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17/2 PartV Bits and Bytes 

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Chapter 1 7 Hardware and Peripherals 

17.1 ... Memory 

The microprocessor was a significant key to 
lowering the cost of the personal computer. However the 
other key and an egually important one was low-cost 
semiconductor memory. Semiconductor memory started 
replacing magnetic core memory around 1967. 

Their are two types of semiconductor Random Access 
Memory (RAM) . Dynamic RAM (DRAM) reguires periodic 
refresh of the memory contents and Static RAM (SRAM) 
retains the contents without refresh. Both types of RAM 
loose their contents when the power is turned off. Read 
only memory (ROM) retains its contents once it is 
programmed, even when the power is turned off. 

The first commercial IK metal oxide semiconductor 
DRAM was the Intel 1103 released in October 1970. This 
chip had a pivotal role in undercutting the price and 
replacement of core memory. Intel continued to improve 
DRAM capacities with the release of the 4K 2107 chip in 
1972 and the 16K 2117 chip in 1977. However, competitive 
challenges from Japanese companies, would have a 
significant impact on Intel and other North American 
producers of memory chips . 

Japan decided to make a strategic investment in 
the semiconductor memory industry around in the late 
1970' s. The effect of this was the first open market 
release of a 64K DRAM chip by Fujitsu Limited in 1979, 
and introduction of the first 1-megabit DRAM chip by the 
Toshiba Corporation in 1985. A number of other factors 
contributed to the dominance of Japanese manufacturers 
in the 1980' s. Some of these were: a cooperative 
relationship between various companies in the Japanese 
industry, illegal use of U.S. technology, superior 
guality that contributed to lower costs and a 
significant investment in new facilities to produce 
memory chips. This resulted in a price war by the 
Japanese producers to increase their market share 
through the early 1980' s. By 1985 the market situation 


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for North American producers had so deteriorated, that 
the U.S. Government accused Japan of unfair trading 
practices and filed an antidumping complaint against the 
Japanese manufacturers. A semiconductor agreement was 
signed by the governments of Japan and the United States 
in 198 6. However, by this time it had adversely affected 
many U.S. companies such as the Intel Corporation that 
had already decided to withdraw from the DRAM market. 
The company also withdrew from the EPROM chip market in 

Erasable Programmable Read-Only Memory (EPROM) 
was invented by Dov Frohman at Intel. The memory 
contents can be programmed then erased by exposing the 
chip to ultraviolet light. Intel released the 2K-bit 
1702 EPROM chip in September 1971. This alterable 
storage medium provided a low cost way to store 
microcomputer programs and became a successful and 
extremely profitable product for Intel until the mid 
1980' s. 

Flash memory was developed by Toshiba. It 
provided the non- volatility of EPROM but the memory 
could be erased electrically. Electrically Erasable 
Programmable Read-Only Memory (EEPROM) was developed by 
National Cash Register (NCR) and Westinghouse companies . 

17.2 ... Storage Devices 

Tape Drives 

Paper tape was one of the earliest forms of 
storage for personal computing. However it normally 
required a teletype machine for input/output that was 
too expensive for the average user. 

Another early storage medium for personal 
computers was the magnetic audio cassette tape and the 
subsequent digital data cassette. Information Terminals 
Corporation (ITC) was the first producer of high quality 
data cassettes. The company was founded by J. Reid 
Anderson in April 1969. Anderson had previously 
developed acoustic-coupler modems and a prototype for a 
"smart" computer display terminal. During the 
development of the computer display terminal, Anderson 

Hardware and Peripherals 17/5 

determined that audio tape cassettes were not a 
sufficiently reliable storage medium for recording 
digital data. The audio cassettes did not have a uniform 
magnetic coating or a precise cassette body that 
resulted in "dropouts" or lost data. This resulted in 
the development of a high guality, precision data 
cassette that ITC started producing in 1970. The company 
became the dominant supplier of digital data cassettes 
in the 1970' s. ITC introduced a mini cassette for 
portable data processors and a guarter-inch data 
cartridge in 1975. A new superior coating media for 
tapes and disks named Verbatim, was announced in 
February 1977. The company changed its name to Verbatim 
Corporation in late 1978, and went public in February 

The 3M company introduced guarter-inch tape drive 
media in 1971. The capacity of these early drives was 
only 30 megabytes. 

Jerry Ogdin developed the concept of using two 
tones on magnetic tape to represent digital data. This 
was implemented in a Popular Electronics construction 
article with the name of HITS (Hobbyists' Interchange 
Tape System) in September 1975. It was inexpensive and 
was adapted by many manufacturers . Initially each 
company had their own formatting standards. However in 
November 1975 BYTE magazine organized a meeting in 
Kansas City, Missouri of interested companies. The 
companies agreed to a format that became known as the 
"Kansas City Standard." This standard facilitated the 
exchange and use of magnetic tapes on different systems. 

