFT, Flight Simulator li $ 50

ORIGIN, Ultima II $ 60

$ 59 PROFESSIONAL Trivia Fever $ 40
$ 39 SPINNAKER, Urge Inventory in Stock

$ 225 SUB LOGIC, Night Mtsskw Pinball $ 40

CASH-n-CARRY COMPUTER STORES. INC.

Over-the-counter sales only. Open Monday through Saturday, 10:00 to 6.00.
SAN FRANCISCO - NEW STORE1 550 Washington Street
(it Montgomery, opposite the Pyramid]. Interstate 80, to Highway
480, take Washington Street Exit. CALL (415) 982-6212.
PORTLAND, OREGON — At Park 217, Tigard at 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.

NO
SALES TAX

OUR REFERENCES:

We have been in computers and electronics since
1958, a computer dealer since 1978 and in compu-
ter mail order since 1980 Banks: 1st Interstate
Bank, (503) 643467a We belong to the Chamber of
Commerce (503) 228-9411 and Direct Marketing
Assoication, or call Dunn and Bradstreet if you are a
subscriber.

;,-ri

M°j

CONROY-
LAPOINTE
CARD

aSH^TOLL FREE
(800) 547-1289

OREGON ONLY (800) 451-5151

Foreign
&

Portland
(503)620-9877

HOT UNE

Information on your order

(503) 620-9878

IfcEKDAYSONLY

ORDER DESK HOURS

Mon-Fri-6AM to 6PM PST
S*«d*-10AM to 4PM PST

(6AM here is 9AM in New York}

Inquiry 7 2 for IBM Peripherals. Inquiry 7 3 for Apple. Inquiry 7 4 for all others.

FEBRUARY 1985 -BYTE 125

THE MAC OFFICE

erated by the hew arrival.

AppleTalk divides node addresses
into two classes: server node and user
node. The system reserves 2 55 pos-
sible addresses; hexadecimal address
FF is a special "broadcast" address
used to reserve the line for transmis-
sion as part of the network's scheme.

AppleTalk is based on an open sys-
tem architecture (see figure 1). Apple
has published detailed information on
the suite of network protocols that
comprise AppleTalk and has held a
number of seminars to aid third-party
vendors that are developing software

and hardware applications for the
network.

The AppleTalk protocols implement
a packet-switching scheme that pro-
vides functional correspondence with
the International Standards Organiza-
tion (ISO) Open Systems Interconnec-
tion (OS1) model. Protocols equivalent
to the ISO OSI layers I through 5
(physical data link, network, trans-
port, and session) are at the core of
AppleTalk.

The access scheme to the network
is based on a CSMA/CA (carrier sense
multiple access with collision

AppleTalk Protocol Architecture

Layered, Open System

Printer
Access
Protocol

Name

Binding

Protocol

Routing
Table

Maintenance
Protocol

AppleTalk

Filing

Protocol

Reliable data transport

AppleTalk

Transaction

Protocol

■ Socket-to-Socket Delivery on an internet

Datagran
Delivery
Protocol

AppleTalk
Link
Access
Protocol

+
Physical
Layer '

• Node-to-Node Delivery on a single AppleTalk

Figure I : A diagram of AppleTalk 's protocol architecture, printed by the
LaserWriter.

avoidance) model. Although both
AppleTalk and Ethernet are based on
a bus topology, they differ in the way
they handle the problem of data col-
lisions on the network.

Ethernet provides hardware capa-
bility for detecting collisions. Apple-
Talk, on the other hand, implements
collision avoidance in software at the
data-link level. The AppleTalk Link-
Access Protocol (ATLAP) software
handles the address-assignment
mechanism, the frame format, and the
frame transmission and reception
process.

In the AppleTalk collision-avoidance
scheme all transmitters wait until the
line is idle. This time interval is deter-
mined by the generation of a pseudo-
random number whose range is ad-
justed based on perceived bus traffic.

As part of this scheme each trans-
mitter can send special broadcast
frames (addressed to all nodes in the
network) that reserve the line by in-
forming other nodes that it is prepar-
ing to send a packet. The transmitters
use directed frames (or packets) to
send data to a single address on the
network.

While a transmitting node is send-
ing to a receiving node, a dialogue
takes place. If a collision occurs dur-
ing the dialogue, the sending node
backs off and tries again, adjusting the
randomly generated time interval.
This adjustment follows a linear back-
off algorithm that changes dynamical-
ly in response to recent network-traffic
history. If the node detects collisions
among recently sent packets, this sug-
gests higher loading and greater con-
tention for the bus. Thus, the random
wait that is generated is calculated
over a larger range, effectively spread-
ing out the different contenders for
the line.

Apple reports that it has extensive-
ly tested AppleTalk's CSMA/CA pro-
tocol and is satisfied with its ability to
remain stable under heavy network
loads.

In addition to ATLAP. AppleTalk
consists of a variety of other protocols
that generally correspond to other
levels of the ISO OSI model.

[continued)

126 BYTE- FEBRUARY 1985

TIEDUP
WITH DAIA RECORDING?

Here comes SEED to set you free.

Are you frequently tied up with typing large
amounts of data from printouts into your personal
computer, or frustrated at not being able to use it
while it is being used as an expensive data collection
device? If so, then let a SEED set you and your PC
free.

These highly portable and cost effective data
recording units allow you to continuously record
data wherever and whenever you want via an RS-
232C serial interface onto a diskette for analysis or
editing later on your PC.

SEED 1 is intended for use with an Apple II
compatible disk drive (single or dual drive - 120
Kbyte memory per disk) and after recording, the dis-
kette can be loaded into your Apple II, lie or III per-
sonal computer.

SEED 2 is intended for use with an IBM PC and
has the additional advantages of a built-in disk drive
unit, a 350 Kbyte memory, single or double sided,
double density disks, and dip switch selectable baud
rate, parity and data bits.

An optional analogue/digital conversion unit
is available for each model.

Both SEEDs can be used for a really wide range of
data recording applications:

in the office where data can be recorded from
mainframe, other computers or serial communica-
tion networks

in the laboratory where results can be recor-
ded from samples being measured continuously, in-
cluding overnight runs

on the factory floor where performance data
can be recorded from instruments undergoing qual-
ity control testing prior to shipment

So now there's no need to get tied up with data
recording. All you need is SEED.

manachioy

Iso-Heikkilantie 14, SF-20200 Turku, Finland,
Tel. (9)21-307 000, Telex 62665 maroy sf

USA, CMK Associates, inc., (408) 374 1805; CANADA, Fisher Scientific, (613) 226 8874; W. GERMANY, LKB InstrumentGmbH, (89) 85830, isolab, (05609) 2736; FRANCE, LKB Instruments
S.A., (6) 928 6507; AUSTRIA, LKB Instrument Ges.m.b.H, (0222) 92 1607; ENGLAND, LKB Instruments Ltd., (01) 657 8822; SWEDEN, SEED Trading, (08) 768 5595.

Apple is a registered trademark of Apple Computer, Inc. IBM PC is a registered trademark of International Business Machines, Corp.

Inquiry 196

FEBRUARY 1985 -BYTE 127

THE MAC OFFICE

While ATLAP handles node-to-node
delivery of packets on a single Apple-
Talk network, a Datagram Delivery
Protocol (DDP) extends this mecha-
nism to socket-to-socket delivery.
Sockets are logical entities in the in-
dividual nodes of a network. An in-
dividual socket is identified by a
1-byte address. Therefore, there can
be as many as 2 56 different socket ad-
dresses on a single node. The DDP is
designed to provide addressing and
packet delivery between several
AppleTalk networks connected by a
bridge. A bridge might consist of a
single node connected to two Apple-
Talk networks or it might consist of
two nodes, each connected to a sep-
arate AppleTalk network, connected
by a communications channel.

Additional protocols include a
routing table maintenance protocol
(RTMP) that permits any AppleTalk
node to "discover" network routing in-
formation, such as the number of the

LAN to which it is directly attached;
a name-binding protocol (NBP) that
permits users to access network ad-
dresses by names rather than num-
bers; and the AppleTalk transaction
protocol (ATP), designed to ensure
loss-free delivery of packets from a
source socket to a destination socket.

On the Macintosh, these protocols
are implemented as 5.5K bytes of
code written in assembly language.
Because the SCC chip handles ad-
dress recognition, the network pro-
tocols take no system overhead unless
a particular node is directly addressed
over the network.

Initially, AppleTalk will link groups
of Macintosh computers to the Laser-
Writer laser printer, an impressive
68000-based electronic printing
system that will provide hard-copy
output of any text or graphical image
that can be displayed on the Macin-
tosh screen. The special significance
of the LaserWriter is that it is in-

Adobe Systems and
the PostScript Language

Adobe Systems Inc.. of Palo Alto.
California, was started by a
number of researchers who left Xerox's
PARC (Palo Alto Research Center). In
particular. John Warnock, president of
Adobe, was a principal scientist at
PARC for raster-graphic display tech-
niques. Charles Geschke, the executive
vice-president, was a manager of the
Imaging Sciences Laboratory at PARC

Adobe is trying to make PostScript—
their text and graphics language— a
business standard. Unlike most print-
file description languages. PostScript is
not a static, data-structured written
description: it is a programming lan-
guage. When the Macintosh commu-
nicates with the LaserWriter, it actual-
ly sends a program across AppleTalk.

According to Geschke, "When the
program arrives at the 68000 in the
printer and begins executing, it has one
very interesting side effect, namely, it
drives the video on that laser and pro-
duces output. But it is really a program
description that is generated on the
Macintosh and is executed on the
printer." By using PostScript, the

amount of information sent across
AppleTalk can be trimmed, in some
cases, to just 10 percent more than the
raw ASCII (American Standard Code
for Information Interchange) data.

PostScript is completely encoded in
the printable character subset of 7-bit
ASCII code and so is completely invisi-
ble across any kind of communications
line, not just AppleTalk. PostScript can
handle any material: text, line-art,
photographies, and even color (for
printers that can use it). While photo-
graphic images are sent as bit maps,
graphics are sent as commands and
the fonts are sent as mathematical
outlines (based on Bezier cubics) that
can be stroked, filled, scaled, oriented,
or used as clipping boundaries. And
it is flexible, as Geschke pointed out.
"If you're really into graphic art you can
adjust the shape of the half-tone dot,
the shape of the tonal production
curve, the orientation of the screen,
and its frequency."

Adobe isn't only working with Apple.
You'll be seeing PostScript in other
systems from other companies.

tegrated with PostScript, a page-
image-description language devel-
oped by Adobe Systems, a start-up
company founded by a group of elec-
tronic-printing experts who recently
left Xerox Corporation (see the text
box "Adobe Systems and the Post-
Script Language" below). PostScript is
essential to the viability of AppleTalk
because it permits extensive com-
pression of the information the Laser-
Writer needs to print bit-map images.

Laser Technology

Laser printers are fast, quiet, and
capable of high-resolution printing.
Until recently, they have also been
very expensive, ranging from $50,000
to $400,000.

A laser printer has a raster-scanning
laser that projects the print image
onto an electrostatically charged
photosensitive drum. A set of rotating
mirrors manipulates the beam— the
laser itself doesn't move. Wherever
the laser beam touches the drum, the
static charge is nullified. Tbner (par-
ticles of colored plastic) is then at-
tracted to those points. The printer
rolls paper against the drum and the
toner sticks to the paper. Finally, a hot
f user permanently affixes the toner by
melting it onto the page.

The price of laser printers has
dropped dramatically because of de-
velopments such as Canon's LBP-CX
marking engine. That engine, which is
also used in Canon's personal copiers,
combines several fundamental printer
components into a single, inexpen-
sive, disposable cartridge. Because
those same components— including
the toner and drum— frequently
needed repair and replacement on
laser printers, the Canon engine great-
ly improves reliability.

The LaserWriter's disposable car-
tridges (made by Canon) cost $99
each and will print approximately
3000 pages. That puts the price in the
range of 3 cents per page. The Laser-
Writer prints on ordinary copy paper
but can also use bond paper, Euro-
pean and legal-size paper, transparen-
cies, envelopes, labels, or even busi-
ness cards. Several different toner

[continued)

128 BYTE • FEBRUARY 1985

WHEN YOU BUILD A HOUSE ... YOU DON'T NEED TO MAKE THE WINDOWS YOUKSEI.K NOW . . . THE SAME IS TKUE WHEN YOU'RE WHITING CODE.

Windows With A View
Toward The Future

The Window
Machine™ occupies
only 12K! Written in
tight, fast Assembler,
it performs like a
racing engine... with
more power than
you'll probably ever
need. Yet, it's an
engine designed to fit
in the vehicle of
your choice... from a
"stripped-down"
128K IBM PC to a
fully loaded AT. The
programs you write
today will run on
the broadest range of
machines possible...
now, and in the
future.

Windows Bigger
Than Your Screen?

Here's where the
VSI part of our name
fits in. VSI means
Virtual Screen Inter-
face. Behind each
window, there's a
much bigger picture.
VSI defines virtual
screens rather than just windows. The
window itself shows 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 (columns x
rows, or rows x columns). And there are
more than 100 screen primitives at your
command.

Multilingual Windows

You can order The Window Machine
with the languageinterface of your choice:
C, Pascal, Compiled Basic, Fortran, Cobol,
or PL1. We've even recently completed

These are
coders'
windows...
designed to be
built into the
programs you
are writing.
They can
overlap, move
anywhere on
the screen,
grow, shrink,
vanish or blink.
They can be
bordered in
anything from
a simple line to
flashing
asterisks... or
even no border
at all. And
you can have
up to 255 of
them at a time!
Color or
monochrome
...of course/

Why did Simon &
Schuster, 3COM,
Tymshare, and
Revlon choose
VSI-TheWindow
Machine?

figured if you wanted ribbons and bows
you could always add them yourself.)

And by offering you the product our-
selves, we were able to cut out all the
middlemen and save you a tremendous
amount of money.

\MWMThe Window
w ^MMachine™

(and how come
you can buy it for
such a low price?)

an interface for Turbo Pascal*, so that
now true, full-featured windowing can be
utilized with this fine compiler. (Turbo's
own built-in "windowing" procedure is
extremely limited).

Windows That Won't Break You

We decided to save you a lot of money.
So, we left behind fancy binders, mono-
grammed slip cases and plastic pre-
sentation boxes. Instead, you'll rind an
extremely powerful tool and a 200 page
manual written with an eye toward
simplicity, clarity and completeness. (We

*Turbo Pascal is a Trademark of Borland International

$59.95

Available for the IBM PC. XT, AT, IBM Compatibles,
and the Wang, T.I., HP 150, and Tandy 2000.

The Window Machine Includes:

■ Zoom Windows
i Multiple Virtual
Screens (up to 255)
Choice of Borders
(including flashing bordersj
i Support for all Color and
Monochrome Video Attributes
[no graphics card required)
m Built-in Diagnostics
• And much, much more

ORDER YOUR COPY OF

VSI— THE WINDOW MACHINE TODAY

For Visa, MasterCard and

American Express orders call toll free:

1-800-227-3800 ext. 986

The Window Machine™ S59.95 Shipping and handling included
LANGUAGE INTERFACE:

D Lattice C QRealia Cobol DMicrosoft Basic Compiler D Microsoft Fortran
DPLl DMicrosoft Pascal DTurbo Pascal (full featured true windowing]
COMPUTER ^_^_

Name _

Address .
City

.State Zip Code.

D Check DMoney Order DVISA DMasterCard D American Express

. Exp. Date _

AMBER SYSTEMS, INC. 1171 S. Saratoga-Sunny vale Road, San )ose CA 95129

Card * .

'California residents: lax included. Orders outside the USA; please add $5

for shippinpnd handling.

AMBER SYSTEMS

1171 S. Saratoga-Sunnyvale Road

San |ose, CA 95129

FOR DEALER INQUIRIES: CALL OUR 800 NUMBER

Inquiry 18

FEBRUARY 1985 -BYTE 129

THE MAC OFFICE

colors are available.

The Canon engine is used in the
LaserWriter and many other new laser
printers, from Hewlett-Packard's
$3495 LaserJet to the $10,000 QMS
800. These laser printers can turn out
eight pages a minute and yet make
only about as much noise as a copier.
All of these machines can print at the
same 300-dots-per-inch resolution.
While far better than standard dot-
matrix printers, they aren't up to the
1200 dots per inch or better that
phototypesetters produce (see figures
I and 2 for samples of the Laser-
Writer's output). Still unless you're a
graphics expert, it is hard to
distinguish this resolution from
typeset text. The difference between
the various Canon-based laser
printers is in the controllers; each
manufacturer uses its own controlling
computer.

Because the laser scans synchro-
nously across the page, image dots
must be fed to the laser at exactly the
right time. That requires data storage
in the printer itself. Shipping data to
the printer memory as a simple bit
map would take too much time for
most users. An RS-232C port running

at 1 9,200 bps (bits per second) would
take nearly 7 minutes to send the
7,920,000 bits for a single page; even
the speedier AppleTalk network
would take half a minute, lb ease that
bottleneck, most manufacturers put
some form of intelligence, such as en-
coded graphics instructions and pre-
loaded fonts, into the printer con-
troller. Then the computer need only
send a condensed form of the print
image to the printer controller.

The least intelligent controllers have
limited printing capabilities. The
Hewlett-Packard LaserJet, for instance,
can only print 6 square inches of
graphics per page and has a limited
set of character fonts. On the other
hand, the expensive QMS printer uses
a standard 'fektronix terminal emula-
tion (a set of graphics protocols). For
example, instead of sending a bit map
of a circle to that printer, a computer
only needs to send the 'fektronix in-
struction to print a circle of a certain
size, shape, and position.

LaserWriter Hardware

The Apple LaserWriter printer can
generate a variety of fonts and high-
quality graphics with the help of a

Figure 2 : Sample output from the LaserWriter.

powerful built-in computer and the
PostScript language.

The LaserWriter's internal com-
puter-controller board was designed
by Burrell Smith, a key figure in the
Macintosh design group, and is built
around an 1 1 .2-MHz 68000 processor,
1.5 megabytes of RAM (random-
access read/write memory), and 0.5
megabyte of ROM (read-only mem-
ory). The ROM contains the PostScript
code.

The laser-printer project's design
goals were formed when Adobe Sys-
tems suggested that a laser printer
could offer graphics without giving up
letter-quality text. Part of this involved
making the printer controller as intel-
ligent and as fast as possible, so that
encoded information could be sent
over the AppleTalk LAN to spare the
network a huge overhead burden.

Of the leaser Writer's 1.5 megabytes
of RAM, half a megabyte is used for
temporary scratch-pad buffers and
font caching and a full megabyte is
devoted to the screen. The Laser-
Writer has other small memory com-
ponents, such as a static RAM cache
of 4K bytes that allows the 68000 to
process faster by executing inner
loops without any wait states. In ad-
dition, Apple built into the hardware
one of the most common input trans-
fer modes. Burrell Smith said, "We do
a classical OR between contents of
memory and the data you wish to
enter to the frame buffer— in a single
bus cycle."

Apple is a high-volume producer. To
that end, it has kept the component
count on the board low— there are
only 34 chips plus memory and
resistor packs. In comparison, one
competing laser-printer controller
board has close to 150 chips. The
LaserWriter board has been designed,
as was the Macintosh, for automatic
insertion and test. The chip tech-
nology used is generally the same as
for the Macintosh: 2 5-nanosecond
PAL (programmable-array logic) chips,
2 56K-byte dynamic RAM chips, and
2 56K-byte ROM chips. Smith noted,
"What we're trying to do is take rela-
tively expensive technologies and

[continued)

130 BYTE • FEBRUARY 1985

A shell

loaded with
software is
impressive,

one simple

program

loaded with

capaDiimes
isbetter.

- ■■' r* A

To get a lot out of a printer, you need a lot of
programs, right?

Wrong,

True, your customers want to change type sizes,
create their own characters, and even print sideways:
But you don't need to stock a lot of different
printer utilities. One simple program will blow all
the others right off your shelf.

Pnrifvvorks. it's loaded.

rlrj

iki Sof tStyle

So.ftStyle. Inc. • 7192 Kalanianaole Hwy • Suite 205
^Honolulu Hia t! 9082f> * Phone (800) 367-5600

$S9.05reto le products are distributed by Softsel and Ingram Software.

Simple Menu Control • Pivot Printing tM lets you print sideways quickly and easily • Prints full IBM character set including Sine graphics, math and science symbols »

Foreign language .characters » Easily set print modes: condensed, emphasized and more* Create new characters or entire fonts • Many fonts included • Supports

thousands of popular software packages including Wordstar, dBase! I and Lotus 1 -2-3.

Printworks enhances over 30 dot-matrix printers. CITOH Prowriter (8510, 1550, 7500 all with the letter "E" included in the model number), CENTRONICS Horizon

(HSQ), EPSON (FX-80/100, RX-80/100, JX-80. LQ-1500, MX-8Q/100 Hi withGraftrax Plus), IBM Graphics Printer, 1NFORUNNER Riteman (Plus, Blue Plus, II, 15),

NE.CPinwriter (P2-3, P3-3), OK DATA (ML 84 Step 2, ML 92 and 93 with or without Plug 'n Play Kit, Pacemark2350 and 2410), and STAR (Gemini 10X/15X, Radix

10/15, Delta 10/ 15). For the IBM PC, PC- XT, PCjr., Compaq and many other IBM compatibles. Needs 128K and DOS 1,1 or later.

Inquiry 284

FEBRUARY 1985 -BYTE 131

THE MAC OFFICE

make them ourselves."

Once the print image has been
completely set in the RAM, the printer
needs to ship it out to the laser ap-
paratus as quickly as possible. That
task is aided by the 68000, which
helps drive the video electronics. The
central processor stores the data in
two FIFO (first-in/first-out) memories.

That scheme allows a minimum
amount of bus contention between
the microprocessor and memory.
Everything on the board is a slave to
the 68000. That flexible architecture
is expoited, for example, by the
margins of the page to be printed.
When the margins move inward, the
frame buffer used for generating the

Each subject is a 3-tape series. The Basics will take you from the beginning and lead you through
dB ASE II commands. You will soon be creating your own databases, editing files, deleting records, etc.
Application Programming will teach you program layouts, loops, structures and so much more. You
will be writing your own programs within hours.

dBASE

#DB125 - THE BASICS

#DB135 - APPLICATION

PROGRAMMING

R :

Coming soon.
dBASE III.
WORDSTAR-
MS-DOS-
CP/M»
LOTUS 123.
MULTIPLAN.

* MultiPlan and MS-DOS are registered trademarks of Microsoft,
Inc. CPM is a registered trademark of Digital Research. Wordstar
is a registered trademark of Micro Pro. dBASE II anddBASE III are
registered trademarks of Ashton-Tate. Lotus 123 is a registered
trademark of Lotus Corp.

VHS-BETA

$14995

BOTH

DB125 & DB135

:°« $279 95

COD, CHECKS, M/O

- ORDER BY PHONE —

Call Toll Free 1-800-624-4525

From California

1-916-546-3371

Western Video
Productions

P.O. Box 2300
8079 N. Lake Blvd.
Kings Beach, CA 95719

bit map is actually reduced in size-
allowing more RAM to cache the
fonts.

The Macintosh has nonvolatile pa-
rameter memory that allows it to
remember certain modifiable control
settings between uses. Apple decided
to further explore that scheme in the
LaserWriter by putting in a 0.5K-byte
EEPROM (electrically erasable pro-
grammable ROM), which is expand-
able to 2K bytes. As Smith points out,
that is "equivalent to 16,000 DIP (dual-
inline package) switches."

The AppleTalk port isn't the only
way to drive the LaserWriter. There is
also a DB2 5 connector with complete-
ly programmable RS-232C protocols.
Adobe indicated that they and others
would provide packages that will use
translators or emulators to drive Tex,
Ttoff. Scribe, and other mainframe-
style composition systems.

What sort of performance does the
built-in computer offer for the Laser-
Writer? According to Smith, when it
is combined with perfect hardware,
the printer is capable of turning out
a page in 6 seconds. With the Apple
controller, "We're expecting a 10-sec-
ond average time per page," he says.

Anything that can be put on the
Macintosh screen can be printed by
the LaserWriter. When you use the
Printer Chooser desk accessory to
select the LaserWriter printer instead
of the ImageWriter, the Macintosh
calls a new printer driver. On the
Macintosh, all screen graphics are
based on QuickDraw routines called
from ROM. Bud TYibble, the Macin-
tosh software manager, says, "The
LaserWriter's strategy is different than
the ImageWriter's. Even though all the
Macintosh's QuickDraw routines are
in ROM, every entry point to Quick-
Draw has a handle on it that allows
us to trap out that call and go some-
place else. That's what happens dur-
ing printing to the LaserWriter driver.
We trap out all the QuickDraw calls,
and when that call comes along, the
system translates it to the equivalent
PostScript call, which ships it over
AppleTalk to the laser printer and
prints out." For now, the printer works

[continued]

132 BYTE • FEBRUARY 1985

Inquiry 329

siajAr—

SPSS SECURITIES, INC.
TRADING ONLINE

1 Place orders

2 Uieu or cancel open orders

3 (lieu conf imations and messages

4 Send m$ws to Spear

Enter itm m«ber or <H>elp* 1

[111111! Hill

111! .
/ /

^l^l^f^l^l WlWt^t^l.^t^\^^wt.^.

Trade over
the counter

Introducing the most complete 24-hour
investment service on the market.

Spear Securities has teamed up with
The Source SM to bring you the most com-
prehensive personal investment service
ever introduced.

Now you can use any personal com-
puter to trade stocks, options or bonds
quickly and inexpensively. Without soft-
ware. But that's not all.

Immediate accessto market intelligence.

If you're going to compete with pro-
fessional investors, you need more than
instant trading. That's why we give you
the ability to analyze and compare thou-
sands of companies. And we provide
immediate access to critical business
news and price changes as they occur.

We even take care of your portfolio up-
dating and record-keeping. And your
account is protected up to $10 million*

Get started for $35 -a-trade.

Between now and February 28, 1985,
most market orders placed with Spear
Securities (up to 1,000 shares) will cost
only $35 each. After that, you'll enjoy our
regular discount rates, which will save
you up t o 70%on stock transactions com-
pared to full -cost broker commissions.

The coupon on the right will get you
all the details. Fast. Our toll-free number
is even faster. Just dial (800) 821-1902.
In California, call (800) 321-6116.

*Combination of SIPC protection and private insurance.
See brochure for details. ^&»w^ Member i

M l NASD L

Available exclusively via The Source k

SPEAR SECURITIES

The Electronic Investment Center

626 Wilshire Boulevard
Los Angeles, CA 9001 7

□ Send me information on how
to trade over the counter.

□ I have a personal computer.

□ I am currently a member of
The Source.

Name

Address

City _

State .

B-2

.Zip .

Spear Securities, a member of the NASD and SIPC, is a wholly owned subsidiary of Investment Resources & Technology, Inc. The Source is a service mark of
Source Telecomputins Corporation, a subsidiary of The Reader's Digest Association, Inc. The Source services are offered in participation with Control Data Corporation.

Inquiry 294

FEBRUARY 1985 -BYTE 133

PREVENT THE DISASTER

OF HEAD CRASH AND

DROPOUT.

The war against dust and dirt
never ends. So before you boot-
up your equipment, and
everytime you replace a
cassette, disk or drive
filter, be sure to use Dust-Off II;
itcounteractsdust, grit and lint.
Otherwise you're flirting with
costly dropouts, head crashes
and downtime.

Dust-Off II is most effective
when used with Stat-Off II. Stat-
Off II neutralizes dust-holding
static electricity while Dust-Off II
blasts loose dust away. There's
also the Dual Extender and Mini-
Vac for vacuuming dust out of
hard-to-reach places.

Photographic professionals
have used Dust-Off brand
products consistently on
their delicate lenses and
expensive cameras for
over ten years. They
know it's the safe, dry,
efficient way to contami
nant-f ree cleaning.

Cleaning not provided by liquid

cleaners.

Dust-Off II's remarkable

pinpoint accuracy zeros in on the

precise area being dusted. And
you have total control — every-
thing from a gentle breeze for

System II

Stat-Off II neutralizes dust-holding
static electricity from media and
machines.

delicate computer mechanisms
to a heavy blast for grimy dirt.
Don't let contamination dis-
rupt your computer operation.
Stock up on Dust-Off II — the ad-
vanced dry cleaning system,
at your local computer or
office supply dealer.

Or send $1.00 (for
postage and handling)
for a 3 oz. trial size and
literature today.

Dust-Offll

The safe dry cleaning system

THE MAC OFFICE

on a first-come, first-serve basis. Later,
the file server will function as a
spooler. (Apple is investigating print
spooling on the Macintosh itself.)

According to nibble, "A page of
QuickDraw calls are translated into
approximately 4K bytes of PostScript
language, which are then shipped
over AppleTalk at ] A megabit per
second— 4K bytes per page is really
no great load compared to the 8
million bits required to represent a full
bit-map page."

Because of this strategy, MacDraw
and MacPaint documents produce dif-
ferent outputs. All of the elements in
MacDraw exist as graphical objects:
a rectangle is stored as a rectangle, a
circle is stored as a mathematical cir-
cle, etc. In MacPaint, all the data
storage takes place on the bit map.
Those 80-dots-per-inch bit maps must
be resolved for the higher-resolution
LaserWriter. So Bill Atkinson devel-
oped a scaling and smoothing pro-
gram that sits in the laser printer itself.

In fact, there is a fairly close corre-
spondence between QuickDraw and
PostScript objects. The Macintosh
downloads into the laser printer a
preamble of PostScript code that
helps it quickly interpret QuickDraw
objects. For example, to paint a
RoundRec (a QuickDraw command),
you would have a RoundRec sub-
routine residing in the LaserWriter.
Half the translation takes place in the
Mac, half in the LaserWriter. Text is
sent as ASCII (American Standard
Code for Information Interchange)
data along with font, orientation, fill,
scaling, and position information.

Apple has built Times Roman,
Courier, Helvetica, and many existing
Macintosh fonts into the LaserWriter,
which handles these fonts intelligent-
ly. For example, once a character is
built it is cached and remembered as
long as possible. Additionally, the
LaserWriter driver in the Macintosh
permits direct generation of Post-
Script commands. Both Adobe and
Apple expect independent devel-
opers to make use of this facility.
Apple reports that there are already
more than 20 active, independent
LaserWriter software projects. ■

Falcon Safety Products, Inc., 106b Bristol Road, Mountainside, NJ 07092
134 BYTE • FEBRUARY 1985

Inquiry III

SIGN-MASTER™

Number 1 in word charts

for presentations and reports

Create powerful head-
lines using SIGN-
MASTER's color, size,
and font options. Here we
chose Bold Roman font.

Highlight a single charac-
ter, word or an entire line
at the touch of a button.
Here we focus attention
on one number with color
and underline.

Indicate source, date, au-
thor, etc. with SIGN-
MASTER's footnote op-
tion. Bold Standard font
was used in this example.

■T HE BOTTOM LINE

PROJECTED EARNINGS
(Millions of $)

'78

'79

'80

'81

'82 A

Sales

86.4

121.0

144.0

163.8

182.0

Net Income

5.9

8.8

11.4

13.4

15.7

ROS(%)

6.9

7.3

7.9

8.2

8.6

Mkt. Share

48%

61%

65%

71%

76%

Capital expenditure required: $5 Million
1 Net present value = $24.25 Million
(opportunity cost of capital = 24%)

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Inquiry 88

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\>'i

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Inquiry 143

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Little Tramp character licensed by Bubbles Inc., s.a.

A program to take

the tedium out of converting

C programs to Pascal

138 BYTE • FEBRUARY 1985

ILLUSTRATED BY WILLIAM LOW

BY TfeD CARNEVALE

^yA o matter how much you
Mim prefer a particular pro-
Wj M^ gramming language, there
W W* are times when it is neces-
sary to use a different one. 1 found
myself in this situation recently after
I had written a graphics subroutine
library in C for the Pixeltronics high-
resolution graphics display board that
uses the NEC 7220 GDC (graphics dis-
play controller) chip. Since the display
was attractive, I decided to incor-
porate the routines into our lab's high-
speed data-acquisition system.

The data-acquisition program,
which controlled A/D (analog-to-
digital) conversion and signal averag-
ing, was compiled with Digital Re-
search's Pascal/MT+ compiler. I chose
this implementation of Pascal
because it supports floating-point
operations using the AMD (Advanced
Micro Devices) 9511 A, a high-per-
formance arithmetic coprocessor that
allows faster on-line data averaging
and scaling, lb run the A/D converter
at top speed, special drivers were
written in assembly language. The
package's weak link was its subroutine
to display data on a nonstorage
oscilloscope, using the D/A (digital-to-
analog) section of the converter
board. The time required to sweep
multiple traces across the oscil-
loscope screen limited the maximum
rate of data acquisition.

It didn't seem practical to rewrite all
of the data conversion software in C
just to use the graphics display. Fur-
thermore, we would have to write new
drivers to use the AMD 951 1 A for
floating-point calculations in C. Worse
yet, the floating-point format and

dynamic range of the AMD 9 5 1 1 A are
radically different from their counter-
parts in our version of C (Software
Toolworks C80 with optional floats
and longs).

For a while 1 considered linking the
rel (relocatable) files produced by C80
(which contain the graphics routines)
to the erl (extended relocatable) files
generated by Pascal/MT+ (which con-
tain the data-conversion routines).
This proved to be especially cumber-
some for two reasons.

First, both of these languages use
the stack to pass parameters to sub-
routines. Pascal/MT+ assumes that
the subroutine will pop the param-
eters from the stack, which has the
side effect of restoring the stack
pointer to its position before the sub-
routine call. However, C80 expects the
calling program to restore the stack
pointer. Therefore, repeated calls
from a Pascal program to C subrou-
tines would make the stack grow
larger and larger, potentially over-
writing vital regions of memory. Cir-
cumventing this problem requires the
crude but effective dodge of inserting
a special "unstack" routine after each
C routine call, so that the stack
pointer would be properly restored.

The second problem is more diffi-
cult to deal with and relates to the fact
that Pascal lacks local static variables.
LIN KMT, the linker for Pascal/ MT+,
issues error messages when it en-
counters certain conditions in the
data segment. Some of my graphics
procedures used local static variables,
and these modules could not be pro-
cessed by LINKMT

In theory this can be overcome by

using LIBMTto convert the Pascal erl
files to rel files and then linking them
to the C80 rel files with Microsoft's
L80. But somehow I could never get
this technique to work right. Even if
L80 could have produced a function-
ing mongrel, it would have been need-
lessly bulky, since the graphics drivers
would have their own arithmetic and
logic routines extracted from the C
library with much needless duplica-
tion of similar functions provided by
the Pascal library. Still, if it had worked
1 would have used it.

Having failed to weld C routines to
Pascal I had to rewrite the graphics
drivers in Pascal. At first this seemed
less awful than it really was. There are
enough similarities between these
two descendants of ALGOL that
major revisions are not necessary for
most simple routines. Many of the re-
quired changes can be done with any
editor using global search/replace
commands. For example, C's block
delimiters { and } are direct counter-
parts of Pascal's begin and end.

This method is fine if you only have
to translate a few short programs, but
it has some major problems other-
wise. Suppose you accidentally re-
place the C comment delimiters /*
and */ with { and } before replacing
the block delimiters with begin and
end? And how about the different
uses of = in C and Pascal? If you re-
place each = with :=, then C's

{continued)
Ted Camevale is an assistant professor of
neurology at the State University of New York
at Stony Brook. He can be reached in care
of the neurology DepL SUNY. Stony Brook,
NY 11794.

FEBRUARY 1985 -BYTE 139

C TO PASCAL

Listing I : The C-to~Pascal program, written for the Software Toolworks C80 compiler.

I* C to Pascal — filter to replace C punctuation and certain key words with
their Pascal equivalents.

C form

{
}
<tab>

II
comment start
comment end

! =

printf '

scant

while

Pascal form

BEGIN

END;

<2 blank spaces >

< nothing >

AND

< >

writeln
read In
WHILE

Usage: ctp <infile >outfile
7

#define EOF - 1
#define EOS \0'

main ()
{

char c,*letter,word[100];
int wordlnth;

letter = word;
wordlnth = 0;
while ((c=getchar()) != EOF) {

if (isalpha(c)) letter[wordlnth + +
else {

if (wordlnth >0) {

letter[wordlnth] =
wtest(word);
wordlnth = 0;

}
ctest(c);

}

•\0';

/* word ready to check */

/* pass or replace it */
/* reset index */

/* process following char */

} /* note: the last word in the file will be missed if it is immediately followed

by EOF with no intervening nonalphanumeric character. This is not a problem for
Pascal or C program sources. However, a general-purpose word filter would have
to check for a nonzero wordlength after EOF is reached. */

wtest(word)
char *word;

char *swapword;

swapword = word;

switch (word[0]) { /* test first letter, then rest of word */

case 'p': if (strcmp(word,"printf\0")= =0) swapword = "writeln\0";

break;
case 's': if (strcmp(word,"scanf\0")= =0) swapword = "readln\0";

break
case 'w': if (strcmp(word,"while\0")= =0) swapword="WHILE\0";

break;
default: break; /* pass unchanged */

[continued)

The C functions printf
and scanf could be
replaced by writeln

and readln.

equality test == becomes : = :=,
<= turns into <:=, and > =
becomes >:=.

You could step manually through
the file, verifying all replacements one
at a time, and this might not take too
long if you have excellent eye-hand
coordination. If you're really good,
you might catch most of the errors
before your compiler does. However,
1 wouldn't even attempt it. 1 was faced
with the task of editing 27 separate
files, totaling about 30 pages of
drivers and test programs to convert
from C to Pascal. After manually
translating three of these to Pascal, 1
decided to write a "filter" that would
do as much of the dirty work as
possible.

The first step in developing this C
program, called CTP.C (see listing 1),
was identifying what substitutions
could by made easily, reasonably, and
safely by an unsupervised, i.e., non-
interactive, program. The C functions
printf and scanf could be replaced by
writeln and readln. Where necessary,
the In suffixes can be deleted manual-
ly at the same time the argument lists
are revised.

The only other word substitution
that 1 made was to capitalize WHILE.
It is a trivial matter to change the pro-
gram to perform case substitutions on
other words (e.g.. for or if). You will
also want to replace switch with case
and delete any case that appears in
the C source. In addition to the block
and comment delimiters, the non-
alphanumeric characters that I de-
cided to replace included tab (re-
placed with two spaces, my own for-
mat preference for Pascal), double
quote, empty pairs of parentheses,
logical "and" (&&), logical "or" (!!), and
the various uses of = .

[continued)

140 BYTE- FEBRUARY 1985

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Inquiry 207

FEBRUARY 1985 -BYTE 141

C TO PASCAL

}

swap(swapword);

ctest(c)

char c;

switch (c) {

case ""

putchar(\ ');
break;

case '{'

swap("BEGIN\0 M );
break;

case '}'

swap("END;\0");
break;

case \t'

swap(" \0");
break;

case '&'

• swapif('&\ '&'," AND \0");
break;

case '|':

swapifCl', T,"OR 0");
break;

case '(':

swapif('C. ')'."\0"); /* () simply deleted 7
break;

case 7':

swapif(7\ l *\"{\0");
break;

case '*'

swapif('*\ 7 , I "}\0");
break;

case '!':

swapif(T, ' = ',"<>\0"); /* != -><>*/
break;

case '<

'•

case ' >

': putchar(c); /* <x and >x are passed unchanged */
c = getchar();
putchar(c);
break;

case ' =

': identassign(); /*==-> = ,= ->:=*/
break;

default:

purchar(c);

}

break;

swap(s)

char *s;
{

}

swapif(fi

while (*;

s! = EOS) putchar(*s + + );

rst.second

.replacement)

char first,second,*

replacement;

char c;

if ((c = getchar()) = = second) swap(replacement);

else {

putchar(first);

}

putchar(c);

}
identassign()

char c;

if ((c= getchar())! =' = '){ /* assignment */

putchar(':');

putcharC = ');

}

f
putchar(

c)'

The next question was how to per-
form the substitutions. I decided the
program should read through the file
one character at a time, building
words and testing them one at a time,
while checking nonalphanumeric
characters for any necessary replace-
ments. For my purposes, I defined a
word as a string of alphanumeric char-
acters bounded by nonalphanumeric
characters (including underline and
numerals). This convention places
restrictions on the labels that can be
used in a program. For instance,
printfl would change into writelnl,

and new scanf would become

new readln. If you use reasonable

prudence in choosing names, you will
avoid such undesired side effects.

An array of type char is used for
temporary storage of each word. This
array is arbitrarily much longer than
any variable, function, or constant
label that I am ever likely to use.
Words are built one character at a
time, starting with the first alpha-
numeric character encountered. The
appearance of a nonalphanumeric
character signals the end of each
word. An index variable keeps track
of the length of the word, and a
pointer indicates the location for the
next character.

When a nonalphanumeric character
is found, the length of the word is ex-
amined. If the word length is nonzero,
the program branches to a string com-
parison and conditional replacement
routine. This routine handles each
word in a similar fashion. It seemed
easiest to use C80's strcmp (string
compare) function to identify replace-
able words. This function is not dif-
ficult to simulate if it is lacking from
any particular C implementation.

Nonalphanumeric characters are
treated in a somewhat different man-
ner. Some, like tab or ", are simply re-
placed directly. Others, like / or &, are
replaced only if followed by a second
character such as * or another &, re-
spectively. The various = constructs
are all handled differently.

For the sake of convenience, 1 used
a UNIX-like command-line specifica-
tion for input and output filenames.

{continued)

142 BYTE- FEBRUARY 1985

^ V

Networking Raised to a
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This means that instead of spending $3,000 per worksta-
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Although designed to take advantage of the AT, MultiLink
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Inquiry 287

MultiLink Advanced M &
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of The Software Link, Inc.

C TO PASCAL

Listing 2: Sample output of the CTRC program, a partial processing of the
programs own source file.

#define EOF - 1
#define EOS \0'

main
BEGIN

char c,*letter,word[100];

int wordlnth;

letter: = word;
wordlnth: = 0;

WHILE ((c: = getchar) < > EOF) BEGIN
if (isalpha(c)) letter[wordlnth + +]: = c;
else BEGIN
if (wordlnth >0) BEGIN { word ready to check }
letter[wordlnth]: = \0'\
wtest(word); { pass or replace it }
wordlnth: = 0; { reset index }
END;

ctest(c); { process following char }
END;
END;
END;

The typical command line reads
CTP <INFILE.XXX >OUTFILEYYY

Listing 1 is my current version of
CTRC Listing 2 is part of the file
CTRPAS produced by using CTP to
process itself.

This filter program was designed to
perform simple substitutions. It
passes #define, #ifdef, and #include
statements unchanged. It does not
label functions or procedures,
generate type definitions, reorganize
variable declarations, or perform
other radical alterations. Nor does it
eliminate the need for program re-
structuring to compensate for major
differences between C and Pascal (the
lack of local static variables in Pascal
being one of the more annoying prob-
lems). However, it does remove most
of the error-prone aspects of building
a Pascal program on the framework
of a C program. ■

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144 BYTE • FEBRUARY 1985

Inquiry 15

Think BEFORE YOUR NEXT PC!

Your PC to Time Sharing System
KT-7/PC

Why buy

' 'ADDITIONAL EXPENSIVE PC'S 5 '

just to get additional users!

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-^ Santa Clara CA 95050
= 408-727-1510 TWX : 910-338-0237

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Inquiry 171

Revelation. Because the object is to win.

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Inquiry 75

COSMOS

Seattle, WA 98188, (206) 824-9942

by Don Stauffer

SIMULATE A

SERVO

SYSTEM

Letting the computer
handle the math eases the designer's job

A servo mechanism is essentially a small motor that controls a larger motor.
A servo-control system consists of the logical instructions needed to guide
the servo mechanism. Control systems were brought out of the laboratory
and into practical use about the time guided missiles were developed for
World War II. The original vacuum-tube type was big, heavy, and expen-
sive, but integrated-circuit (IC) technology has reduced the size of control-
system technology as well as others. Now. almost the entire servo-control
electronics package fits into a single IC, as in present model-airplane radio-
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tools.

A reduction in the size and cost of servo-control systems, however, has
not reduced their complexity. The design of servo-control systems remains
one of the most intricate of the electrical engineering sciences. However,
the computer's simulation ability has simplified the designer's job. Simula-
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computers.

As an example, let's design an electronic weighing scale. Figure I is an
illustration of how such a scale would be arranged. A balance beam forms
the main part of the scale, along with the weight pan on the left. On the
right side, instead of the normal balance weights, we attach a solenoid.
The solenoid is designed so that the pull on the solenoid armature is directly
proportional to the current in the coil. A sensor, such as a low- [continued)

Don Stauffer is a senior research scientist at Honeywell Systems and Research who
went from building model airplanes from balsa wood to modeling advanced avionics systems
on computers. He can be reached at 674H57tA lane NW. Anoka, MN 55303.

FEBRUARY 1985 'BYTE 147

SERVO SYSTEM

friction potentiometer, forms an error
detector that gives a voltage propor-
tional to the angle by which the scale
is out of balance. The servo-control
system uses this error signal to
change the current through the sole-
noid to eliminate the imbalance. The
current in the solenoid coil is now pro-
portional to the weight in the pan, and
a current meter is calibrated to read
in weight units.

Figure 2 is the type of diagram a
designer would draw for this kind of
feedback servo-control system. The
circle at the left represents a summing
junction. The output to the right of the
junction is the sum of the inputs to the
other two (or three) quadrants. As
shown here, the junction indicates the
difference between the commanded
or desired quantity, Q c . and the actual
quantity, Q. The servo-control com-
puter operates on this difference and
outputs a voltage to the actuator. The
actuator is a physical device usually
a force transducer that drives the

quantity to be controlled either up or
down so that the actual value equals
the desired value. At this point the
system is balanced, and the error
signal (or feedback) will remain at
zero unless some perturbing force
displaces the system or a new input
value is commanded.

A servo-control designer is con-
cerned with several aspects of the sys-
tem's behavior. First and foremost is
stability. That is, does the system in-
deed act to reduce the error, and not,
as servo-control systems have a habit
of doing, actually cause the error to
increase wildly? How soon will the
system reach a new equilibrium? If it
takes too long to settle down, the sys-
tem may not be usable in practice. Is
the amount of error that remains after
the system reaches a new equilibrium
sufficiently small? Ideally, you'll have
no error but in practice you'll prob-
ably have some and will have to
decide if it is tolerable.

Without simulation you have to use

L°J

•

SERVO
CONTROLLER

*sr

* — »

[SOLENOID

V c

\JA

ERROR

(IMBALANC
DETECT

,E)
OR

-V

Figure I : The servo system holds the balance beam level.

INPUT
COMMAND

*(P\

CONTROL
COMPUTER

ACTUATOR

r Q ~

«Sfr/

FEE

DBACK

complicated differential equations to
try to predict a mechanism's behavior.
Computer-based simulation does the
math for you. In addition, simulation
lets you design more complex servos,
whose behavior could not be pre-
dicted easily by normal differential
equation methods. Figure 3 charts a
typical simulation. After setting the
initial conditions, the program enters
the iterative loop (input, model, out-
put, update). It scans user or process
input to see if conditions are to be
changed. If the simulation is sup-
posed to be continuous, such as the
physical simulation we will be work-
ing with, input is best done with a
keyboard-monitoring routine to keep
the program running between inputs.
The heart of the simulation is the next
step— the math model. In this block,
the computer performs its mathe-
matical operations on the equation
that describes the system being
simulated. Almost any system or

[continued)

Figure 2: A servo system operates by measuring the difference between the
commanded and actual values of some quantity and uses a function of that difference
to drive an error-reducing actuator.

f START J

INITIALIZATION

PROCESS
INPUTS

MATH
MODEL

DISPLAY

OUTPUT

UPDATE
TIME

HED J>
YES

C END j

Figure 3: A typical simulation-program
flowchart.

148 BYTE • FEBRUARY 1985

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SERVO SYSTEM

situation that can be mathematically
described in a cause-and-effect rela-
tionship can be simulated by a com-
puter. Next, the program displays or
prints an output. Then the time vari-

able is incremented and, if the pro-
gram is not terminated by some con-
dition that exceeds its limits, the pro-
gram repeats.

{continued)

Listing I: Tfe program is written in TRS-80 Level II BASIC but can be adapted
to any of the BASIC dialects.

10 REM SCALE SERVO CONTROLLER

20 REM by Don Stauffer

30 CLEAR 200

40 REM EDIT ASSIGNMENT STATEMENTS TO ALTER CONTROL CONSTANTS

50 PR =
60 TH =
70TM=0
80 W =
90 JS = 5
100 D = 5
110 K=10
120 K1 = -0.4
130 K2 =
140 K3 =
150 DT = 0.2
160 T =
170ST =

REM
REM
REM
REM
REM
REM
REM

PRINT CONTROL VARIABLE

SCALE BALANCE BEAM ANGLE
BEAM ANGLE DURING LAST ITERATION
INITIAL WEIGHT IN PAN
BEAM MOMENT OF INERTIA
DISTANCE FROM PIVOT TO WEIGHT OR SOLENOID
SCALE FACTOR, SOLENOID CURRENT TO FORCE
: REM PROPORTIONAL SERVO CONSTANT

REM RATE SERVO CONSTANT

REM LAG SERVO CONSTANT

REM TIME INCREMENT

REM INITIAL TIME
REM STOP PARAMETER
180 REM BEGIN SIMULATION LOOP
190 IF PR > 1.5 GOSUB 5000
200 REM CHECK FOR INPUT
210 GOSUB 1000

220 REM COMPUTE CONTROL FORCE
230 GOSUB 2000
240 REM COMPUTE MOTION
250 GOSUB 3000

260 REM DISPLAY AND PRINT OUTPUT
270 GOSUB 4000
280 REM UPDATE TIME
290 T = T+DT
300 IF ST< 0.5 THEN 200
310 STOP

1000 'CHECK FOR INPUT
1010 IF PEEK(1 4400) =128 THEN GOTO 1010
1020 IF PEEK(14340) = 8 THEN ST=1
1030 IF PEEK(1 4340)<> 128 THEN RETURN
1040 PRINT@65," ";
1050 INPUT"CHANGE WEIGHT";W
1060 IF W<0 THEN W =
1070 RETURN

2000 REM COMPUTE CONTROL CURRENT
2010 ER = TH

2020 IF ER<-10THEN ER=-10 ELSE IF ER>10.0 ER=10.0
2030 I = K2*(TH - TM)/DT + K1 * ER + K3*(ER + EM)
2040EM = ER
2050 RETURN
3000TM = TH
3010 J=JS + W*D[2
3020 F = K*I
3030 LC = F*D
3040 LW = W*D
3050 AA = (LC-LW)/J
3060 WD = WD + AA*DT
3070 TH=TH + WD*DT

[continued)

150 BYTE • FEBRUARY 1985

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FEBRUARY 1985 -BYTE 151

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SERVO SYSTEM

3080 IF TH<-10THENTH= -10 ELSE FTH>10THEN TH = 10

3090 RETURN

4000 CLS

4010 PRINT"ACTUAL WEIGHT= ";W

4020 PRINT@384 1 "TIME", "ANGLE", "CURRENT'V'WEIGHT"

4030 PRINT@448 I T,TH,I,F

4040 IF PR<0.5 THEN RETURN

4045 IF PR> 1.5 GOTO 4080

4050 LPRINT T,W

4060 LPRINT AA.WD.TH.F

4070 RETURN

4080 NF = T:NI = INT(NF): RX = NF-NI

4090 IF (RX<DT) THEN LPRINT CHR$(51); ELSE LPRINT CHR$(54);

4100 PP = 10*F:IFPP<2THEN PP = 2

4110 IF PP> 134 THEN PP=134

4120 IF PP = 134 THEN CH = 74 ELSECH = 47

4130 NS=PP-2:IF NS<0 THEN NS =

4135 FOR NZ = 1 TO NS:LPRINT CHR$(88);:NEXT

4140 LPRINT SP$;CHR$(CH)

4150 RETURN

5000 LPRINT CHR$(27)CHR$(81):LPRINT CHR$(27)CHR$(84);"12"

5010 LPRINT CHR$(27)CHR$(35)

5020 FOR N = 1 TO 135

5030 NF = N/10:NI = INT(NF):RX = NF-NI

5040 IF (RX<1E-2) THEN LRPINT CHR$(49); ELSE LPRINT CHR$(53);

5050 NEXT N

5055 LPRINT CHR$(10)

5060 RETURN

The program shown in listing 1
follows this flowchart closely. The pro-
gram is written in TRS-80 Level II
BASIC, but I have attempted to use as
few nonstandard instructions as possi-
ble. You can adapt this program to
any of the BASIC dialects (see the text
box "Program Changes" on page 153,
for more information). Lines 50-170
set the physical constants' values and
give initial values to variables. The
stop variable ST (in line 170) is used
to terminate the program upon com-
mand. The program must be edited
to change the values of any of the
constants except weight, which can be
changed by the operator. PR is a vari-
able printout control. PR = results
in no hard copy, PR = 1 gives you a
tabular list of the variables shown on
the screen, and PR = 2 gives a graphic
trace of the indicated weight. Line
5000, referenced if PR > 1.5, is used
to set up the scale of the printer and
to print an axis.

Line 200 is where the main loop
begins. Line 1 000 looks for a user in-
put. If you press the W key, the pro-
gram stops and expects a new value
for the weight on the pan. The S key

and the space bar also have functions,
which I'll describe later. The sub-
routine starting on line 2000 is the
math model of the control computer
block in figure 2. We will be able to
understand this block better after we
begin to play with the servo simula-
tion. The subroutine that begins at
line 3000 is also part of the math
model and represents the physics of
our scale. It represents Newton's sec-
ond law of motion as applied to
rotating systems. (The text box
"Physics Math Model" on page 153
has more details about the mathe-
matical model of our scale.) The force
applied to the solenoid equals the
current after it is multiplied by a scale
factor (line 3020). Tbrque is equal to
the product of a force (F) multiplied
by a distance (D), so the torque in the
beam is equal to the product of F
multiplied by D (line 3030). Assume
that the distance from the pivot to the
weight is the same as that from the
pivot to the solenoid, so line 3040 cal-
culates the torque due to the weight.
Therefore, line 3050 determines the
angular acceleration by finding the
net difference between the torque

152 BYTE • FEBRUARY 1985

SERVO SYSTEM

due to the weight and the torque due
to the solenoid current, and then that
net difference is divided by the mo-
ment of inertia. Lines 3050 and 3060
integrate the acceleration to angular
velocity and angle.

The subroutine starting at line 4000
displays the output on the screen. The
program displays elapsed time, the
deflection angle, the solenoid current,
and the indicated weight. For refer-
ence, the actual weight is also dis-
played in the upper left corner. If a
hard copy is desired (PR equal to or
greater than 1 ), the print routine con-
tinues. Lines 4050-4070 output the
table, and the graphic output is begun
by the command at line 4080. The
table output routine slows down ex-
ecution considerably, so don't use it
unless you find an interesting case. If
you don't want a hard copy, the sub-
routine returns to the main program.
If you haven't set the stop variable, the
program loops back to line 200 and
continues.

The subroutine starting at line 5000
scales the characters per inch in both
directions and draws an axis. In opera-
tion, the graph is drawn vertically
down the paper. (The values given are
those needed with a C. Itoh ProWriter.)
Other printers will require different
values in lines 5000 and 5010. Line
5000 puts the ProWriter in condensed
(17 characters per inch) mode and
sets the vertical feed to 12 lines per
inch. You can set these values to any
you like. Line 5010 puts the printer
into the graphics mode. Be fore-
warned: The program does not take
the printer out of the graphics mode.
You have to do it manually.

You usually start the program with
no weight on the pan (W = 0). Press-
ing the W key for about one second
stops the problem and the computer
will prompt you for the value of
weight you want to add. The scale will
work well with any weight less than 10
units. Other keys include the S key,
which will stop the program (you can
also hit the Break key) and the space
bar, which freezes the operation for
as long as you hold it down. You have
to edit the program to alter the servo-
control constants, the physical param-

eters of the scale, or the printout com-
mand. I recommend that you avoid
printing anything until you have a
setup you really want to document.
The printer slows down the simula-
tion; especially when you call for
graphics. In fact, while the computer
is executing the subroutine that does
the scaling (line 5000), expect a

lengthy pause. After several seconds
the normal screen and simulation will
appear.

Servo Theory

After typing in the program with the
values given in listing I, go ahead and
run it to see that it works. Don't worry

{continued)

Program Changes

The BASIC I used in this program
is Radio Shack Level II BASIC, but
you can easily convert the program to
other computers. I minimized com-
mands unique to the Level II inter-
preter. The CLEAR command in line
30 clears for string space and is
needed only for the graphic print op-
tion. The keyboard-scanning routine in
lines 1010 to 1030 checks the keyboard
for depressed keys. Using a normal IN-
PUT statement would stop the pro-
gram once every iteration, while we
want the program to continue. The
PEEKs look at the memory area of the
memory-mapped TRS-80 keyboard.
The Apple should use the same tech-
nique, although the memory locations
will be different. Line 1010 looks for the
space bar and freezes the program for
as long as that key is depressed. Line
1020 looks for the S key. Line 1030
looks for the W key. For the Com-

modore 64 use the GET command.

The other main thing to watch for is
the manner in which an output is sent
to a line printer. If no printer is used.
PR in line 50 will always be set to zero,
and no changes are required. If a
printer is used with another computer,
however, modifications must be made.
The TRS-80 merely uses the command
LPRINT followed by the desired out-
puts, as in line 4050. For Apples,
change all LPRINTs to PRINTs,
precede each one with a PR#1. and
follow it with a PR#0. For the Com-
modore 64, you must use the OPEN
command before each output to the
printer, followed by an OPEN 1,3 to
return the output to the screen.

The other area of the program you
may need to modify contains the
graphics commands to printers other
than the ProWriter. These parameters
are discussed in the main text.

Physics Math Model

The code in lines 3000-3090 is a
mathematical model of the
physics of our scale. The scale operates
according to Newton's second law of
motion, but it is expressed in a form
for angular motion, which may make
it seem a little unfamiliar. Newton's sec-
ond law is ordinarily expressed as:
F=MA. For rotary or angular motion,
however, it is expressed as: AA=L/J,
where AA is the angular acceleration
(degrees per second squared), L is the
net torque (difference between the
torques in opposite direction), and J is
the moment of inertia. Moment of in-
ertia is the resistance to a change in
rotation and is the rotary equivalent of
mass. The moment of inertia is a func-

tion of the beam's structure and of the
weight added to the pan (line 3010),
Ibrque equals force times distance. For
our scale, we assume that the distance
between the weight and the pivot is the
same as the distance between the pivot
and the point where the solenoid ap-
plies its force. Thus, line 3030 repre-
sents the torque generated by the sole-
noid, while 3040 represents the torque
from the applied weight. Line 3050 cal-
culates the angular acceleration. Line
3060 integrates the acceleration to find
the angular velocity; 3070 integrates
once more to find the angle. Line 3080
represents mechanical stops that pre-
vent the beam from rotating more than
10 degrees in either direction.

FEBRUARY 1985 'BYTE 153

■ ■ N,

SPERRY PERSONAL COMPUTER

SPECIFICATIONS

OPERATING

KEYBOARD /

SYSTEM

84 keys, 6 ft. cord \

MS DOS Version

AUXILIARY

2.11 with

MEMORY

G.W. BASIC

Up to two internal

MICRO-

5%" diskettes

PROCESSOR

10MB internal

16-bit 8088

fixed disk when

DISPLAY

configured with

SCREENS

single diskette.

High Definition

USER MEMORY

monochrome

Standard 128K

display IBM com-

bytes, expandable

patible graphics.

to 640K

COMMUNI-

DIAGNOSTICS

CATIONS

Power-on self test

Built-in

1 Asynchronous

©Sperry Corporation, 1984

IBM is a registered trademark of International Business Machines Corporation.

MS DOS is a registered trademark of Microsoft Corporation.

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SERVO SYSTEM

about making sense out of the Simula- simple form of servo controller. This

tion yet. Before we do any experi- is known among servo designers as

ments, let's look at some elementary a proportional control system. The

servo theory. Figure 4 shows the most controller merely takes the error

Oc-

K1(Q C -Q)

ACTUATOR

f ^ CONTROLLED

q " VARIABLE

Figure 4\ \n a proportional control system, the error between the actual and the
commanded value is multiplied by a gain constant to drive the actuator.

6 8 10 12

TIME (IN SECONDS)

Figure 5: Continuous oscillation is a common feature of a proportional control system
with no damping.

— &)—

K1(Q C -Q>

ACTUATOR

A+A

^^^

* K2Q

Figure 6: A proportional-plus-rate system uses the output variables rate of change as
part of the control calculation.

signal (Q c -Q) and multiplies it by a
constant, known as the "gain con-
stant." In our example, we want the
angle of the scale to be zero. Thus, the
commanded value of Q (Q e ) will
always be zero, and our error is always
equal to -Q, where Q is the scale's
actual angle. The output signal to the
actuator and, as mentioned previous-
ly, the restoring force on the scale are
proportional to the error.

Now consider for a moment how
you want your scale to act. Obvious-
ly the weight readout should be close
to the actual weight in the pan. There
are other desirable features, too.
Beam balances seem to take forever
to settle down and show whether they
are indeed in balance. Electronic
scales can also exhibit such oscilla-
tions, so we would like ours to settle
down quickly Additionally, if the scale
comes to rest with the beam not level,
there may be an inaccuracy. With
these three criteria, let's run the pro-
gram with the initial values from listing
1 and see how the scale performs.

As we start out, the scale is in
balance and everything stays at rest
with the scale at zero angle. Now
press the W key until you see the
prompt for weight. Type in a value,
such as 5.0. This adds 5 ounces to the
scale. The scale is now out of balance,
and the beam swings to a negative
angle. The control system senses this
angular error and increases the
solenoid current. This attracts the
beam and slows it down. Now the
current-generated force exceeds the
weight, and the beam's angle moves
back toward zero. When this happens,
the solenoid shuts off the current and
the cycle repeats. We have built a
good oscillator. Our simulation will
continue to oscillate like this forever.
Figure 5 is a plot of a cycle of this con-
dition. Stop the program now, as it is
neither exciting nor instructive
beyond this point. Pivot friction in an
actual scale would eventually reduce
these oscillations. However, it would
take a long time and its effect would
be small in a well-built scale. Conse-
quently, I left friction out of my simula-
tion model. Playing with the value of
K\ will affect the period of the oscilla-

156 BYTE- FEBRUARY 1985

SERVO SYSTEM

tion but won't eliminate it.

The way the servo designer elimi-
nates eternal oscillation is to add
"rate damping" to the system. Figure
6 shows a proportional-plus-rate sys-
tem. The symbol O with a dot over it
(pronounced "Q dot") represents O's
rate of change over time. Again, O is
our controlled variable, the angle of
the scale. In calculus, this is the time
derivative. We add rate damping to
our system by setting K2 to some non-

zero value. Try a value of -4 in line
130 and run the program again.
Figure 7 shows a typical result. Now
we have reduced most of the oscilla-
tion, although a small amount of ex-
cess motion remains. The excess mo-
tion eventually stops, but the speed
at which it stops is sluggish. The scale
could almost be considered practical
now. However, in addition to the slug-
gish response and the excess motion,

[continued)

■

o
uj 6

F-

■

.../''.•.'.,

I 4

Xr« > *• -*. v *%- ■■

fe^ > ""

weight/

ADDED 1

, 1 t 1 1 1 1 -J

I l _l

6 8 10 12
TIME (IN SECONDS)

Figure 7: The addition of rate-of -change feedback creates a damped oscillation.

— ®—

K1(Q C -Q)

K2Q

\+X J *■

K3/Q

ACTUATOR

Figure 8: The addition of a quantity proportional to the integral of the controlled
quantity reduces error when the system reaches equilibrium.

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FEBRUARY 1985 -BYTE 157

ERG/68000

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SERVO SYSTEM

WEIGHT

^ADDED
i i i i ii

i i i i i i i

6 8

TIME (IN SECONDS)

Figure 9: The integral partially offsets the effect of rate damping so you get quicker
response and some overshoot, which is quickly damped out. You can't see the reduction
of the weight beam's angular error in this plot of indicated weight versus time, but
including the integral Q increases the scale's accuracy.

we have another problem. As the sys-
tem approaches equilibrium, we still
have an angle error of about 1 degree.
This is not drastic, but we can do
much better.

Specifically, we will add yet another
block to the system (shown in figure
8) and create a proportional-plus-rate-
plus-integral, or proportional-plus-
rate-plus-lag, system. Although this is
beginning to look like a formidable
circuit, don't be dismayed. This is as
complicated as it gets. We can create
a proportional-plus-rate-plus-lag servo
by changing Ki to a nonzero value.
Try a -3 for K3 in line 140 and run
the system again. We've speeded up
the response and increased the ex-
cess motion. But as the system damps
out, we see that a greatly reduced
angle is obtained. Since an increase
in K2 reduced the excess motion
before, let's try increasing it again, this
time to -8. Now that's more like it.
Although there is still some excess
motion, it quickly stops (see figure 9).

The reading reaches equilibrium in a
few seconds, and the angular error is
less than one-tenth of a degree. You
can improve your results even more
by further refining K2 and K3. We
have now designed a practical servo-
controlled scale that is stable and
becomes quiescent with reasonable
speed. Play around with the system.
As with any computer simulation, you
can't hurt anything. If you want to see
things really go awry, try putting in a
value for any of the three servo con-
stants with the opposite sign.

This simplified simulation illustrates
much of the behavior of the typical
servo system. You can easily modify
the program to represent a speed-
control servo (e.g., an automobile's
cruise control). The professional engi-
neer must still dabble in the realms
of complex variables, nonlinear dif-
ferential equations, and other forms
of higher math, but simulations
similar to this one are revolutionizing
the design of servo systems. ■

158 BYTE • FEBRUARY 1985

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FEBRUARY 1985 -BYTE 159

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162 BYTE- FEBRUARY 1985

Inquiry 103

INTRODUCTION TO

IMAGE

PROCESSING

IMAGE PROCESSING, or I/P as it is often
abbreviated is a branch of computer
graphics based on image data— the
pieces that make up a picture. In
essence, image processing is a special
form of two-dimensional (and sometimes
three-dimensional) signal processing.
Scenes are developed from a camera-like
sensor, either a conventional film-based
system or a scanner, and manipulated so
that they provide more information. I'd

Image

manipulation

reveals hidden

information

ike to show
just how common I/P is and describe some of its fun-
damentals.

Image processing is a powerful suite of techniques
for uncovering information. Some of the techniques
are comparable to photographic darkroom processes,
but much more is involved. The principal idea behind
image processing is to make an image more infor-
mative, or, in communications jargon, to extract more
signal from the noise.

Commercial television has trouble displaying more
than a dozen different gray levels. The human eye can
perceive more levels of gray but not many. If you need
to be able to distinguish between shades of gray that
are finer than you can see, you enter the realm where
image processing can help. A black-and-white image-
processing system can usually distinguish at least 32
gray shades.

Typically, computer systems treat images as arrays,
or series of elements. The number of elements in an
array determines the resolution of the image, and the
number of bits available to any element of the array
(or word size) determines the number of "colors" or
gray-scale values each element can have. The smallest
element of a picture corresponds to a single element
of the data array. This element is called a pixel, an ab-
breviation for picture element. Popular choices for the
number of pixels in an image are either based on
powers of 2 (2 56 by 256, 512 by 512, or 1024 by 1024)
or on hardware standards like the gy

52 5-line commercial television system. , y Q

The number of bits in a given pixel JEFFREY L. bTAR
determines the number of unique gray b-^— mm

values or colors available. Eight-bit pixels
provide 2 56 different gray values in black
and white or 2 56 unique colors. Most
larger systems have 24-bit pixels— 8 bits
each for red, green, and blue— which
translates into over 16 million unique
colors. That many colors is more than
one can display on a monitor, and cer-
„_„ tainly more than you can distinguish
visually.
At least three standard systems are used to describe
color. (See reference 2 for more background on color
theory.) The additive system works by considering the
amount of red, green, and blue light you would have
to add together to create a specific color. Color televi-
sion works precisely this way. If you take a close look
at a color television or video monitor screen, you'll
see triplets of colored dots. Each triplet contains a
dot of each of the additive primary colors, red, green,
and blue. This triplet represents the single pixel, the
smallest element in the picture whose color you can
specify. Similarly, I/P systems are almost always based
on the red-green-blue additive system.

In contrast, when you're mixing paint, you mix the
subtractive primary colors. The subtractive primary
colors are cyan, magenta, and yellow.

Finally, human visual perception is often parame-
terized by hue, saturation, and intensity (or value). Hue
is the simplest to understand; it is the "color" or domi-
nant wavelength you see, for example, red versus
green. Saturation, sometimes called purity, is easy to
think of in terms of mixing white into a pure color.
Red and pink are the same hue, but they differ in
saturation— red is more saturated than pink. Intensity
(or value) is the relativetive brightness of a color.
When the relative brightness of a color. When you
view a red wall with the sun shining brightly on it and
then when the light is dim, the difference in "reds"
appears only in intensity. {continued)

Dr. Jeffrey L. Star is a development engineer at
the Remote Sensing Research Unit, Department
of Geography, University of California, Santa
Barbara. CA 93106.

FEBRUARY 1985 "BYTE 163

Since all three of these systems are alter-
native ways of describing colon you might ex-
pect that you could freely convert (or "trans-
form") between them, and you'd be right (see
references 2 and 3). From here on, however,
I'll be discussing the red-green-blue additive
system.

Photo la:

Color composite

image of southern

California
by NASA landsat
Thermatic Mapper.

Imaging in Action

My particular area of interest is image processing for
satellite remote sensing. Several U.S. federal agencies, in
particular NASA (National Aeronautics and Space Ad-
ministration) and NOAA (National Oceanic and Atmo-
spheric Administration), fly satellites with imaging sensors.

NASA's Landsat 5 is the most interesting such satellite
now in operation. Landsat has two imaging systems: the
Multispectral Scanner (MSS) and the Thematic Mapper
(TM). Both are multiband imaging systems. Because of
their fields of view and the satellite's orbital parameters,
they cover the globe between latitudes 80 north and 80
south about every 18 days. Ground resolution for MSS is
approximately 80 meters (that is, each pixel represents
an area on the ground that is 80 meters on a side). For
TM, ground resolution is approximately 30 meters. (Data
from these sensors is available to the public from NASA.
Ask for The landsat Tutorial Workbook: Basics of Satellite Remote
Sensing: see reference 6.)

Photo 1 comes from the NASA Landsat TM, showing
a portion of southern California at the edge of the Salton
Sea. The different colors correspond to rock type, and the
San Andreas and associated faults run generally parallel
to the shore. The image in photo la is a multiband color
composite, produced as if several cameras with different
filters were providing distinct information on the same
scene. The image in photo lb is pseudocolor processed
(see explanation below). Photos 2a and 2b are from the
Landsat MSS.

I/P Systems and Software

Systems for image processing range over almost all of the
computer field— from Apples and IBM Personal Com-
puters (PCs), through small minicomputers, to mainframe
installations. While small PDP-I Is have been the standard
in the past, the Motorola 68000 microprocessor and DEC
VAX systems seem to be the emerging standards. The fol-

lowing are a few of the commercially avail-
able systems.

ApplePIPS, for the Apple II with Apple
DOS 3 . 3, and MicroPIPS, for the IBM PC with
PC-DOS 2.0, are available from The Telesys
Group Inc., Columbia, Maryland, at a cost of
^^^^_ $495 each. These packages come with dem-
onstration Landsat satellite data and are an
excellent way to learn the rudiments of image
processing. Classification (see definition below) and other
higher mathematical functions are included in an ad-
vanced version of the software.

RIPS (Remote Image Processing System, Spectral Data
Corp., Hauppauge, New York) is a Z80, S-100 bus 8-inch
CP/M system with a 2 5 6- by 2 40- by 1 2-bit image memory.
The base price is under $20,000 for the complete system.
Software packages cover a broad range of applications.
RIPS will process satellite data that the EROS Data Center
(Sioux Falls, South Dakota) now supplies on 8-inch floppy
disks. Upgrades include video input and a 9-track tape
drive.

The IIS Model 75 (International Imaging Systems,
Milpitas, California) and COMTAL/3M Vision One (COM-
TAL/3M, Altadena, California) are dedicated image-
processing systems that include display memory, a video
processor, a parallel interface to a computer, a track ball
and function pad, digital-to-analog (D/A) converters, and
a comprehensive software library. A typical small system
as a peripheral to another computer might cost $50,000,
and upgrades include a Motorola 68000 or DEC PDP-11
embedded microcomputer, with Winchester and 9-track
magnetic-tape storage. These systems are typically used
at universities and research agencies.

The only specialized hardware you must have for im-
age processing is a display driver and a monitor, although
when performance or image quality is important a great
deal of specialized equipment is available. Among the
components of display drivers are frame buffers, D/A con-
verters, and lookup tables.

A frame buffer is the key to any image-processing system.
This bank of memory stores the image data. Most
medium-size systems use several banks of 512 by 512
elements; in I/P jargon, the rows of the frame-buffer matrix
are the lines of the image, and the columns are the samples
along each line. A typical choice for a color I/P system

164 BYTE • FEBRUARY 1985

is to have four memory banks or channels-
one each for red, green, and blue, and a
fourth for intermediate calculations and
superposition of graphics and annotation.

Frame buffers and their associated control
circuitry can get complicated. Some systems
give you an option to segment memory on ^^^^^^
the fly. For example, a given system can have
128K bytes of image memory, and you could
configure it as either 512 by 512 by 4 bits (16 colors), or
1024 by 1024 by I bit (black versus white), or 2 56 by 256
by 16 bits (64 kilocolors). Often, a system implements
zoom and pan, which let you expand a smaller area in
the image space to cover the entire display You can ac-
complish zoom most easily by pixel replication; for any
original pixel, the system displays a 2-pixel by 2-pixel
square on the screen. This procedure provides a twofold
magnification of any linear feature, and, of course, a four-
fold reduction in the area displayed.

A digital-to-analog converter transforms the contents of the
image memory into a form compatible with your moni-
tor. The number of different intensity levels that a D/A con-
verter can output is related to the number of bits it is de-
signed to handle; the more bits, the more distinct colors
or gray levels it can produce. Few systems use D/A con-
verters with more than 8 bits of resolution. As mentioned
earlier, for a full-color system this arrangement translates
into 8 bits on each of three channels (red, green, and blue),
a total of 24 bits of color information per pixel, or over
16 million unique colors. The outputs of the D/A converters
are generally formatted to either a standard RS-I70 com-
posite video or, in higher-resolution systems, sent to the
display via separate R, G, and B (red, green, and blue)
cables.

A lookup table is an important part of an image-processing
system and, like other lookup tables in the computer field,
it is a table of stored data for reference purposes. The
lookup table performs mapping between each unique in-
put data value and some predefined output value. Appli-
cations include color or density mapping and calculations
that must be performed rapidly You could also use a
lookup table to assign any particular value in image mem-
ory to any arbitrarily displayed color; this method of color
determination is pseudocolor processing (more later). You
could also use a lookup table to change the contrast range

Photo lb:

Pseudocolor

processing highlights

specific features

of the image.

of a displayed image by setting up the table
with a nonlinear transformation between in-
put and output gray values; this adjustment
of range can make the output intensities
more distinct from one another or compen-
sate for a nonlinear film emulsion or an elec-
^^^^_ tronic sensor response. In the same way, you
could use the lookup tables, for example, to
take square roots of the image values. This
capability is particularly valuable if you are using the data
in the image in a mathematical model or a statistical
classification. You can then "recycle" the output of the
lookup table back into a memory plane, which allows you
to save enhanced images and manipulate them further.
Video processors are essentially array processors designed
to work with the contents of frame buffers. They are
dedicated computation units for performing certain rou-
tine operations on images, such as computing the ratio
of two colors in an image. They permit relatively small
computers and I/P systems to work in "real time," which
is comparable to the time it takes to refresh an image on
the screen (typically 1/30 second for a standard interlaced
display, such as on a color television or microcomputer).
A frame grabber digitizes the output of a video camera
and places the resulting image into memory. Video inputs
are usually limited in terms of geometric accuracy and the
number of available gray levels.

A video film writer is designed to produce color slides and
prints with better resolution than a standard color CRT
(cathode-ray tube). Again, on a color monitor a red, green,
and blue dot make up a single pixel. The monitor's ability
to display color depends on the limits of your eye's re-
solving power to merge the three color dots. Simply tak-
ing a photograph of a monitor works moderately well, but
the quality is limited by the nature of the phosphor array
(not much better than 1 -millimeter resolution at best) and
the curved screen.

Inside a video film writer are a black-and-white, high-
resolution flat-screen monitor and three color filters. A
single piece of film (color slide film or instant print film)
is exposed to the monitor three times— first through the
red filter, then the green, and finally the blue filter. This
way, instead of the red, green, and blue dots being at a
different place (as on a CRT), they are superimposed for
each and every pixel. The business computer [continued)

FEBRUARY 1985 -BYTE 165

IMAGE PROCESSING

graphics and computer-aided design/computer-aided
manufacturing (CAD/CAM) uses for video film writers are
numerous, with video film writers now available for under
$4000. Some of the manufacturers include Celtic, Polaroid,
Dunn, and Matrix.

If you want to turn an image into an array of numbers
and you need more resolution and accuracy (or "spatial
detail") than you can get from a video camera, you prob-
ably need an electromechanical scanner. The original
image— transparency, film negative, or paper print— is
mounted on a cylindrical carrier (similar to an old Edison
cylinder phonograph). As the cylinder rotates, a photo-
detector scans along its axis and picks up image data.
These scanners are generally large and expensive
machines, but they have spatial resolution (in terms of
pixel size) in the tens of micrometers.