Disk Drives 

The Beginning at IBM 

Hard disk drive technology was developed by IBM 
in the 1950's as described in Section 1.3. The first 
Winchester hard disk drive was announced by IBM in March 
1973 as the Model 3340 Disk Storage Unit. It was 
developed as a low-cost drive for small to intermediate 
computer systems. The term Winchester was used by the 
engineers due to the storage capacity characteristics 
and similarities to the name of a popular rifle as 

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described in Section 20.4. A principal in the 
development was Kenneth E. Haughton who had assumed 
responsibility for the project in 1969. The drive 
assembly used a removable sealed cartridge with 14-inch 
diameter disks and was available in 35 and 70 megabyte 
storage capacities. 

Floppy disk drives were developed at IBM 
laboratories by David L. Noble during the period of 1967 
to 1971. They were initially developed by IBM as a means 
of storing and shipping microcode for Initial Control 
Program Load (ICPL) software programs on mainframe 
computers. The jacket enclosing the diskette was 
developed to protect the disk during handling and 

The initial eight inch diameter read only units 
had a product designation of 23FD, a code name of Minnow 
and shipped in 1971. The diskette on the read only units 
rotated at 90 revolutions per minute and data was 
recorded on one side only. The diskette capacity was 
81,664 bytes on 32 tracks which were hard sectored with 
eight holes around the outer edge of the disk. 

The eight inch diameter read-write units had a 
product designation of 33FD, a code name of Igar and 
shipped in 1973. The diskette on the read-write drive 
units rotated at 360 revolutions per minute, had a 
capacity of 242,944 bytes on 77 tracks which was 
recorded on one side only and used magnetic soft 
sectoring (no sector holes) . The 33FD diskette drive was 
a success and was used in data entry products which 
started to replace IBM card systems . 

In 1976 the 43FD unit was shipped with data being 
recorded on both sides and capacity increased to 568,320 
bytes on 154 tracks. In 1977 the 53FD double-density 
unit was shipped with capacity increased to 1,212,416 
bytes . 

IBM's research and development activities created 
the Winchester hard disk drives and the floppy disk 
drives. However other companies entered the market to 
compete with IBM products and to provide disk drives for 
other computer systems . Some of these manufacturers were 
Control Data Corporation (CDC), Conner Peripherals, 

Hardware and Peripherals 17/7 

Maxtor, Micropolis Corporation, MiniScribe, Quantum 
Corporation, Seagate Technology, Shugart Associates and 
Western Digital Corporation. In the mid 1970' s, hard 
disk drives were not suitable for use with 
microcomputers due to their large size and high cost. 
However by 1976, inexpensive floppy disk drives became 
available for personal computers. 

Floppy Disk Drives 

Alan F. Shugart joined IBM as a customer engineer 
in 1951. After a number of positions related to memory 
and storage technology he became manager for direct 
access storage products. Shugart left IBM in 1969 to 
become manager of storage products at Memorex. In 1973 
Shugart left Memorex and with Finis F. Connor and Donald 
J. Massaro founded Shugart Associates. The company 
announced the SA-900 8-inch floppy diskette drive that 
retailed for $500 in the summer of 1973. After two years 
Shugart had a dispute regarding capitalization of the 
company and left. Shugart Associates announced the SA- 
400 5.25-inch minifloppy disk drive for $390 in December 
1976. The drive used a single-sided single-density 
floppy disk with a capacity of 110 kilobytes. Shugart 
Associates was acquired by Xerox Corporation in 1977. 
However it was not profitable and resulted in Xerox 
terminating Shugart operations in 1985. 

The first advertisement for a microcomputer 
floppy disk drive in the Byte magazine appeared in the 
August 1976 issue. The eight inch drive is described as 
"iCOM's Frugal Floppy. At $995, your microprocessors 
best friend." It was produced by iCOM Microperipherals 
that was a division of the Pertec Computer Corporation. 
Then in the February 1977 issue of Byte, iCOM advertised 
a 5.25-inch Microfloppy disk drive system for $1,095. 

North Star Computers, was another early 
manufacturer of floppy disk drives for MITS Altair and 
compatible microcomputers. The company advertised the 
Micro-Disk System (MDS) in the January 1977 issue of 
Byte magazine. The unit used a Shugart SA-400 mini 
floppy disk drive and sold for $599 as a kit, or $699 
assembled . 

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Reference Section 5.5 for information on the 
Apple Disk II floppy disk drive introduced by Apple 
Computer in 1978. In the late 1970' s, other companies 
such as Alps Electric Company of Japan (who supplied 
Apple Computer) , Sony Corporation and Tandon Corporation 
entered the floppy disk drive market. During 1982, 
various Japanese manufacturers offered half-height 5.25 
inch floppy disk drives. 