The reverse process— turning digital data into a photo-
graph—is performed by a device called a film writer. In this

case, the cylinder holds a piece of film, which is exposed
to a modulated light source (sometimes based on a laser
in some commercial instruments). Such a device is capable
of much higher resolution output than any monitor or
video film writer; one manufacturer's specifications report
a 2 5-micrometer raster over a 2 50-millimeter film negative.
Negative and positive images and transparencies can be
produced this way with high accuracy and geometric
fidelity

Image-Processing Operations

The principal operations involved in image processing are
relatively simple. (Problems arise when you have large data
sets. For example, the latest images from space derived
from the Landsat Thematic Mapper satellite are from a
piece of the earth's surface about 180 kilometers on a side
and contain 300 megabytes of data.) A number of the key

[continued)

Photo 2a: Raw landsat satellite data.

Photo 2b: landsat data contrast-enhanced.

Photo 2 c: Upper portion is original data, lower portion
has been rectified to a base map.

Photo 2d: Pseudocolor-enhanced image.

166 BYTE • FEBRUARY 1985

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IMAGE PROCESSING

image-manipulation functions are explained below.

Radiometric operations manipulate the intensity of the pixels
in an image. For example, a given image may be washed
out; all the pixel values are in a small range, and they are
all very light. One type of radiometric operation, called
contrast stretching, takes the darkest values in the image and
forces their value to black, forces the lightest values to
pure white, and linearly varies all the intermediate values.
An example of contrast stretching is shown in photo 2,
a series of images based on a test case in Sweden. Photo
2a shows the raw Landsat satellite data. In 2 b, the image
has been contrast-stretched so that the dark areas, repre-
senting water, show up better.

Photo 3: A \0-nanosecond x-ray pulse generated during the
heating of a magnetically confined argon plasma. Red indicates
the most intense x-ray emission and blue the least. {Courtesy of
COMTAL/3M and Sandia National laboratories.)

Photo 4: A neck x-ray image is shown on left. On the right is
the same image enhanced by a spatial filtering operation.
(Courtesy of International Imaging Systems.)

Another radiometric operation is density slicing, where you
display only those pixel values whose intensity is in some
specified range. This operation is often used to highlight
or classify objects in the image that have a characteristic
brightness or color. Photo 3 illustrates a I O-nanosecond
x-ray pulse during the heating of a magnetically confined
argon plasma. In this image, red indicates the most intense
x-ray emission and blue the least intense emission. The
radial lines indicate the direction of the plasma motion
prior to x-ray emission.

Sometimes color coding aids in the interpretation of the
density-sliced image; for example, objects whose bright-
ness is in a specified range are displayed in red. This pro-
cess, known as pseudocolor processing, is shown in photos lb,
2d, and 3.

Spatial operations are another family of manipulations that
fall into several categories. One such category is registra-
tion procedures, which are used to take an image and force
it to "overlay" another. For example, any map projection
is a distortion of the earth's surface, and to superimpose
an aerial photograph onto a map you need to "stretch"
the photograph. (Imagine painting the photograph on a
rubber sheet and then stretching the sheet until objects
on the image overlay the same objects on the map.) Photo
2c shows the effect of a registration procedure. The up-
per portion is original data, and the lower portion has
been rectified to a base map. Notice that features are both
rotated and changed in shape; this is a typical application.

Another category of spatial operations is filtering, a term
used in a signal-processing context. For those who are
mathematically minded, think of a Fourier analysis, in this
case, a two-dimensional Fourier transform. By isolating the
high-frequency components in a scene (those that recur
repeatedly), you can find edges, as shown in photo 4, a
neck x-ray. The first view is the original x-ray, while the
second has been enhanced by spatial filtering. The im-
provement in the ability to see structure is dramatic. Other
smoothing operations remove high-frequency noise from
an image in the same way that a filter on your stereo can
reduce the sound of scratches and pops on an old record.

Spatial texture, the variation in pixel brightness in a small
specified region, can be important in understanding an
image. Texture is often calculated as the standard devia-
tion of the nearest neighbors around a pixel, and this
deviation can be displayed as an image itself.

Feature extraction and classification, also spatial operations,
are powerful tools for image analysis. For example, if cer-
tain features in an image are a unique color or gray level,
a simple statistical exercise is to "teach" the system to find
the features. Unfortunately, feature extraction is almost
never this easy. Pattern recognition is a complicated
science itself and enters the realms of multivariate
statistics, geometry, artificial intelligence, and radiative
transfer theory. The end result of feature extraction is
similar to photo 2d, where water is represented by the
color purple and the regions that are peppered with yellow

[continued]

168 B YTE • FEBRUARY 1985

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IMAGE PROCESSING

correspond to known ground cover.

In the realm of multiple-image operations, another family of
I/P manipulations, image processing can be considered
three-dimensional; x and y are the rows and columns of
the image, and z (the third dimension) is a spectral or time
component. For example, you can have high-altitude color
infrared images of agricultural crops taken at different
times through the growing season. An image of a hydrau-
lic system from both visible and infrared scanners can help
detect overheating in the system by interpreting the in-
frared band as heat. In each case the data has a third
dimension.

Data compression can be an important feature in an image-
analysis system. At a theoretical level, the most efficient
representation of a scene is to describe the location and
orientation of the highest-level object description. ("High-
level" is used here in the same way that BASIC is described
as a high-level programming language as compared to
assembly language. A high-level object description is 'This
is a house," as compared to 'This is a square white ob-
ject 2 5 feet by 2 5 feet in size.") This form of representa-
tion requires that you be able to distinguish all the ob-
jects in the scene, which is possible in only limited cir-
cumstances. On a more practical level it is often possible
to describe the image, using statistical techniques like prin-
cipal-components analysis, or reduce the size of the data
set with other techniques, such as run-length and dif-
ference encoding. Data compression becomes most im-
portant when image data must be transmitted or where
large amounts of image data must be stored.

Down-to-Earth Applications

Image processing is now being used in a number of
disciplines. Medical people use image processing to con-
struct pseudocolor images from CAT (computer-aided

As hardware prices drop while
capabilities improve, image processing
be used more.

Photo 5: PET scan images in a medical study of blood flow.
(Courtesy of COMTAL/3M and the Positron Diagnostic
Research Center. University of Texas Health Science Center.)

tomography) or PET (positron emission tomography) scan-
ners. Photo 5 shows a series of images generated during
a study of blood flow in a rabbit's heart.

Art, advertising, and publishing people use pseudocolor
and other techniques in the pursuit of more effective
graphics. In the era of computer text editing, the idea of
"cut and paste" is common; here, however, this approach
includes full-color images and graphics. While straight
graphics systems, in general, have difficulty with halftone
illustrations and precise color balancing, an image-
processing system can handle text, line art, and images
in full color.

Structural engineers use I/P to examine weld x-rays for
imperfections. Photographers can use I/P for a multitude
of image enhancements that are either difficult or impos-
sible in a conventional darkroom.

In each of these settings, people are interested in im-
proving an image's ability to convey certain kinds of in-
formation. As hardware prices continue to drop while
capabilities improve, image processing will become even
more widely used. Courses in image processing are
already available at many universities around the coun-
try, and in a remarkable range of subject areas; at the
University of California, Santa Barbara, for example, I/P
is taught in the geography department at levels ranging
from beginning to advanced. ■

ACKNOWLEDGMENTS

I'd like to thank David Eckhardt and Earl Hajic, University of California,
Santa Barbara, for their help preparing this article, as well as Robert Crippen
(University of California. Santa Barbara). SATSCAN (San Francisco. Califor-
nia), COMTAL/3M (Altadena, California), and International Imaging Sys-
tems (Milpitas, California) for providing data and images.

REFERENCES

1. Andrews, H. C, and B. R. Hunt. Digital Image Restoration.
Englewood Cliffs, NJ: Prentice-Hall, 1977.

2. Baldwin, Lee. "Color Considerations." BYTE, September 1984,
page 227.

3. Buchanan, M. "Digital Image Processing: Can Intensity, Hue,
and Saturation Replace Red, Green, and Blue?" Electro-Optical
Systems Design. March 1980.

4. Moik, Johannes G. Digital Processing of Remotely Sensed Images.
NASA SP-431. Washington, DC: National Aeronautics and Space
Administration, 1980.

5. The Manual of Remote Sensing (2nd Ed.). Falls Church, VA. American
Society of Photogrammetry, 1983.

6. Sabins, Floyd F. Remote Sensing: Principles and Interpretation. New
York: WH. Freeman and Co.. 1978.

7. Short, Nicholas M. The landsat Tidorial Workbook. Basics of Satellite
Remote Sensing. NASA Reference Publication 1078. Washington,
DC: National Aeronautics and Space Administration, 1982.

170 B YTE • FEBRUARY 1985

Potent Pascal*

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manipulate data at the system and
machine level.

It gives you single and double

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172 BYTE • FEBRUARY 1985

HE EXCITEMENT IS BACK

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GVTE

Sciences

The Birth of a Computer

conducted by }ohn G Hash 177

A LowGost Data-Acquisition System

by Kiyohisa Okamura and

Kamyab Aghai : Tabriz 199

Fourier Smoothing Without the
Fast Fourier Transform

by Eric E. Aubanel and Keith B. Oldham . 207

paranoia: a floating-point

Benchmark

by Richard Karpinski 223

Modeling Mass-Action Kinetics

by Alan Curtis 239

Viewing Molecules
with the Macintosh

by Earl }. Kirkland 251

Laboratory Interfacing

by Lincoln E Ford. M.D. 263

Interfacing for Data Acquisition

by Thomas R. Clune 269

WHEN I WAS ASKED to find articles under the umbrella of scientific com-
puting, I realized that BYTE readers would probably best be served by ar-
ticles focusing on the main aspects of microcomputer applications in science:
development of tools of the trade, data acquisition, data analysis and reduc-
tion, and modeling of scientifically interesting systems or phenomena. This
month's theme articles delve into those areas.

In "The Birth of a Computer" Dr. James H. Wilkinson. F. R. S., tells a fascinating
story of the building of one of the earliest digital computers based on the
designs of Alan Hiring. Despite the 30-odd years since this work took place,
the account is surprisingly fresh and relevant to today's use of computers in
science.

The arithmetic underlying calculations is often ignored by users, regardless
of their scientific background, yet it is important to know that the basis for
these fundamental computer "tools" is sound. Richard Karpinski discusses
one approach to learning about the arithmetic implemented on computers,
the program Paranoia. This work, like so many others in the realm of scien-
tific computation, owes much to the careful and detailed analyses performed
and persistently reported by Professor William Kahan of Berkeley.

Data acquisition can be a difficult task involving expensive equipment. Some
of the issues in the analog-to-digital conversion aspect of data acquisition are
described by Dr. Lincoln Ford. For those with tight budgets. Kiyohisa Okamura
and Kamyab Aghai-Tkbriz present the hardware and software design of a Com-
modore 64-based system, lb round out data acquisition, BYTE Technical Editor
Tbm Clune reviews the main avenues for interfacing experiments to computers.

Once the data is in the machine, it must be processed before it can be regard-
ed as useful information. One technique for removing noise from data is
Fourier smoothing, discussed by Eric Aubanel and Keith Oldham.

Having gained some understanding of a system, a scientist can attempt to
model it— to generate or simulate the outcomes of experiments and "pictures"
of what is going on. Earl J. Kirkland literally pictures molecules with an Apple
Macintosh. Alan Curtis introduces the subject of modeling dynamic systems
such as large-scale chemical or nuclear processes.

We have tried to strike a reasonable balance between depth and breadth
in our coverage of scientific computing. In a field as large and sophisticated
as this, the editorial choices made are never entirely satisfying. Nonetheless,
we think that these articles present some fascinating glimpses into a com-
plex domain.

—)ohn C. Nash, Contributing Editor, Scientific Computing

FEBRUARY 1985 -BYTE 175

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SCIENCE

THE BIRTH OF A
COMPUTER

CONDUCTED BY JOHN C. NASH

An interview with James H. Wilkinson on the building
of a computer designed by Alan luring

The story of the construction of the first computers is both fascinating and instructive. Under-
standing the insights and decisions of computing's innovators may explain how the technology
evolved to its present state and may illuminate the directions it might take in the future.

Among computing's innovators were Alan Hiring (see page 65 for a review of a Taring
biography) and the men he assembled to help him build a computer based on his Universal
machine. Turing's team included \ames H. Wilkinson, a mathematician who had studied at
Cambridge and worked for the British government as a ballistics engineer doing numerical
analysis of explosives problems during World War II.

This interview was conducted for BYTE by Dr. )ohn C. Hash and took place on July 13,
1984, at the Ninth Householder Gatlinburg Conference held at the University of Waterloo,
Waterloo, Ontario, Canada.

BYTE: Dr. Wilkinson, how did you become
involved with Alan Turing and his computer?
JHW: Shortly after the war, I dis-
covered that a Mathematics Division
was being set up at the National
Physical Laboratory (NPL). I got in
touch with E. T. Goodwin, who had
been a colleague of mine at Cam-
bridge in the Maths Lab. He was one
of the first to join this new division.
He invited me to have a chat with him
at NPL in Bushy Park, 'Ikddington. and
there I met 'IUring, who I knew already
by reputation as something of an ec-
centric. 'Hiring and 1 had a long discus-
sion, and 1 was very impressed with
him. Presumably he must have been
reasonably satisfied with me since he
said if 1 came to NPL he would like me
to work with him. I think that this offer

and my friendship with Goodwin were
the decisive factors. So in May '46, six
and a half years after I joined the
government service, 1 moved to NPL
(as I thought then, temporarily) in-
stead of going back to Cambridge
University.

'IUring had worked alone on the
logical design of an electronic com-
puter. When I arrived, he had pre-
sented his plans to what you might
call a "review committee" at NPL. This
consisted of a small group of Fellows
from the Royal Society. The commit-
tee decided that 'IUring's ideas were
basically sound, and they gave him a
mandate to go ahead and recruit the
appropriate staff.

Up to that time everything associ-
ated with the project had been done

by 'Hiring himself. He was a man with
an original and inventive mind. His
design had practically nothing in com-
mon with the group of computers
which arose out of discussions at the
Moore School of Electrical Engineer-
ing at the University of Pennsylvania.
John W. Mauchly and J. Presper Eckert
had already successfully completed
the construction of the first electronic
computer, the EN1AC (this was not a
stored-program computer), and their
influence was at its peak. When 1 went
to NPL in May '46, TUring was work-
ing on what he called version 5 of [his|
computer, though 1 never saw any
documents relating to versions I to
4. 'Hiring was not a great documented
and no doubt the earlier versions
were buried in the rubble on his desk.
Perhaps I should attempt to give
some idea of the flavor of version 5,
a typical 'Iliringesque creation. It was

[continued)

Dr. )ohn C. Nash (Nash Information Services,
1975 Bel Air Dr., Ottawa, Ontario. K2C
OX I. Canada) is an associate professor with
the Faculty of Administration at the Univer-
sity of Ottawa, Canada. He is the author of
two books on scientific computing and
numerous journal articles.

FEBRUARY 1985 -BYTE 177

INTERVIEW

a serial machine using mercury delay
lines for storage, with a pulse repeti-
tion rate of what I still call a megacy-
cle, being rather old-fashioned in such
matters.

BYTE: Define a megacycle.
JHW: The basic pulse frequency was
provided by a master clock which had
a I -megacycle pulse rate. It worked in
binary, of course. That decision was
taken early on and was regarded as
irrevocable. The word length was 32
binary digits, which is rather better
than 9 decimals.

BYTE: They were fixed point?
JHW: Yes. They were fixed point, but
one of the earliest things that I did (at
Turing's request) was to program a set
of subroutines for doing floating-point
arithmetic. These were later to be-
come rather important in the history
of NPL. Right from the start, Hiring
was impressed with the importance of
speed. It is possibly not widely known
that at that time most people weren't.
For instance, Maurice Wilkes at Cam-
bridge (who quite early became one
of our principal competitors) took the
view then that electronic computers
were so fast that it was much more im-
portant to get one built than to make
special efforts to increase its speed,
and his views were generally shared.
Hiring took the opposite view, and
most of the special features of his
machine were designed to make it as
fast as possible. There was merit in
both views, but it was certainly true
that the machines we were designing
then were not nearly so fast as they
appeared to be. However, Turing's
obsession with speed certainly made
for a very untidy machine. A great
weakness of mercury delay lines is ac-
cess time. In order to make them rea-
sonably economic, it is necessary to
store a number of words in each delay
line. Clearly, if one stores consecutive
instructions in consecutive positions
in a delay line, one could perform
only one instruction per major cycle,
and indeed the early machines (other
than ACE) that were based on mer-
cury delays suffered from this weak-
ness. (Editor's note: ACE— for " automatic
computing engine"— was the name given to

Photo 1: English mathematician ]ames H.
Wilkinson, one of the builders and program-
mers of the early ACE computer.

Turing's machine by Mathematics Division
head ). R. Womersley.\

BYTE: "Major cycle" meaning. . . ?
JHW: "Major cycle" meaning the time
of circulation of the main storage
units, each of which held 32 words of
32 binary digits and hence had a cir-
culation time of 1024 microseconds,
i.e., approximately a millisecond. A
conventional design would have
meant that the maximum speed of
operation was one instruction per
millisecond.

BYTE: Because, unlike a dynamic RAM.
where you can get at any cell with one or two
clock cycles, this had to use a thousand clock
cycles.

JHW: The other two early machines to
work— EDSAC at Cambridge (which
Wilkes built) and SEAC at the National
Bureau of Standards (which Samuel
Alexander built)— did, in fact, store
consecutive instructions in consecu-
tive positions, so that by the time one
instruction had been executed the
next one had been "missed," and one
had to wait a full cycle for it to
emerge. To avoid this, TUring stored
consecutive instructions in such
relative positions that the next instruc-
tion emerged just when the previous
one was completed. Since different in-
structions took different times for
their execution, consecutive instruc-
tions were irregularly spaced in the

store. As you can well imagine, this
made for what one would call "dif-
ficult" coding. I'm not sure that "dif-
ficult" is the right word. 1 would say
such coding was tiresome or tedious.
Also it made the design of automatic
programming languages more labori-
ous, while at the same time it made
them more desirable. However, this
feature of the machine turned out to
be rather important; it meant we
could do up to 16 instructions per ma-
jor cycle, i.e., about 64 microseconds
per instruction.

This practice later became known as
"optimum coding" or "latency cod-
ing," but TUring never used that term.
It was characteristic of him to see his
machine as the basic one, all the
others being out of step.

BYTE: What was the ACE's total memory?
JHW: Well, TUring envisioned a
memory of 200 long delay lines,
which would have given 6400 words.

BYTE: About 24K bytes?
JHW: Yes, and although that may
sound rather small now, it was really
very ambitious for that time. I am sure
TUring would never have contem-
plated or supported the building of
a smaller machine.

Shortly after I joined NPL, TUring
moved on to version 6 and then rapid-
ly to 7 and 8. Those were four-address
code machines. | Editor's note: A four-
address machine had up to four address
operands after an instruction, one of which
would be to give the memory location of the
next instruction]

The earlier machine, version 5, is
hard to describe in these terms. But
its successors performed instructions
of the type A+ B to C and selected the
position D of the next instruction,
which was necessary because they
were not in consecutive positions.

BYTE: A complete instruction would occupy
one word?

JHW: Yes, but it was a more powerful
instruction than that on a conven-
tional one-address code machine. An-
other striking difference in Turing's
design was that he had a number of
one-word delay lines and the arith-

(continued)

178 BYTE • FEBRUARY 1985

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FEBRUARY 1985 -BYTE 179

Inquiry 222

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180 BYTE • FEBRUARY 1985

INTERVIEW

metic and logical operations were dis-
tributed among them. On a conven-
tional one-address code machine the
use of one accumulator leads to a
tremendous bottleneck. One is always
taking one number out of the ac-
cumulator to put in another. By hav-
ing a number of one-word stores
(delay lines), this is avoided. You see,
this was all related to Turing's objec-
tive of making his computer faster.

BYTE: When a word had an instruction, it
would also have an address in it?
JHW: Oh, yes.

BYTE: So it wasn't like a modern microcom-
puter with instruction, operand, operand?
JHW: No.

If Hiring had stayed at NPL he would
have gone for the full-scale computer
with 200 delay lines, and quite frank-
ly we had neither the facilities nor the
experience to embark on such an am-
bitious project. It should be appre-
ciated that the full-size computer was
far larger than the one Wilkes was
planning and eventually built as
EDSAC.

Although I have used the term "op-
timum coding," most programs fell a
good deal short of the optimum
speed attainable. To achieve this
would have been far too tedious.
However, when it came to very impor-
tant subroutines such as floating-point
arithmetic, optimum speed was
almost achieved. As I mentioned
before, I produced the first set of
floating-point routines, but when in
1947 Donald Davies, Mike Woodger,
Gerald Alway, Billy Curtis, and John
Norton joined the team, they all
played a part in polishing them up.

BYTE: This was all on paper?
JHW: Naturally; we had no working
computer. Because of the optimum
coding, floating-point arithmetic (and
other important routines such as dou-
ble-length arithmetic) was much faster
on Turing's machines than it was on
its competitors. The speed of floating-
point arithmetic turned out to be very
important for me. When we finally
built our computer, we dusted down
our early routines and polished them
up further. By the standards of the

time they were very fast indeed, and
this enabled me to get really exten-
sive working experience with floating-
point computation before it was prac-
tical elsewhere. I am sure this is why
floating-point error analysis first made
headway at NPL.

Hiring continued with the logical
design of machines, but after a while
he began to get very dissatisfied. The
policy had been adopted that the ac-
tual construction of the computer
should be undertaken by some other
government department such as the
Ministry of Supply, where personnel
experienced in pulse techniques as a
result of working on radar were avail-
able.

I never liked that decision, but the
director of NPL, Sir Charles Darwin
(great-grandson of the great Charles
Darwin), was not a very easy man to
argue with. Remember, I was quite a
junior member of the NPL staff at that
time. But as I saw it, there were only
two possibilities. Either the external
group would be successful, in which
case, if they had any imagination at
all, they would take control of the
computer themselves. Alternatively,
they might fail. It seemed to me that
we were in a no-win situation, and I
couldn't understand why Hiring ac-
cepted the proposal. This attempt to
get the machine built outside con-
tinued very unsuccessfully, and Hiring
got more and more morose about it.

Finally, very belatedly, in 1947, Dar-
win agreed to set up a very small elec-
tronics group (not a division) at NPL.
It was recruited mainly from people
from other divisions of NPL, and in-
evitably most of the recruits were far
from being experts in electronics, so
they were going to have to learn on
the job. A disaster struck almost im-
mediately. The person who was put
in charge of the team— a Dr. Thomas-
is often criticized, but in my view
rather unjustifiably. Thomas was much
more interested in industrial elec-
tronics than in building a computer.
I do not feel that this was unreason-
able; it was not easy to have the imag-
ination to foresee that computers
were to become one of the most im-

[contimed)

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Inquiry 208

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INTERVIEW

portant developments of the century.
However, from our point of view
Thomas's preferences were unfor-
tunate. But worse was to come.
Thomas and Hiring had absolutely
nothing in common and were scarce-
ly capable of being civil to each other.
So there we have the situation where
the leaders of the two groups were
completely incompatible.

This, naturally, made Hiring even
more unhappy, and he began to talk
seriously of leaving. Finally, he left in
1 948 and joined the group led by
Freddy Williams and Tbm Kilburn at
Manchester. They were making rapid
strides in the construction of a com-
puter based on what became known
as the "Williams-Kilburn store." Tur-
ing's decision was, in my opinion, an
unfortunate one. He should have
returned to Cambridge where he still
held a fellowship at Kings.

I was left in charge of a team which
consisted of six people including
myself. We had virtually no contact
with the electronics group, and at that
stage Goodwin, who was in charge of
the Desk Computing Section, had a
long discussion with me. He said,
"You know this enterprise looks now
as though it's going to founder. Before
you can be held responsible for its
failure, would you not prefer to
become a member of the Desk Com-
puting Section?"

Well, I just couldn't accept that. By
this time I was hooked on computers,
so I said I would sweat it out and see
what could be done.

Then a miracle occurred. Thomas
left and went into industry where he
had always belonged. The person
who succeeded him, F. M. Colebrook,
was an old radio engineer with very
little knowledge of pulse techniques
but a great fund of common sense.
When he'd been in the post about two
weeks, he came over to see me and
he said, "You and I appear to be
holding a very unhealthy baby." He
went on to invite the four senior
members of our group (Alway Davies,
Woodger, and myself) to join him in
the Electronics Section on a semiper-
manent basis and attempt to achieve
something together. This would be

182 BYTE • FEBRUARY 1985

INTERVIEW

about May or June of 1948. Cole-
brook was a remarkable tactician, and
soon we were all working rather well
together. There were one or two
uneasy weeks, but soon the animosi-
ty died down. E. Newman was in tech-
nical charge of the electronics group;
he had worked on the H2S airborne
radar system during the war and
already knew quite a lot about pulse
techniques. He and I got on remark-
ably well and that was a great help.
In those days supplies were a prob-
lem, but fortunately one member of
the electronics group, W. Wilson, a
giant of a man, knew everybody in the
supply world and was able to solve
this problem satisfactorily. After we
had spent a month or two building
bits and pieces and generally finding
our feet, Colebrook said, "Why don't
we get together now and try to build
a pilot machine, the success of which
will demonstrate to the authorities
that we are competent and therefore
ensure the continuation of the enter-
prise." Then, in the light of success—
we didn't hint at failure— we would go
on and build the full-scale ACE.

Now it so happened that we had
done a little experimental work in
1947 in the the Mathematics Division
when Harry Huskey had spent a sab-
batical year with us. At that time we
had designed just such a miniature
machine based on Turing's version 5.
This enterprise had been stopped by
Darwin when the Electronics Section
was formed.

lb a large extent we resurrected this
machine, incorporating, of course, a
substantial number of improvements.
It was to be called the Pilot ACE and,
effectively, it would be the smallest
machine based on the logic of version
5, which would demonstrate the prac-
ticality of it.

BYTE: How large a machine was the Pilot
ACE?

JHW: I suppose I was largely respon-
sible for deciding on the size and
scope of the machine, but any of the
other three could by that time equal-
ly well have done so. In order to have
some specific objective, I decided that

[continued)

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FEBRUARY 1985 -BYTE 183

Speed^QuaEtyi

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Contact your nearest distributor for
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Inquiry 116

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INTERVIEW

it should be capable of solving fully
automatically a set of 8 to 10 linear
equations by Gauss elimination. This
it would do in a matter of a second
or two, very impressive for that time.

BYTE: So you needed to store at least 1 50
numbers and the word width was 32 bits?
JHW: In fact we decided to have 10
long delay lines, that is, 320 words. We
started to design the chassis in late
'48, some chassis being designed by
the "mathematicians" and some by
the "engineers." In the event, the
mathematicians probably designed
slightly more than half the chassis. I
must emphasize that 1 am now talk-
ing about the detailed electronic
design, not just the logical design. We
put our newly won knowledge of elec-
tronics to immediate use.

We started to send our blueprints to
the NPL workshop towards the end of
that year. As each chassis arrived
from the workshop, we put it into the
main frame.

BYTE: Literally a main frame?
JHW: Yes, there really was a frame. We
decided to use a plug-in assembly
and planned to have spares of key
chassis.

By the standards of the time it was
an incredibly small machine physical-
ly, and yet it was in many regards
more powerful than either EDSAC or
SEAC. Direct comparisons are not
really possible but Pilot ACE was sub-
stantially faster on most problems,
and it could solve some problems the
other two couldn't.

BYTE: And the clock cycle was still 1 mega-
cycle?

JHW: Yes, still I megacycle, a slightly
tough decision. Wilkes had decided
on 500 kilocycles. Certainly some of
the problems we had would have
been a lot easier at 500 kilocycles.

BYTE: It is interesting that the Apple II is
a \ -megacycle or Vmegahertz machine, by
comparison. \ Editor's note: This refers to the
instruction rather than clock rate]
JHW: Yes, that's right.

The completed chassis would have
started to arrive, I imagine, well

through '49; I'm afraid progress was
not documented. It so happened that
the first chassis to arrive had been
designed by Alway and myself, two of
the mathematicians of the team, and
naturally we put them into the main
frame and got them working.

Then when the next chassis arrived—
which Alway and I had not designed—
we assisted in its installation because
we already knew about the earlier
chassis. Thus, without any conscious
decision being made, Alway and I
became the debuggers.

BYTE: Weren't the chassis somewhat different
from each group? Or were these different
components?

JHW: Of course, the various chassis
had entirely different functions. Thus
several were associated with the line
counter, several with the logical con-
trol, and then there was one chassis
for each delay line. (The latter were,
of course, all identical.)

BYTE: The line counter is ... ?
JHW: This was the section which
counted the basic 32 pulses in a word
time.

BYTE: All this is now on one chip?
JHW: Yes, of course, and much more.
Our units were vast by today's stan-
dards in spite of being small by the
standards of the contemporary
design. Pilot ACE was also unique
among the early computers in being
extremely mobile. The main frame
was on wheels and when the com-
puter was finished, we wheeled it
back to Mathematics Division without
affecting its performance.

BYTE: Was it power-hungry?
JHW: It consumed somewhat less than
10 kilowatts, which was quite low. But
we didn't have any forced cooling,
and perhaps the construction was a
little too compact for that. When we
were assembling it we were, of
course, standing in front of it all day.
It was like working in front of a IO-kilo-
watt fire, a rather trying experience.

BYTE: Did you have much component
trouble?

JHW: Not really. Our main problem

{continued)

FEBRUARY 1985 -BYTE 185

Inquiry 226

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INTERVIEW

was with germanium diodes, which
fortunately we didn't use on the same
scale as SEAC. We used them for
some gating requirements. Because
our machine was so compact and
didn't have forced cooling, the diodes
were working at a temperature which
was much higher than specified by
the manufacturer.

BYTE: So they would fail?
JHW: Yes, there were some good
diodes and some bad diodes. The
bad diodes would fail after perhaps
a week in the computer. A good
diode, on the other hand, would go
on almost indefinitely, so bad diodes
were eventually weeded out.

Then came a key stage in the assem-
bly of the computer. This was the day
the first delay-line chassis was inte-
grated. This was designed by
Newman, and, as usual, he joined
Alway and myself while it was in-
stalled, but from then on he stayed
with us. The three of us worked well
together and debugged the whole of
the rest of the machine.

BYTE: When did the first program run?
JHW: On May the tenth, 1 950. It is in-
teresting that, unlike Wilkes, who had
built everything he intended to have
and then made it work, we added
chassis by chassis as they were com-
pleted, and as soon as it was possi-
ble to do something (which was as
soon as we had the control unit work-
ing, the adder and the subtracter, the
logical operations and one long delay
line), we tried it.

BYTE: How would you feed the data in?
JHW: Oh, at that point we fed the in-
structions in (in binary) from a set of
32 keys. When it worked on May the
tenth, it could perform only the sim-
plest of programs. In fact, our first pro-
gram achieved the following: it took
the binary number set up on the 32
keys, and every major cycle it added
that number into the accumulator un-
til it overflowed. Now, in addition to
the 32 input keys we had a set of 32
output lights. When an overflow took
place, the program put on the next
light. So successive lights would come
on at a speed which was directly

Inquiry 366

186 BYTE • FEBRUARY 1985

INTERVIEW

related to the size of the number on
the switches. Now this program, ad-
mittedly rather small, had to be fed
in one instruction at a time, in binary,
from the 32 keys. At the time the
design of the delay lines needed im-
proving; the amplifiers were some-
what unstable. So we kept feeding in
the program, and it kept being forgot-
ten before we could complete the in-
put. So 1 said to Alway, "Let's try it
four or five more times, and if it
doesn't work, we'll call it a day and go
home."

Well, we put it in about four times,
and suddenly all the lights came on.
This could have happened in any
case, and it didn't guarantee the pro-
gram was working. However, we made
the input number smaller and the
lights came on more slowly.

BYTE: So the amplifiers had settled down?
JHW: Yes. Then we doubled the
number, and the lights came up twice
as fast. We made the number three
times as large and they cameup three
times as fast. On a binary machine
that was quite convincing, so we said,
"It must be working," and went home
rejoicing. That program later became
rather famous on the machine. It was
known affectionately as "Successive
Digits" or "Suck Digs."

Sometime before this, 'feddy Bullard
(later Sir Edward) had succeeded Dar-
win, and when he visited the Elec-
tronics Section (in late April 1950) he
asked me how it was going. 1 replied
that we should have something going
in a week or two. Bullard was a very
forthright chap, and he said with
some scorn, "Come on, you can't pull
the wool over my eyes. I've heard it's
going very badly." (He had heard this,
quite justifiably, via Harry Huskey.) I
said, "You may well have heard this,
and indeed it was true, but it's com-
ing along nicely now, and in a week
or two I confidently expect it to be
working."

Naturally, when it did work, I tried
to get in touch with him as I had
promised to do. I tried to phone him.
He wasn't there. Now the machine
wasn't really very good at that stage

[continued)

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Inquiry 134

FEBRUARY 1985 -BYTE 187

Inquiry 104

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INTERVIEW

and might stop working at any time.
The director could not be traced, and
I was pacing up and down, saying,
"The bloody director is never here
when you want him," when he
stepped into the room via the win-
dow. His opening words were, "Here's
the bloody director. 1 hear it's work-
ing."

1 showed him this program, and he
played with it and agreed that it was
working. Then he turned to me with
a grin and said, "It may be working,
but the program's somewhat less than
epoch-making," with which we had to
agree, but it was very heartening for
us.

We continued to add the chassis
one by one, and by the end of June
most of it was assembled. We didn't
at that time have a multiplier, nor had
we planned to have one, on Pilot ACE.

BYTE: You would use successive addition?
JHW: Yes; it was to be done by a sub-
routine, optimum coded so that it was
not too slow. In fact, the optimum-
coded version was about as fast as
the automatic multiplier on EDSAC.
So as soon as it began to do signifi-
cant things, Bullard began to press us
to have an Open [House| Day and to
demonstrate it to the world. Well, I
was a bit anxious about that because
it wasn't really reliable enough. The
amplifiers on the delay lines were still
inclined to be unstable. However,
Bullard was a very impetuous man,
and he finally landed us with these
"demonstration days."

BYTE: When was that?
JHW: It would have been November
of 1950. By that time we could do a
variety of significant things, but it was
still not a very reliable machine.

One of the troubles we had at that
time was with the power supply— not
our power supplies but that of the
Central Electricity Generating Board.
For instance, in the evening when
everyone arrived home and switched
on electric fires, the voltage would
drop suddenly, and that gave us
problems.

BYTE: Historically there was a coal shortage

[continued)

188 BYTE • FEBRUARY 1985

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FEBRUARY 1985 -BYTE 189

INTERVIEW

at that time?

JHW: Yes. Such things added to our
difficulties. We knew, too, that when
SEAC had had its first demonstra-
tion—a little before us— it had been a
fiasco, even though SEAC had, in
general, been working reasonably
well. During the whole of the time
allotted to the press demonstration,

it never once worked. You will find the
early years abound with such bad-
luck stories.

I must confess to having been pes-
simistic. We decided to have two
popular programs for the daily press.
For the first, they would give us a six-
figure decimal number and the com-
puter would tell them if it were a

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prime, and if not, output a factor.

For the second program, they would
give us any date from the year up
to the year 9999 and it would output
what day of the week it was. It
covered both the Julian and Gregorian
calendars and dealt with all leap
years. In all. quite an amusing little
program. Mike Woodger produced
that program.

BYTE: And where did he discover the tech-
nique?

JHW: He worked it out for himself.
Such programs are good fun, of
course, but they leave one merciless-
ly exposed to the vulgar gaze. Some-
one puts in the current date, which is
Wednesday, say, and the machine
promptly says Thursday! So they're
very much more dangerous. If you tell
the press it's solving a partial differen-
tial equation, you can swear blind it's
solving a partial differential equation
and they would be hard put to prove
it is not. Finally, we were to have one
serious program; this traced skew rays
through a set of lenses.

Well, we decided on this last pro-
gram and announced it, only to find
that we couldn't get the program to
work. TWo days before the press show
it had still never worked, and we didn't
know whether the program had a bug
or whether it was due to computer
malfunction. Then, just two days
before the show, Alway and I acciden-
tally found it was a minor machine
fault which was not invoked at all in
our other programs.

We got all three programs working-
then, just in time. The arrangement
was that Bullard would entertain the
popular press and I would give the
demonstrations. The whole thing was
to cover three days; one day with the
popular press, one with the technical
press, and a third day for VIPs includ-
ing our competitors. Wilkes had his
machine running in Cambridge and
was justifiably proud of it. Williams
and Kilburn from Manchester were
also coming.

BYTE: They had a machine too, didn't they?
JHW: They had a little hookup at that

[continued)

190 BYTE • FEBRUARY 1985

Inquiry 32

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FEBRUARY 1985 -BYTE 191

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192 BYTE- FEBRUARY 1985

Inquiry 7

INTERVIEW

time, but it could scarcely be called
a computer. They hadn't built the
Mark I by that time. Their little hook-
up was the first anywhere ever to run
a stored program. It worked in 1947
and found the highest common fac-
tor of two numbers. This was, of
course, a great deal smaller even than
the Pilot ACE. However, it was an im-
pressive "first" and I well remember
being very heartened when I saw it
working.

My point then, is that Open Day was
doomed to be a failure. The plan for
the first day was that Bullard was to
entertain the press upstairs, while
downstairs we made sure the com-
puter was working. We were to receive
a signal when Bullard was almost
through. We did, and immediately the
machine stopped working. We found
out, almost at once, that it was a
chassis associated with one of the
delay lines. We plugged in a spare, but

unfortunately we knew that the
amplifier, as it warmed up, would
become unstable; the amplifier would
then need to be retuned and in 10
minutes all would be fine from then
on.

So we were expecting to run into
trouble almost as soon as the dem-
onstration started. Well, the press ar-
rived. They threw numbers at us and
the computer factorized them like a
charm. It was indefatigable!

We moved on to the "dates" pro-
gram. It worked as it had never
worked before: the day of Trafalgar,
Waterloo, King George V's birthday.

We moved on to the ray tracing. It
traced rays like a fiend; nothing could
stop it. It continued in this vein from
10 till I o'clock. Then the press went
away to lunch. We immediately looked
at the output from the delay line, that
is, the shape of the pulse coming out.
It was the best output we'd ever seen!

The computer

factorized numbers

like a charm.

Further press representatives came in
the afternoon; still a faultless per-
formance.

The next day we had the technical
press, and it was the same story.
Never before had it worked for any-
thing approaching this time period
without a fault. The third day the VIPs
came. Surely it would let us down
now? Not a bit of it. Wilkes was there.
I have always found him a very fair
man, but naturally he was not pre-
pared to give anything away. He didn't
get a chance; it was perfect. It had
already been decided that there
would be a fourth day when it would

(continued)

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Inquiry 182

FEBRUARY 1985 -BYTE 193

INTERVIEW

Photo 2: A hand-cranked desk calculator, like the one used by Wilkinson to perform
numerical analysis during World War II. This machine was manufactured by Brunsviga.

be put on show for the staff of NPL.
This was a Saturday. The computer
had a small fault before our audience
arrived, but we soon put this right
and once again it performed flawless-
ly The chances of such a performance
must have been a million to one
against.

On Monday we came in feeling
rather jubilant. The computer was
down, and it took us about a week to
get it working again!

BYTE: Today a lot of people are coming into
computing with no background in calculation.
Many of the machines they're using don't have
the properties that ACE did. with double-
precision accumulation of inner products. Peo-
ple haw wry little knowledge of this. How
can these ideas be got across to them?
JHW: It's a really difficult question,
and I wouldn't claim to know the com-
plete answer to it. Our experience
with the Pilot ACE was really rather
special. In order to get the most out
of a machine with such a small store,
user cooperation was essential on a
scale which in many ways is not
achieved even now. This gave one an
intimacy with the machine; we were
forced to look at the numbers and
thereby achieved a deep understand-
ing of what was going on. One can.
of course, do this with modern com-
puters; indeed the potential for doing
it is actually greater, but one has to

realize what it is one should be do-
ing and why. For iterative methods we
used acceleration techniques which
were actually under the direct control
of the operator. (For instance, when
we were using the power method for
the determination of the dominant
eigenvector of a matrix, we could
follow the progress of the vector on
a cathode-ray tube screen. We had a
cathode-ray display which showed the
contents of any long delay line. We
would look at the screen (which
showed 32 components of the current
vector), and we would see how fast it
was converging. We would put a piece
of paper over it, and we could say, for
example, "It's gaining a binary digit
every three iterations, so the ratio of
the dominant to the subdominant
eigenvalue must be about 2 to the
power !/3." We could then set up a shift
of origin on the input keys that would
give much faster convergence.) This
work was commonly done by assis-
tants who were in no sense qualified
mathematicians, but they became
very expert indeed. It is surprising
how well they understood the battery
of acceleration techniques available
and how efficiently they used them.
When later we went over to more
automatic techniques, they com-
plained we were "taking the guts out
of their work." They really loved these
early programs. The familiarity and in-

timacy gained with the computing
process was fully comparable with
that which one gets on a hand desk
machine, where perforce you see
every number. But on ACE that
familiarity was gained quickly and
painlessly. This experience was in-
valuable. Is there any way you can get
it now? Of course there is, but one
needs to know what is worth having
and to have the incentive to output it.

BYTE: I would say my own experience is that
we are transferring large-machined faceless"
programs down to the personal computers,
where in fact one can go back to the ACE
ideas.

JHW: Yes. I agree. The potential is
there, and it's much greater, really,
than it was on ACE. But in my experi-
ence, many people who do comput-
ing are reluctant to look at numbers.
At Stanford the general level of our
students has been pretty high, but I
would say their main weakness is in
their inability to look at outputs and
extract the meaningful information in
them. In fact, somewhat to my sur-
prise, they are generally less efficient
at this than the assistants 1 used to
have at NPL in the ACE days, in spite
of having far superior mathematical
qualifications. Most of those assis-
tants had experience with desk com-
puters and had learned to "look at
numbers." The Pilot ACE forced them
to continue with this habit.

I certainly do not want to suggest
that the way to acquire this habit is
to serve an apprenticeship on hand
desk computers, but we have yet to
learn how to instill the relevant knowl-
edge. ■

FURTHER READING
This interview examines James H. Wilkin-
son's role in building the computer de-
signed by Tbring. For additional informa-
tion on this subject see Wilkinson's "llir-
ing's Work at the National Physical Labora-
tory," in A History of Computing in the Twen-
tieth Century, N. Metropolis. ]. Howlett. and
G. C. Rota. eds. (New York: Academic
Press, 1980) and his articles on this topic
in The Radio and Electronic Engineer (July 1975).
plus a transcript of an oral history in
Pioneers of Computing. C. Evans, ed. (London:
Science Museum. 197 5).

194 BYTE ' FEBRUARY 1985

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FEBRUARY 1985 -BYTE 195

AUTHORIZED DISTRIBUTORS • AUTHORIZED DISTRIBUTORS • AUTHORIZED DISTRIBUTORS • AUTHORIZED DISTRIBUTORS •

electronic components

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ALABAMA

Birmingham American Elect. Supply

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Tuscaloosa Radio Parts Inc.

ALASKA

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ARIZONA

Riviera. Riviera Elec ronics

Sierra Vista. B&S Electronics

Tucson Electronic City

Yuma Yuma Electronics

ARKANSAS
Little Rock Southern Electronics

CALIFORNIA

Anaheim R.F. Electronics

Bakersfietd Jay Kern Electronics

Berkeley AJ Usfter's Electronics

Carpinterra. Electronic Resources

Chico Payless Wholesale

Chico. The Electronics Wherehouse

Chula Vista Lion Electronics

Cleatlake Clearlake Electronics

Concord. Pacilic/Valley Electronics

Costa Mesa Mar-Vac Electronics

Covtna. G&H/AMCO Beet Supply

Cucamonga. Abletronics

Dublin Pacific/Valley Electronics

El Cajon Radio Shack

Eureka Redwood Electronics

Fonlana Fontana Electronics

Fresno. Sparky Electronics

Fresno Whitcomm Electronics

Fullerton Industrial Electronics

Glendale Eagle Electronics

Goleta Bill's Stereo

flair Moon &y. . . . Strawftaw EJecJRadio Shack

Harbor City Bluff Electronics

Hawaiian Gardens. Carson Electronics

Hollywood Pacific Radio Exchange

Inglewood Radioland/lnglewood Elect

Lancaster Consumer Elec ronics

Lompoc L&H Electronic Emporium

Modeslo Inland Electronics

Modesto Pacific Radio

Monterey. . . Zackit

Morro Bay. Coast Electronics

National City. Willy's Electronics

Oakland Cass Electronics

Oakland Wenger Electronics

Oceanside Electronic Center

Oroville Radio Mart

Palo Alto U.S. Electronics

Palo Alio Zack Electronics

Pasadena Dow Radio

Redding Radio Mart

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Salinas Salinas Radio

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San Fernanda San Fernando Electronics

San Francisco Zack Electronics

San Jose Peninsula Elect. Supply

San Jose United Radio and TV

San Luis Obispo Mid Slate Electronics

San Rafael Electronics Pius

Santa Clara. Digital Pacific

Santa Cruz. Santa Cruz Electronics

Santa Maria Caps Communications

Santa Maria Electronic Parts Superman

Saratoga Wagon master Electronics

Sunnyvale Sunnyvale Electronics

Torrance Signal Electronics

Torrance. Torrance Electronics

Vallejo -Zackit

Van Nuys Thrifty Electronics

Westminster J K Electronics

Whittier Whittier Electronics

•1ST JtM-PAK DISTRIBUTOR 9/6/77

COLORADO

Boulder. ,..;..,,.., Hapco

Colorado Springs. . . . ,? . . Centennial Electronics

Denver. Fisteii's Microelectronics

Lakewood. D.H. Crump Co.

CONNECTICUT
AvorW, . < • • ■ ■ ... .Heathkit Electronic Center
Now Haven, .: . . .]:::', Customized Computer ClV:

Wallingford Tron Town USA

DELAWARE

Newark. Computerland

New Castle. .-. . . . . . Delaware Amateur Supply

Wilmington. ... . . S ..... . . Micro Products

Wilmington. Whulfisale Electronics

FLORIDA

Clea water Amateur Electronic Supply

Daytona Beach C&S Bectronics

Fort Lauderdale:.;, . , , . . Tecktron Enterprises

Gainesville Skipper Electrons

Hialeah. . . . _, Heaihkit Electronic Center

Hollywood. -' ... .., . . ... .,...'... Errico Inc.

Jacksonville Hcathkit Electronic Center

Oakland Park.,, .7, ....„.;,.., . ... Lafayette Radio*.

Panama City ..Bay-Mar Electronics

Pensacela. . /.■..... . . Pensaeola Electronics

Pensaeola. . Quad Electronics

Plantation Heathkit Electronic Center

Tampa. .........: Heaihkit Electronic Center

GEORGIA

Atlanta. '. , . A.C.M. Computer Mart

Atlanta. . .... . . ... Heaihkit Electronic Center

Dallon. ...:..,.:'.. .ACM. Computer Mart

La Grange ,..../.... Electronic Supply

Stone Mountain. . . /.-. . Coleman's. Electronics

Warner Robbins. . - C&L Electronics

HAWAII

Hilo Al's Electronics

Honolulu. ■: Industrial Electronics

Honolulu Integrated Circuit Supply

Pearl City -Heaihkit Electronic Center

IDAHO

Boise. , . Kimball Electronics

Boise". R.J.M. Electronics

Caldwell. .,. .;.'. .-: A-Gem Supply

Pocatelfo. ,,....,,,.. .... Kimball Electronics

Twin Falls, Central Electronics

ILLINOIS

Addison. ..-,.-:.-... Digital World, Inc.

Berwyn B.B.&W. Electronics

Carbondale. . . lj , ... . .... Pick's Electronics

Chicago. ..... V University of Illinois Bookstore

Downers Grove. . Suburban Electronics

Groveland '....,..;. Mover Electronics

Harvey George Electronics

Mount Prospect. Trt-Stile Elect.

Miles. Joseph Electronic

Peoria \. . . ,:,;> ,,.:, .... . Computerland

Peoria. ...!.. ■, .,.,..'.. . Warren Radio Co.

Rock Island. ,;....v Team Electronics

Skokie , Lillipute Computer

South Holland. . ....... Union Electronic Oist.

.'INDIANA .
Angola. . . . ''.'. \ . . ■':(, . . . Lakeland Electronics

Bloomington. , — 3 Stansiter Radio

Chesterton. ,, Chesterton Electronics

EvansviHe^ . t _ . . . \. . t -. . Hutch & Son

Gary.;.,'", ........ .'/',7; , . Calumet Bectronics

Indianapolis Heatbkil Electronic Center

Indianapolis -.'.'■ Warren Radio CO.

South Bend Genesis Electronics

Terre Haute Industrial Electronics

W. Lafayette Van's Electronics

IOWA

Ames Electronic Supply, Inc.

Burlington Union Supply Co.

Clinton. RJ.S, Electronics

Davenport Warren Radio Co.

Des Moines Radio Trade Supply

KANSAS

Overland Park. Burstein & Assoc

Salina. Electronics Inc.

Wichita Amateur Radio Equipment

Wichita ..,,... . Lloyd's Radio S> Bet.

Wichita. : ''-,..,'. R.S.C. ■Electronics

KENTUCKY

Lexington Radio Electronic Equip. Co.

Louisville .Heaihkit Electronic Center .

Louisville. .:.... Peerless Electronic Equip. Co.

Mt. Sterling. Electronic Shack

Paducah Warren Radio Co.

LOUISIANA
1 - i ! Rouge. . , . Davis Wholesale i Electronics

Baton Rouge Industrial Elect. Supply

Baton. Rouge. .......... Menard Electronics :

Broussard.:. W. . .'„ Menard Electronics
Gretna. .....".:......,-, pelican Electronics

Hourna. Pelican Electronics

Lake Charles. . ..... Wholesale Radio & Equip.

Motairte. Pelican Electronic Supply

New Orleans Wm, B. Allen Supply Co.

Shreveport Elect Supply ol Shreveport

Shreveport ...... Industrial Electronic Supply

Shreveport. Southern Electronics

MARYLAND

Aberdeen Harco Electronics

Annapolis. Computers. Etc.

Baltimore. ,< Heathkit Electronic Center

Baltimore. .' Tri ironies Inc.

Beltsvilte Mark Electronics

College Park. Electronics Plus

Damascus. .' Damascus C.B.

Glen Butnie '. Revacto of Maryland

Laurel. . ■ . , : ...,., The Comm Center .

Lavaie. ...... 7,'. .... . ; ; J8rM Electronics

Rockvilie Heathkit Electronic Center

Rockvllle. Revacto Electronics

Suitland. Suburban Wholesalers

; Towson t B»jnewtllB Eleclronln

MASSACHUSETTS

Peabody . .1 .. Healhkil Electronic Center

Pittslield. . Pittslield Radio Equipment

Springfield. Sydlee Electronic Supply

MICHIGAN

■Adrian. \, .',' r . ..... . . ... E&B. Bectronics

Adrian. ..'. Wedemeyer Electronics

Ann Arbor. Wsstemrftr Elect Supply

i Battle Creek.' . Warren Radio

Bay City. i. Kinds Distributing

Dearborn. . Westside Radio & TV.

i Detroit. ....-....' Electronic Parts Co.

Detroit. . S4S 'Electronics

East Detroit Electronic Parts Co.

East Detroit Heathkit Electronic Center

Hint. -.7 ..":.' . , ...'■.. , Slund Electronic*

Grand Rapids, Micro World Inc.

Grand Rapids Radio Parts Inc.

Grand Rapids.' T&W Electronics

Grand Rapids, Warren Radio

Houghton. .• .'. — Techtronics

Jackson Fulton Radio Supply

Lansing. , ,. Fulton Radio Supply.

Lansing.'.''. ....... Wedemeyer Elect Supply

Livonia . . Newest Electronics

Madison Heights Warren Radio

Melvin Dale. Advance Bectronic Services

Midfand, Computronix

Muskegon. .' :....'... :-a ..H&fl Electronics

Ni(es;C.. : Jv:";'. .Niles Radio Supply

Saginaw Ryder Distributing

Saginaw. Shanrj Electronics

Saint Clair Shores Bell Electronics Co.

. Taylor. ". ,.,.,, Tel Van Electronic Supply

Traverse City Traverse City Elect Supply

Wesilarsd.;. '., The Electronic Connection

MINNESOTA

Bemidji Bemidji Electronics

Duluih...... Northwest Radio of Duluth

Hopkins Healhki! < ■ ■ ■ • >\

Minneapolis, . Acme Electronics

Saint PauL Heathkit Bectronic Cenler

Winona Hiawatha Electronics

MISSISSIPPI

Biloxi. ...;.', :', X Electronic Parts

Blloxi. Hooper Bectronic Supply

Brookhaven. . .' Giliis Audio 4 Bectronics

Jackson EHinglonj:lectronic Supply

Pascagoula. . Hooped Bectronic Supply

MISSOURI

Heathkit Electronic Center

Cap§ Girardeau Show Me Electronics

Columbia. , Show Me Electronics

Kansas City Electronic Supply Co. Inc.

Kansas City. "'..... Wallers Radio

**' -• -.^ Me Electronics

Sedaiia. ; . , . Show Me Electronics

Springfield Show Me Electronics

iablG MONTANA

Wings Conley Radio Supply

q%$man Electronic Service & Dist

Great Falls Electric City Radio

NEBRASKA

Grand Island GlBectronics

Lincoln .- . Scott Electronic Supply

Omaha. Scott Bectronics

NEVADA

Las Vegas Century 23

Sparks %.., Computer House

NEW JERSEY

Edison. William ElectronicSupfjiy

Fairlawn. Heathkit Electronic Center

Mantua :. . . . Bectronic World

Ocean Heathkit Bectronic Center

Trenton Uraco/Lalayetls RarJio

Vmetarid ,...:,... Laraco/Vinetand

NEW MEXICO

Alamagordo ...:... Basin Electronics

Hobbs. Trice Electronics

NEW YORK

Amherst Heathkit Bectronic Center

Bethpage, ........... .;.Bectronlc No. 24 inc.

Buffalo. .-.Radio Equipment Corp.

Commack ■-.'■. Spartan Electronics

Homeil Homeii Electronics

Jamestoyyn, Warren Radio

Jericho! . ........ Heathkit Bectronic Center

Johnson City ?::■, Unicorn Electronics

Kingston Greylock Electronics

MkJdlatort Greylock Electronics

Newburgh Action Audio Inc.

New York Talt Electronics

H, White Plains. . . . . Heathkit Bectronic Center

Poughkeepsie L. Greylock Electronics

Rensselaer .Electronic Stockroom

Rochester Heathkit Bectronic Center

Troy Trojan Bectronic Sypply

Utica. Central Electronics

NORTH CAROLINA

Greensboro Heathkit Bectronic Center

Winston-Salem Trayer Inc.

NORTH DAKOTA

Fargo. Radio & TV Equipment

Fargo ..,....-.,,.. s/S Electronics

; MaincJan. ■..-.. .John Iverson Company

OHIO

Akron. Warren Radio

Canton. , '. Electronic Center Inc.

Cincinnati Heathkit Electronic Center

Cleveland ■ , . Heathkit Electronic; Center

Dover .'. .... T.V. Specialties

Lima Warren Radio

Mogadore Olson Electronics

Parma Superior Electronics

Reync-ldsburg ■ . . Universal Amateur Radio

Toledo. Haalhkit Bectronic Center

Toledo. ....,., , Warren Radio

lifl Amateur Electronic Supply

Youngslown Ross Radkt Co.

OKLAHOMA

Enid Trice Electronics

Lawton .7. Trice Electronics

McAllister Trice Electronics

Oklshomi City Trice EtecMct

Ponca City Trice Electronics

Tulsa Trice Electronics

OREGON

Albany. ..\\ . . . Oregon Ham Sales

Beaverrxn Norvac Electronics

Corvallis Zero Gee Electronics

Eugene Norvac Electronics

_ Portland .,.,. Portland Radio Supply

Salem : ". Computer Specialties

PENNSYLVANIA

Braddock Left Electronics

Buller Computer Center

Chambersburg Sunrise Electronic Oist

Drexel Hill. Kass Electronic Dist

Erie Warren Radio

Frazer. Heathkit Electronic Center

Uncaster Harco Bectronics

McKeesport Barno Radio

Norristown Computer Corner

Philadelphia Heathkit Electronic Center

Philadelphia Spectrum Electronics

Phoenrxville Stevens Radio Shack

Pittsburgh South Hills Electronics

York. Computer Center of York

RHODE ISLAND

Cranston Jabbour Electronics

Pawtucket Jabbour Electronics

Providence Hope Electronics

TENNESSEE

Bristol Shields Electronics

Chattanooga. Metro Computer Center

Chattanooga. Shields Electronics

Knoxville Shield's Electronic Supply

Memphis BluftCity Electronics

Memphis MemphisAmateur Electronics

Memphis. Warren Radio

Murfreesboro Standard Auto Parts

Nashville Eddie Warners Inc.

Nashville Electra Dist Co.

Oak Ridge National Electronics

Smyrna Delker Electronics

Tullahoma. H&H Electronics

TEXAS

Brownsville George's Electronic Mart

Dallas. . . . : Heathkit Electronic Center

Fort Worth Heathkit Electronic Center

Harligen George's Electronic Mat

Lubbock Trice Electronics

McAllen George's Electronic Mart

McKinney Collin Business Equipment

Richardson. Martin Wholesale Bectronics

Richardson Trice Electronics

Waco L&M Wholesale

UTAH

Midvale Heathkit Electronic Center

Ogden Carter Supply Co.

Provo Alpine Electronic Supply

Salt Lake City Kimball Electronics

Salt Lake City Mountain Coin Distributing

VERMONT

Burlington Greylock Electronics

Essex Junction I.E.S. Lafayette Radio

VIRGINIA

Alexandria. Heathkit Electronic Center

Annandale Arcade Electronics

Arlington Arlington Bectronic

Wnoluileri

Blacksburg Scotty's Radio & TV

Charlottesville Graves Electronics

Hamplon Cain Electronics

Harrisonburg Electrical Wholesalers

Lynchburg Electronic Service Co.

Norfolk Avec Electronics

Norfolk Cai'n Electronics

Norfolk Priest Bectronics

Richmond. Avec Electronics

Roanoke Avec Electronics

Vienna. Electronic Equipment Bank

Virginia Beach Cain Electronics

Virginia Beach Heathkit Electronic Center

Woodbridge E.G.E.

WASHINGTON

Bellevue A.B.C. Communications

Bellingham Cascade Electronics

Kennewick Satellite T.V.

Moses Lake Ron's Electronics

Olympra. The Bectronic Shop

Pullman H&O Bectronics

Richland Radio Shack

Seattle A.B.C. Communications

Seat le Amateur Radio Supply

Seattle Electronic Supply Co.

Seat le Heathkit Electronic Center

Spokane Bits. Bytes & Nibbles

Spokane Don's Stereo Center

Tacoma. C&G Bectronics

WEST VIRGINIA

Elkins CustomComputingCo.

Fairmont T.P.S. Electronics

Morgantown Electro Oist Co.

Wheeling Industronics

WISCONSIN
Kenosha. Chester Electronic Supply

FOREIGN

Gum: Agana. Marianas Electronics

Gtotermli Electronica Pan Americana

Pinimi Sonitel SA

Ptflima Tropelco SA

Puerto Rico Hato Rey Microcomputer Store

For Distributor Information, write or phone J1M-PAK, 1355 Shoreway Road, Belmont, CA 94002 [415] 595-5936

AUTHORIZED Dl

DISTRIBUTORS •

196 BYTE- FEBRUARY 1985

Inquiry 165

lim-pak One-Stop Component Center

M l Jimi.l!m.U ! .l.U.lll Quality Components O Over 700 Items Available From Our 500 i

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MICRO CHARTS

Instant Data on the Most Popular
Computer and Microprocessor Parts

• Fully decoded data

• Compact 8 1 £" x 1 1 " size

• Durable credit card plastic

• Clear and concise two-sided tables for:
Full instruction set, disassembly, ASCII,
base conversion, pinout & much more...

Part No. Description

MLZ80

ML6502

ML7400

ML8080A

ML8086

Z80 CPU
6502 (65XX)
5400/7400 TTL Pinouts
8080A/8085A
8086/8088

DATA
BOOKS

Part No.

Description

30001 Nat. CMOS (CD4000/74C)

30003 National Linear

30005 National TTL Logic

30009 Intersil Data

30013 Zilog Microprocessor

300 1 4 National Intuitive IC CMOS
Evolution

3001 5 National Intuitive Op Amps

300 1 6 National Voltage Regulator

30017 National MOS Memory

30018 National CMOS
(74HC, RAMs, PROMs)

30019 National Interface, Bipolar
(LSI & Memory), Prog. Logic

21 0830 Intel Memory Components

230843 Intel Microsystem

Components

FIBEROPTICS

The EDU-LINK Learning Kit

The EDU-LINK fiber optic
system is a low-cost, TTL
compatible data trans-
mission system designed
specifically as an educa-
tional tool for students and
engineersworking in many
different industries.

Includes:

• Transmitter PCB

• Receiver PCB

• One meter of plastic optic fiber

• All necessary electrical hardware

• Complete step-by-step instructions

• Theory of operation

• Tutorial information

Part No. ELK-1

OWI Educational
Electronic Robot Kits

Part No.

Description

PEPPY

MV915 Piper-Mouse (Sound Sensor)

MV91 6 Peppy (Sound/Touch Sensor)

MV918 Memocon Crawler

(Programmable Memory)

MV931 Mr. Bootsman (Wired Control)

MV935 Circular (Remote Control)

MV939 Medusa (Sound Sensor)

Additions to
INTEGRATED CIRCUITS

74LS00 Series

Part No.

Description

74LS273
74LS640
74LS641
74LS645

Part No.

8-Bit D Type Register
Octal Bus Transceiver (Inv.)
Octal Bus Transceiver (True)
Octal Bus Transceiver (True)

Linear

Description

LM387N Low Noise Dual Pre-Amp
NE558N Quad Timer
LM3905N Precision Timer

Microprocessor

Part No. Description

2732 A 32KEPROM(21V)

41 64N-200 64K Dynamic RAM (200ns)

61 1 6LP-4 1 6K Static CMOS RAM

(200ns) Low Power
6264P-1 5 64K Static CMOS RAM

(150ns)
6502B MPU with Clock (3MHz)

6845 CRT Controller (CRTC)

8085A CPU 8-Bit N Channel

8086 CPU 1 6-Bit (8MHz)

8088 CPU 1 6-Bit (8-Bit Data Bus)

8251 A Programmable Comm. I/O

(USART)
8253-5 Programmable Interval Timer

271 28 1 28K EPROM 250ns (21 V)

MM58167 Microproc. Real Time Clock

Part No.

OPTO-ISOLATOR

Description

4N33

Single Channel
Photo-Darlington

FANS

AND

ACCESSORIES

Part No. Description

MU2A1 Muffin Style Fan (4.68 inch square)

PWS21 07 Sprite Style Fan (3.1 25 inch square)

MFG481 Muffin-style steel wire finger guard

SFG648 Sprite-style steel wire finger guard

JgJi^

Part No.
Model 100

DATASHIELD

SURGE
PROTECTOR

Eliminates voltage spikes and
EMI-RFI noise before it can
damage your equipment or
cause data loss.

• 6 sockets • 6 ft. power cord

• Brown-out/black-out reset
switch • Brown-out notification
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DIODES

CRYSTALS

TRANSISTORS

SOCKETS

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SWITCHES
RESISTORS

LEDS
HEAT SINKS
KEYBOARDS

WIRE

SPEAKERS

TOOLS

CORDS

SOLDER

IC'S
BOOKS
CAPACITORS
and more...

CONNECTORS

SOLDER-TYPE CONTACTS

Part No. Description

57-30360 36 Contact Plug (Centronics)

57-60360 36 Contact Socket (Centronics)

57-30500 50 Contact Plug

57-60500 50 Contact Socket

GENDER
CHANGERS

CSS*

Part No.

Description

JRSMM Gender Changer (Connects 2 DB25P) RS232

JRSFF Gender Changer (Connects 2 DB25S) RS232

JCENMM Gender Changer (Connects 2 Male Centronics cables)

JCENFF Gender Changer (Connects 2 Female Centronics cables)

The Famous Silicon Chip

includes the popular verse:
"I'm a computer memory chip

Just a little brain
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Look through my window

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Part No. MKC-1
Memory Key Chain (Gold)

Inquiry I65

FEBRUARY 1 985 • BYTE 197

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Give yourself. United V\fay

£SuKil A Public Service of This Publication

United Way H>84

198 BYTE • FEBRUARY 1985

SCIENCE

A LOW-COST
DATA-ACQUISITION

SYSTEM

BY KlYOHISA OKAMURA AND KAMYAB AGHAI-TABRIZ

A compromise between cost and quality,
this system is adequate for many research projects

COMMERCIALLY AVAILABLE data-
acquisition systems are quite expen-
sive. A decent system may cost as
much as or more than the entire an-
nual equipment budget of an engi-
neering department at a small educa-
tional institution like ours. Our solu-
tion to this problem was to design
and build our own system. A reason-
able compromise between price and
quality, our system includes a Com-
modore 64 computer, a video display
a disk drive, and some miscellaneous
hardware for about $800. It has only
8-bit data acquisition, but you can
design a 12-bit system by using one
and one-half I/O (input/output) ports
(i.e.. 12 bits) as the data-input pins.
Furthermore, during breaks between
experiments, our system can provide
you with entertainment. Have you
ever heard of a data-acquisition
system you can play Pac-Man on?

Hardware

The circuit diagram to interface the
real world to the Commodore 64 is
shown in figure I, and the corre-
sponding hardware is shown in photo
1 . For analog-to-digital (A/D) conver-

sion, we use an 8-bit ADC0804. To
multiplex the multichannel analog
input signals, we use the multiplexer
(MUX) chip 4051. The outputs are
connected to data lines PB0-PB7 of
Complex Interface Adapter 2 (CIA2)
through the Commodore 64's User
Port CN2. The input channel selection
is done by the three bits PBO, PBI,
and PB2 of CIA1. which are connected
respectively to C(MSB), B, and A(LSB)
of the 4051. For example, channel
is selected by CBA-000, channel I by
CBA-00I, and so on. This multiplexing
arrangement can accept up to eight
analog signals. However, our plotting
software is limited to three channels.
The graphic resolution decreases as
the number of channels displayed on

Kiyohisa Okamura, an associate professor of
mechanical engineering and director of the
Applied High : Tech laboratory at North
Dakota State University (Fargo. ND 58105),
holds a Ph.D. from Purdue University. He is
also a technical consultant for US.-]apanese
biomedical engineering and computer busi-
nesses. Kamyab hghai^abriz is a graduate
student of mechanical engineering at North
Dakota State University.

the screen increases. Handshaking
between the ADC and CN2 can be
don e through a pa ir of connections:
WR(ADC) to PC 2 (Com modore 64)
and INT(ADC) to FLAGfCommodore
64). The latter is optional, and we
don't use it in our software.

The analog signal to be connected
to each input terminal of the MUX
CD4051 in figure I should be properly
conditioned, which involves amplify-
ing and biasing the signal so that the
voltage level is between and + 5 V.
because + 5 V is used as a voltage
reference in the ADC. The signal
should be made to come as close as
possible to the full range of the ADC,
without exceeding the full-range limit,
for maximum resolution. Therefore,
you may need an amplifier between
each transducer and the MUX. In our
case, since the output of each trans-
ducer was relatively large, we used an
analog computer for signal condition-
ing. For a very small signal you can
use a differential amplifier. According
to figure I , one of the two lead wires
for the input signal is for return and
should be grounded.

[continued)
FEBRUARY 1985 • B Y T E 199

LOW-COST DATA ACQUISITION

The ADC converts analog input volt-
age to 8-bit binary data with V cor-
responding to 00000000 and + 5 V to
11111111. The computer shows only
the decimal equivalent on the screen,
that is, to 2 55 for to 5 V, respec-
tively. Any value between thes4 two
extremes is proportionally converted.
For example, a converted data I (dec-
imal unity) corresponds to an analog
input to 0.02 V(I x 5/2 5 5). Similarly,
a data value of 37 corresponds to
0.73 V (3 7 x 5/2 55), and so on. If you
want to store or display the value of
input directly expressed in voltage, all
you have to do is divide the acquired
data by 51 (25 5/5).

Using this method of conversion to-
gether with a manufacturer's calibra-
tion data sheet for a transducer, we
can determine the correlation be-
tween the original physical quantity
and the acquired data in the com-
puter. Another method we often use
is direct calibration.

The accuracy of the A/D conversion
depends partly upon the accuracy
and stability of the voltage supplied
to REF/2 (pin 9). We used the refer-

ence voltage from the Commodore
64's 5-V power supply. Our measure-
ment shows that this voltage is actual-
ly 4.98 V with a ripple component of
less than 0.5 percent. It is quite stable
and accurate enough for under-
graduate experiments conducted in
our laboratories. If you want greater
accuracy, use a more reliable voltage
reference for pin 9.

The serial data is output to pin M
of CN2, which is connected to the
coaxial cable as shown in figure 2.
The other end of the cable is con-
nected to the serial port of a receiv-
ing computer either directly or
through a line driver/receiver, depend-
ing on the compatibility of the two
computers' serial ports. For example,
the Commodore 64 and TRS-80 we
are using in our laboratories are not
RS-232C-compatible. In the Commo-
dore 64, binary state I corresponds
to + 5 V and binary to V at pin M.
On the other hand, at the RS-232C
terminal of the TRS-80, binary state I
corresponds to V and binary to
+ 12 V. Therefore, these two com-
puters are incompatible in both

voltage levels and polarity. This in-
compatibility can be resolved by line
driver MCI 488 as shown. If the receiv-
ing computer uses + 12 V and - 12 V
with inverted polarity, you should con-
nect point P to the receiving RS-232C
With noninverted polarity, use point
Q instead.

We use a 500-foot coaxial cable to
connect a Commodore 64 in one
laboratory to a TRS-80 in another
laboratory. We haven't noticed any
voltage drop or noise at the receiv-
ing end.

Software

I Editor's note: The program for data acquisi-
tion is available for downloading via BYTEnet
Listings. The telephone number is (603)
924-9820.| The main portion of the
program uses several assembly-lan-
guage subroutines that are loaded in
machine-language form via BASIC
DATA statements. When you load the
program, the menu in photo 2 ap-
pears. The menu and software are
self-explanatory, so we'll only discuss
the software briefly. When download-
ing the program, eliminate all state-

<Z>

CONTROL
PORT 1
CN9

8 CHANNEL
INPUT

+ 5V

CD4051B

ft?

>10K

; ioopF

+5V

V |N+ WR

INTR

CLKR DB0

DB1

CLKIN

D82

CS ADC0804

RD DB3

V, N - DB4

AGND DB5

DGND DB6

DB7
REF/2

-wv-

+ 5V

0.1/iF

I SW1

SER OUT

+ 5V

■1

/p0.1/iF

PC 2

FLAG2
PB0

USER
PORT
CN2

Figure I : A schematic for the A/D converter for the Commodore 64 data-acquisition system.

200 BYTE- FEBRUARY 1985

LOW-COST DATA ACQUISITION

ments headed with REM except for
line 10, since they are strictly for com-
ment and if typed in, they occupy too
much space in RAM (random-access
read/write memory).

When the main program is ex-
ecuted, all subroutines written in
assembly language are poked into the
appropriate locations as sequential
data. Therefore, you should store the
data (listings 2, 3, 4, and 5) as sequen-
tial files. Assign names (listing2,
listing3, and so on) to these files.
When the main program is executed,
these programs will be poked into the
locations shown in the first column of
each listing.

A data-transmission subroutine is
part of the main program. The trans-
mission format is 2400 bps (bits per
second), 7 data bits, 1 stop bit, and
no parity check. This part of the pro-
gram is also self-explanatory, but you
have to remember to throw switch
SW1 to the + 5 V position when you
use it. The screen displays the data as
it is being transmitted from the Com-
modore 64. At the end of transmis-
sion, the screen displays an instruc-
tion: switch to ADC and press any key.
You then throw SW1 back to the
previous position so that the CIA is
connected to the ADC

The standard sampling rates of A/D
conversion programmed in the main
program are 1000, 500, and 100
samples per second; you can select
the rate as part of the data-acquisition
subroutine. In addition, you can set
any sampling rate by yourself by ad-
justing parameters qq and ww in line
1 1 10. This setting corresponds to the
default value when the instruction for
selecting the sampling rate is dis-
played on the screen. The maximum
rate available is 4360 samples per
second at ww = qq = 1 . If you have
three channels, this implies the sam-
pling rate of 1453 samples/second for
each channel. To lower the sampling
rate, just increase qq and/or ww.
These parameters are used in time-
delay loops in the assembly program
with parameter ww in the inner loop
and parameter qq in the outer loop.
Delay parameter ww has a greater ef-
fect on lowering the sampling rate

than parameter qq does. quency of the crystal oscillator is quite

To calibrate the exact sampling rate, accurately known, the sampling rate

we used a square wave from a crystal can therefore be determined,
oscillator as an input. Since the fre- [continued]

+12V

+ 12V

<*r^

SHIELD!

-12V

500 ft.

C-64

1
1
1

i
i

USER PORT CN2

i
i

/fc

-12V

+12V TRS-80H
4 PORT A

■JF

Figure 2: TTL (transistor-transistor logic) to RS-232C-level conversion.

Photo I : The A/D converter.

FEBRUARY 1985 • BYTE 201

.TM ,

The Silver Fox Trots
through Lotus like 1,2,3

The Silver Fox has always run hundreds
of programs originally written for the IBM-
PC. Now with its new compatible video
board and G W Basic it runs the most popular
and powerful software in microcomputing,
including Lotus 1,2,3, dBASE II, Multiplan,
the PFS series, and even Flight Simulator.
Yet you still get an incomparable combination
of hardware and software at a price that
invites comparison.

MORE HARDWARE

Each Silver Foxcomes with an8088CPU,
256K of RAM, monochrome and color video,
and a printer port all on a single board. Plus
you get more than twice the storage of a
standard PC, 1.6 Megabytes on dual 5 1/4"
f loppys, and the Fox will read and write to all
popular PC formats.

Standard equipment also includes a better
keyboard, and a 12" high-resolution, green
monochrome monitor, with a full 25x80
column display. AndalthoughtheSilver Fox
doesn't have "compatible" expansion slots
you can add serial ports, modems, plotters,
printers, joysticks, and 8087 co-processor,
and/or a hard disk.

Because the Silver Fox is born on a totally
automated line in Japan it is simply more
reliable than PC's that are assembled by
hand. So we back each Silver Fox with a one
year limited warranty, four times the industry
standard.

FREE SILVERWARE

Were this not enough, each Fox comes

with the best free software bundle in the
business including:
MS-DOS 2.11 Sketch Spell

Color BASIC 15 Games Mailit

GW BASIC WordStar FILEBASE

HAGEN-DOS CalcStar PC ftle III

Qwikdisc Easy Writer PD Disk

Datemate

If you didn't think your

$1397

could buy you this much computer,
give us a call at

602-941-5856

and we'll rush you a brochure that will
tell you how it can.

C'nlnrFnx $16HH

The Silver Fox is sold exclusively by Scott ad ale Systems
Ltd., 617 N. Scottsdale RoadffB. Smttsdale, AZ 8.5257.
Trademarks: Silver Fox. HAGEN-DOS. Qwikdisc. hatemate.
and Mailit; Scottadale Systems Ltd. WordStarand CalcStar.
Micropro International. MS-DOS. Multiplan. Microsoft
Corporation. F1I.KBASE. KWDP Software. Inc. dUASE II.
AshtonTate. IBM-PC, International Business Mochinvs
Corporation. Ordering: Telemarketing only. Silver Fox
price in for cash. F.O.B. Scottsdale. prices subject toehantfe.
prnduetsubject to limited supply. We arcept purchase orders
from Fortune 1000 companies and major universities with
Kood credit - adil U'l. Visa, Mastercard add ;l%, AZ residents
add (K. Returned merchandise subject to a 2(>"" restocking
fee. Personal or company check* take up to, 'J wt>eks to clear.
No COIVs or APO's.

LOW-COST DATA ACQUISITION

Photo 2: The software menu for the data-acquisition system.

The colors of screen background
and data dots are determined by line
1470 in listing I . You can change these
colors by replacing the number 22
with another number. The number
should be calculated as: 16 x (code
number of dot color) + (code number
of background color). In our example
we used the white dots and a blue
background. Hence, the number to
be poked in is: 16x1+6-22. You
can find the color codes in the
Commodore 64 reference manual.
You can also manipulate the color of
the border in graphic display by
changing the second number in line
1520.

When one channel of data is plotted
on the screen, each data point is
represented by one of 200 pixels in
the vertical direction. The resolution
represented by the error resulting
from bit mapping is 0.5 percent. With
three channels, the software divides
the vertical axis into three sections:
66 (top), 67 (middle), and 67 (bottom)
pixels. Hence, the resolution of each
channel is 1 . 5 percent. As the number
of channels increases, the resolution
decreases.

The program stores data sequential-
ly in RAM. In case of multiple chan-

nels (e.g., displacement x for channel
0, velocity v for channel 1, and ac-
celeration a for channel 2) the data is
stored in the following order: x(l), v(l),

a(\),x(2),v(2),a(2),x(3) where x(l)

and x(2) are the first and the second
bytes of data for x, and so on. They
are stored sequentially in RAM with
the starting address of 32769. The
number of data points for each chan-
nel is 320 by default but can be
changed. Since there are 320 pixels
in the horizontal direction of the
screen, 320 data points per channel
is the maximum number of data
points that can be displayed at one
time.