Microfloppy disk drives were introduced in the 
early 1980' s for portable computers and to provide a 
more durable diskette and a less expensive drive 
assembly. The term floppy was not accurate as the disk 
was contained in a hard-shell cartridge. It also 
included an automatic shutter that closed over the 
recording surface when it was removed from the drive . 
Initially there were different incompatible disk sizes. 
Companies such as Hitachi introduced a 3.0 inch drive, 
Seagate supported a 3.25 inch dive, Sony and Shugart a 
3.5 inch drive, Canon a 3.8 inch drive and IBM a 4.0 
inch drive. This resulted in the Microfloppy Industry 
Committee (MIC) being formed in May 1982 to reach a 
consensus on a common configuration standard. In 
September a 3.5 inch system was proposed. Sony became a 
dominant supplier of 3.5 inch disk drives in 1983. The 
initial Sony disk drive had a storage capacity of 438 
kilobytes that was subseguently increased to 1 megabyte 
(720 kilobytes formatted) . Early applications of the 3.5 
inch drive were in the Hewlett-Packard HP-150 computer 
and the Apple Macintosh computer. 

Hard Disk Drives 

Hard disk drive technology changed significantly 
in the years following its initial development by IBM. 
The storage capacity, access time and physical size have 
been dramatically improved. The original 14-inch 
diameter disk was reduced to 8-inches in 1978, then to 
5.25-inches in 1980, to 3.5-inches in 1984 and to 2.5- 
inches in 1989. 

The first Winchester 8-inch hard disk drive was 
introduced by Shugart Associates in 1978. Alan Shugart 
and Finis F. Conner who had been cofounders of Shugart 
Associates founded Shugart Technology in 1979. A major 

Hardware and Peripherals 17/9 

investment was made in the new company by the Dysan 
Corporation, a disk manufacturer. Shortly after the 
company name was changed to Seagate Technology, Inc. The 
first Winchester 5.25-inch hard disk drive with a 
storage capacity of 10 megabytes was announced in June 
198 0. Conner left Seagate and founded his own disk drive 
company called Conner Peripherals, Inc. in 1985. Seagate 
Technology became a dominant supplier of disk drives 
when it acguired the disk operations of Control Data 
Corporation in 1989. In early 1996, Seagate purchased 
Conner Peripherals and became the largest U.S. 
manufacturer of hard disk drives. 

David Brown, James Patterson and others founded 
the Quantum Corporation in 1980. The companies first 8- 
inch hard disk drive was produced in early 1981 and a 
3.5-inch hard disk drive was introduced in 1988. The 
company is now the second largest manufacturer of hard 
disk drives . 

Western Digital Corporation was founded as a 
manufacturer of calculators and semiconductors in 1970. 
In the mid 1980' s, the company reorganized and changed 
product lines to concentrate on storage devices. The 
company acguired the disk drive operations of Tandon 
Corporation in 1988. Western Digital is now the third 
largest U.S. manufacturer of hard disk drives. 

Apple Computer's first mass storage system called 
the ProFile was introduced in September 1981 for the 
Apple III computer. The unit used Winchester technology, 
had a 5 megabyte storage capacity and was priced at 
$3,495. The hard drive within the ProFile unit was the 
ST-506, a 5.25-inch drive manufactured by Seagate 
Technology. The drive had a built-in power supply and a 
Z-8 based controller. 

Compact Disk 

Compact disk (CD) technology was developed as a 
joint effort by N.V. Philips of the Netherlands and Sony 
Corporation of Japan in 1976. This led to a number of 
specifications to define the disk format standards for 
the various types of media by the early 1980' s (see 
Section 20.3). Compact Disk - Read Only Memory (CD-ROM) 
drives with a capacity of 550 megabytes were introduced 

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in the USA in the fall of 1984. However with an initial 
price of over $2,000 they were expensive. High price, 
lack of applications and a need for format recording 
standards inhibited the early proliferation of the 
device . 

Bernoulli Drive 

David Bailey and David Norton founded the Iomega 
Corporation in 1980. Iomega introduced the Bernoulli 
removable disk drive with a storage capacity of 44 
megabytes for personal computers in 1983. It is also 
known as a Bernoulli Box and features capacity 
comparable to a hard disk and a removable assembly for 

The name Bernoulli is from an eighteenth century 
mathematician Daniel Bernoulli who described the air 
dynamics utilized in the drive. The concept enables an 
extremely close read/write head to disk relationship but 
also a more tolerant protection from drive-head crashes. 

A 100 megabytes Zip drive was introduced in 1995 
and became guite popular as a removable high capacity 
disk storage system. The larger Jaz drive was introduced 
later, but had a number of problems. 

Optical Drives 

The first 12 inch diameter optical drives with 
Write Once, Read Many Times (WORM) recording 
capabilities were introduced in 1983. This was followed 
by 5.25 inch drives that were introduced in 1985. The 
principal feature of the optical drive is its extremely 
large storage capacity, up to 1 gigabyte. The NeXT 
computer was one of the earliest applications of the 
optical disk drive. 