Conclusion

We've found this system perfect for
student use and adequate for some
types of research. Though the system
has many limitations, it is inexpensive
and, above all, it's better than no sys-
tem at all. ■

We would like to express our apprecia-
tion for the help Mr. William Welscher, a
graduate student of agricultural engineer-
ing at North Dakota State University, gave
us during the preparation of the manu-
script of this article.

202 BYTE • FEBRUARY 1985

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204 BYTE- FEBRUARY 1985

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CBS Mastering the SAT 81.00'

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Orion JBird(OBart Look Alike) 22.00*

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Spinnaker Most Amazing Thing

Virtual Comblnatlca Micro Cookbook

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(Pieaee add $2.50 shipping and handling tor each title order from below.)
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ATI How to use Multimate f> 42.00*

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Ash ton-Tale Fud ay! 158.00*
Borland Side Kick (Protected) 33.95*
Central Point Copy II PC 23.00*

► Conceptual Inatrumenta Desk Organizer 157.00*
Digital Research CP/M-86 33.00*
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Funk Software Sideways 36.00*
Harvard Harvard Project Manager 21 5.00*
Howards oft Tax Preparer 1985 165.00*

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Human Edge The Management Edge 145.00*
Human Edge The Sales Edge 145.00*
Human Edge Mind Prober 28,45*
Lattice C Compiler 270.00*

► Lotus Development Lotus- 1-2-3 ; 269.00'

MICroRIm RBase 4000
Microsoft CCompiler
Microsoft Word with Mouse—Latest Version
Microsoft Multipian
Monogram Dollars & Sense
► Multimate Multimate (Latest Version)
Oaala The Word Plus

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Samna Samna III Word Processor
Satellte Software WordPerfect
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Inquiry 246

We apologize for our evasiveness. After our
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The Shoebox Accountant:™ A complete accounting system for small business. 2160 East Brown Road, Mesa, Arizona 85203. 1-800-292-2962. CYMA

McGRAW-HfLL

206 BYTE • FEBRUARY 1985

Inquiry 80 for Dealers. Inquiry 81 for End-Users.

SCIENCE

FOURIER
SMOOTHING

WITHOUT THE
FAST FOURIER TRANSFORM

by Eric E. Aubanel and Keith B. Oldham

Ah in-depth look at using the Fourier transform
to remove noise from your data

IN THE SCIENTIFIC AND BUSINESS communities, gather-
ing and analyzing data are very important activities. Data
is often collected as a set of values of some variable (e.g.,
sales in business or current in electrochemistry) against
some independent variable, most often time, at evenly
spaced intervals. The data is then analyzed for the
presence of significant trends. Sometimes these trends are
difficult to discern because of the presence of noise or
other short-duration perturbations in the data. You can
attenuate the noise either by performing replicate ex-
periments and signal averaging or by smoothing the data.
The second approach is probably the less satisfactory of
the two; it is commonly adopted, however, because the
alternatives are more costly or time-consuming.

The three most common methods for smoothing data
are moving-average, least-squares, and Fourier transfor-
mation. In the moving-average method, each data point
is replaced by the average of itself and n neighboring
points on either side of it. The advantage of this method
is that it is very easy to program. The disadvantages in-
clude: the first and last n points are not smoothed to the
same degree as the rest of the data set because they don't
have n neighbors on each side of them; you must sample
at a rate much faster than the fastest transient that you
wish to study; and the method flattens the signal more
than other smoothing methods.

The least-squares method identifies the line of the order
you specify that minimizes the sum of the squares of
distances between the data points and the calculated line.
The advantages of this method are that it will permit you

to easily generate statistical information on the goodness
of fit, and it does not require that the data be collected
at regular intervals. The disadvantages of the method are
that it assumes that you know the basic form of the equa-
tion that the data satisfies, and the method is dispropor-
tionately biased by one or two very bad data points
because it will twist the line of fit to spread the error over
the entire data set.

Fourier transformation and inversion is probably the best
method, since it lends itself naturally to identifying and
eliminating noise. The reason for this is that noise is usual-
ly present at high frequencies, whereas the signal proper
is usually at low frequencies. Fourier transformation pro-
duces the frequency spectrum. By eliminating the high-
frequency portion of the spectrum and performing an in-
verse Fourier transform, you can obtain the original data
without much of the noise— the "smoothed" data. The
primary disadvantage of this method is that the data
points must be collected at regular time intervals.

There are several reasons why Fourier smoothing is not
practiced as often as other methods. Descriptions of
Fourier transformation are often couched in unfamiliar
jargon, though a few authors have succeeded in explain-
ing Fourier transformation theory in simpler terms (see

[continued)
Eric E Aubanel a fourth-year student at Trent University, is interested
in applications of mathematics to chemistry. Keith B. Oldham, a pro-
fessor of chemistry at Trent University, has taught and researched in
England, California, Australia, and Canada. Both authors can be
reached at Trent University, Peterborough, Ontario K9J 7B8, Canada.

FEBRUARY 1985 • B Y T E 207

FOURIER SMOOTHING

references). A second reason is the common misconcep-
tion that Fourier transformation and inversion are massive
number-crunching operations that require large computers
and cannot be implemented on the small personal com-
puters that people are increasingly using for data collec-
tion and processing. Further, the success of the "fast
Fourier transform" has spawned the belief that it is the
only practical algorithm for transformation and inversion.
Before discussing the principles and operation of our
BASIC subroutine for Fourier smoothing, let's look at the
discrete Fourier transform, the removal of high frequen-
cies, and the features of the fast Fourier transform. Our
program does not execute fast Fourier transformation,
though it does incorporate some of the same features.
It is not especially fast when executed in a high-level pro-
gramming language on a microcomputer, but it can achieve
excellent smoothing in an acceptable length of time.

Discrete Fourier Transformation

A good explanation of the continuous and discrete trans-
formations can be found in the article by Stanley and
Peterson in the December 1978 issue of BYTE (reference
I). We will outline only some of the important features
of the discrete Fourier transform.
Performing a discrete Fourier transform on a sequence

of real valued data x QI x ] x N _ { produces two sets of

real valued transforms:

(I)

] N-l

Re, = — E xi cos

* N ho >

(2)

'k =

_ 1 N-l

— L x\ sin

N /.o ]

ffl

k = 0,1 A/- 1

k = 0.1 A/- I

To regenerate the real valued data from the transforms,
the following operation is performed:

f fk

1 ■

■
■

■

Figure 1 : When the digital filter function is incorporated into
the FT algorithm, it eliminates all frequencies corresponding to
k > E from the discrete Fourier transform spectrum. Frequencies
corresponding to k < E are gradually attenuated.

(3)

Xj =

N-l

ft-0

/ 27rfe/\

R k cos y N J

j = 0,1 A/- I

The operation above is called Fourier inversion.

The information content of the original data is trans-
ferred, on Fourier transformation, into about the first half
of the Rfc Ifc numbers, i.e., those having < k < ^
(if N is odd; < k < f if N is even). The second half
merely duplicates the first in magnitude: R N _ k = R k , I N _ k
= -I k (see Stanley and Peterson for a good illustration
of this).

Removing High Frequencies

The procedure for removing high frequencies can be rep-
resented as a multiplication,

(4)

R k -* fk R k- l k - fk'k

by a function f k (the so-called digital filter function). The
simplest filter function is a rectangle, which would cut off
the transforms for k > E. Such a sudden cutoff can lead
to a false accentuation of frequencies corresponding to
transform points in the vicinity of E. lb avoid this you can
use a quadratic filter function, which results in a gradual
attenuation (see figure 1). The filter function we have in-
corporated into our algorithm is

(5)

1 -

(i)

k = I, 2, 3,. ..£-
k = E, £+1. ...

The smaller the value chosen for the integer E, the more
denuded of high frequencies the subsequent invert will
be: the closer E is to ^ (or to ^ if N is even), the less
affected the regenerated signal will be.

Because there is no purpose in calculating those values
of R k and I k that duplicate others or that will be replaced
by zeros, the equations for Fourier transformation and in-
version can be abbreviated to the following equations:

(6)

*o =

(7)

1 N-\

IT £ */

N N

/-i

( 2vjk '

K = 1,2 £-1

[continued]

208 BYTE • FEBRUARY 1985*

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Inquiry 265

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FOURIER SMOOTHING

(8)

-1 "-' . (2vjk\
\u = — £ Xj sin I — ■- 1

k = 1.2 £-1

(9)

(10)

R + 2

£-1

E
it- 1

= *0 + 2

£-1

*-i

//e*/e

/ftfycos (2*SE\ -/fe/ftsin /Ml

/27rfe/\ _/ fe/feSi n /2rfg\

j = 1. 2,

,N-

where x ; . is the high-frequency-stripped analog of x r Note
that R Q is now expressed separately from Rfc as well as
x from x., and that / = because sin = 0. The factor
of two in equations 9 and 10 is present as a result of
restricting E to be less than # and by taking advantage of
the symmetries (R N _ k = R k , I N _ k = -I k ) already noted.

Though we used the word "abbreviated" to describe
equations 6 through 10, their implementation still requires
a lot of computation. Approximately 20/VE multiplications
or divisions and 4/VE cosine or sine evaluations are
needed to implement these equations straightforwardly.
For example, if N=200 and £=20, about 16,000
trigonometric functions are needed, along with 80,000
multiplications. Some microcomputers take as long as 0.2
second to calculate a single trigonometric function and
would spend almost an hour on this aspect of a Fourier
program alone.

Fast Fourier Transforms

lb meet the problem of the large number of multiplica-
tions and other operations required to implement Fourier
transformation and inversion straightforwardly, the fast
Fourier transform (FFT) algorithm was invented. Books
have been written on this topic, but here we can do no
more than cite some of the features of the FFT,

The FFT has several advantages. (I) By using the prop-
erties of the sine and cosine functions, the number of
needed sines and cosines is drastically reduced. (2) Simi-
larly, the number of multiplications is drastically reduced,
these, in effect, being replaced by additions. (3) The same
routine, virtually unchanged, can be used for Fourier trans-
formation and inversion. (4) No storage space is needed
beyond that required for the initial data; the transforms
simply "overwrite" the original numbers. (5) The total pro-
cessing time is massively reduced, especially when N is
large.

The disadvantages of the FFT algorithm, for our present

purposes, are as follows. (1) lb function efficiently, N is
required to be a power of 2. (2) Even though far fewer
are needed, the evaluation of sines and cosines may still
be a bottleneck and therefore a memory-consuming "sine
lookup table" must be incorporated into time-efficient FFT
algorithms. (3) The algorithm is inherently "square," being
designed to generate 2/V outputs from 2N inputs; thus it
cannot exploit the potential savings in the "rectangular"
task of producing only £ outputs from N inputs. (4)
Because of the need to perform "bit inversions," program-
ming in anything except machine language is not efficient.

lb deal with situations in which the number of input data
cannot be conveniently made a power of 2, the technique
of "zero-filling" is often used. This inflates the number of
points to be processed from N to the next higher power
of 2— for example, from 200 to 2 56— with a consequen-
tial increase in storage and time requirements but without
any benefit to our present task. On the contrary, because
it may introduce a sharp discontinuity (see examples),
zero-filling hinders smoothing.

For data-smoothing purposes, the disadvantages of the
FFT often outweigh its advantages. This was the conclu-
sion we reached after we had implemented a smoothing
procedure that relied on a standard FFT routine. We there-
fore designed the algorithm that is the subject of this ar-
ticle. This new algorithm is not an FFT. It shares with the
FFT the first two advantages cited above but does not
share any of the disadvantages.

Principles of the Algorithm

Notice that equations 7, 8, and 10 are all of the form

(11)

r $ n (2irml\ _. . (2ml\

J m

when G, m. U m , V m , M, and ! are appropriately interpreted.
To evaluate expression 1 1 our algorithm uses the follow-
ing principle: The sum is split into odd-m and even-m terms,

(12)

MorM-l / 27T(m+l) ( ZTTl\

G = Jt, 3 "mCOs(-V-— )

+ V m sin

' 27r(m+lH 2jd\
N - N J

/ 27r(m+l)l 2t1 \
[ N - N )

M or/Vf-l

+ E

m-2,4

n ( 2iml \

Um cos (—)

+ V m sin

( 2wml \
\ N )

and the arguments of the trigonometric terms are
modified in the odd-m moiety. Next, addition formulas are
used to expand the modified functions and the m is then
replaced by 2m- 1 in the first summation and by 2m in
the second. After collection of terms, this leads to

[continued)

210 BYTE- FEBRUARY 1985

MICRO CAP and MICRO LOGIC
put your engineers on line...
not in line m@>

VUM«i

S~B

TfcfOVS

u a

< .

% /Vfc-XT/

" KJ

,Vf

lAyOhlrt WORKSTATION

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MICROCAP II lets you be even more
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employs sparse matrix techniques for
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■

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Demo prices are credited to the
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Now, to get on line, call or write today!

Spectrum Software

1021 S. Wolfe Road, Dept. B
Sunnyvale, CA 94087
(408)738-4387

Inquiry 295

FOURIER SMOOTHING

Listing I : The Microsoft BASIC version of the Fourier-
smoothing algorithm.

2 '*******************************************<
4 '* FOURIER SMOOTHING WITHOUT THE FAST FOURIER

TRANSFORM PROGRAM
6 '* By Eric E. Aubanel and Keith B. Oldham

8 '********************************************

10 CLS

12 INPUT "ENTER NUMBER OF DATA POINTS";N

14 REM LEAVING R AND I ARRAYS UNDIMENSIONED
LIMITS VALID VALUES OF E TO < = 1

16 N2 = INT((N + 1)/2+1):DIM X(N),X1(N),U(N2),V(N2)

18 FOR l = 0TO N-1

20 INPUT "ENTER DATAPOINT VALUE";X(I)

22 LPRINT "X(";l;") = ";X(I)

24 NEXT I

26 GOSUB 60

28 LPRINT "WHEN E = ";E;" THE SMOOTHED DATA
VALUES ARE:"

30 FORI = 0TON-1

32 LPRINT "X(";l;") = ";X1(I)

34 NEXT I

36 INPUT "IF YOU WANT TO TRY A DIFFERENT E,
ENTER 1 ELSE ENTER 0";MORE

38 IF MORE = 1 THEN GOSUB 60 ELSE IF MORE< >0
THEN 36 ELSE 42

40 GOTO 28

42 END

44 REM FOURIER ALGORITHM SUBROUTINE BEGINS
AT LINE 60. LINE NUMBERS ARE THE SAME AS
FOR THE HP VERSION OF THE SUBROUTINE

60 PI =3. 141593

70 PRINT "NUMBER OF TRANSFORM POINTS
TO BE KEPT";

80 INPUT E

90 IF E>INT((N + 1)/2) THEN PRINT "E TOO LARGE"

:GOTO 70
100 IF E< >INT(E) OR E< = 1 THEN GOTO 70
110 IF E<=QTHEN 870
120 REM

130 IF QoOTHEN 330
240 'CALCULATE R(0)
250 G =

260 FOR J = 0TO N-1
280 G = G + X(J)

290 NEXT J
300 R(0) = G/N
310 Q = 1
320 REM
330 PRINT "WORKING ON R(K) TRANSFORM

CALCULATIONS"
340 J2=INT((N-1)/2)
350 P1 = INT(LOG(2*J2 - 1)/LOG(2))
360 FOR K = QTO E-1
370 J1=J2

380 S = PI*K*2/N

390 C = COS(S):S = SIN(S)

400 FOR J = 1 TO J1

410 L = 2*J-1

420 U(J) = X(L)*C + X(L+1)

430 V(J) = X(L)*S

440 NEXT J

450

S = 2*S*C:C = 2*C*C-1

460

FOR P = 1 TOP1

470

U(J1 + 1) = 0:V(J1+1) =

480

J1=|NT((J1 +1)/2)

490

FOR J = 1 TO J1

500

L = 2*J-1

510

U = U(L)*C-V(L)*S + U(L+1)

520

V(J)=U(L)*S + V(L)*C + V(L + 1)

530

U(J) = U

540

NEXT J

550

S = 2*S*C:C = 2*C*C-1

560

NEXTP

570

R(K) = (X(0) + (U(1)*C + V(1)*S))/N

580

NEXTK

590

REM

600

PRINT "WORKING ON l(K) TRANSFORM

CALCULATIONS"

610

FOR K = Q TO E - 1

620

J1=J2

630

S = 2*PI*K/N

640

C = COS(S):S = SIN(S)

650

FOR J = 1 TO J1

660

L = 2*J-1

670

U(J)=-(X(L)*S)

680

V(J) = X(L)*C + X(L + 1)

690

NEXT J

700

S = 2*S*C:C = 2*C*C-1

710

FOR P=1 TO P1

720

U(J1 + 1) = 0:V(J1 + 1) =

730

J1 =INT((J1+1)/2)

740

FOR J = 1 TO J1

750

L = 2*J-1

1 760

U = U(L)*C-V(L)*S + U(L+1)

770

V(J) = U(L)*S + V(L)*C + V(L+1)

780

U(J) = U

790

NEXT J

800

S = 2*S*C:C = 2*C*C-1

810

NEXTP

820

l(K)=-((U(1)*C + V(1)*S)/N)

830

NEXTK

840

REM

850

IF E>QTHEN Q = E

860

REM

870

PRINT "WORKING ON INVERSE TRANSFORM"

880

REM

890

'CALCULATE X1(0)

900

F1 =0:F2 =

910

FOR K = 1 TO E-1

920

T = R(K)

930

F1=F1+T

940

F2 = F2+K*K*T

950

NEXTK

960

X1(0)»R(0) + 2*(F1-F2*(1/E/E))

980

REM

990

P1 = INT(LOG(2 * E - 3)/LOG(2))

1000

FOR J = 1 TO N - 1

1010

T2 = E*E

1020

FOR K = 1 TO E-1

1030

F=1-K*K/T2

1040

U(K) = R(K)*F:V(K)=-(I(K)*F)

1050

NEXTK

1060

K1=E-1

1070

S = 2*PI*J/N

[continued)

212 BYTE • FEBRUARY 1985

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FEBRUARY 1985 -BYTE 213

FOURIER SMOOTHING

1080

C = COS(S):S = SIN(S)

1090

FOR P = 1 TO P1

1100

U(K1+1) = 0:V(K1+1) =

1110

K1=INT((K1+1)/2)

1120

FOR K = 1 TO K1

1130

L = 2*K-1

1140

U = U(L)*C-V(L)*S + U(L + 1)

1150

V(K) = U(L)*S + V(L)*C + V(L+1)

1160

U(K) = U

1170

NEXTK

1180

S = 2*S*C:C = 2*C*C-1

1190

NEXTP

1200

X1(J)

= R(0) + 2*(U(1)*C + V(1)*S)

1220

NEXT J

1230

RETURN

Listing 2: The straight-line procedure for eliminating the
"end effect" can be MERGED with listing 1 without
modification. Note that this listing is not a stand-alone
program.

140 'STRAIGHT LINE CALCULATION
150 S1=0:S2 =
160 D = INT(N/10)
170 FOR J = 0TO D-1
180 S1=S1+X(J)

190 S2 = S2 + X(N-J-1)

200 NEXT J
210 X1 =S1/D:X2 = S2/D
220 M = (X2-X1)/(N-D)
230 B = (X1+X2)/2-M*N/2
270 X(J) = X(J)-M*J-B

970 X1(0)=X1(0) + B
1210 X1(J) = X1(J) + M*J + B

(13)

(14)

G = Jf, W2m-\c-V 2

■ls+U2m]cos(iSi)

[ u 2m-\ s + v 2

[C + V m \ Mil

(47rm[\
N )

where c and s are abbreviations for cos (lirllN) and sin
(lirllN). respectively. If Af is odd, equation 13 calls for the
values of U M+] and V M+] , which were not present in
equation 1 1 ; these terms are to be interpreted as zero.
A comparison of equations 1 1 and 1 3 shows that, at the
expense of having to evaluate two new coefficients, we
have condensed the number of summed terms by a fac-
tor of (almost or exactly, according to the parity of M)
2. A careful analysis shows that if such a condensa-
tion procedure is repeated P times, where P =
Int{log 2 (2M-l)}, then a single (m=l) term

G = newest U coefficient
+ [ newest V coefficient

1 ( 2 p+1 7rl \
j COS i^^J

remains, from which G is easily calculable.

By adopting this P-fold condensation procedure, we have
reduced the number of sines and cosines that each need
to be evaluated from M to P+ 1 . or from 1 98 to 9, for ex-
ample. In fact, you can get away with evaluating only one
sine and one cosine, since the arguments involved (2tIIN,

AvllN, SirllN 2 p+1 7r!//V) form a sequence in which

each is double the previous argument, allowing the
duplication formulas sin20 = 2sm0cos0 and cos20 =
2cos 2 - 1 to be used with advantage. It must be em-
phasized that our algorithm is for Fourier smoothing alone.

Operation of the Algorithm

{Editor's note: The listings reprinted here are Microsoft versions of
the authors HP programs. The HP listings are available on the
FROMBYTE file area of BYTEnet Listings, (603) 924-9820, under
the names FT.BAS and FTEXT.BAS.|

The data to be smoothed is entered into array X[f). I =
to N- 1, where N is the number of points. The number
of iterations of the condensation procedure, Q is initial-
ized to zero. Lines 140 through 230, 270, 970. and 1210
have been omitted from the subroutine listing. These lines
can be filled with a straight-line modification of the data,
which we will discuss in the next section.

The degree of smoothing, E, must be an integer greater
than 1 and less than Nil (half the total number of points).
The first transform calculated is R , followed by the evalua-
tion of R fc and \ k for k = Q to E- 1 (see below). Then the
first inverse transformed point lc is calculated, using
the quadratic filter function and R k . Finally, the rest of the
inverse transforms x^-, for / = 1 to N- 1, are calculated
using R k , l k and the quadratic filter function. These inverse
transforms consist of the smoothed data and are stored
in array X\{J), I = to N-\.

After one pass through the subroutine, you may want
to select a different degree of smoothing. To do so, you
execute the subroutine again. Since many of the trans-
forms will have been calculated previously (the number
currently existing is Q), this second execution of the sub-
routine will require fewer transform calculations (or none
if greater smoothing— i.e., a smaller E— is chosen).

Examples

Let's take a look at three types of applications of our al-
gorithm: on scientific data, meteorological data, and an-
nual agricultural statistics.

Our first example concerns electrochemical data ac-
quired in this laboratory during studies of very low con-

{continued)

214 B YTE • FEBRUARY 1985

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FEBRUARY 1985 -BYTE 215

FOURIER SMOOTHING

centrations of heavy metal in water. Because the signal
is so small it is contaminated with noise (see figure 2).
Fourier smoothing the data eliminates the noise, leaving
the signal proper. This illustrates the virtue of Fourier
smoothing experimental data acquired electronically, since
it can eliminate the high-frequency noise originating from
the instrumentation. The peak height, which is propor-
tional to the metal concentration, can be quantified easi-
ly from the smoothed curve.

Choosing the right degree of smoothing, by varying E,
is a matter of trial and error. The effects of undersmooth-
ing and oversmoothing are illustrated in figure 2. We ob-
tained the best smoothing when 3 < E < 9.

Consider a graph of daily maximum temperature
readings for the period of January 1982 to June 1983,
shown in figure 3. There is a clear seasonal variation, but
there is also a great deal of scatter. This scatter is caused

by short-term variations in the temperature due to chang-
ing weather conditions. To better examine the underlying
seasonal variations, it would help to eliminate the short-
duration fluctuations of temperature. A direct application
of Fourier smoothing, however, produces the red line
shown in figure 3, which is obviously not satisfactory. The
smoothed curve does not match the data at the ends. The
cause of this "end effect" is that some high frequencies
not due to noise were eliminated in the smoothing pro-
cess. The "genuine" high frequencies come from the
discontinuity between the beginning and the end of the
data. The discrete Fourier transform treats the data as
periodic; that is, it assumes that the last points are fol-
lowed by replicas of the initial points (see figure 4a). Thus
the transform "perceives" a sudden jump between the end
of one period and the beginning of the next. Sudden

[continued)

Figure 2: An example of Fourier smoothing scientific data. The
data represents a derivative neopolarogram at a static-mercury-
drop electrode. The black line, showing proper smoothing, was ob-
tained by N = 72. E = 8. 1m the red line, showing under-
smoothing, E = 20. \n the oversmoothed blue line E = 4.

Figure 3 : Daily maximum temperatures at the Peterborough.
Ontario, weather station from January 1982 through }une
1983. The red line (N = 546, E = 9) provides an example of
false smoothing due to an "end effect." To correct for this effect,
subtract a straight line (black) joining the ends of the un-
smoothed data. The resulting "normalized" smoothing is shown
by the blue line (E = 7).

(a)

* #

* M *

■ • * *

* *
# *

• . . '

Figure 4: An explanation of the "end effect',' which results
from the discrete Fourier transform treating the data as periodic
(a). The sudden jumps between one period and the next produce
"genuine" high frequencies (not associated with noise) in the
transform spectrum. To eliminate the "end effect',' subtract a

straight line joining the ends from the data. The result of this
operation is shown in (b). Notice that now the data begins and
ends at the same ordinate value, which means that there are no
sudden discontinuities from the transform's point of view.

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FOURIER SMOOTHING

jumps correspond to high frequencies, which in turn result
in more high frequencies in the transform spectrum.

The solution to the problem of retaining genuine high
frequencies from transformed data is to subtract a straight
line joining the beginning and the end of the unsmoothed
data Initially we thought of subtracting a line joining the
first and last points. However, since the unsmoothed data
contains a lot of scatter, the straight line joining the end
points would not necessarily match the beginning and end
of the trend. We dealt with this problem by taking the first
and last 10 percent of points, averaging each set, and join-
ing the two resulting points. The procedure consists of sub-
tracting the line from the unsmoothed data, smoothing
the modified data, then adding the line on to the
smoothed data. As mentioned before, the effect of sub-
tracting the line is to eliminate end discontinuities (figure
4b). To include this procedure in the smoothing
subroutine, you should merge the program steps shown
in listing 2 with listing I.

The result of treating the data in figure 3 with a straight
line is shown as a blue line, which produces a much bet-
ter fit. Note that a greater degree of smoothing is used
here than in the "unnormalized" (red) line. Since we have
now eliminated most "genuine" high frequencies, we can
filter out more high frequencies.

Historical statistics can be found on such varied sub-
jects as wheat production and the number of hospital
beds. In many cases there is an upward trend, due to the
increasing population and increasing costs, lb examine
a trend over a long period of time, you may want to
smooth the data.

Our third case concerns wheat production in Canada
from 1906 to 1974 (see figure 5). Here there is a great
deal of noise, which makes it difficult to draw a definitive
trend "by eye." The Fourier-smoothed curve shows an up-
ward trend, as expected, but not in a straight line. This
is important, because a straight-line fit might be an over-
simplification for a particular analysis.

There are other, more subtle sources of high frequen-
cies that will not be discussed but should be mentioned.

700000

OF BUSHELS )

o o
o o
o o

JSANDS

' •■#'

PRODUCTION

| 100000

1910

1920

1930

19d0

1950

1960 1970

YEAR

Figure 5: Unsmoothed (dots) and smoothed (line) statistical data
on wheat production in Canada from 1906 through 1974. The
large amount of scatter makes it difficult to draw a straight curve
through the data. Fourier smoothing accomplishes this quite well
given an appropriate choice of the degree of smoothing.
Smoothing parameters: N = 69, E = 3.

Sudden discontinuities other than the end type may oc-
cur in the data, and these may be treated by subtracting
several straight lines where appropriate. You can also han-
dle this problem by smoothing the continuous segments
separately instead of treating the data as a whole. Another
source of high frequencies is a sudden change in slope,
which is more difficult to correct. Here it is necessary to
subtract an appropriate curve that matches the portion
of the data that changes slope abruptly. ■

REFERENCES

1. Stanley, W. D., and S. J. Peterson. "Fast Fourier Transforms on
Your Home Computer." BYTE, December 1978, page 14.

2. Zimmermann, M. "A Beginner's Guide to Spectral Analysis,"
parts 1 and 2. BYTE, February 1981, page 68, and March 1981,
page 166.

3. Lord, R. H. "Fast Fourierforthe 6800." BYTE, February 1979,
page 108.

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68000 CROSS-ASSEMBLER - With
exhaustive field testing completed, our
68000 assembler is available for imme-
diate shipment. XMAC68K supports
Motorola standard assembly language for
the 68000 and 68010. Macros, cross-
reference, structured assembly statements,
instruction optimization and more. Linker
and librarian included. Comprehensive,
well- written manual.

To find out more, call us toll-free.

1-800-448-8500

(in

the U.S. Except Alaska and Hawaii)

VISA iind Mcislercoid aecepted. All pupuliirdi.se formats now available
please specify. Pncesdonoi include shipping t md handling uill (orexai I
quotes. OEM INQUIRIES INVITED.
Trademark of [ Jiqiuil Research **Tr«)ck'm.irk o( Murosod

AVOCET jf~
SYSTEMS INC,

Sales and Development:

10 Summer Street

P.O. Box 490. Dept. 285-B

Rockport, Maine 04856

(207) 236-9055 Telex: 467210 AVOCET CI

Corporate Offices:
804 South State Street
Dover, Delaware 19901

Inquiry 27

FEBRUARY 1985 -BYTE 219

74F00 NEW 74ALS00

Digitalker

SM7400N
SN7401N
SN7402N
SN7403N
SN7404N
SH7405N
SN7406N
SN7407N
SN7408N
SN7409N
SN7410N
SN7411N
SN7412N
SN7413N
SN7414N
SN7416N
SN7417N
SN7420N
SN7421N
SN7422N
SN7423N
SN7425N
SN7426N
SN7427N
SN7428N
SN7430N
SN7432N
SN7433N
SN7437N
SN7438N
SN7439N
SN7440N
SN7441N
SN7442N
SN7443N
W444N
SN7445N
SN7446N
SN7.147N
SN744SN
SN7454N
SN7459N
SN7460N
SN7470N
SN7472N
SN7473N

74LS0O
74LS01
74LS02
74LS03
74LS0.1
74LS05
74LS08
74LS09
74LS10
74LS11
74LS14
71LS15
74LS20
74LS2I
74LS2G
7-1LS27
74LS28
74LS3Q
74LS32
74LS37
74LS38

74LS47
74LS51
74LS73
74LS74
74LS75
74LS76
74LS85
74LS86
74LS90
74LS92
74LS93
74LS96
74LS107
74LS109
74LS112
74LS114
74LS122
74LS123
74LS125
74LS126

74S0O
74S02
74S03
74S04
74S05
74S08
74S09
74S10
74S11
74S15
74S20
74S22
74S30
74S32
74S37
74S38
74S51
74S64
74S65
74S74
74S85
74S36
74S112
74S113

CA3010H
CA3039H
CA3046N
CA3059N
CA3060N
CA3065E
CA30S0E

C0400I
CD4002
CD4006
CD4007

CD4010 16 4!

CD4011 14 2!

CD4012 14 ,2!

CD4013 14 ,3!

C04014 16 .8!

CD4015 16 .3!

CD4016 14 .4!

CD4017 IS .7!

CD40I8 16 7!

CD4019 16 4!

CD4020 16 .7!

CD4021 16 .7!

CD4022 16 .71

CD4023 14 2'.

CD4024 14 6!

CD4025 14 2!

C04026 IS 15!

CD4027 16 .4J

CD4028 16 .6!

CD4029 16 7<

C04030 14 3!

CD4034 24 1.7'

CD4035 16 J£

k CD4040 16 .7:
^^ (Msie In Ditilajl

Part No.

SN7474N

SN7475N

SN7476N

SN7479N

SN7480N

SN7482N

SN7483N

SN7485N

SN7486N

SN7489N

SN7490N

SN7491N

SN7492N

SN7493N

SN7494N

SN7495N

SN7496N

SN7497N

SN7410ON

SN74105N

SN74107N

SN7ni09N

SN7411EN

SN74121N

SN74122N

SN74123N

SN7412SN

SN74126N

SN74128N

SN74132N

SN74136N

SN74141N

SN74142N

SN74143.V

SN74144N

SN74145N

SN74147N

SN74148N

SN74150N

SN74151N

SN74152N

SN74153N

SN74154N

SN74155N

SN74156N

SN74157N

Pan No, Pins Price

SN74159N 24 195

SN74160M 16 50

SN74161N 16 59

SN74162N 16 ,59

SN74163N 16 59

SN74I64N 14 .69

SN74165N 16 69

SN74166N 16 69

SN741G7N 16 Z%

SN74170N 16 159

SN74172N 24 4.95

SN7.H73N 16 85

SN74174N 16 59

SN74175N 16 .59

SN74176N 14 79

SN74177N 14 79

SN74179N 16 1 49

SN74180N 14 69

SN74181N 24 1.95

SN74182N 16 1.05

SN74184N 16 2.29

SN74185U 16 229

SN74190N 16 69

SN74191N 16 69

SN74192N 16 69

SN74193N 16 .69

SN74194N 16 69

SN74195N 16 .49

SN74195N 14 .75

SN74197N 14 .75

SN74198N 24 1.19

SN74139N 24 1.19

SN74221N 16 119

SN74251N 16 79

SN74273N 2D 1 95

SN74276N 20 249

SN74279N 16 .79

SN742B3N 16 139

SN742MN 16 295

SN74285N 16 2.95

SN74365N 16 55

SN74366N 16 .55

SN74367N 16 .55

SN74368N 16 .55

SN74390N 16 149

SN74393N 14 1.49

74LS132
74LS133
74LS136
74LS138
74LS139
74LS145
74LS147
74LS148
74LS151
74LS153
74LS154
74LS155
74LS156
74LS157
74LS158
74LS160
74LS161
74LS162
74LS163
74LS164
74LS165
74LS168
74LS169
74LS170
74 LSI 73
74LS174
74LS175
74LS181
74LS190
74LS191
74LS192
74LS193
74LS194
74LS195
741S1S6
7.ILS197
74LS221
74LS240
74LS241

74LS244 •

74LS245

74LS251

7.1LS253

74LS257

74LS258

74LS260

74LS2G6

74LS273

74LS279

74LS280

74LS299

74LS322

74LS323

74LS347

74LS353

74LS364

74LS365

74LS366

74LS367

74LS368

74LS373

74LS374

74LS375

74LS386

74LS393

74LS3<19

74LS490

74LS533

74LS534

74LS540

74LS541

74LS640

74LS641

74LS644

74LS645

7.1LS670

74LS688

81LS95

81LS96

8tLS97

81LS98

H^Qg^j|^a

74S114

74S124

74S13?

74S133

74S135

74S136

74S138

74S139

74S140

74S1SI

74S153

74S157

74S158

74SI

7.1S169

74S174

74S175

74S188*

74S194

74S195

74S196

74S240

74S241

74S242
74S243
74S244
74S25I
74S253
74S257
74S258
74S260
74S273
74S280
74S287-
74S288"
74S299
74S373
74S374
74S387-
74S471-
74S472"
74S473-
74S570'
74S57V
74S572'
74Sr.73*

CA3061N
CA3082PJ
CA3083H
CA3086N
CA3089N
CA30S6N

CA313QE
CA3M0E

CA~li',.jH

(j'u St;:;-

CA3161E

■ l ,
CA318QE
CA340IN

CD4041
CD4042
CD40-13
CD4044
C04046
CD4047
CD4048
CD4049
CD4050
CD4051
CD4052
CD4053
CD4056
CD4059
CD4060
CD4066
CD4068
CD4069
CD4070
CD4071
C04072
CD4073
CD4077
CD4078
CD4081
CD4093
CD4094
CD4098
CD4099

CO4506

CI }■'.;.!)/
CD450B

CD-r-.H)
C0451I
CD4512
CIS4514
CD4515
CD4516
CD4518
CD4519
CD4520
CD4526
CD4528
C04529
CD453I
CD4538
CD454 1
CD4543
CD4562
CD4566
CD4583
CD4584
CD4723
CD4724
MC14410
MC14411
MC14412
MC14433
MC14572

74FOO 14 i:.,!/':: :■.:■'■■ ! :/

74F02 U Oirad 2-1npul NOR Gate 75

74F04 U Hex Inverter 89

74F0U 14 Ouad 2-lnjwl AND Gate 75

74F10 14 Tiiplc 3-lnpnl NAND Gale 75

74F32 14 Ouad2-lnputOFI Gale .79

74F74 14 Dual D Flip-Flop 85

74FB6 14 Ouad Exclusive ORGate. 1.15

74F109 IB Dual JK Positive Edge Flip-Flop ... 95

74F13B IB Expandable 3/8 Oecodct. . . 169

74F15/ 16 Quad 2 Input Multiple If, 9

74F158 IB Quad Hnpu IV.) . 1.6 l J

74F193 IB I H I ■ i 529

74F240 20 In -Si.n.- (lf:.i L.i'i- Unw. (.Inverting) 375

74F244 20 Tir-Staic Ocial Line Driver 149

74F257 IE T, Vi'i U ' n i i ?,' r, ^a 179

74F373 20 In :-,:.!•■. Qt hi LW.h 4 69

74ALSM) 14 Quad 2-tipul NANDGale 59

74ALSD2 14 Quad 2-lnput NOR Gale 59

74ALKM 14 Hcxlnvciter 59

74ALSOB 14 Quail 2-lnput AND Gale , . .59

74ALS1Q 14 Triple 3-lnput HAND Gate 59

74ALS3Q 14 8-lnpul HAND Gate 59

74ALS32 14 Duad 2-lnput ORGate 65

74ALS74 14 Dual D Flip-Flop 79

74ALS103 16 Dual JK Pos. Edge Flip-Flop 79

74ALSt3a 16 ExD.inil.iblc 3/8Dccodcr 1.25

74ALS24D 20 Til-State Octal Line Driver (Inverting) .... 2.25

74ALS244 20 li-Slate Dclal Line Driver 2 25

74ALS245 20 Dctal Bus Transceiver (Noa-lnv) 2 59

74ALS3/3 20 Tn-Slale Octal Lalch 2.59

MICROPROCESSOR COMPONENTS

— MICROPROCESSOR CHIPS -

Pins Functun

D765AC

1'.Sf;!.ii-

Z80

Z80CTC

Z80-DART

Z8D-DMA

Z80 P10

Z80S10/0

Z80-S1071

Z80-SI0/2

Z80S10/9

ZBDA

Z8QACTC

Z80A-DART

Z8DADMA

Z80A-PIO

Z8QAS10/0

Z80A-S10/1

Z80A-S10/2

Z80ASI0/9

Z80B

Z80D-CTC

Z80B-DART

Z80B-P10

Z8001B

Z800?fi

6502
6502A
6502B
6520
6522
6551

8031

8035

8039

8O40N-6

8060

B073N

8156
8205
8212
8224
8228
8237-5

S251A

8253

8255

B255A-5

8259

8272

8274

8279

8303
830-1
8310

INS1771-1
FD1791
F01793
FD1795

F0I797

40 Floppy Disk Controller

28 Ad* Multiplexer & Relrish Cnunlur

40 Syntlironous Daia inlt'ilatc (SIRCI.

Z80.Z80A.Z80B. Z8DO0 SERIES —

40 CPU (MK3880N) I780C) 2.5MH;

28 Counter Timer Circuit

40 Dual Asynchronous Rec.iTrans

40 Direct MemoryAcccssCircmt . . .

40 Parallel l/Q Interlace Controller. . .

40 Scnall'O (TxCB and RxCB Bonded) .

40 Serial I/O (LacksDTRB)

40 Serial I/O (Lacks SYNCH).

40 Serial I/O

40 CPU (MK3880N-4) (780C-1) 4MHj:

28 Counter Timer Circuit

40 Diiai AsynchronousRec /Trans

40 Dtiect Memoiy Access Circuit

40 Paiallel I'D Interlace Conlroller

40 Scti.il I/O (IxCB ami FlxCB Bonded) .

40 Serial I/O (Lacks DIRIi)

40 Serial I/O (Lacks SYNCI!)

40 Serial I/O

40 CPU (MK38B0N-6I 6MHj

ZB Counler limer Circuit

40 Dual Asynchronous Rec /Trans

40 Parallel l/Olnlerfacc Contmller. . .

48 CWSeGmented (10MM;)

40 CPUNon-Segiiienlc-illlOMlli) .

- 6500/8B00/6B000 SERIES

40 MPUwilh Clock 11MHz)

40 MPUwiltiClock (2MHz)

40 MPU wilh Clock I3MH/)

40 Peri[)heral Inter. Adaplc/

40 Penplieral Inlet Adapler

28 Async Comm Inteitace Aifapter

40 MPU

40 MPUwilh Clock anilRAM

40 CPU - 8-Bil (On-Ctiip Oscillator) . .

40 CPU - il-Ril (External Clockrng). .

40 CPU - 8-Bil (Ext Clocking) 2MHi .

24 128x8 Sialic RAM (2MHi|

40 Peripheral Inter. Ariapl (MC6820)

40 Peripheral IntsirtaccAdantcr (2MHz|.

40 CR1" Contioller (CRTC)

40 CUT Conlroller (CHIC) ?M\\i

24 Asynchronous Comm. Adapler .

24 0-600bps Digital MODEM

64 MPIJ16-Bit(8MH2)

40 General Purpose Int. Adapler

8000/80000 SERIES

40 Contnl Oriented CPU w/RAM S I/O. .

40 MPU -

1-Bit.