17.3 ... Input/Output Devices 

Prior to the introduction of low cost monitors, 
printers and storage devices the teleprinter was a 
common computer input/output device. The teleprinter had 
an alphanumeric keyboard for input and a character 
printer to produce hardcopy output. It could also 

Hardware and Peripherals 17/11 

include a communications interface, magnetic tape unit 
or a paper tape punch and reader for data storage 
input/output. The teleprinter was often loosely referred 
to as a "Teletype" due to the dominant position of the 
Teletype Corporation in the market. 

The other significant supplier of teleprinters 
was IBM. The market was generally divided between 
Teletype and IBM compatible teleprinters. 


The Teletype Corporation produced many different 
teleprinter models, however popular units included the 
Models 33 and 35 which were announced in 1963. Three 
versions of each model were produced with different 
system designs. The ASR-33 (Automatic Send-Receive) 
version was priced from $755 to $2,000 depending on the 
configuration. The printer speed was 10 characters per 

For the personal computer user a new machine was 
not only expensive but difficult to obtain. The use of 
used or rebuilt machines at more affordable prices was 
more common. 

17.4 ... Displays 

The September 1972 issue of Electronic Design had 
an article describing how to build a circuit that could 
display 1,024 ASCII characters on a TV set. 

Don Lancaster was an electrical engineer who in 
the late 1960's started writing articles for Popular 
Electronics and Radio-Electronics magazines. One of 
Lancaster's articles described a project on how to build 
a decimal counting unit. Then in the September 1973 
issue of Radio-Electronics Lancaster had an article 
entitled "TV Typewriter" [433] that described how the 
computer could be connected to a television set. A TVT-1 
prototype was built by Lancaster and sold as a kit for 
$120 in 1973. The unit could store up to 1,024 
characters and display 16 lines of 32 characters. The 
unit had text editing capabilities and construction 
details were available for $2 . 

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The VDM-1 Video Display Terminal was a prototype 
only that was developed by Lee Felsenstein in 1974. It 
was the first video terminal to be used interactively 
with a personal computer. 

In 1972 the IBM 3270 Information Display system 
was announced. This provided improved speed and silence 
of operation. It also facilitated interaction between 
the user and the computer. 

Lear Siegler Inc. (LSI) was an early supplier of 
"glass teletype" terminals after introducing the LSI 
ADM-1 terminal at a price of $1,500. Another major 
supplier of microcomputer monitors was Amdek, founded by 
Go Sugiura in 1977. 

17.5 ... Printers 

Wire Matrix 

The initial development of wire matrix printing 
was by Reynold B. Johnson at IBM. The initial concept 
used a 5 by 7 array of wires to form a character. It was 
introduced with the Type 26 keypunch in 1949. 

In 1954 Burroughs Corporation announced a wire 
printer producing 100 character lines printing at 1000 
lines per minute. In 1955 IBM announced two high speed 
printers capable of printing 1000 lines per minute. 
These high speed wire printers experienced numerous 
problems and were not successful. 

In 1969 IBM introduced the Model 2213 seven-wire 
printer. This printer was unidirectional and printed at 
a rate of 66 characters per second. 


Centronics Data Computer Corporation was founded 
by Robert Howard as a computer systems company. The 
company designed a dot matrix printer called the Model 
101 which was introduced in the spring of 1970. It had a 
speed of 165 CPS (Characters Per Second) using a 5 by 7 
matrix and sold for $2,995. The Micro-1 printer with a 
print speed of 240 CPS and a price of $595 was released 
in 1977. Then in 1979, the company introduced the 
Centronics 700 series that included the Model 779 that 

Hardware and Peripherals 17/13 

was priced at less than $1,000. Centronics was a 
dominant supplier of dot matrix printers in the 1970' s. 


Epson was one of the initial developers of low 
cost dot matrix printer technology. Epson's technology 
evolved from a printing device developed to print 
results from Seiko's quartz watch which was introduced 
at the 1964 Olympics in Japan. Subsequently a miniature 
printing device called the EP-101 was marketed by Seiko. 

In 1975 Seiko established a subsidiary which they 
named Epson America, Inc. It was established to market 
and distribute microcomputer products worldwide. The 
name Epson was derived from the "son" of the EP-101 
printer. Initially the company sold component parts to 
original equipment manufacturers (OEM's) who 
manufactured printers under their own brand name. Epson 
released its own dot-matrix printer, the TX-80 in 1978. 
This was the first low cost printer for microcomputers 
and was an immediate success. 

The MX series of printers were introduced in 
1980. This series was sold for the IBM Personal Computer 
under an OEM agreement. Subsequently Epson has developed 
an extensive range of printers using various 
technologies . 

Reference Section 11.7 for Epson computer 
developments . 


The IBM ProPrinter was introduced in the spring 
of 1985. It had a speed of 200 CPS, NLQ (Near Letter 
Quality) and was priced at $549. 

Other Printers and Developments 

In the late 1970 's additional wires were added to 
the printhead to improve the resolution of dot matrix 
printers. The early 7-wire heads were changed to include 
9, 12, 14, 18 and by the early 1980 's the 24-wire head 
was introduced. These improvements have provided what is 
called "Near Letter Quality" (NLQ) and "Letter Quality" 
(LQ) printed output. 

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Color dot matrix printers became available in 
the late 1970' s. A four color ribbon was used with 
overprinting to obtain various colors . 

C.Itoh Electronics (CIE) , Inc. was established in 
December of 1973. It was an early supplier of low cost 
printers for personal computers. A low cost, 80-column 
desktop printer was developed in June 1976. The Apple 
Computer company marketed the C.Itoh printer under the 
name of ImageWriter. Apple introduced the ImageWriter in 
December 1983 at a price of $675. 

In the 1980 ' s many other companies started 
competing in the low cost dot matrix printer market. 
Some of these were NEC, Okidata and TEC. Currently there 
is a rapid shift in the market to move from wire matrix 
printers to ink jet and laser type printers. This is due 
to the noise, print guality and print speed of the wire 
matrix printer. Also the decreasing cost of ink jet and 
laser printers is a significant factor. 

Ink Jet 

Ink jet printing technology has evolved from a 
long history of development. However during the 
1960/70 ' s research and development accelerated. In 1976 
IBM introduced the Model 6640 continuous ink jet printer 
which set new standards for print guality. 

Canon Inc., a Japanese camera company founded in 
the 1930' s, introduced what they called "Bubble Jet" 
concept of printing in 1978. Then starting in 1978 
Hewlett-Packard developed a thermal drop-on-demand 
concept of printing. Color printing capabilities were 
introduced in the 1980 's. 


The ThinkJet printer was introduced by Hewlett- 
Packard in 1984. The printer used a disposable printhead 
with twelve individually controlled chambers that 
expelled drops of ink from the nozzle. The printer had a 
speed of 150 CPS with a 11 by 12 dot character and a 
resolution of 96 dots per inch. The printer ink had some 
limitations on the type of paper that could be used. The 
price of the ThinkJet printer was $495. 

Hardware and Peripherals 17/15 


Laser printing technology evolved from Chester 
Charlson's electrophotographic inventions in 1938. It 
was further developed as a copying technology at Haloid 
Corporation which became Xerox Corporation in 1961. 

Electrophotographic printing is a complex process 
involving six steps: Charge of a photoconductor (PC) 
surface, exposure of the PC surface to a light pattern 
of the print image, movement of the toner to the 
appropriately charged areas of the PC surface, transfer 
of the developed image to a sheet of paper, fusing the 
transferred image to the paper and finally cleaning the 
PC surface in preparation for the next printing. Most 
electrophotographic printers use either a gas or diode 
laser printhead to scan the PC surface. Typical 
resolutions for laser printers are from 240 to over 800 
dots per inch. 

The first laser printer was developed by Gary 
Starkweather at Xerox PARC in 1971. Starkweather 
modified a Xerox 7000 copier and named the machine 
"SLOT," an acronym for Scanned Laser Output Terminal. 
The digital control system and character generator for 
the printer were developed by Butler Lampson and Ronald 
Rider in 1972. The combined efforts resulted in a 
printer named EARS (Ethernet, Alto, Research character 
generator, Scanned laser output terminal) . The EARS 
printer was used with the Alto computer system network 
and subseguently became the Xerox 9700 laser printing 

An inexpensive laser printer was introduced by 
Canon in 1983. The Canon LPB-CX had a resolution of 300 
by 300 dots per inch and a operator changeable 
disposable cartridge. The Canon engine was sold to 
Hewlett-Packard and Apple Computer. The engine includes 
the laser diode, lens and mirror system, photosensitive 
roller, toner cartridge and paper handler. The Hewlett- 
Packard printer was named the HP LaserJet and was priced 
at $2,500. The Apple Computer printer was named the 
LaserWriter and was priced at $6,000. Hewlett-Packard 
subseguently became a dominant supplier of laser 
printers . 

17/16 PartV Bits and Bytes 

Burrell Smith was a principal in the development 
of the Apple LaserWriter printer. The printer was 
developed for the Macintosh computer and included a 
Motorola MC68020 microprocessor. The LaserWriter Plus 
was introduced in January 198 6 and the LaserWriter II 
family of printers in January 1988. 

Thermal Printers 

The concept of thermal printing was developed 
during the 1960/70 's using special sensitive paper. 
Thermal wax transfer printers were introduced by 
Brother, Toshiba and others in 1982. A resistive ribbon 
thermal transfer printer was introduced by IBM in 1983. 

17.6 ... Peripheral Cards 

Manufacturers developed many peripheral or add-on 
cards for various personal computers. These add-on cards 
extended and enhanced personal computer capabilities 
beyond those envisioned by the computer manufacturers . 
The following is representative of some of the more 
significant cards . 