40 CllJ-Sgl Chip8-Bil (128bls RAMI.

40 CPU I258 bytes RAMI

40 CPU - 8-Bit NMDS

40 CPU w'Basic Microlnlerpreler

CPU

DS002GCN

MC3470P

■:•:■: l; .".Of-.
>'■; . •• .:■ i
MM5B 1 74AN
V.'. r.i.-A.'l

'.".i-vwirsr

40 Cl'l

40 CPU - 8- Bit N-Channel (5MHz) ... .

40 CPU 16-tiil 8MHi

40 Arithmetic Processor

40 CPU 8/16-Bit

40 HMDSRAM 1/0 Hnt-Tiinci.

40 HAM with l/DP»rtand Timci

16 Hi Speed I ou I o 1 8 (liiiaryDecoder.

24 8-Bit liipuVOutput (74S412) . .

16 Clock Gciicralr/Dnver

28 System Cont./BusDnver (74S428). . .

40 High Peri. Proij. DMA Com (5MH;I

28 System Controller (74S438)

24 l/D Expanderloi48 Scncs

40 Async Comm. Elcmeril

28 Prog Comm l/D (USART1 ......

28 Piot] Comm Interlace (USART).

24 Prog Interval Timer

40 Pioij. Penpheral I/O (PPI)

40 Proij, ftripheral l/D (PPI1 5MHi

28 Prog InterruptConlrol

40 SgleJOblc Density Floppy Disk Cont , .

40 Multi-Protocol Serial Cont, (72011

40 Prog toytioard/Drsplay Inieiiacc

Z0 Dctil Latch ■

18 Clock Gcneralor/Onvei

Zfl Dctal Bus Traascciver

20 Oclal Bus Transceivei (Inverted)

Z0 Bus Controller

20 8-BilTn-StatcBi-DirectioiialTrans ..

20 8-Bit Bi-Oirecliona! Receiver .......

20 OctalLatcncd Peripheral Driver

40 8-Bil Uniu Peripheral Inlertace. ....

40 HMDS EPROM MPU

40 MPU 8 Bit (EPROM Version ot B049I.

40 16KEI»HDMwilhl/D

68 Hi[|h Integration 16-liitMCU

68 High Integra 16-Bil MPU (8-Bil Dala Bus)

DISK CONTROLLERS

40 SinglcDensily

40 Single/Dual Density (Invj

40 Single/Double DcnsityfTmcl

40 Dual Density/Srde Select (Inv)

40 Dual Density/Side Select (Tiue)

SPECIAL FUNCTION -

alMOSCIockDrivtr |5MHi). .

. ComniumcalianChiP . ...

B Flnnpy Disk Read Amp 5yslem

K TV Camera Sync Geiwrator
Asynchionous Transniitter/ltecetve
Microprocessor Real TimcClock
Micio Compatible Time Clock. . .
Prof Oscrllator/TJivider (60H^) . .

8 Prog Oscillalor/Drvkler (lOOiti)

Low Profile [Tin) Sockets

ftiUti. 19 10-99 IMup

8pmLP
14pinLP
tOpinLP

1 8 pi n L P 26

20pinLP 30

22pmLP .31

24pmLP .33

28 pin LP .40

40pinLP .49

.46

SoldaiUil (Gold) Standard

PirtHn. |-9 10 99 100 up

SpinSG .39 .35 .29

14 pin SG .49 .45 .39

16 pinSG 55 .49 45

18 p.nSG .65 59 .51

20pmSG .75 .65 59

22pinSG .79 .69 .65

24pinSG .79 .69 65

28 pinSG 95 85 75

3B pinSG 1.25 1.15 99

40 pm SG 1.39 1.25 1.15

Puce

1103
4027

-111',!, ?

aiii-.'M
.Hint;.!
41MH-IM
. i if. ii
V i !

m ,■

: ■ i

VM '■?,■:
M.'.i :■,'■',:■ 1
1 :.".-. I'.U

2111
2112
2114N

2148HN

TMS4045

TMS40L47-45

5101

MM5257

HM6tl(iLP-3

HM6264P-12

HM6264P-15

IIM6264LP-15

27LSOO

74B9

74C921

74C930

7JSI89

74S289

82S10

82S25

10?4xl (300ns) 99

4096x1 (ZSOrtsI 1.49

1fi.3o-1x1 (15()ns) . 1.39-8/10.95
10.384x1 (200nsl 1.15 — B/8.95

lb'W-1.1 (250nsl 89 -8/6 95

65,536x1 (150ns) 519 - 8/4095

65.536x1 1200ns) . . 4.95 - 8/38.95

)!);'■! xl CJOtinsl 35-8/1.95

2(M8«1 |J65(t!) 35 - 8/1.95

k i,.,, ,ii. •

4096x1 (200ns) 2107 395

Hi 92x1 1200ns} 59

:'i'.2.l-l.l«lil50ns| 34.95

i,:M-Mxl ( 200ns) 31.95

131.072x1 (200ns) 24.95

— STATIC RAMS

255x4 (450ns) 8101 1 95

1024x1 (350ns) 89

1024x1 (250ns) LP 19 1L0?) . 1.49

256x4 (450ns)81l1 2.49

256x4 (450ns) MOS 2.49

1024x4 (450ns) . ... 1.29-8/9.95

1024x4 (450ns) LP .... 1.95 - B'13.95

1024x4 (200ns) I 39 - B/10.95

1024x4 (200ns) LP 1.69-8/13.49

4096x1 (70nsl 4.49

1024x4 (70ns) 4.95

1024x4 (450ns) 3.95

1024x4 (450ns) 1.95

206x4 (450ns) CMOS 3.95

■ |450ns) 4().14.

Z4 2048x8 (l?(n,-,iO.'!iS

795

1702A
2708
TMS2516

1MS2716

2716

27C16

2716 1

2/ti.!.J -3

2732

2732A-20

;»/.;:'A> ;
?7C:i?
,'/i ■-. 'i
2/ii-i-; v n
27(,i : ,; .

2764-45

?7(;(i.t
'.I

?,VM :•■:■.
.": .i .
74S188
/■l.'i.'ii,'
/ !.>;.■<;:(
/'.,'•

/•is-;;;'
/;s.:/:i

74Si/4

/-!:,-:/■>

M;;.;/<:
/■JSa/;-!

7-l!, ; /1

74S':.'.'

-/■K;i\
:i/S.'3

■;:-:, i,:;.

82SI23

:<.-■;•. i '(;
k;->;;i."»

HiSl.ii)
■!>-;ifi-;

82S191

DM87S181N

DM87S184N

DM87S185N

DM87S191N

(I2()nsil PCMOS

2U4HXH (150ns) CMOS 4.5ft

2l)4HxH (l-,)h )l •"'-. li.:y

,'iiivn en ■; '.r.,

:-'l).l!i,ll (200ns) LI 1 CMOS 549

8192x8 (120nsl CMOS 37.95

8192x8 |I20«s|LPCMOS. . 3995

8192x8 (150ns) CMOS 34 95

8192x8 (15011 i I i :.',;••:

ib 2:.f.xi ifiii-i.ii.p :•'<:.

15 Ilix4 (50ns) 3 101 2.25

18 ?!,!.» 4 (25llnsi CMOS 595

IB in M i

1G 16x4 (35ns)93405 2.95

16 16x4 (35ns) 3101 2.95

16 lu;»-'..l i>::n.,i(IC (93415) 3.95

16 16x4 (M)nslOC (/4S289) . , .2.25

PROMS/EPROHS

24 2'.6xB |l|.s| 3.95

U 1(174x8 (4MJ-15) .. 395

24 'nil,.,- i4L,"i,i./ir -155

24 ,;>,i ; .hxrt i-i5'.:ni .i nmqv? s-;y

::: - " ,, |4' i 10.95

i ' viillant: .... 7.95

Z< 2048x8 (450ns).
24 2048x8 CMOS. .
Z4 2048x6 (350ns)
24 204(1x8 (550ns) ... J./5

24 4' i'ri,/) i4!uj:i:,i 4.95

Z4 4090x8 (200ns) 21V 1149

1 I ieB (250ns) 21V 7,19

24 409(i*8 1450ns) 21V 649

24 -l';'!!-y;i CMOS 19.95

?4 4!,si'.xS 1300ns) 21V (CMOS) 2295

28 -• l ';,'«; i/i;.,:in-,l71V. , . 14 95

ZB 8192x8 (250ns|21V 7.19

ZB 8192x8 (450ns) 21V 649

28 8192x8 CMOS 21V. 2295

i ■! Vi (450ns)21V. . . 24 95

Z8 10384-t- '/' ' 'i i '. l C..i.-n2iV 2195
23 ' , , i I, K", ,!., , ,

16 32x8 <r "ii i i~

PROMTS |(m()1-1i l ,'J

PROM IS. 16.13 1-1) 1.79

1 1 > , ' '! ':><:.

i'ii'.JM IS Kvitjg-ll 4.95

PliOM IS IR349-H 4 95

PiiOMOC r6348) 4.95

FROM IS lDMt!7S296NI 4.95
i-fiiWiM: 16340). ' '

14 95

256x4

ZS6x4
256xfl
51?xB

'.i:sh

256x4

,-,.4
512x4

DC10

ADC0801

ADC0803

ADC0804

ADC0808

DAC0830
DAC0831
DAC1000
DAC1008
DAC1020
DAC1022

OAC1230
DAC1231
AT-5-10I3A

6 95

9.95

512x4 PROM OC. (6305) 2.95

512x4 PROM TS (6306) 2.95

1024x4 PROMOC (G352). . . . 4 95
1024x4 PROMTS 1K2SI37) . . , 4.95

32x8 PROMOC. (27S 18) 2.95

512xB PROM IS. (27S15) 9.95

37x8 PROM IS. (27S19) 295

PROMOC. (27S20) 2.95

PliOM IS (J7521) . 2.95

PROM OC (27512) 3.95

2043x4 PROM IS (TBP24S81). . 9.95

i 2048x8 (80ns) 14.95

I 1024x8 PROM TS. (B2S181) 9.95

t 2048x4 PROM i' i

I 204Bx4 PROMTS (82S185) .. . 9.95

I 2048x8 PROMTS. (82S 191) . . 14.95

- BATA ACQUISITION

f.!.-!-,l(*LlC.[>C<;i'iri>fK'r -5VtO"9V 2 95

'0 S Hit A.O I ill

!0 8- EIH A/D Converter I ' 1/2LSB) 4.95

!0 fl-flilA/UConwitcr (1LSB) 3.49

!8 8-Rit A/D Conv.w/8- Channel Analog 9.95

!B K-fH A-'D CwivcilL'i (B-Cfi Mulli.|. . . 4.49

10 8-fiil A'DConv w/16-Channel Analog 14 95

ID 8-fiil A/D Convener (16-Ch. Multi.) . 9.49

IB 8-Bil D/A Converter (0.78*0 Lin )...., 1.95

ID 8-liil D/A Converter (MC1408-7) 1.49

16 8-Iiil D/A Convertei (MCI 408-8). . . 2.25

!0 filii!l);)il.'Afeiv (!;', -.Lin i ','.•;;

!0 8-Bil Up D.'A Conv ( 10% Lin.l. . . 4.49

!4 U) ■>■[[} A Cimv Micro. Comp (005-;) 7.95

!0 10-BitD/AConv Micro. Comp. (0 70-. :| 6 95

16 10-Bil D/A Conv (0 05--:+i Lin.) 7.95

16 tO-Bil D/A Conv (0.20*6 lid) 5.95

18 12-Bil D/A Conv (0 20% Lin.) 6.95

to 12-Bil Up D/A Conv (.05% Lin.) 14.95

!0 12-Bil Up D/A Conv ( 10% Lin.) 13.95

10 30K BiurJ OART (TRISOZI 3.95

Win trtop f-m
Sockets ^•'
|Gold| Level #3

PirtHa. 1-9 10 99 100 up

8 pm WW .55 .49

10p.nW\V .69 65

14pinWW .75 69

16pinWW .79 72

IBpmVAV .95 85

20 pin WW 1.19 109

22prnWW1.29 t.19

24pmWW1.35 1.19

28pmWW1.69 1.55

36 pin WW 1.89 1.79

40pinWiM2.29 195

1.79

Header Plugs (Gold]

irtNn. 1-9 1099 100 -up

14 |

mil'

Id 1

nHP

.,9

24 [

n HP

t 15

Header Covers

14 pin HC .15 .13
16 pin HC 19 .17

24pinHC .29 .25

$10.00 Minimum Order - U.S. Funds Only
California Residents Add 6'/j% Sales Tax
Shipping - Add 5% plus $1.50 Insurance
SendS.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

VISA 9

1355 SHOREWAY ROAD, BELMONT, CA 94002
2/85 PHONE ORDERS WELCOME — (415) 592-8097 Telex: 176043

DT1050 — Applications: Teaching aids,
appliances, clocks, automotive, telecommunica-
tions, language translations, etc.

The DT1D5D is a standard DIGITALKER 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 of 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 DT1050 consists of a Speech Processor Chip, MM54104 (40-pin)
and two(2) Speech ROMs MM52164SSR1 and MM52164SSR2(24-prn)
along with a Master Word list and a recommended schematic
diagram on the application sheet.

DT1050 Digitalker™ $34.95 ea.

MM54104 Processor Chip $14.95 ea.

DT1 057 - Expands the 0T1 050 vocabulary from 137 to over 260
words. Includes 2 ROMs and specs.

Part No. DT1057 .$24.95 ea.

■llf&ffliEilgglllH

7045IPI 28 CMOS Precision Timer ... 14 95

7045EV/KH 28 Stopwatch Chip. XTL (Evaluation Kitl 1995

7I06CPL 40 3<? Digil A/D (LCD Drive) 10.43

FE0202D 40 4 Digit ICO Display lor 7105 & 7116 14 95

FE0203D 3W Digit LCD Display tor 7 1 06 S 7 1 1 6 1495

7106EWK.1 40 IC, Circuit Board, Display (Evaluation Kill .... 4695

7107CPI. 40 3'5 Digit A/0 ILED Drivel. . 1095

7107EV/Kit 40 IC. Circuit Board. Display (Evalualion Kil) 46.95

7116CPL 40 3<?0ig<tA/DLCDDis.HLD 10.95

72011US Low Battery Will Indiotor 2 25

7205IPG 24 CMDSLED Stopw.ilch/limer 14 95

7205EWKit 24 Stopwatch C/iip.XTL (Evalualion Kill 1695

7206CJPE 16 Tone Generator 4.95

7206CEV/XH IB Tone Geneialor Chip. XTL (Evaluation Kit). ... 7 95

7207AIP0 14 Dscillalor Controller. . 5 95

7207AEV/Kit 14 Freq Counter Chip. XTL (Evaluation Kil) 8.49

72I51PG 24 4 Func. CMDSSbpwatch CKT 1695

72t5EV/Kit 24 4 Func. Stopwatch Chip. XTL (Evaluation Kil). 1949

7216AUI 28 8 Digit Univ. Counter CA .. . 3149

7216D1PI 28 8 Digit Fieq. Counter C.C .2149

7217IJI 28 4 Digit LED Up/Down Counter CA 1095

72I7A1PI 28 4 Drgrt LED Up/Down Countei C C 9 95

7224IP1. 40 LCD % D.gil Up Counter DRI 10 95

7226AEV/Kj| 40 5 FunclionCounlcr Chip. XTL (Evaluation Kil) . . 9995

1 30009 19B3 INTERSIL Data Book i

74HC High Speed CMOS

74HC00 14

74HC02 14

74HC03 14

74HC04 14

74HCU04 14

74HC08 14

74HC10 14

74HC11 14

74HC14 14

74HC20 14

74HC27 14

74MC30 14

74HC32 14

74HC42 16

74HC51 14

74HC58 14

74HC73 14

74HC74 14

74HC75 16

7.1HC76 16

74HC85 16

74HC86 14

74HC107 14

74HC109 16

74HC112 16

74HC123 16

74HC125 14

74HC132 14

74HC137 16

74HC138 16

74HC139
74HC147
74HC151
74HC153
74HC154
74HC157
74HC158
74HC160
74HC161
74HC162
74HCI63
74HC164
74HC165
74HC166
74HC173
74UC174
74HC175
74HC190
74HCI91
74MC192
74HCI93
74HC194
74HC195
74HC221
74HC237
74HC240
74HC241
74HC242
74HC243
74HC244

74HC245

74HC251 16

74HC253 16

74HC257 16

74HC259 16

74HC266 14

74HC273 20

74HC280 14

74HC299 20

74HC366 16

74HC367 16

74HC373 20

74HC374 20

74HC390 16

74HC393 ?4

74HC533 20

74HC534 2d

74HC595 16

74HC688 20

74HC4024 14

74HC4040 t6

74HC4060 16

74HC4075 14

74HC4078 14

74HC4511 16

74HC4514 24

74HC453B 16

74HC4543 16

74COO
74C02
74C04
74C08
74CI0
74C14
74C20
74C30
74C32
74C42
74C48
74C73
74C74
74C85
74C86
74C89
74C90
74C93
74C95

74C107
74C15I
74C154
74C157
74CI60
74CI61
74C162
74C163
74C164
74C165
74C173
74C174
74C175
74CI92
74C193
74CI95
74C22I

IZLAim

74C240
74C244
74C373
74C374
74C90I
74C902
74C903
74C906
74C907
74C9II
74C9I2
74C915
74C917
74C922
74C923
74C925
74C926
80C95
80C97

TL07ICP 8

TL072CP 8

TL074CN 14

TL081CP 8

1L082CP 8

TL084CN 14

LM109K

LM301CN 8

LM302H

LM304H

LM305H

LM307C/J 8

LM308CN 8

LM309K

LM310CN i

LM311CN 8

LM312H

LM317T

LM317K

LM318CN 8

LM319N 14

LM320K5

LM320K12

LM320K-15

LM320K-24

LM320T-5

LM320T-12

LM320T-15

LM320T-24

LM322/J 14

LM323K

LM324N 14

LM329DZ

LM331N 8

LM334?

LM335Z

LM336Z

LM337MP

LM337T

LM338K

LM339N 14

LM340K-5

LM340K-12

LM340K15

LM340K-24

LM340T-5

LM340T-12

LM340T-15

LM340T-24

LF347N 14

LM348N 14

LM350K

LF351N 8

LF353N 8

LF355N

LF356N

LM358N

LM359N

LM370N

LM373N

LM377N

LM380CN

LM380N

LM381N

LM382N

LM3B4N

LM386N-3

LM387N

LM389N

LM391N-80 16

LM392H

LM393N

LF398N

LM399H

LF412CN

TL494CN

TL496CP

NE531V

HE544N

NE550A

NE555V

XR-L555

LM556N

NE558N

NE564N

LM565N

LM566C^;

LM567V

NE570N

NE571N

NE592/J

LM703CN

LM710N

LM7I1N

LM723N

LM733N

LM739N

LM741CN

LM747N 14

LM748N 8
OA760HC

LM1456V 8

LM145BCN 8

LM1488N 14

LM1489N 14

LM1496N 14
LM1605CK

LM1800N 16

LM1871N 18

LM1872N 18
LM1877N-9 14

LM1883N 18

LM1896N 14
LM2002T

ULN2003A 16

XR2206 16

XR22Q7 14

XR2208 16

XR2211 14 :
LM2877P

LM2878P ;

LM2901N 14

LM2902N 14

LM2907N 14 :

LM2917N 8

LM3900N 14

LM3905CN 8 1

LM3909N 8

LM3914N 18 \

LM3915N 18 !

LM3916N 18 !

RC4136N 14 l

HC4151H8 8 I
RC4195TK !

LM4250CN 8

LM4500A 16 I

NE5532 8 1

NE5534 8
79W05AH

ICI.8038 14

LMI3080N 8

LM13600N IB

76477 28
K0RE HW81E

30003 1982 Nat. Linear Data Book ti952pgs) $11.95

220 BYTE ■ FEBRUARY 1985

Inquiry 16 1

Commodore Accessories ProModem 1200 and Options Apple® Accessories

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. A 4-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

Gre a - «

JE520AP

JE52QCM

• Over 250 word vocabulary-affixes allow the formation of more
than 500 words • BuilUn 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'/<"L x 3V«"W x 1-3/8"H

APPLICATIONS: • Security Warning • Telecommunication

• Teaching • Handicap Aid

• Instrumentation • Games

JE52QCM ForCommodore 64 & VIC-20 $114.95

JE52QAP ForApplelt. II+. and//e $149.95

Computer Memory Expansion Kit

IBM PC, PC XT and Compatibles

Most ol the popular Memory Boards (e.g. OuadrarrT Expansion Boards)
allowyou lo add an addilional 64K. 1 28K. 192K or 2S8K. The IBM64K Kil will
populale these boards in 64K byle incremenls. The Kil is simple lo install-
just insert the 9 - 64K RAM chips in the provided sockets and set the 2 groups
or switches. Complete conversion documentation included.

IBM64K (Nine 200ns 64K RAMs) $43.95

IBM PC AT

Each kit comes complete with nine 1 28K dynamic RAMs and documentation
tor conversion.

IBM128K (Nine 200ns 1 28K RAMs) $1 99.95

APPLE He

Extended 80-Column/64K RAM Card. Expands memory by 64K to give 128K
when used with programs like VisiCalc". Fully assembled and tested.

JE864 $99.95

TRS-80 MODEL I, III

Each Kitcomescamplete with eight MM5290IUPD41 6/4 1 16) 16K Dynamic
RAMs and documentation lor conversion. Model 1: 16K equipped with Ex-
pansion Interlace can be expanded to 48K with 2 Kits. Model (II: Can be
expanded from 16K to 48K using 2 Kits. Each Kil will expand computer by
16K increments.

TRS-16K3 200ns (Model III) $8.95

TRS-16K4 250ns (Model 1) $6.95

TRS-80 MODEL IV & 4P

Easy tomstallKitcomescompIele wilh 8ea.4164N-20 (200ns) 64K Dynamic
RAMsand conversion documentation. Conveits TRS-80 Model IV computers
from 16K to 64K. Also expands Model 4Pfrom 64K to 128K.

TRS-64K-2 $38.95

(Converts the Model IV from 16K to 64K or will expand the Model 4Pf rom
64Kto 128K)

TRS-64K2PAL (Model IV only) $59.95

(8 ■ 4164s with PAL Chip to expand from 64K to 128K)

TRS-80 COLOR AND COLOR II

Easy to install Kil comes complete with 8 each 4164N-20 (200ns) 64K
Dynamic RAMs and documentation lor conversion. Converts TRS-80 Color
Computers wilh D, E. ET F and NC circuit boards lo 32K. Also converts
TRS-80 Color Computer II to 64K. Rex DOS or OS-9 required to utilize
lull 64K RAM on all computers.

TRS-64K-2 $38.95

£1 ^d^steies Protect Yourself...

1**. DATASHIELD®

fjl^A Surge Protector

I ^A^ft^^ • Eliminates voltage spikes and EMI-RH noise

1^^^^ before i! can damage your equipment or cause

\ J data loss • 6 month warranty • Power dissipa-

1 00 ■-* tion (1 00 microseconds): 1 .000.000 watts • 6

1 ~*T J^~ sockets ■ 6 foot power cord • Normal line volt-

\ *^ age indicator light ■ Brown out/black out reset

Model 100. . Tff. $69.95

Protect DATASHIELD

Yourself... Back-Up

r — Power Source

k Provide sup to 30 minutes of continuous 120

■Sfe j- I '■' i VAC 60Hz power to your computer system

\ a fj (load dependent) when you have a black out

\. or voltage sag • Six month warranty • Weight

X (PC200): 24 lbs.-(XT300): 37.5 lbs.

PC200 (Output rating: 200 watts) $299.95

^XT300 (Output rating: 300 watts) $399.95

p£ Intelligent 300/1 200 Baud
Prometheus Telephone Modem with
Real Time Clock/Calendar

The ProModem™ is a Bell 212 A (300/1200 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-1 6K (Options Processor Memory - 1 6K) $1 0.95

PMO-32K (Options Processor Memory - 32K) $20.95

PMO-64K (Options Processor Memory - 64K) $39.95

PM-ALP (Alphanumeric Display) $79.95

PM-Special (Includes Options Processor, 64K Memory

and Alphanumeric Display) 5189.95

5W APPLE™

Direct Plug-In

Compatible Disk Drive

and Controller Card

The ADD- 51 4 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 3WW x
8-9/16"D ■ Weight: 4% lbs.

ADD-514 (Disk Drive) $169.95

ACC-1 (Controller Card) $ 49.95

More Apple Compatible Add-Ons...

APF-1 (Cooling Fan with surge protection). . . . $39.95

KHP4007 (Switching Power Supply) $59.95

JE614 (Numeric/Aux. Keypad for He). $59.95

KB-A68 (Keyboard w/Keypad for II & |]+) $79.95

MON-12G (12" Green Monitor for ll.ll+.J/e.llc). . . . $99.95

JE864 (80 Col. +64K RAM for lie) $99.95

ADD- 12 (5<V Half-Height Disk Drive) $179.95

DISK DRIVES

KEYBOARDS

■asms

13Vb"Lx4V'Wx VH

New!

16-9/16"Lx6WVx1VH

NEW!

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 • SPST mechanical 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 11+

•Keyboard: Direct connection with 16-pin ribbon

connector -26 special functions -Size: 14'^"L x

5VWx1'A"H

• Case: Accommodates KB-A68 • Pop-up tid for

easy access ■ Size: 15MTW x 18*0 x 4Y*"H

Price

KB-EA1 Apple 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 . amp (also +30VDC regulated) • Input: 1 1 5VAC. 6 H z

• Two-tone (black/beigo) self-enclosed case • 6 foot, 3-conductor black
power cord • Size: 6'?" L x 7" W x 2V H ■ Weight: 3 lbs.

PS51194 $14.95

Document ation " Vv ^ 1 ■ 5i^^ ° e $t
Included V.^^^ ^W

MPI51S (MPI 5 1 /4" SS full-ht.) $ 89.95

RFD480 (Remex 5 1 /4" DS full-ht.) $129.95

TM100-2 (Tandon 5V4" DS full-ht.) $159.95

FD55B ' (Teac 5V4 " DS half-ht.) $149.95

SA455 (Shugart 5 1 /4" DS half-ht.). ... $1 59.95

FDD100-8 (Siemens 8" SS full-ht.) $139.95

PCK-5 (5V 4 " Power Cable Kit) $2.95

PCK-8 (8" Power Cable Kit) $3.95

UV-EPROM Eraser

| 8 Chips - 21 MinuteT

i% ^St L}

Power/Mate Corp. REGULATED POWER SUPPLY

• Input: 105-125/210-250VACat 47-63 Hz • Line regulation: ±0.05% • Three
mounting surfaces • Overvoltage protection • UL recognized • CSA certified
Part No. Output Size Weight Price

EMA5/6B
EMA5/6C

5V@3A/6V@2.5A 4VL x 4"W x 2 VH 2 lbs.
5V@6A/6V@5A 5 VL x 4VW x 2VH 4 lbs.

$29.95
$39.95

KEPCO/TDK 4-OUTPUT SWITCHING POWER SUPPLY

• Ideal for disk drive needs of CRT terminals, microcomputers and
videogames • Input: 1 15/230VAC, 50/60Hz- Output: +5V@ 5 Amp, + 12V@
1.8 Amp, +12 V @ 2 Amp. -12V @ 0.5 Amp • UL recognized • CSA certified

• Size: 7VL x 6-3/1 6"W x 1 %"H • Weight: 2 lbs. CCQ QC po c K or

MRM 174KF 2 for $99.95

Switching Power Supply for APPLE II, II+ & //e™

• 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, +12V @ 1.5A, -5V @ .5A. -12 V @ .5 A

• Direct plug-in power cord included • Size: 9%"L x 3WW x 2V4"H
■ Weight: 2 lbs.

KHP4007 (SPS-109) $59.95

4-CHANNEL SWITCHING POWER SUPPLY

* Microprocessor, mini-computer, terminal, medical equipment and process
control applications -Input: 90-130VAC. 47-440Hz -Output: +5VDC @ 5A,
-5VDC@1 A;+12VDC@1A.-12VDC@1A- Line regulations: ±0.2% • Ripple:
30mV p-p • Load regulation: ±1% • Overcurrent protection • Adj: 5V main
output ':10% • Size: 6%'Lx 1VW x 4-1 5/16"H • Weight: 1fe lbs.

FCS-604A. $69.95

$10.00 Minimum Order — U.S. Funds Only
California Residents Add 6V?% Sales Tax
Shipping — Add 5% plus $1.50 Insurance
Send S.A.S.E. tor Monthly Sales Flyer!

Spec Sheets — 30c each
Send $1.00 Postage for your
FREE 1985 JAMECO CATALOG
Prices Subject to Change

E32

Ml!i >

ameco

ELECTRONICS

1355 SHOREWAY ROAD, BELMONT, CA 94002
Z/85 PHONE ORDERS WELCOME — (415) 592-8097 Telex: 176043

1 Chip - 15 Minutes

Erases all EPROMs. Erases up to 8 chips within 21 minutesd chip
in 15 minutes). Maintains constant exposure distance of one inch.
Special conductive foam liner eliminatesstatic 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

3r>. - J

JE664 EPROM PROGRAMMER
8K to 64K EPROMS - 24 & 28 Pin Packages

Completely Self-Contained - Requires No Additional Systems lor Operation

• Programs and validates EPROMs ■ Checks for properly erased EPROMs

• Emulates PROMs or EPROMs • RS232C Computer Interlace (or editing and
program loading • Loads data into RAM by keyboard ■ Changes data in RAM
by keyboard • Loads RAM from an EPROM < Compares EPROMs for content
differences - Copies EPROMs • Power Input: 1 1 5VAC. 60Hz. less than 10W
power consumplion ■ Enclosure: Color-coordinated, light tan panels wilh
molded end pieces in mocha brown - Size: 15VL x8*TD * 3VH • Weight:
5fc lbs.

The JE664 EPROM Programmer emulates and programsva/ious 8-Bil WordEPROMslrom 8Kto
64K-0il memoiycapactty. Data can be entered inlo Ihe JEB64's internal 8K x B-Bil RAM in three
ways: ( I ) from a ROM or EPROM; (2) Irom an external computer viatheoptional JE665 RS232C
OUS: 13) from iis panel keyboard. The JE664's RAMs may be accessed for emulalion purposes
from Ihe panels lest socket to an external microprocessoi. In programming and emulalion, Ihe
JE664 allows for examination, change and validation of program lonient The JE664's RAMs
can be prog rammed QuicWy loali "l"s (or any value), allowing unused addresses m the EPROM
to be programmed later without necessity of W erasing. The JE664 displays 0ATA and
ADDRESS in ionvemenl hexadecimal (alphanumeric) formal A "DISPLAY EPROM DATA"
button changes Ihe 0ATA readout Irom RAM word lo EPRGM word and is displayed in boll)
hexadecimal andbinarycode.Thelrontpanel featuresa convenientoperalingguide.Tlie JE664
Programmer includes one JM16 A Jumper Module(as listedbetow).

JE664-A EPROM Proorammer ,

Assembled S Tested (Includes JM16A Module)

JE66& - RS232C INTERFACE OPTION - The RS232C interlace Optra

computer access to Ihe JEG64's RAM. This allows Ihe computer to manipulate, store and
transler EPROM data toand from Ihe JE664, A sample program listing is supplied in MBASlC for
CP/M computers. Documentation is provided lo adapt the software to other compule/s wilh an
RS232port. 9600 Baud.8-bil word, odd pantywith 2 stop Oils

EPROM Programmer w/JE665 Option
JE664-ARS $1195.00

Assembled & Tested (Includes JM16A Module)

$995.00

EPROM JUMPER MODULES - The JE6G4s JUMPER MODULE (Personality Module) is a
plug-in Module lhal presets Ihe JE664 for Ihe proper programming pulses totheEPRDMand
conligures Ihe EPROM socketconnections torthal particular EPROM.

JBHIHW

«rtW

EPWK UMlff/OTUa

ABBA

2SV

AU;1. KKycta, K?.;_ h: L : II

. 114 95

JMT6A

27t6.TMS2S1&(TI)

25V

Intel MolmKa. Nat. NEC. Tl,
AMD. H.lachi. htosfc* .

. 11495

JM16B

TMS27I6I3VSI

5V.+SV,M2^

Vtasu. 11

11495

JM32A

TMS2532

2SV

MotwoU Tl. Mxtn. OKI

S14.9S

JM3S

2732

25V

AMD. FupUu. NEC MUttl. In*

S1495

.M32C

2732A

21V

FuHsu. hid . . .

SH.S5

MCM6S764.
MCM66L764

21V

MOUVOU

11495

JM648

2764

2 IV

Irwl f.'MChila, OKI .

. , , S14.M

..114.95 k

Inquiry 161

FEBRUARY 1985 -BYTE 221

GREAT OFFERS

Marketing & Consultants

MONITORS

MODEMS

GREAT PRICES

TAXAN

210 Color RGB

100 Green ...

105 Amber

400 Color RGB

410 Color RGB

420 Color IBM

121 Green IBM . ■

122-AmberlBM

ZENITH

ZVM 1 22A Amber

ZVM 1 236 Green

ZVM 124 Amber -IBM

ZVM 131 Color

ZVM 133 RGB

ZVM 135 Composite
ZVM 136 Hi Res Color

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222 BYTE • FEBRUARY 1985

Inquiry I9I

SCIENCE

PARANOIA: A

FLOATING-POINT

BENCHMARK

by Richard Karpinski

Test the quality of your software, not just its speed

FLOATING-POINT ARITHMETIC was
created to make programming easier
and programs faster. It is complicated
so that your programs can be simple,
but rough edges and pitfalls are com-
mon in floating-point systems.

The Paranoia benchmark was de-
signed to find and notify you of those
places where actual results are not
good enough. It reports pitfalls
discovered in a systematic checkout
of the arithmetic used by the com-
puter running it. Why Paranoia?
Webster's Ninth New Collegiate Dictionary
(Springfield, MA: Merriam-Webster
Inc., 1983) provides the following as
its second definition of paranoia: "a
tendency on the part of an individual
or group toward excessive or irra-
tional suspiciousness and distrustful-
ness of others— an apt description of
this program, which looks for prob-
lems at every turn. This article looks
into the workings of floating-point
arithmetic to see why you need such
quality tests and how they work.

Life Without Floating Point

Remember those heavy mechanical
calculators with 10 long rows of keys?

If you wanted to use measurements
in fractions rather than whole
numbers, you could set the decimal
point somewhere in the middle of the
field. Numbers could grow or shrink
on either side of it, but the point itself
was really fixed. This is enough for
many hand calculations where you
need only 5 or 10 steps to get the final
result. Fixed-point calculations like
this are simple and match the pencil-
and-paper methods we learned in
grade school. They are easy to under-
stand and use, and they work quite
well almost all the time.

Almost is not enough, however. Even
events that happen quite rarely re-
quire careful attention when you are
designing a computer system.
Because computers are so much

Richard Karpinski (IEEE p854 Mailings.
U-76 UCSF, San Francisco, CA 94143) is
the manager of UNIX services at the com-
puter center at the University of California
at San Francisco. With interests in software
engineering, Modula-2, and other aspects of
computer science, Dick has enjoyed being "the
consultant of last resort" for many in the past
two decades.

faster than we are, a system that works
correctly on 99.999 percent of its data
can still fail once every second. With
paper and pencil, if a few numbers
don't fit within the limits you have
chosen, you can write smaller or use
another sheet of paper. Mechanical
calculators and computers are not so
flexible.

If you set up a calculator for
numbers of the form nnn.nnn.nnn.nnn,
for example, an intermediate result of
I million is hopelessly damaged.
There is no place to put the digit in
the millions place. This problem is
called overflow. There are calculators
with 20 or 30 digits or even more, but
you can't really solve the problem this
way. Long calculations continually re-
quire you to copy an intermediate
result from the calculator's dials back
onto the keys in order to shift it to the
left or the right to accommodate the
overflow. The copying process is
error-prone and tedious for those
who do it. (Originally, these people
were called "computers.")

Very small numbers in this format
also suffer. Numbers smaller than 1

[continued)
FEBRUARY 1985 • BYTE 223

PARANOIA

one-millionth are lost entirely. They
underflow to zero. Even numbers as
large as 1 one-thousandth lose most
of their significant digits. Only 3 of the
12 digits of precision initially provided
remain.

When overflow and underflow prob-
lems arise in hand calculations, and
even in many computer applications

that have tight constraints on hard-
ware and timing, you can solve them
by rescaling the numbers— multiplying
or dividing them by 10, 100, or 1000-
to bring the number back into view.
Naturally you must keep track of each
scaling operation you perform so that
you can readjust the final answer
properly.

What do you get when you cross
1200 baud, free online 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-Line 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 227

Trademarks— MultiModem. MultiCom

PC: Multi-Tech Systems. Inc.— Compu-
Serve: CompuServe Information Services.
anH&R Block company— NewsNet:
A/ewsWef. Inc.— Crosstalk: Microstuf,
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.

MultiTech(S)

Systems ^JBF

The right answer every time.

You must also check to see if this
problem arises at every possible
place, although such checking makes
every program longer and more com-
plicated. This high cost of being ex-
tra careful must be weighed against
the fact that the unchecked version
works most of the time. In fact you
may have tested the unchecked version
with thousands of cases and consider
it completely debugged.

In principle if you know enough
about the numbers that arise, you can
build the rescaling shifts into your
procedure so that they don't take any
extra effort during the calculation
itself. This can save up to two-thirds
of the time that floating-point calcula-
tions take. John von Neumann, often
called the father of computing, held
the view that such a priori analysis
was the proper approach. He saw no
need for floating point. However,
most programmers now agree that
the analysis required is far too costly
and error-prone to ignore floating-
point hardware.

Scientific Notation

As researchers and scientists have
probed the further reaches of our
world, they have developed scientific
notation to express very large and
very small numbers with equal preci-
sion. For example,

602,300,000,000,000

becomes 6.023 x 10 14 while

0.000,000,000,000.006,62 4

becomes 6.624 x 10" 15 . The preci-
sion or uncertainty figures for these
numbers look very different until you
express them in scientific notation:
5.0 x 10 10 for the first versus
5.0 x 10" 18 for the second.

When you consider imprecise
numbers, it is easy to become con-
fused between absolute uncertainty
and relative uncertainty— relative to
the size of the value involved. The
relative uncertainty here is referred to
as "half a unit-in-the-last-place" or T2
ulp." Since we want computers to
cope quickly and precisely with a
wide range of numbers, we adapt the

{continued)

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TE3 ng"i

PARANOIA

scientific notation to the task. You
don't need to store the l, x I0" part
because it doesn't change between
various numbers, so you represent
each number with a fractional signifi-
cand and a whole-number exponent.

The rescaling hasn't gone away. The
"exponent" is the variable in which
rescaling operations note their ad-
justments. As you might expect, ex-
ponents are represented and used in
different ways— each with its own par-
ticular problems— and each number is
rescaled automatically after each
operation to eliminate any leading
zeros and to preserve the maximum
number of significant digits.

We use decimal notation (radix 10)
for numbers, but computers usually
use binary notation (radix 2) to match
their memory and logic-circuit com-
ponents. In binary you can, for exam-
ple, use a significand between Vi and
I, that is, between l-over-the-radix
and I . Some computers use hexadec-
imal (radix 16) instead; their signifi-
cands can lie between y i6 and I . Radix
2 packs the most range and precision
into any given word (the number of
bits devoted to representing a
number). Radix 10 is also very useful
because there are no errors introduced
in moving ordinary decimal numbers
into the computer. There are errors,
but there are no new errors.

If your computer uses six decimal
digits of precision, you have a pretty
good idea of what happens to num-
bers like ] A. However many digits you
type, the most precise estimate you
can ever get is 0.333,333. This con-
tains a small error— only ] A ulp— but
this error is inherently present for
such fractions in any floating-point
notation.

There are systems for maintaining
rational numbers that avoid the prob-
lem of precision as long as possible,
at a high cost in size and speed. They
keep two whole numbers to represent
a fraction— 1 and 3 here— and save the
division for later. Thus, if ] A is later
multiplied by 3, the threes cancel and
the answer is exactly I . Unfortunate-
ly, in long calculations both of these
numbers grow unreasonably large all
too rapidly. Unless your need for high

precision is very great, this method is
uneconomical.

If you multiply 0.333,333 times 3,
0.999,999 is as close to I as you can
get, given the round-off error of 1 ulp.
Sometimes you can accept answers
within several ulps of the best possi-
ble answer. In this case you must ac-
cept the 0.999,999 result if you're go-
ing to use floating point; but, even
here, 0.999,998 is clearly unaccept-
able because we can do better.

Round or Chop?

Some computers offer you the choice
of rounding off or chopping (trun-
cating) the result of each calculation.
Rounding off preserves an extra Vi ulp
of precision in each step. If the
numbers are all positive, rounding off
avoids the systematic underestimating
error that truncation introduces.

This is an important matter. For ex-
ample, the Wall Street journal reported
on November 8, 1983 (page 37), that
the Vancouver Stock Exchange main-
tains a stock index rather like the Dow
Jones average. It began with a
nominal value of 1,000.000 and was
recalculated after each recorded
transaction. At each stage, the value
was calculated to five decimal places,
but the last two were truncated.

The exchange found that after 22
months of operation, with about 2800
transactions per working day, the
index had fallen to the 520 range
while stock prices were reaching new
highs. Investigation showed that all
those lost fractions of thousandths of
a point had mounted up to a major
inaccuracy.

The solution the exchange planned
was to round off instead of chop. If
this was done in the usual way— 01 to
49 round down, 50 to 99 round up-
then a consistent error still remains.
The error is only one percent as large
as it was and tends to inflate rather
than deflate the index, so the ex-
change might even consider it an ad-
vantage. This new error is that while
49 of the values round down and one
stays the same, 50 of them round up.

The point is that even tiny errors,
when they all go the same way, can

[continued)

226 BYTE • FEBRUARY 1985

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Inquiry 96

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FEBRUARY 1985 • BYTE 227

PARANOIA

do serious damage to numerical
results. The Paranoia benchmark
checks your arithmetic to see whether
rounding is done correctly if at all.

Guard Digits

Round-off errors are unavoidable.
These errors are not mistakes in the
process but the inevitable result of re-
stricting the width of floating-point

numbers. A carefully built arithmetic
system can round meticulously when-
ever approximation is required. How-
ever, in order to round correctly, extra
(guard) digits are needed temporari-
ly in the course of ordinary calcu-
lations.

Guard digits reduce error. In a four-
digit system you may need five or
more digits to maintain accuracy un-

IEEE Arithmetic and
Paranoia Availability

The IEEE has specified a particularly
careful floating-point arithmetic
intended to avoid the worst problems
of the older arithmetics used on com-
puters. One committee (p754) de-
signed a very specific binary floating-
point arithmetic with three sizes of
numbers. A second working group
(p854) relaxed some of those specifica-
tions to permit different sizes of
numbers and different radixes to be
used. These IEEE arithmetics are so
good that Paranoia finds no fault with
them at all.

An example of IEEE arithmetic is the
way it avoids the problem of more
numbers rounding up than down (50
versus 49): it rounds numbers ending
in 50 up only half the time, i.e., when
the previous digit is odd. The rest of
the time, the numbers round down. For
this reason, the normal IEEE rounding
mode is called round-to-even.

The drafts of the IEEE specifications
are highly technical and quite compact.
The dozen or so pages require careful
reading and often some deliberate
studying to fully comprehend. Still that
task is rewarding to those who seek to
achieve numerical results of the highest
quality with their programs.

If you would like a copy of the IEEE
p754 (binary) or p854 (binary and
decimal) drafts, you may write to the
author (IEEE p854 Mailings, U-76
UCSF; San Francisco, CA 94143). The
full Paranoia test program will also be
available, on floppy disk, for a distribu-
tion charge of $15. The author also has
order forms' for the disk. The floppy
formats of the Paranoia disk will in-
clude at least the PC-DOS 9-sector
5^ -inch double-sided format. A page

or two of documentation will help you
run the program.

The second, corrected release of
Paranoia in MS-BASIC should be avail-
able by this issue's cover date. Versions
in FORTRAN and Pascal are also ex-
pected to be ready. Although the
author of the Paranoia program, Pro-
fessor William Kahan, is a key member
of the IEEE Computer Society commit-
tees, the IEEE does not guarantee the
program in any way.

If you request these test programs,
you will be asked to assist Professor
Kahan and Mr. Karpinski by reporting
back the results you get when you use
them. Please send us your resultb for
any system that is either commercial-
ly available or interesting in its own
right. You may copy the test program
freely, maintaining its copyright notice,
and pass it on to your friends. We
would appreciate their results as well.

When you run Paranoia, you will get
several pages of messages about the
details of the arithmetic. So far results
have been collected on more than six
different BASIC systems, but some of
these results are already obsolete.
Perhaps you can help us to bring them
up-to-date. We are especially interested
in hearing about any errors you may
discover in the tests themselves. We
would also like to hear of any problems
you have running or interpreting the
tests, although we do not promise any-
thing but our thanks in return.

A benchmark of this complexity may
take years to reach its full value to the
computing community. When enough
arithmetics have been tested to make
the results interesting, the authors will
try to publish them.

til the result is rescaled. For example,
1.144 x 10 1 minus 8.336 x 10° really
needs five digits. Without the extra
digit this simple subtraction suffers an
error of 4 to 6 ulps, a serious defect
that makes numeric programming
even more difficult and error-prone.
To illustrate: with the guard digit, 1 1.44
minus 8.336 yields 03.104, which
results in an answer after rescaling of
3.104 x 10°; without the guard digit,
11.44 minus 8.33 (if truncated) yields
03.11 for a result of 3.110 x 10° and
11.44 minus 8.34 (if rounded off)
yields 03.10 for a result of 3.100 x 10°

The need for guard digits becomes
quite clear. What about your com-
puter? Often the specific details of the
arithmetic used on a given computer
are known only to its designers. Yet
they are important to programmers
and other users who want to get
good, precise, accurate answers.

Professor William Kahan at the Uni-
versity of California at Berkeley wrote
Paranoia for just this reason. Paranoia
checks many of the arithmetic details
of your computer. For each aspect
that is not handled in the best way,
Paranoia reports what sort of difficulty
will ensue from its use.

The full Paranoia program is some
700 lines of BASIC. Listings 1 and 2
show an extract sufficient to test for
the use of a guard digit in addition
and subtraction. If some part of the
routine seems confusing, you may
find it helpful to try a pencil-and-
paper example with a four-digit sys-
tem like the one above. These pro-
grams were simplified from the Pascal
translation of Paranoia by B. A.
Wichmann of the National Physical
Laboratory in England. The full pro-
gram guards itself against many (rare)
problems that might possibly arise.
Full Paranoia also rechecks critical cal-
culations by a second method, just to
be sure.

Test Your Calculator

You can use essentially the same
guard-digit procedure to test your
pocket calculator. Without checking
for radix, etc., the results of two sim-
ple expressions will signal the

{continued)

228 BYTE • FEBRUARY 1985

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PARANOIA

Listing I : A Microsoft BASIC program to test for the presence of a guard digit
in subtraction. Note: fpwidth is the smallest number formed by multiplying one
by the powers of the radix. \t is calculated by successive multiplications, until the
product when added to l.O no longer gives an exact result. (Width is a
Microsoft BASIC reserved word and cannot be used as the variable name.)

10 '
20 '

70 '

80 *

90 '
100 '
110 '
120 '
130 '
140 '
150 '
160 '
170 '
180 '
190 '
200 '
210 '
220 '
230 '
240 '
250 '
260 '
270 '
280 '
290
300 '
310
320
330
340
350
360 '
370
380 '
390 '
400 '
410 '
420 '
430 '
440 '
450 '
460
470 '
480
490
500
510 '
520
530 '
540
550 '
560 '

Guard — Test if add/subtract has a guard digit

One
Half
Zero
MinusOne

variables:

Radix
Precision

fpwidth
Wide

UlpOne
UlpRadix

OneMinus
RadixMinus

s, t, u
x, y, z

1.0 ' Floating-point constants
= 0.5
= 0.0
= -1.0

Calculated floating-point radix
Significant digits in base Radix

Precision
Radix (or Radix * Precision)

First estimate of fpwidth

Unit in last place of just less than one
Radix * UlpOne

One - UlpOne calculated with care
Radix - UlpRadix

Working variables

Find a Wide so big that adding one does not change it by one
Wide = One

Wide = Wide + Wide
x = Wide + One

Wide
One

Double it until it grows so large that
Adding one does not change it or
(with rounding) changes it by 2
So the difference is zero or 2
And this becomes + / - one

IF ( MinusOne + ABS( z ) )

Zero THEN 310

Find the radix (or number base) as the minimum increase in Wide
Remember that Wide is just large enough that the units place
is not represented, so a one in the last represented place
(the tens place, for decimal) is exactly the radix itself.
Try it by hand.

One

Radix = Wide + y ' No change on first addition

y = y + y ' So double y

Radix = Radix - Wide ' Until some change happens

IF Radix = Zero THEN 480
PRINT "Radix = "; Radix

The change is the radix

230 BYTE • FEBRUARY 1985

PARANOIA

570 '

580 '

590

600

610 '

620

630

640

650 '

660

670 '

680

690 '

700

710 '

720

730 *

740

750 '

760

770

780 '

790

800

810 '

820

830

840

850 '

860

870

880

890 '

900

910

920

930

940

950

960

970 '

980

Is imprecise

Find the precision in Radix digits

Precision = Zero
fpwidth = One

Precision = Precision + One ' Count the digits

fpwidth = fpwidth * Radix ' And increase fpwidth

y = fpwidth + One ' Until adding one

IF ( y - fpwidth) = One THEN 620 '

PRINT "Precision = "; Precision

PRINT "fpwidth = "; fpwidth

UlpOne = One / fpwidth

PRINT "Closest relative separation found is UlpOne = "; UlpOne

OneMinus = ( Half - UlpOne ) + Half
UlpRadix = Radix * UlpOne

RadixMinus = Radix - One

RadixMinus = ( RadixMinus - UlpRadix ) + One

x = One
y = One
z = One

UlpOne

OneMinus

s = Radix - UlpRadix
t = Radix - RadixMinus
u = Radix - s

IF y = UlpOne THEN 920

GOTO 960

IF t = UlpRadix AND u = UlpRadix THEN 940

GOTO 960

PRINT "Add/subtract has a guard digit as it should."
GOTO 980

PRINT "Add/subtract lacks guard digit, cancellation obscured."

END ' Guard

Listing 2:

subtraction.

Pascal program to test for the presence of a guard digit in

program Guard;

{ Test if add/subtract has a guard digit

}

const
One
Half
Zero
MinusOne

= 1.0;
= 0.5;
= 0.0;
= -1.0;

{ Floating-point constants

}

var
Radix
Precision

: real;
: real;

{ Calculated floating-point radix
{ Significant digits in base Radix

}
}

Width
Wide

: real;
: real;

{ Precision

{ Radix (or Radix - Precision)

{ First estimate of Width

}
}
}

(continued)

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FEBRUARY 1985 -BYTE 231

Inquiry 371

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1EJ

PARANOIA

UlpOne : real; { Unit in
UlpRadix : real; { Radix :

ast place of just less than one
< UlpOne

}
}

OneMinus : real; { One -
RadixMinus : real; { Radix -

- UlpOne calculated with care

- UlpRadix

}
}

s, t, u : real; { Working variables
x, y, z : real;

}

begin {Guard}

{ Find a Wide so big that adding one does not change it by one.

}

Wide : = One;
repeat

Wide : = Wide + Wide;
x : = Wide + One;

y : = x - Wide;
z := y - One

Double it until it grows so large that
Adding one does not change it or
(with rounding) changes it by 2
So the difference is zero or 2
And this becomes + / - <

Dne

}

}
}
}
}

until ( MinusOne + abs( z ) )

> = Zero;

{ Find the radix (or number base) as the minimum increase in Wide
{ Remember that Wide is just large enough that the units place
{ is not represented, so a one in the last represented place
{ (the tens place, for decimal) is exactly the radix itself.
{ Try it by hand.

}
}
}
}
}

y : = One;
repeat

Radix := Wide + y; {

y := y + y; {

Radix : = Radix - Wide {

No change on first addition
So double y

Until some change happens

}
}
}

until Radix < > Zero; {

The change is the radix!

}

writeln( 'Radix = ', Radix );

{ Find the precision in Radix digits

}

Precision : = Zero;
Width := One;
repeat

Precision := Precision + One;
Width : = Width * Radix;
y := Width + One

{ Count the digits

{ And increase Width

{ Until adding one

}
}
}

until ( y - Width ) < > One;

{ Is imprecise

}

writeln( 'Precision = ', Precision );

writeln( 'Width = ', Width );

UlpOne := One / Width;

writeln( 'Closest relative separation found is UlpOne = ', UlpOne );

OneMinus := ( Half - UlpOne )
UlpRadix : = Radix * UlpOne;

+ Half;

[continued)

232 BYTE • FEBRUARY 1 985

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FEBRUARY 1985 -BYTE 233

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234 BYTE* FEBRUARY 1985

Inquiry 331

PARANOIA

RadixMinus
RadixMinus

Radix
( RadixMinus

-One;
UlpRadix ) + One;

x : = One - UlpOne;
y := One - OneMinus;
z : = One - x;

s := Radix - UlpRadix;
t : = Radix - RadixMinus;
u := Radix - s;

if (y = UlpOne) and (z

(t = UlpRadix) and (u
then

writeln( 'Add/subtract has a guard digit as it should.' )
else

writeln( 'Add/subtract lacks guard digit, cancellation obscured.' )

end {Guard}.

UlpOne) and
UlpRadix)

presence or absence of a guard digit.
If their results are equal, the guard
digit is present. Otherwise, it is prob-
ably not. Those expressions are

1 - ( 9 / 27 * 3 )

and

1/2 - ( 9 / 27 * 3 ) + 1/2

For four-function calculators without
parentheses or memory, you can use

- 9 / 27 * 3 + 1
and

- 9 / 27 * 3 + .5 + .5

A smaller test in Pascal could be:

if (- 9 /27 * 3 + 1 ) =

(- 9 I 27 * 3 + .5 + .5)
then writeln( Add/subtract has a

guard digit.' )
else writeln( Add/subtract lacks

guard digit.' )

Conclusion

Paranoia is an unusual benchmark: it
tests the quality of your software, not
just its speed. Most common com-
puter arithmetics have a half-dozen or
more flaws that Paranoia finds, report-
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FEBRUARY 1985 -BYTE 235

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238 BYTE • FEBRUARY 1985

Inquiry 221

SCIENCE

MODELING

MASS-ACTION

KINETICS

by Alan Curtis

In the future, microcomputers may have a substantial role
in major scientific computations

AT THE UNITED KINGDOM Atomic
Energy Research Establishment, Har-
well, we have assembled scientific and
technological applications of our FAC-
SIMILE reaction-kinetics program. All
can be run on one mainframe or an-
other, but for the purposes of this ar-
ticle I have selected a few of those
that now run on an IBM PC with 512K
bytes of RAM (random-access read/
write memory).

Like other simulation modelers such
as DYNAMO, FACSIMILE facilitates
the calculation of a set of differential
equations that describe the con-
tinuous evolution of a system from a
known initial configuration and then
flexibly formats the output.

Simulation models solve problems
repeatedly and carry out thorough
statistical analyses to find the best fit
among parameters. For such work,
whether the microcomputer is prac-
tical depends on your point of view.
A fairly large program that takes, say,
three minutes on an IBM mainframe
might well run all night on the PC, pro-
vided you use an 8087 math copro-
cessor; without it, running time would
probably be about 10 times longer

(this is a guess— we haven't checked
it out).

Let's take a look at several examples
of how simulation models can be
used.

Uranium from Seawater?

Seawater contains uranium, an ex-
tremely valuable fuel at an extreme-
ly low concentration. Suppose we
want to extract the uranium. The
question is whether an economically
• viable extraction process exists. We
might try pumping the seawater
through an ion-exchange column, a
tube tightly packed with minute
spheres of a resin that preferentially
absorbs uranium ions from solution
and replaces them with ions of an-
other metal. When sufficient water
has been pumped through, the col-

Alan Curtis leads the Applied Mathematics
Group in the Computer Science and Systems
Division at the U.K. Atomic Energy Research
Establishment, Harwell He is a graduate of
Cambridge and a former lecturer at the
University of Sheffield. He can be reached
at AERE, Harwell, Didcot, Oxfordshire
OX 1 1 OR A, England.

umn is removed and cut up, and or-
dinary chemical means remove the
uranium (now at high concentration in
the resin) for further processing. Ob-
viously the value of the recovered
uranium must offset the costs of
manufacturing the resin and the
tubes, of the pumping power, and of
the postprocessing to recover the
uranium from the resin.

A feasibility study of the problem
called for a simulation model because
the rate coefficients for the absorp-
tion of uranium by the resin were not
known. Experiments removed sup-
posedly identical ion-exchange col-
umns at different times, pumped dif-
ferent rates of seawater, and analyzed
uranium contents at various points
along the columns. Parameter-fitting
options might have determined the
best fit for these experimental results.

As it turned out, variations in prop-
erties, mainly the density of packing
of the resin from one column to
another, and even along the length of
a single column, invalidated the
model, which assumed a single
uniform column. A more complicated

(continued)

FEBRUARY 1985 -BYTE 239

MODELING

model might have involved some of
the variability, but the experiments
had shown that the whole process
was not likely to be economical
anyway.

Such negative results are not fail-
ures in scientific investigations. On the
contrary, we understand far better the
requirements for the simulation if we
decide to pursue it again.

A modified model now used for
demonstration purposes, contains
parameter values chosen to exhibit
significant saturation. (There are other
ways of solving the problem of model-
ing an ideal ion-exchange column if
you know that saturation is negligible.)

To model the behavior of the col-
umn, we divided its length into 20
equal-size sections. One array of 20
variables represents the concentra-
tion of uranium in the seawater in
each section, a second array

represents the concentration in the
resin, and a third array checks for
saturation by monitoring available ab-
sorption sites in the resin. The simula-
tion models the flow of seawater by
passing material from one element of
the array to the next at a rate reflect-
ing the time it takes for the water to
move the length of a section.

The first element receives material
with the concentration in the incom-
ing water; the last element sends
material to a "waste" variable. The
simulation of the exchange process
between solution and resin uses
modeling features for chemical reac-
tions; a second-order reaction be-
tween corresponding elements of the
first and third arrays represents ab-
sorption, and a first-order reaction
represents the reverse process. The
program runs on the IBM PC in about
550 seconds (compared with 2.5 sec-

PLOTTING PAPAMETERS fOR GRAPH STREAM 2

INDEPENDENT VARIABLE :DIST (PLOTTED VERTICALLY)

DEPENDENT VAPIABLES (PLOTTED HORIZONTALLY):

X SCALE 1.0000D-0S X

V SCALE 1.0000D-04 Y

S SCALE 1.0000D-04 S

0.5 1

1.000D+00 I Y I I I I S X!

3.000D+00 I Y I ! I I S X I

5.00 0D + 00 I Y-l I I I-S X t

7.000D+00 t Y I J t I S X I

9.000D + 00 I Y I 'I' I IS I

1.10 0D+01 I Y I I I I XS J

1.3000+01 I Y i I I IX S I

1.500D + 01 I Y - - I I I XI--S- : I

1.700D+01 I Y | i 1 X \ S I

1.900D+01 I Y 1 I I X I S I

2.100D+01 I Y 1 I I X \ S I

2.300D+01 I Y I I I X I S I

2.500D + 01 I Y I I I---X I---S I

2.700D+01 I Y I I IX I S I

2.900D+01 I Y I I IX I S I

3.100D+01 I Y I I IX iSt

3.300D+01 I Y I I X IS I

3.S0 0D + 01 I Y I I XI I S I

3.70 0D+01 I Y I I XI i S [

3.900D+01 I Y I I XI I S I

Figure 1 : A snapshot graph from the ion-exchange-column problem.

ondsonthelBM 308 IK), so that even
a parameter-fitting run, which ex-
ecutes several dozen simulation runs,
could be done overnight on the micro.
It is fair to say that this investigation
could have been done on the PC from
the beginning.

The model provides three types of
output: "snapshot" graphs, which
show how the concentrations vary
along the column at any time; "time-
course" graphs, which illustrate how
integrated quantities, such as the total
uranium trapped in the resin, vary
with time; and tables of numbers that
give more accurate time histories of
these integrated quantities. Figure I
is a snapshot graph from this prob-
lem. By plotting the independent vari-
able (distance along the column)
along the y-axis and the dependent
variables along the x-axis, a printer
can plot graphs of any length. Points
X represent the concentration of
uranium in solution, multiplied by
100,000,000; points Y represent con-
centration in the resin, multiplied by
10,000; points S represent available
sites, multiplied by 10,000.

Starting up a
Chemical Reactor

In a 1981 thesis for Imperial College,
London, I. T Cameron proposed this
chemical-engineering problem. It is
much simpler than the others de-
scribed here, but in practice it had
proved difficult to solve.

Initially a chemical reactor contains
neutral gas. A pump starts to supply
liquid feedstock through an inlet
valve, compressing the gas and re-
ducing the flow from the pump
because of back pressure. A chemical
reaction takes place in the vessel, and
product mixed with unused feed-
stock, driven by the gas pressure and
the liquid head, flows out through an
outlet valve. In time the system
reaches a steady state, but the main
focus of the simulation is the start-up
transient. Results of interest include
the peak gas pressure and tempera-
ture (for vessel design) and the loss
of unused feedstock and substandard
product. The model includes the ef-

[continued)

240 BYTE • FEBRUARY 1985

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Inquiry 223

FEBRUARY 1985 -BYTE 241

MODELING

PLOTTING

INDEPEND

DEPENDEN

CP1

.000D+
5.000D-
1.00CD-
1.S00D
2 .000D-
2.S0CD
3. OOOD-
3. 50.0 D-
■i.OCOD-
4.S00D-
5.000D-
5.500D-
6.000D-
6.S0CD-
7.C00D-
7.S00D-
S.OOOD
5. 5000
o.OOOD
o.SOOD
1. COCD
l.OSOD
1.100D-
1. 15CD
1. 200D
1.2S0D-
1 .3C0D-
1.350D-
1. «iOOD
1. hSOD
1 .SOOD
l.SSOD
1.600D
1.650D-
1.700D-
1 .7S0D-
1.600D-
1 .65CD-
1.SCCD-
1.0SOD
2 . OOOD-
2. 05CD-
2.100D-
.150D-
.200D-
.250D-
300D"
.3S0D-
. 400D-
.4S0D-
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.550D-
.600D-
.65CD-
.700D-
.7S0D-

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.900D-
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3.000D-
3.CS0D-
3.100D
3.150D-
3.200D-
3.2S0D-
3.3C0D-
3.35CD-
3 . <iOOD -
3.4S0D-
3.500D-
3.5S0D"
3.600D-
3.6S0D-
3.7C0D-
3.75 0D-
3.£00D
3.£S0D
3.900D-
3.«50D-
4.000D-

PAPAMET

ENT VAPI
VAPIAB
SCA
SCA
SCA
SCA
SCA

EPS FOP GPAPH STREAM 1

ABLE :TIME (PLOTTED VERTICALLY)

LES (PLOTTED HORIZONTALLY):

LE 2.4000D+00 A

LE 1.5000D-02 B

LE 2.4000D+00 P

LE 1.2000D+02 1

IE 1.2000D+02 2

0.5

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2 P 1 I All I B

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2 I P I I A II IB

2 P I I A II IB

2 P t I A II IB

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2 PI I A II Bl

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12 IP A I IB I

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I 2 I A P I B II I

I 2 I A P I B 1 I I

I 2 I A P I--B II I

I 2 I A P I B II I

I 2 A P I B II I

I 2 A P IB II I

I 2--A P--IB 1-1 I

I 2 Al P IB II I

I 2 A I P B II I

I 2 Al P B II I

I 2A I PB I It I

I 2-1 PI 1-1 I

I 2 1 PI II I

I 2 1 BP I II I

I A2 I BPI II I

I A- 2 I B--P 1--I I

1 A 21 B P II I

I A 2 I B P II I

I A 21 B P II I

I A 2 B P 1--I I

I A 2 B IP 1 I I

I A 2 B I P II I

I A 2 B I P II 1

I A 2 B IP 1--I I

I A 12 B IP 1 I I

I A I 2 B IP II I

I A I 2 B I P 1 I I

I A 12 B I P 1 I I
I A I 2B I P 1 I I
I A 1 2B I P 1 I I
I A I 2B J P 1 I I
I A I-2B I-F 1 I 1

feet of pressure on inlet and outlet
flow rates as well as the progress of
the reaction, the depth of the liquid,
and the thermodynamics of the gas.
Output consists of time-course
graphs and tables of numbers. The
graphical output (see figure 2) illus-
trates an interesting phenomenon
that occurs fairly often. There is a long
transient before the approach of the
steady state, but the initial transient
is very fast, lb study the initial part ef-
fectively, it is necessary to plot many
points at small time intervals. Graphs,
therefore, have the independent
variable (time in this case) plotted
downward and the dependent vari-
ables plotted from left to right; thus
(with continuous paper) there is no
limit to the length of the plotted
graph. However, if the PC screen dis-
plays the graph as it is produced, only
about 2 5 lines are shown at a time,
so a printer is essential.

Death of a Star

When a typical "main sequence" star
has been burning and radiating
energy away for a few billion years, it
has transmuted all of its original
lighter elements into carbon and oxy-
gen and must enter a carbon-burning
phase. During this time, the internal
pressure needed to support the star's
weight against its own gravitational at-
traction has required high density and
temperature, which in turn make the
star opaque to radiation.

According to Planck's law, the star
radiates at a rate determined by its
surface area and temperature. There-
fore, when the star's lighter elements
are exhausted and its energy from
nuclear reactions becomes inade-
quate to support its weight, it starts
to contract under gravity; this in-
creases its internal temperature until
it reaches about I billion degrees

[continued)

Figure 2: A time-course graph from
Cameron's reactor problem. A =
concentration of feedstock: B =
concentration of an intermediate [on larger
scale): P = concentration of product: I =
inlet flow rate: 2 = outlet flow rate.

242 BYTE' FEBRUARY 1985

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Inquiry 187

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FEBRUARY 1985 -BYTE 243

MODELING

Generation of smog
in urban areas is a
complex phenomenon
that involves numerous
reactions among over
100 trace gases
in the atmosphere.

Kelvin. This temperature is sufficient
to cause carbon nuclei to begin fus-
ing together to form heavier elements.
This carbon-burning process supplies
the necessary energy to make further
gravitational contraction unnecessary.
If the star is an ordinary one— not

too big— the temperature generates
enough pressure to keep the star
stable until the carbon is exhausted.
The temperature and density do not
rise further, and the carbon-burning
phase takes place relatively slowly in
conditions of hydrostatic equilibrium.
In a more massive star, however, the
pressure is inadequate, contraction
continues, the temperature and den-
sity continue to rise, and carbon burn-
ing proceeds explosively fast; the star
becomes a supernova. In either case,
the phase is extremely short in rela-
tion to the earlier leisurely history of
the star; typical durations may be a
week or two for an ordinary (less
massive) star or about a second for
a supernova.

Simulations have been successful
for both the hydrostatic and the ex-
plosive carbon-burning phases. In
both cases, the set of nuclear reac-
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cients depend on temperature and
density, variables that vary with time
in a way determined by the stellar
dynamics. To model the hydrostatic
version, temperature and density are
kept constant and rate coefficients are
computed only once, at the start of
the run. For the supernova version,
temperature and density are defined
as functions of time, and the rate coef-
ficients are frequently recalculated
during the run.

The coding of the nuclear reactions,
although they are numerous, is rela-
tively easy because their structure is
exactly that of chemical reactions.
Protons, neutrons, neutrinos, alpha
particles, and 36 heavier nuclides are
simulated.

A run of the hydrostatic version takes
about 8200 seconds (2.3 hours) on the
PC compared with about 2 5 seconds
on the IBM 308 IK. This is a larger
speed ratio than average— about
3 30:1— but we may be able to improve
the performance. The supernova ver-
sion takes about 67 seconds on the
3081, so we expect it to take about
22,000 seconds (say, 6 hours) on the
PC. Output consists of time-course
graphs of the mass fractions of the
various nuclides, plotted on loga-
rithmic scales for time and for the
mass fractions, and of tables giving
numerical values for the mass fractions
as functions of time. The graphs show
clearly the stages at which the various
nuclides are produced or used up; in
many cases, this occurs in straight lines
on the log-log plot, indicating mass
fractions proportional to a (positive or
negative) power of the time.

Photochemical Smog
Generation

The generation of photochemical
smog in urban areas is an extremely
complex phenomenon that involves
numerous reactions among well over
100 trace gases in the atmosphere.
Important elementary steps in the
process involve the breaking of
chemical bonds when a molecule ab-
sorbs solar radiation; these steps
switch off rapidly as sunset ap-
proaches and switch on equally fast

[continued)

244 BYTE • FEBRUARY 1985

Inquiry 174

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Inquiry 292

FEBRUARY 1985 -BYTE 245

MODELING

at dawn. Rate coefficients also de-
pend on smaller day/night variations
such as temperature and water vapor
content. Thus the behavior of the
chemistry during the night is quite dif-
ferent from that during the day, and
the switching processes are technical-
ly difficult for many differential-
equation solvers to handle.

The model of this process is by far
the largest and most complicated of
those described here. The model in-
volves a total of 300 reactions among
135 chemical species; the data oc-
cupies about 620 lines of code. The
model also requires larger working
arrays than the others, but it can
be fitted into 470K bytes of RAM.

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Simulating 50 hours of real time (thus
seeing how much greater the pollu-
tion is on the second day than the
first) takes about 1 10 seconds on the
IBM 3081 K; we are not yet able to run
it on the PC. but we might expect a
speed ratio similar to that for the
astrophysical problem. It is thus at the
limit of practicability on the PC (at pre-
sent) so far as. running time is con-
cerned, but it is interesting that the
model would still run faster than real
time. Simulation of the second 24
hours takes about one-third of the
total time and we would expect sub-
sequent days to run at approximately
this speed.

Output consists mainly of time-
course graphs, which illustrate clearly
the buildup, with afternoon peaks and
nighttime troughs, in the concentra-
tions of the important pollutants.

Conclusion

I have presented only a few of the
many scientific and engineering appli-
cations that are practicable on a micro'
like the IBM PC with 512K bytes of
RAM and an 8087 math coprocessor.
1 hope, nevertheless, that I have con-
veyed a feel for what I am sure has
a very big future— the use of micro-
computers for major scientific compu-
tation. ■

For Further Information

For information on some specific

microcomputer simulation modelers,

contact:

Atomic Energy Research

Establishment
Harwell, Didcot, Oxfordshire OX11
ORA, England (FACSIMILE)

Pugh-Roberts Associates Inc.
5 Lee St., Cambridge, MA 02139
(Micro-DYNAMO)

ACKNOWLEDGMENT
I would like to thank the United Kingdom
Atomic Energy Research Establishment,
Harwell, for permission to publish the
material about FACSIMILE contained in
this article; and I would also like to thank
my colleagues Philip Sweetenham and
Kevin McPherson for providing me with
information about the test runs they
executed.

246 BYTE- FEBRUARY 1985

Inquiry 300

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■ The 136 can be used for viewing single shot events, or
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Inquiry 252

Consider its Engineering & Field Service Applications:

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FEBRUARY 1985 • BYTE 247

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248 BYTE • FEBRUARY 1985

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Inquiry 192

FEBRUARY 1985 • BYTE 249

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SCIENCE

VIEWING

MOLECULES WITH

THE MACINTOSH

by Earl J. Kirkland

A BASIC program provides 3-D images
of complex molecules

RESEARCHERS HAVE GAINED valu-
able insights into how molecules work
by examining the basic physical struc-
tures of the molecules, which in part
determine their functions. Scientists
have learned, for example, that the
physics of electronic conduction in a
silicon crystal is influenced by the
basic symmetries of the crystal.

The relative physical sizes and
shapes of two molecules may also in-
fluence the rate at which they interact
chemically (since, for two chemicals—
i.e., atoms or molecules— to interact,
they must first come into contact with
each other). This is the case with a
particular class of biochemical sub-
stances called enzymes, which are re-
sponsible for controlling the rate of
biochemical activity without them-
selves being changed (i.e., they are
biological catalysts). The size and
shape of the enzyme molecule in-
fluences which other biochemical
substances (molecules) may bind to
it and hence be influenced by it.

We can gain some understanding of
the basic functions of molecules by
examining the size and shape of a
given molecule, using either a real

physical model or a computer-graph-
ics representation of the molecule.
References 1 , 2, and 3 give some ex-
amples of graphic representations of
molecular structure and their useful-
ness in understanding molecular
function.

Molecules are far too small to be
seen with optical microscopes, and
electron microscopes are just becom-
ing capable of directly imaging a few
specialized types of molecules. Most
of the molecular structures that we
know today have been determined by
X-ray diffraction studies of large
crystals. A crystal can be thought of
as a very large, single molecule com-
posed of a small structure of a few
atoms repeated many times. This
repetitive nature allows researchers to
analyze many identical molecules at
one time and obtain a reasonable
"signal-to-noise" ratio in the results.

Earl J. Kirkland (Cornell University. Ithaca,
NY 14853) holds a doctorate in applied
physics and is a research associate at Cornell's
School of Applied and Engineering Physics.
His work involves computer image processing
of electron micrographs.

X-ray diffraction patterns cannot be
directly interpreted but require a com-
puter to digest the diffraction pattern.
The computer outputs a sequence of
numerical data describing the three-
dimensional (3-D) positions of the
atoms inside the molecule. This
numerical data is rather difficult to
understand without further reduction.
Simple structures with only a few
atoms may be intuitively visualized
from the raw numerical data, but the
more interesting or important struc-
tures often contain hundreds of
atoms, each with its own numerical
coordinate (x.y.z). Intuition is inade-
quate for complicated structures such
as these.

Before the advent of computer
graphics, researchers had to go
through the elaborate process of
building 3-D models of each molecule
for futher study. Because this molec-
ular-structure data is often generated
by a computer, it is a practical alter-
native to also let the computer draw
a 3-D perspective view of the mole-
cule using computer graphics.

Computer graphics is a powerful

(continued)

+— Inquiry 3 1 5

FEBRUARY 1985 -BYTE 251

VIEWING MOLECULES

tool for visualizing the structure of
large molecules in three dimensions.
Sophisticated (and expensive) com-
puter hardware and software systems
for displaying molecules and crystals
in 3-D perspective are discussed in
references 4 and 5.

The Apple Macintosh has enough
resolution and speed to draw 3-D
perspective views of relatively large
molecules and to rotate them in space
(not in real time but fast enough to be
interactive). Although not as good as
the more sophisticated systems
(several of which are discussed in
references 4 and 5), the Macintosh is
certainly less expensive and can pro-
vide quite usable and educational
results. MODEL3D, a program written
in Microsoft Macintosh BASIC 1 .0 and
designed to run on the 128K-byte
Mac, is capable of displaying up to
600 atoms in three dimensions, with
hidden-surface removal and azimuth-
al and polar rotations (these terms are
defined below).