Creative Technology 

Sim Wong Hoo, Chay Kwong Soon and Ng Kai Wa 
founded the Singapore company Creative Technology Ltd., 
in 1981. The company started by producing Apple II and 
IBM PC clones. Subseguently the focus was changed from 
clones to peripherals with the introduction of the Sound 
Blaster audio card in 198 9. The company is a world 
leader in the manufacture of sound cards and multimedia 
accessories. Creative Labs, Inc., is a wholly-owned U.S. 
subsidiary and Creative Technology became a public 
company in 1992 . 

Crontemco Inc. 

Cromemco was founded by two Stanford University 
professors, Harry Garland and Roger Melen in 1975. The 
first product was an add-on board called "Bytesaver" for 
the MITS Altair 8800 microcomputer. The board had a 2704 
EPROM memory chip that could be programmed to load a 
monitor program to simplify the startup or "booting" of 

Hardware and Peripherals 17/17 

the computer. A kit cost $195 or $295 assembled. The 
second board produced by Cromemco was called the "TV 
Dazzler" and enabled the microcomputer to be connected 
to a color television set. The board provided a 128-by- 
128 pixel display. A software program called 
Kaleidoscope provided an impressive demonstration of the 
board capabilities. A kit cost $215 or $350 assembled. 
In October 1976 the company released a Zilog Z-80 board 
for the MITS Altair 8800 microcomputer. The Z-80 
microprocessor was faster and had more extensive 
instruction set. The Z-80 board cost $195 as a kit or 
$295 assembled. 


Microsoft conceived the concept of an add-on card 
that would enable their software to run on an Apple II 
computer. The Apple II computer used a 6502 
microprocessor, but most of Microsoft's software had 
been developed for the Intel series of microprocessors 
and the CP/M operating system. With the increasing sales 
of Apple II computers, this segment of the software 
market was growing. 

Microsoft had Tim Paterson of Seattle Computer 
Products develop what became the Z-80 SoftCard. 
Microsoft announced the Z-80 SoftCard with a price of 
$399 in March 1980. Included with the card was the CP/M 
operating system from Digital Research and two versions 
of BASIC: MBASIC (which was compatible with Microsoft 
BASIC-80) and GBASIC with high resolution graphic 
enhancements. The card was an immediate success. 

The RamCard was released around 1981/82 for the 
Apple II Plus computer to extend the memory by 16K to 
64K bytes. This additional memory allowed the computer 
to run CP/M applications that reguired 64K bytes. 

Processor Technology 

Processor Technology Corporation was founded by 
Robert Marsh and Gary Ingram in April 1975. The first 
product was a 4K static RAM memory expansion board for 
the MITS Altair 8800 microcomputer. This computer only 
had 25 6 bytes of memory in the standard unit and the 4K 
memory board produced by MITS was not reliable. The 

17/18 PartV Bits and Bytes 

memory board was first advertised at the Homebrew 
Computer Club in April 1975 and the first order was from 
Cromemco. It cost $218 as a kit or $280 assembled. A 2K 
memory board was also available. The company also made 
other boards for the S-100 bus such as a 2K ROM Board, a 
3P+S (parallel/serial) board, VDM-1 (Video Display 
Module) board designed by Lee Felsenstein and an 
improved motherboard for the Altair 8800. 

Seattle Computer Products 

Rod Brock owned Seattle Computer Products, Inc., 
that supplied memory cards for the S-100 bus computers 
around 1978. In late 1978 Tim Paterson, an employee of 
the company started developing a card using the new 
Intel 8086 microprocessor. The first prototype card was 
completed in May 1979. It was then demonstrated using 
the new Microsoft 8086 BASIC interpreter at the June 
1979 National Computer Conference in New York City. 
Production units shipped in November 1979. 

Tim Paterson also developed the operating system 
called QDOS for the CPU card in 1980 (see Section 13.1). 
This operating system later became MS-DOS. 

Other Early Manufacturers 

Robert Metcalfe, Greg Shaw and Howard Charney 
founded 3Com Corporation in 1979. 3Com is an acronym for 
the three corn's in computer, communication and 
compatibility. The company's main product is 
communication interface hardware for computer networks . 
Metcalfe had previously been a principal in the 
development of the Ethernet communications software at 
Xerox PARC. 3Com became a public company in 198 4, and 
acquired U.S. Robotics Corporation in 1997. 

Applied Engineering released the Transwarp 
accelerator card which more than tripled the speed of 
the Apple lie was released in January 198 6. In November 
198 7 the PC Transporter card was introduced to run MS- 
DOS programs on an Apple II computer. 

The Hercules Card is a display adapter card 
developed by Hercules Computer Technology to display 
high resolution text. 

Hardware and Peripherals 17/19 

North Star Computers advertised in the January 
1977 issue of Byte magazine, a FPB Model A floating- 
point board to provide faster mathematical calculations . 
The board sold for $359 as a kit or $499 assembled. They 
also developed cassette tape and floppy disk interface 
boards . 