Molecules

For the purposes of this discussion,
think of a molecule as a group of
atoms that are bound together in a

well-defined structure. Each molecule
has a given number of one or more
different types of atoms and each
atom has a specific 3-D coordinate
associated with it. A molecule may be
as simple as two atoms or as com-
plicated as the DNA molecule with its
thousands of atoms. The atom-to-
atom spacing varies from one
molecule to the next and is deter-
mined by the chemistry and physics
of the bonds. Typical atomic spacings
are on the order of a few angstroms
(1 angstrom =10" 8 centimeters).

Each atom in the molecule or crystal
has a further substructure consisting
of a small nucleus of positive charge
(protons and neutrons) surrounded by
a larger, negatively charged electron
cloud. The outer electrons in this
cloud form the actual bond to the
neighboring atoms. The radius of the
atom (i.e., the electron-cloud radius)
varies from one type of atom to the
next. (Typically, atomic radii are on
the order of 1 angstrom.) This atomic
structure may be modeled graphical-
ly as a slightly fuzzy sphere whose
radius is the radius of the electron
cloud. The specific 3-D coordinate of
the atom is associated with the center

x.z PLANE (CRT VIEWING SCREEN)

VIEWING POSITION

(x.y.z);

-VIEWING DISTANCE D —

y<0

Figure I : A perspective view of a three-dimensional object as projected onto a
two-dimensional CRT screen. The point (x.y.z). represents the center of a 3-D sphere,
and (x.z). represents the projected screen coordinates.

or nucleus of the atom. Therefore, to
describe a whole molecule all you
need is a list containing the 3-D coor-
dinate and size of each atom in the
molecule. This will be represented as
the coordinates (x,y,z)i and atomic

sizes (or radii) s it for i= 1,2,3 n,

where n is the total number of atoms
in the molecule.

Rotation

Once you have the list of atomic coor-
dinates inside the computer, you can
rotate the atomic structure to any
angle prior to viewing it. In three
dimensions there are two possible in-
dependent rotations about a given
center (or any other given point). They
will be referred to as an azimuthal
rotation (about the z-axis) and a polar
rotation (about the x-axis). To
azimuthally rotate the molecule about
its center point (x,y.z) through an
angle 0, you must transform each
atomic coordinate (x,y,z)i as:

Xt = (Xi-x )cos(<t>) + (yi-y )sm((t>)

yl = -(Xi-x )s\n(<t>) + (yi-y )cos(<t>)

and to rotate through a polar angle
0, you must transform each atomic
coordinate as:

yi = y/costf) + (z,-z o )sin(0)

z/ = -^/sin(0) + (z,--Zo)cos(0)

The computer uses the new result-
ing rotated coordinates (x'.y",z')i to
calculate the 3-D perspective view of
the molecule. For convenience you
may define the center of rotation
(x,y,z)o to be halfway between the
minimum and maximum extent of the
molecule (along each axis).

3-D Perspective

To display a molecule in 3-D on a
computer screen, the light coming
from the two-dimensional CRT
(cathode-ray tube) screen must be
made to appear as if it comes from
a three-dimensional object (i.e., the
molecule). One way to do this is il-
lustrated in figure 1 (see also refer-
ences 4 and 6). The human observer
is in the "viewing position" at a
distance D from the CRT screen,
which is illustrated as a two-dimen-

252 BYTE • FEBRUARY 1985

VIEWING MOLECULES

sional x,z plane, seen from the side.
Projected on this "screen" is a 3-D
molecule, of which one atom has the
coordinates (x,y,z)i.

We then trace several light rays from
the viewing position through the
three-dimensional-object points. The
points where these rays intersect the
CRT plane is where the object should
be placed when drawn on the CRT
screen. By comparing similar right
triangles formed with the viewing
position, the i^-axis, and either the
(x,y,z)i or (x.z) is points, we can calculate
the screen coordinates as:

x,-, = Dx,/(D-^)

and

Zi^DZiKD-yt)

In practice, the leading multiplica-
tive factor of D will be dropped
because the screen coordinates will
be rescaled later to fill the screen. The
apparent size of each atom should
also be scaled as above so that the
atoms appear smaller as they get fur-
ther away.

In realistic 3-D perspective, some
atoms will be in back of other atoms
and hence should not be visible. This
is the so-called "hidden-surface prob-
lem." An easy, if crude, solution is to
simply sort the atoms by depth and
draw from the back forward, always
overwriting each successive layer of
atoms. When each successive atom is
drawn it exactly overwrites the por-
tion of the object that it would nor-
mally obscure. This is the approach
1 have used here.

The Program

I have implemented the theory out-
lined above in MODEL3D (listing 1),
a program written in Microsoft BASIC
for the Macintosh. {Editor's note: The
source code for MODEL3D is available for
downloading via BYTEnet Listings. The
number is (603) 924-9820.) The pro-
gram first asks for the name of the
data file containing the atomic coor-
dinates of the molecule you wish to
draw. You can obtain this information
from college-level chemistry or
physics textbooks, or from the

(continued)

Listing 1: The Source listing o/ MODEL3D, a Microsoft BASIC 1.0 program
to draw 3-D perspective views of molecules.

*** MODEL3D.BAS ***
Draw a 3D perspective view of a molecule with rotation
For private, noncommercial use only.
©E. Kirkland 4-JUL-84, added printer distortion 9-SEP-84

NOTE: Remember to shrink command window to lower left
hand corner so that the lower right side of screen is visible

90 DEFINT l-N:DEFSNG 0-Z:DEFSNG A-G

100 DIM E(4),IP(12),X(600) I Y(600),Z(600) ) S(600)

110 '

120 ' Define shading bit patterns for sphere

130 IP(0) = &H4411:IP(1) = IP(0):IP(2) = IP(0):IP(3)=IP(0)

140 IP(4) = &H55AA:IP(5) = IP(4):IP(6) = IP(4):IP(7) = IP(4)

150 IP(8) = &HFFFF:IP(9) = IP(8):IP(10) = IP(8):IP(11)=IP(8)

160 '

1 70 ' Ask what to do

180 CLS:INPUT "Data file name : ".FILES

190 INPUT "Azim., polar angles : ", PHI.THETA

200 INPUT "Viewing distance : ",VIEWD:INPUT "Size mag. : ",SMAG

210 INPUT "Type 1 for printer: M ,IPRINT

220 ' Printer distortion correction factor

230 IF IPRINT=1 THEN DISTORT= 1.094 ELSE DISTORT=1!

240 TIM# = TIMER

250 PHI = PHI*3.14159/180!:THETA = THETA*3. 14159/180!

260 CP = COS(PH l):SP = SIN(PHI):CT = COS(THETA):ST = SIN(THETA)

270 '

280 ' Read atomic coordinates from data file and scale

290 OPEN FILES FOR INPUT AS #1

300 XMIN = 1E + 25:XMAX= -XMIN:YMIN = XMIN:YMAX = XMAX

310 ZMIN = XMIN:ZMAX = XMAX:N =

320 WHILE NOT EOF(1)

330 N = N + 1

340 INPUT#1 ) X(N) ) Y(N),Z(N),S(N)

350 IF X(N)>XMAX THEN XMAX = X(N)

360 IF X(N)<XMIN THEN XMIN = X(N)

370 IF Y(N)>YMAX THEN YMAX = Y(N)

380 IF Y(N)<YMIN THEN YMIN = Y(N)

390 IF Z(N)>ZMAX THEN ZMAX = Z(N)

400 IF Z(N)<ZMIN THEN ZMIN = Z(N)

410 WEND

420 PRINT N "atomic coord."

430 XMIN = .5*(XMAX + XMIN):YMIN = .5*(YMIN + YMAX)

440 ZMIN = .5*(ZMIN + ZMAX):PRINT "Rotating..."

450 '

460 ' Rotate molecule around its center

470 FOR I = 1 TO N

480 XA = X(I)-XMIN:YA = Y(I)-YMIN

490 X(I) = CP*XA + SP*YA:Y(I)= -SP*XA + CP*YA

500 YA = Y(I):ZA = Z(I)-ZMIN -

510 Y(I) = CT*YA + ST*ZA:Z(I)= -ST*YA + CT*ZA

520 NEXT l:PRINT "Sorting..."

530 '

540 ' Sort by depth (shell sort)

550 IGAP = INT(CSNG(N)/2!)

560 WHILE IGAP> = 1

570 FOR l = IGAP + 1 TO N

580 FOR J = I-IGAP TO 1 STEP - IGAP

590 JG = J + IGAP

[continued)

FEBRUARY 1985 -BYTE 253

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VIEWING MOLECULES

600 IF Y(J)< =Y(JG) THEN GOTO 640

610 SWAP X(J),X(JG):SWAP Y(J),Y(JG)

620 SWAP Z(J),Z(JG):SWAP S(J).S(JG)

630 NEXT J

640 NEXT I

650 IGAP = INT(CSNG(IGAP)/2!)

660 WEND

670 '

680 ' For perspective projection and scale coordinates

690 SCALE = - 1 E + 25:SMAX = SCALE

700 FOR I = 1 TO N

710 YA = 1 !/(VIEWD - Y(I)):X(I) = X(l)* YA:Z(I) = Z(I)*YA:S(I) = S(l)* YA

720 IF SCALE<ABS(X(I)) THEN SCALE = ABS(X(I))

730 IF SCALE<ABS(Z(I)) THEN SCALE = ABS(Z(I))

740 IF SMAX<S(I) THEN SMAX = S(I)

750 NEXT IrSCALE = 1 1 0!/(SCALE + .5*SMAX*SMAG)

760 SCALEX = SCALE*DISTORT

770 '

780 ' Plot shaded circles (emulating spheres)

790 FOR I = 1 TO N

800 IX = FIX(X(I)*SCALEX + 350!): IY = FIX(Z(I)*SCALE + 1 30!)

810 IR = FIX(S(I)*SCALE*SMAG):IRX = IR*DISTORT

820 GOSUB 880

830 NEXT I

840 PRINT TIMER - TIM# " sec"

850 CLOSE#1:END

860 '

870 ' Sphere plotting subroutine using Quickdraw FILLOVAL

880 IE(0) = IY-IR:IE(1) = IX-IRX:IE(2) = IY + IR:IE(3)=IX+IRX

890 CALL FILLOVAL(VARPTR(IE(0)),VARPTR(IP(0)))

900 IR2 = .8*IR:IRX2=.8*IRX

910 IE(0) = IY-IR2:IE(1)=IX-IRX2:IE(2) = IY + IR2:IE(3) = IX + IRX2

920 CALL FILLOVAL(VARPTR(IE(0)),VARPTR(IP(4)))

930 IR2 = .65*IR:IRX2 = .65*IRX

940 IE(0) = IY - IR2:IE(1) = IX - IRX2:IE(2) = IY + IR2:IE(3) = IX + IRX2

950 CALL FILLOVAL(VARPTR(IE(0)),VARPTR(IP(8)))

960 RETURN

crystallographic technical literature.
Wyckoff's six-volume series (see
reference 12) offers an encyclopedic
tabulation of many molecular struc-
tures. [You can also make up your own coor-
dinates, following the format below,, to experi-
ment with the program]

Prepare the data file using MacWrite.
As shown in the example in figure 2.
each line of the file represents one
atom in the molecule and has four
numbers. The first three numbers of
each line are the (x,y,z)i coordinates
of the ith atom and the fourth number
is the size or atomic radius of this
atom. These numbers may be in any
convenient set of units as long as all
the numbers are in the same units.
Note that MacWrite sometimes leaves
several blank lines at the end of the
file that must be deleted. You must

also save the file as "text-only" in-
stead of the default "entire-docu-
ment."

Alternatively if the molecule is a
crystal you can generate a data file
containing the atomic coordinates for
it by programming the rules for the
repetitive structure of the crystal in a
separate BASIC program, as I did for
the crystal silicon (see below).

After asking you for the name of the
data file, the program asks for the
rotation angles (in degrees), the view-
ing distance (D in figure I; in the same
units as the atomic coordinates and
sizes), the atomic-radius size mag-
nifier (this can be used to expand or
contract the apparent size of each dis-
played atom; to get the normal size
from the input file, type I), and finally,

[continued)

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FEBRUARY 1985 'BYTE 255

VIEWING MOLECULES

0,0,0, .15

• Jj i J } U j i 1 J

.5,0, .5, .15

U j i J) • Jj • 1 J

• J) • J ) 1 y • 1 J

• J j 1 f • O f i 1 J

1 J • J ) • J) I 1 J

.25, .25, .25, .15
.25, .75, .75, .15
.75, .25, .75, .15
.75, .75, .25, .15
0,0,1, .15
0,1,0, .15
0,1,1, .15
1,0,0, .15
1,0,1, .15
1,1,0, .15
1,1,1, .15

Figure 2 : A sample data file showing the three-dimensional coordinates for one unit
cell of silicon. This was generated by the program in listing 2.

Listing 2: A Microsoft BASIC program to generate the three-dimensional
coordinates for a silicon lattice.

10 ' -***SIGEN.BAS ***

20 ' Generate a Silicon lattice of Nx, Ny, Nz unit cells

30 'E. Kirkland 15-SEP-84

40 DEFINT l-N:DEFSNG A-G.O-Z

50 INPUT "Generate Nx.Ny.Nz Silicon unit cells : ".NX.NY.NZ

60 INPUT "Output file name : ".FILES

70 OPEN FILES FOR OUTPUT AS #1 :SIZE = .15

80 FORIX = 0TONX

90 FORIY = 0TONY
100 FOR IZ = 0TO NZ
110 WRITE#1 1 IX,IY 1 IZ,SIZE

120 IF (IX = NX) OR (IY=NY)OR(IZ = NZ)GOTO230
130 WRITEnjX+.SJY + .SJZ.SIZE
140 WRlTEn.lX+.SJYJZ + .S.SIZE
150 WRITEnjXJY+.SJZ + .S.SIZE
1 60 WRITE#1 ,IX + .5JY + .5JZ + 1 .SIZE
170 WRITE^.IX+.SJY + UZ + .S.SIZE
1 80 WRITE#1 .IX + 1 . IY + .5.IZ + .5.SIZE
1 90 WRITE#1 .IX + .25.IY + .25.IZ + .25.SIZE
2Q0 WRITE#1 ,IX + .25JY + .75JZ + .75.SIZE
210 WRITE#1 ,IX+ .75JY + .25.IZ + .75.SIZE
220 WRITE#1 .IX + .75.IY + .75.IZ + .25.SIZE
230 NEXT IZ
240 NEXT IY
250 NEXT IX
260 CLOSE#1:END

A circle appears
elliptical printed
with the Imagewriter.

whether the drawing is to be printed.
The Apple Imagewriter printer has a
slightly different aspect ratio than the
screen, so that a circle on the CRT
screen appears slightly elliptical when
printed. The program can apply a
predistortion to the drawing (multi-
plying the x coordinate by 1.094) so
that it will appear normal when you
print it.

The program then reads from the
data file until it encounters an "end-
of-file" (EOF) condition (the total
number of input lines determines the
total number of atoms in the mole-
cule). An "Input Past End" error in-
dicates that the data file contains
extra characters.

After reading in the atomic coor-
dinates and size data, the program
rotates them about the center point
and sorts them by depth using the
Shell sort method (see references 7,
8, and 9). The program then projects
these new coordinates into the view-
ing screen coordinates with a 3-D
perspective and scales them. If at this
point the program signals, "Out of
Memory," type CLEAR, 20000 and
run the program again.

The final portion of the program
draws a sphere at each of the pro-
jected atomic coordinates, from the
back forward, to fulfill the hidden-
surface requirements. The "sphere" is
drawn using three QuickDraw FILL-
OVAL calls with different shading pat-
terns (see Appendix E of the
Microsoft BASIC 1 .0 manual). The first
call draws a light-gray circle filling the
whole atomic radius, the second
draws a dark-gray circle with a slight-
ly smaller radius, and the third draws
a black circle with a still smaller
radius. The net effect is a shaded cir-
cle that looks like a sphere. For a print-
out of the drawing, use the print-
screen (Shift-Command-4) command.

[continued)

256 BYTE • FEBRUARY 1985

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VIEWING MOLECULES

Note that if two atoms are located
at exactly the same depth (distance
from the viewer), this program will ar-
bitrarily draw one atom in front of the
other. (Obviously this will make a dif-

r 6 File Edit Control

ference only if the atoms are close
enough to each other so that their
radii overlap.) This problem will prob-
ably not be significant in most cases
and may be easily overcome by

M0QEL3D.BflS

■Data file name : SILICON2.DAT
JAzim, polar angles : 0,0
■Viewing distance : 7
Is&emag. ; 1
J Type 1 for printer: 1

107 atomic coord.
iRotating...
I Sorting...

39 sec

= Command =

Figure 3: A 3-D perspective view of 2- by 2- by 2~unit cells of a silicon lattice.
The data file was generated by the program in listing 2.

Figure 4: Another 3-D perspective view of the 2- by 2- by 2-unit cell structure
in figure 3.

258 BYTE • FEBRUARY 1985

VIEWING MOLECULES

rotating the molecule so that one
atom is slightly in front of (or behind)
the other. A proper solution to this
problem is beyond the scope of this
exercise.

Examples

As I mentioned above, a crystal may
be thought of as a single large
molecule whose structure is a simple
pattern repeated many times. Silicon
forms a crystal structure with a basic
repeat distance of 5.43 angstroms. It
is composed of two interpenetrating
face-centered cubic (fee) lattices (see
references 10 and 1 1), with one fee lat-
tice offset from the other by
[ { A}A}A) x 5.43 angstroms. There are
roughly 6.2 5 x IO 18 unit cells per
cubic millimeter of silicon. Large
crystals of silicon in this form (with
suitable treatment) are commonly
used to make the vast majority of in-
tegrated circuits in use today. For ex-
ample, the Motorola 68000 processor
used in the Macintosh is made out of
a single crystal of silicon. Listing 2
shows SIGEN, a short Microsoft
BASIC 1 .0 program that generates a
data file of the positions of the atoms
in crystalline silicon. The data file in
figure 2 was produced by SIGEN and

r # File Edit Control

contains the coordinates for one 1- by
1- by 1-unit cell of silicon. Figures 3
and 4 show computer-graphic repre-
sentations of the crystal with two
slightly different orientations: the face
of the cube (figure 3) and an edge of
the cube (figure 4). Note the slight
slope (like a roof of a house) visible
in figure 4. The vertical edge in the
center is nearer to the observer than
the two outer edges on the left and
right and hence appears larger (taller)
than the outer edges in 3-D perspec-
tive. Note the characteristic symmetry
of silicon that the graphic represen-
tation reveals.

Figure 5 is a computer-graphic rep-
resentation of the aspirin molecule,
whose structure is given in reference
12. The chemical formula for aspirin
is (HOOC)C 6 H 4 -OC(0)CH 3 . I have ar-
bitrarily depicted the hydrogen atoms
with a small radius to distinguish them
from the other atoms in the molecule.
The aspirin molecule has a large hex-
agonal carbon structure (benzene) on
the bottom and clusters of carbon,
hydrogen, and oxygen on the top.

Conclusions

Computer graphics offers a conve-
nient way to visualize three-dimen-

M0BEL3D.BRS

iData file nam* : ASPIRIN DAT

Azinv, polar angles :
Viewing distance : 2
Size mag. : 9
Type 1 for printer: 1

2 1 atomic coord.
Rotating...
Sorting...

11 sec

160,45

:"; v :: : ., ."-'■

Figure 5: 3-D perspective view of the aspirin molecule.

sional structures of molecules as an
aid to understanding the behavior of
the molecules. The Apple Macintosh
computer is capable of displaying a
graphic representation of fairly com-
plex molecules. Although there are
large computer systems that can pro-
duce better graphic representations,
they are beyond the price range of
most individuals. The Macintosh gives
a spectacular performance in relation
to its cost. Even though MODEL3D is
written in interpreted BASIC, most of
the actual graphics is done by the
Macintosh ROM via the QuickDraw
subroutine. Hence, the program runs
relatively fast. These built-in graphics
routines make the Macintosh very
useful for this application. ■

REFERENCES

1. Bechgaard, K., and D. Jerome. "Organic
Superconductors." Scientific American. July
1982, pp. 52-61.

2. Ptashne, M., A. D. Johnson, and C O.
Pabo. "A Genetic Switch in a Bacterial
Virus." Scientific American, November 1982,
pp. 128-141.

3. Dickersoa R.E. 'The DNA Helix and
How it is Read." Scientific American,
December 1983, pp. 94-111.

4. Foley, J. D., and A. Van Dam. Fundamen
tals of Interactive Computer Graphics. Reading,
MA: Addison-Wesley, 1982, plate 15.

5. Greenberg, D., A. Marcus, A. H
Schmidt, and V. Gorter. The Computer Image:
Applications of Computer Graphics. Reading
MA: Addison-Wesley, 1982, pp. 58-59.

6. Newman, W. M., and R. F. Sproull. Prin-
ciples of Interactive Computer Graphics. 2nd ed.
New York: McGraw-Hill, 1979, pp
339-342.

7. Shell, D L. "A High Speed Sorting Pro-
cedure." CACM 2, 7 (July 1959) pp. 30-32

8. Rich, R. P. Internal Sorting Methods Illustrated
with PL/1 Programs. Englewood Cliffs, NI
Prentice-Hall, 1972.

9. Kernighan, B W., and P. J. Plauger. Soft-
ware Tools. Reading, MA: Addison-Wesley,
1976, p. 106.

10. Ashcroft, N. W, and N. D Mermin. Solid
State Physics. New York: Holt, Rinehart, &
Winston, 1976, p. 106.

1 1 . Kittel, C. Introduction to Solid State Physics.
4th ed. New York: John Wiley & Sons, 1971,
pp. 30, 31.

12. Wyckoff, R. W G. Crystal Structures: Vol.
6, Part 1 , The Structure of Benzene Derivatives.
2nd ed. New York: John Wiley & Sons,
1951, pp. 234-235.

FEBRUARY 1985 • BYTE 259

IT ALL ADDS UP...

IBM SYSTEMS

Starting as low as

$1399

64K, 1-DS/DD DRIVE
KEYBOARD

SEC

NEC PRINTERS

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TANDON

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VISICORF
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SPI
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PES

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ELECTRONIC ARTS
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260 BYTE • FEBRUARY 1985

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PRINTERS

AXIOM

AT-lOO Atari Interface Printer$159.00
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Inquiry 67

FEBRUARY 1985 • BYTE 261

5*%-^*

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Inquiry 368

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SCIENCE

LABORATORY
INTERFACING

by Lincoln E. Ford, M.D.

A medical researcher examines the capabilities and limitations
of an important laboratory device

ALMOST ALL LABORATORY com-
puter applications can be described
as one of the following functions: (I)
control of experiments, including tim-
ing and synchronizing external events
and setting external voltages; (2) data
acquisition, usually through the digital
conversion of analog electrical sig-
nals; (3) data storage; and (4) data
analysis. While data storage and
analysis make computers most ap-
pealing in the laboratory, these func-
tions are common to most computer
applications. The functions that make
laboratory applications different from
other computer uses are the first two,
control of experiments and data ac-
quisition. The following discussion is
directed at these two areas. The two
functions together require five distinct
hardware components: analog-to-
digital (A/D) converters, digital-to-
analog (D/A) converters, digital input-
output (I/O) ports, counters, and an ac-
curate frequency generator. This
discussion is developed from my ex-
perience with a hardware device that
provides all five functions.

A/D Conversion

In a typical application, analog signals
from some electronic device are

sampled and converted to digital data
at regular intervals. Usually sampling
continues for some well-defined
period. The sampling may progress at
different speeds at different times. For
example, it is frequently desirable to
record high-speed events that occur
within the setting of lower-speed
events. To record both types of events
with an analog recorder (an oscillo-
scope or chart recorder), it is usually
necessary to make two recordings,
one at a high speed and one at a low
speed. Using a computer, it is relative-
ly simple to record a single input at
different speeds.

Analog-to-digital conversion is
perhaps the most critical of labora-
tory applications because errors at
this step will greatly distort the data.
It is also frequently the function that
most taxes the speed of the com-
puter. Speed at this stage is some-
times limited by the A/D converters,

Lincoln E. Ford, M.D., is an associate pro-
fessor of medicine and cardiology at the
University of Chicago (Cardiology Section.
Department of Medicine. University of
Chicago. 950 East 59th St., Chicago. IL
60637). His hobbies include gardening and
skiing.

but more often it is limited by soft-
ware. Ultimately the software is
limited by the design of the computer,
but more frequently it is limited by
having to perform some other task
concomitantly. One such task is the
generation of control pulses during
A/D sampling.

In many instances the initiation of
an A/D recording must be synchro-
nized with the experiment. Instead of
having an external device initiate the
A/D conversion sequence, it is tempt-
ing to have the computer control the
experiment at the same time that it
is collecting data. An additional ad-
vantage of this combined approach is
that the data collection is very ac-
curately synchronized to the experi-
mental procedure. The difficulty with
this approach is that it requires the
computer to perform two tasks at
once. This can call for some relative-
ly sophisticated programming, par-
ticularly when high speeds are neces-
sary.

Interface Boards

There are several commercially avail-
able devices that will perform at least
four of the five functions required for

{continued)

FEBRUARY 1985 -BYTE 263

LABORATORY INTERFACING

the laboratory applications described
above. Several of my colleagues and
I bought the LabMaster board made
by Tecmar because it provides all five
functions and because it was the first
one available. It also costs less than
more recent devices. It consists of a
motherboard that fits into the IBM PC
and a daughterboard that houses the
A/D converters outside the computer.
This arrangement isolates the incom-
ing analog signals from electrical in-
terference inside the computer.

The Data IVanslation Company
makes a similar board that has the
capability of direct memory access
not available on the LabMaster but
does not have the Tecmar board's
progammable counters. We preferred
the Tecmar board in part because we
wanted to put out logic pulses to con-
trol the experimental apparatus while
collecting data with the A/D converter.
The five programmable counters
simplify this task because they
operate independently of the central
processing unit of the host computer.
The counters can be programmed to
begin counting the same frequency
pulses that trigger the A/D conver-
sions. When they have completed
their count they toggle their external
outputs without intervention from the
computer. Thus, the logic pulses are
synchronized exactly to data acquisi-
tion without interfering with the high-
speed operation of the central
processor.

When very high speeds are not re-
quired, the digital I/O port can be
used for applications control. Al-
though most commonly used as a
single interface to other digital equip-
ment, the individual channels in the
port can be used separately to con-
trol different pieces of apparatus. In
addition, these channels can be con-
figured to accept logic pulses from
the apparatus, thereby allowing a
bidirectional interaction.

A final way of controlling experi-
ments is to use the D/A converters to
set voltage levels for external devices.

Possible Improvements

In spite of our general satisfaction
with the Tecmar board, we found

several areas that need improvement,
both in the LabMaster and in the
other devices that are available. As ex-
plained in John Mertus's letter to
BYTE ("Data Collection with an IBM
PC" October 1984, page 14), the
absence of direct memory access on
the Tecmar board severely limits this
board in multitasking operations.

The cable connections could be
greatly improved. Tecmar sells a set
of cables for external connections to
the board, but they are simply that-
bare cables. Users must make their
own interfaces. We have made an in-
terface box with BNC connectors for
each connection, and while we were
at it, we put in some buffer chips to
protect the digital I/O ports. Several
other manufacturers supply slightly
less primitive connections for their
devices, but at best these consist of
screw terminals for bare wires. I do
not know of many laboratory scien-
tists who relish the thought of bring-
ing their signals out on bare wires.
Any manufacturer who supplied a
device with an interface having stan-
dard connectors such as BNCs and
well-protected inputs would find a
ready market.

There is one improvement related
to signal processing that I would
especially like to see. This is the ad-
dition of filters to the analog inputs
of the A/D converters. It is well known
that no information can be derived
about the frequency components of
a digitized signal that are greater than
half the sampling frequency. Noise
and oscillations in the signal that are
faster than the sampling frequency at
best decrease the signal-to-noise
ratio. In many cases, faster signals in-
troduce "aliasing," spurious low-
frequency oscillations that result from
sampling a high-frequency oscillation
at systematically different parts of its
period. Although filters generally in-
troduce lags in electronic signals, the
lags introduced by antialiasing filters
are likely to cause far less signal
distortion than will high-frequency
oscillations. The antialiasing device
should consist of a low-pass filter with
a sharp cutoff frequency near the
sampling frequency. The main argu-

ment against such a filter is that the
sampling frequency varies widely,
sometimes within the same record, so
that the cutoff frequency must be
made to vary in the same way. The
solution to this problem is to use an
integrator that averages the signal be-
tween sample intervals. A. F. Huxley
and G. L, Reed recently described a
clever circuit that performs this
averaging (see 'An Automatic
Smoothing Circuit for Input to Digitiz-
ing Equipment." journal of Physiology,
volume 292, 1979, page 1 IP). It is trig-
gered by the same clock pulse that
triggers the A/D conversions, so that
its cutoff frequency always varies with
the sampling frequency.

A major way in which A/D con-
verters could be improved is by the
use of separate converters for each in-
put channel and the use of on-board
data buffers. Most computer-con-
trolled multichannel devices have a
single A/D converter with a multi-
plexer that Switches different channels
into it. Only one channel is converted
at a time, so that the samples in each
channel are displaced in time relative
to those in other channels. This time
displacement can cause a systematic
error when the data from one chan-
nel is plotted as a function of that in
another. The samples from different
channels can be brought into coin-
cidence either by using separate A/D
converters for each channel or by
holding the signals from all channels
in sample-and-hold circuits that are
triggered when the first channel
begins its conversion. The advantage
of separate converters and on-board
data buffers is that they increase the
speed of operation while effecting the
synchronization.

Computer Considerations

Your choice of interface board has an
effect on the size of the central pro-
cessor and data bus needed. Most
data is collected from I0-, 12-, or
16-bit A/D converters, so one A/D
conversion will require a 2-byte word.
In a machine with a 16-bit bus (a true
16-bit computer) entire words can be
moved at once. In a smaller computer

[continued)

264 BYTE • FEBRUARY 1985

We make everybody look good.

NEC PC-8800

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IBM PCjr.

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Apple II

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VIC 20

(ajb,c,e)

Atari 800/1 200

(a.b.c.e)

Franklin

(a.b.c.d.e.f)

No matter what kind of computer
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Need the finest in color graphics?
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(e)JB1260:12 rt monochrome; (f)JC1460: 14" colorRGB; (g)JB1410: 14" monochrome; (h)JC1410: 14" colorRGB. Specificationsandprfcesaresubjecttochangewithoutnotice.

For the location of your nearest NEC dealer dial 1-800-323-1728. In Illinois, 1-312-228-5900.

NEC Home Electronics (U.S.A.), Inc., Personal Computer Division, 1401 Estes Avenue, Elk Grove Village, IL 60007, NEC Corporation, Tokyo, Japan.

Inquiry 343

FEBRUARY 1985 -BYTE 265

DeSmet
C

8086/8088

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having an 8-bit bus, words must be
moved in two sequential steps. This
need to make two-step transfers great-
ly slows most of the computer's oper-
ation. Since most time-critical opera-
tions involve data transfers along the
bus, this slowing occurs at a very
vulnerable stage. Although a true
1 6-bit computer transfers data twice
as fast as an 8-bit machine, it does not
follow that a 3 2 -bit computer would
be still faster in handling integer data.
Since integer data occurs in 2-byte
words, increasing the bus size to 32
bits would not produce any increase
in speed unless some way could be
devised to move two words at once.
The 16-bit machines available today
are therefore as large as many opera-
tions require.

A question related to size is
whether it is better to have several
small single-purpose computers or
one large, multipurpose machine. My
own preference is for the former. A
major consideration is cost. In addi-
tion, the failure of a single computer
in a group does not incapacitate the
entire laboratory in the way that the
failure of a single large computer
does. Another advantage of a group
of computers is that each can be
dedicated to a single task. Even with
the best multitasking arrangements,
there will always be some time-critical
operation that requires the uninter-
rupted use of the computer, forcing
other users to wait. With multiple
computers such interactive interrup-
tions do not occur.

The main disadvantage of small
computers is that they are slow. This
disadvantage is usually more than off-
set by the ability to dedicate the
machine to a specific task for an ex-
tended period.

The IBM PC Compromise

In spite of the negative considerations
about the 8-bit bus, my colleagues
and 1 bought several IBM PCs for use
in the laboratory. We selected this
computer rather than a true 16-bit
machine because of its popularity.
Many peripherals and programs are
available for it, and we felt that it
would not go out of production near-

ly as quickly as some of the other, less
popular models.

We have found the PC to be as good
as or better than expected in almost
all areas except for one peculiarity:
the absence of a limited interrupt or
a software-controllable wait state.
Once an A/D conversion is made, a
flag consisting of one bit in a status
register is set. The computer must
then detect the flag and take the
digital data from the converter. The
PC can detect the flag in only two
ways: polling the status register or
generating a full interrupt. A full inter-
rupt, together with its return, requires
83 clock cycles. This many cycles
would take more than 20 microsec-
onds (fus) just to detect the flag. Poll-
ing takes substantially less time. Using
a polling routine, we have written se-
quential A/D sampling programs that
operate at a rate of 22 fxs per conver-
sion. Over half that time is spent poll-
ing the status register. If a more rapid
way of detecting the flag could be
devised, this routine could operate at
more than twice the speed. If the cen-
tral processor could be put in a wait
state immediately before each A/D
conversion and be released by the
'A/D done" flag, detection of the con-
version would be virtually instan-
taneous. An otherwise-similar com-
puter that had such a capability would
be able to accept A/D conversions
about every 10 f.is.

Software

Software is the most crucial part of
any laboratory system. Clever pro-
gramming can introduce great flex-
ibility and compensate for many defi-
ciencies in hardware. Poor program-
ming can hobble even the best sys-
tem. The time required to develop
good programs should not be under-
estimated. Many of us have bought a
piece of equipment that was physical-
ly capable of performing some
desired task only to find that weeks
of programming were required to
make it work. For those of us who
have had this experience, there is no
stronger selling point for equipment
than the concomitant availability of
adequate programs to run it. ■

266 BYTE • FEBRUARY 1985

********•**••**

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*CP/M-86 t MP/M-86 and CONCURRENT CP/M-86 are trademarks of
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**MS'DOS is a trademark of Microsoft.
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Dealer inquiries invited

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Tel: (617) 366-6434 □ Telex.: 4996272

Inquiry 188

For orders outside the U.S., contact our exclusive dealers:

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268 BYTE • FEBRUARY I985

Inquiry 36

SCIENCE

INTERFACING FOR

DATA
ACQUISITION

BY THOMAS R. CLUNE

A comparison of three interfaces

THE USE OF MICROCOMPUTERS for
data acquisition in the sciences is sur-
prisingly limited. It is widely recog-
nized that the need for such applica-
tions exists. But I discovered in my ex-
perience at Brandeis University that
most researchers have either had bad
experiences with data acquisition on
minicomputers or simply don't feel
that they have the time to learn what
they would need to know to retool
their labs. Nonetheless, the advan-
tages of computerizing are so sub-
stantial that microcomputer-based
data acquisition is slowly moving into
the lab. In this article, I'll share some
of my experience with different ap-
proaches to computerizing data ac-
quisition. Since I find the IEEE-488 to
be the most versatile option for
laboratory data acquisition, I will
devote a fair amount of time to ex-
plaining that interface. My hope is that
my experience may ease the prob-
lems that you might encounter in
computerizing your setup.

The Problem

There are three basic reasons why
microcomputers are so important in

the context of data acquisition. First,
for a minicomputer or mainframe to
be affordable, its use must be shared
by more than one person, but in data
acquisition it is crucial to have the
computer's attention when the data
is ready. Microcomputers make single-
user systems affordable. Second,
mainframe computers are generally
not located in the laboratory. Thus, in
any but very low speed data-acquisi-
tion contexts, there is a communica-
tions bottleneck created by the data
transmission. Third, there is no com-
mon standard for interfacing with
laboratory instruments on main-
frames, so each laboratory setup pre-
sents substantial and individual prob-
lems of design and implementation
that exacerbate the financial and
logistical difficulties.

At least one other concern is fuel-
ing the drive toward computerization

Thomas R. Clune is a BYTE technical editor.
Before coming to BYTE, he was the physical-
chemistry lab coordinator at Brandeis Univer-
sity, where he taught data acquisition by
microcomputer. He can be contacted at POB
372, Hancock. NH 03449.

in the lab: The cost of turnkey instru-
ments has become so high that most
institutions are unable to afford the
state-of-the-art equipment needed to
conduct research. This is particularly
irritating because most instruments in
the sciences have essentially the same
components. You end up paying over
and over again for a built-in chart
recorder, a waveform digitizer, a
monochrometer, a photomultiplier,
etc. And when the new generation of
an instrument comes out with a
broader dynamic range or some other
improvement in one component, the
entire turnkey instrument must be re-
placed. We simply can't afford to pay
for research done that way any more.
With the availability of microcom-
puters, we don't have to. We can tie
chart recorders, waveform digitizers,
and whatever else we need together
into a dedicated instrument and re-
cycle the components as the field or
our research evolves.

A/D Converters

The least expensive way to automate
a lab is with an analog-to-digital (A/D)

[continued)

FEBRUARY 1985 -BYTE 269

INTERFACING

The speed of a

transient tracked
by D/D equipment
is not limited by the
computer's throughput.

converter. There are, however, a
number of limitations to this ap-
proach. First, an A/D converter
samples only one voltage source at
a time, lypically, an experiment re-
quires correlating one reading to
others for the same instant of time
(e.g., pressure versus temperature at
time t). If the time requirements are
sufficiently lax, that is, if readings
taken 10 or 20 microseconds apart
can be treated as simultaneous, an
A/D converter may be acceptable. But
often this time lag is sufficient to make
the data hopelessly imprecise. The
second problem with A/D converters
is that they are slow. The maximum
sampling rate on most "high-speed"
A/D converter boards is 100 kilohertz
(kHz). Practically speaking, this means
that you can't track a transient of
greater than approximately 20 kHz.
Much of scientific data acquisition
now requires at least the ability to
track a transient of a few megahertz.
A third problem with A/D converters
is that, because the boards are made
to be inexpensive, their linearity is not
very good. A 12-bit board may have
an effective resolution of only 7 or 8
bits. Finally, A/D converters are very
susceptible to noise in a lab. Com-
monly, the cabling will be either
twisted-pair or ribbon cable— very
good antennae. In a well-designed
board, the cabling is simple coax,
which may still not give the level of
noise immunity required in a labora-
tory environment.

Nonetheless, an A/D converter is a
good buy if it will do your task. My
feeling is that the best use of an A/D
converter is to connect it to the chart
output of a stand-alone instrument.

Instead of junking a high-quality
analog instrument in the interests of
modernizing, use the capabilities
available in your lab now. One big ad-
vantage of this kind of setup is that
you can use a very slow A/D con-
verter. This is desirable for two
reasons: first, a slow A/D converter
will be better made than a compar-
ably priced high-speed board, and
second, since you will only need a
30-Hz-or-so A/D converter, most noise
in the lab will be too fast for the A/D

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Full text of "Byte Magazine Volume 10 Number 02: Computing and the Sciences"

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