Howard Fulmer founded Parasitic Engineering. The 
company initially provided add-on boards for the MITS 
Altair 8800 microcomputer. 

SwyftCard is a card developed for the Apple II 
computer by Jef Raskin at Information Appliance Inc., in 
the early 1980 ' s. It facilitated a number of convenient 
operations such as printing, calculations, 
telecommunications and sold for $89.95. 

Vector Graphic is a company operated by Lore Harp 
and Carol Elly. They manufactured memory and other 
boards in the late 1970' s. The boards were designed by 
Bob Harp. 

IBM PC Cards 

Tecmar, Inc. is a company founded by Martin A. 
Alpert around 1974, that provided add-on cards for the 
IBM Personal Computer. 

In April 1982 the Xedex Corporation announced the 
Z-80 coprocessor card named "Baby Blue" for the IBM 
Personal Computer. The card had a Z-80B microprocessor 
that enabled CP/M programs to be run on an IBM PC. 

Some other suppliers were: Quadram' s Quadboard, 
which provided a clock, 64K bytes of additional memory, 
parallel and serial ports for $595 and the AST Research 
Combo Card. 

17.7 ... Modems 

The modem was invented by AT&T in 1960 and one of 
the earliest hobby modems called the Pennywhistle was 
described in the March 1976 issue of Popular 
Electronics . 

Paul Collard, Casey G. Cowell and Steve Muka 
founded the U.S. Robotics Corporation in 1975. The first 
product was an acoustic coupler followed by modems. U.S. 

17/20 PartV Bits and Bytes 

Robotics became a public company in 1991 and was 
acquired by the 3Com Corporation in 1997. 

Dennis C. Hayes and partner Dale Heatherington 
founded D.C. Hayes Associates Inc., in January of 1978. 
The company name changed later to the Hayes 
Microcomputer Products Inc., then to the Hayes 
Corporation. Although modems were common in the business 
world, Hayes was an early commercial developer of modems 
for microcomputers. Hayes introduced the 80-103A Data 
Communications Adapter modem for professional and hobby 
communicators in April 1978 . The unit was priced at 
$49.95 for a bare board and $279.95 assembled. The 
Micromodem 100 was introduced for S-100 bus 
microcomputers in 1979. It could transmit data at 110 to 
300 bbs and had a price of $399. In mid 1981 the 
Smartmodem 300 was released. Hayes also developed 
software to facilitate the transfer of information by 
modem on a phone line . 

In late 1979, a company called Novation, Inc., 
introduced the CAT acoustic modem that was advertised at 
a price of "less than $199." 

The VICMODEM was introduced by Commodore in March 
1982 for use with the VIC computer. An interface program 
named VICTERM was included with the unit . The modem was 
priced at only $109.95 and included free offers from 
CompuServe, Dow Jones News and The Source. 

17.8 ... Miscellaneous 

Bus Systems 

A bus system is a set of hardware connections 
used for power, signal and data transfer between 
components of a computer system. The bus system is 
characterized by its size, such as 8-bit or 16-bit and 
the number of lines or connection points . One of the 
earliest bus systems for a personal computer was the 
Altair Bus developed by MITS, Inc., for the Altair 8800 
in January 1975. Other manufacturers adapted this bus 
and it became known as the S-10 Bus. 

Subsequently the IEEE established a standard for 
the S-100 Bus. Then a working group of the IEEE Computer 

Hardware and Peripherals 17/21 

Society developed the IEEE 696 bus standard. It is an 
augmentation and extension of the S-100 bus to 16 bits 

Southwest Technical Products Corporation (SwTPC) 
developed the SS-50 bus for the SwTPC 6800 Computer 
System that they released in November 1975. It was used 
by a number of other manufacturers in computers using 
the Motorola 6800 microprocessor, such as the Smoke 
Signal Broadcasting Chieftain and the Gimix Ghost. 

The release of the IBM Personal Computer in 
August 1981 established another new bus standard, the PC 
Bus. This was an 8-bit bus with 62 connection lines. IBM 
then added additional connection lines to the bus with 
the release of the 16-bit AT computer in August 1984. 
The AT Bus subseguently became known as the Industry 
Standard Architecture (ISA) bus. 

Micro Channel Architecture (MCA) is a proprietary 
32-bit multitasking bus architecture of IBM. It was a 
design feature of the Personal System/2 (PS/2) family of 
computers that were released by IBM in April 1987. 

The Extended Industry Standard Architecture 
(EISA) was developed by a consortium of nine companies: 
AST Research, Compag, Epson, Hewlett-Packard, NEC, 
Olivetti, Tandy, Wyse and Zenith and was announced in 
September 1988. It was developed as an alternative to 
the IBM MCA (Micro Channel Architecture) bus used on the 
PS/2 computers and provided some of the MCA features. 
EISA has a 32-bit data path and maintained compatibility 
with the earlier ISA architecture. 

NuBus is a high-performance expansion bus used in 
the Apple Macintosh computer that was developed at the 
Massachusetts Institute of Technology (MIT) . SCSI (Small 
Computer System Interface) that is pronounced "scuzzi," 
is an input output bus that provides a high-speed 
interface for connecting personal computers to 
peripheral devices. The VL Bus is a design established 
by the Video Electronics Standards Association (VESA) in 

17/22 PartV Bits and Bytes 


The first digitizer was called the Bit Pad with a 
11-inch active area and was advertised by the 
Summagraphics Corporation in November 1977. The unit had 
a price of $555 . 

Floppy Disks 

Development of the floppy disk drive by IBM in 
1971, created a reguirement for floppy disks. 
Significant suppliers of floppy-disks were 3M, Dysan, 
Elephant, IBM, ITC (later Verbatim) , Maxell, Memorex, 
Sony and Xidex. 

Information Terminals Corporation (ITC), a 
dominant supplier of digital data cassettes, obtained a 
license from IBM to manufacture 8-inch floppy disks in 
June 1973. The company produced its first floppy disks 
in December and became a dominant supplier of floppy 
disks. ITC collaborated with Shugart Associates to 
provide disks for the new 5.25-inch disk drive 
introduced in December 1976. The single-sided, single- 
density disks had a storage capacity of 180 kilobytes. 
Then in July 1978, ITC introduced a 720 kilobyte double- 
sided, double-density disk. The company name changed to 
Verbatim Corporation in 1978. Between 1979 and 1980 
Verbatim had severe and costly guality problems . A 
license was obtained from the Sony Corporation to 
manufacture 3.5-inch diameter hard plastic case 
microdisks in the spring of 1983. Verbatim also 
introduced a high-density minidisk with a storage 
capacity of 1.2 megabytes in 1983 and increased it to 
1.44 megabytes in 198 6. 

Between 1984 and 1985, Verbatim started 
encountering significant financial difficulties due to 
increasing competition and falling prices for disks. 
This resulted in the company being purchased by the 
Eastman Kodak company in June 1985 for $175 million. But 
by 1990, Kodak was also having problems and sold 
Verbatim to Mitsubishi Kasei, a large diversified 
Japanese company in May. Mitsubishi Kasei changed its 
name to Mitsubishi Chemical Company in October 1984. 
Verbatim is still a dominant supplier in the floppy disk 
market . 

Hardware and Peripherals 17/23 


An article entitled "A Short History of the 
Keyboard" in the November 1982 issue of Byte magazine 
describes variations in keyboard layouts. 

Another article entitled "Keyboard Karma" in 
DIGITAL DELI [190, pages 267-269] describes the problems 
the Japanese have with keyboards. 

Microsoft introduced a new ergonomic Natural 
Keyboard in 1994. 


The mouse concept was invented by Douglas C. 
Engelbart at the Stanford Research Institute in 1964. 
Roger Bates and William K. English assisted in the 
development. The first public demonstration was at the 
ACM/IEEE Fall Joint Computer Conference in December 
1968. Engelbart ' s mouse was an analog device with a 
wooden housing that contained a button (subseguently 
three buttons) and wheels that rotated two 
potentiometers. The potentiometers converted the 
movement of the mouse on a surface into electrical 
signals that controlled the position of the cursor on a 
terminal screen. The buttons were used for selection and 
to enter commands . 

A digital wheeled type of mouse was developed by 
Jack Hawley for the Alto research computer at the Xerox 
PARC (Palo Alto Research Center) in 1972. Also at PARC 
in 1972, Ronald Rider developed the ball type of mouse 
that was subseguently changed by Hawley to improve its 
operation . 

The first commercial implementations were on the 
Xerox Star in 1981, and on the Apple Lisa and Macintosh 
computers in 1983 and 1984 respectively. The Xerox Star 
digital mouse used two buttons for control purposes. 
Apple Computer designed a new digital mouse for the Lisa 
computer that used a rubber ball with optical scanners 
to detect motion and one button for control purposes. A 
degree of controversy exists regarding the number of 
buttons to include on a mouse. Human factor studies to 
determine the simplest operation, tend to favor a two 
button mouse. 

17/24 PartV Bits and Bytes 

A company called Mouse Systems introduced the 
first commercial mouse for the IBM Personal Computer in 
1982. It was a three-button mouse. 

Microsoft introduced a mouse with an add-on card 
for the IBM Personal Computer and a mouse for any MS-DOS 
computer using the serial port in May 1983 (see Section 
12.1) . It was priced at $195 with interface software. A 
new design resembling a bar of soap was released in 
September 1987. In late 1996, Microsoft announced the 
Intellimouse priced at $85. The principal new feature of 
the Intellimouse was an additional miniature wheel 
located between the left and right buttons that could be 
used for scrolling in application programs.