A History of the Personal Computer

Part II

1970' s - The AUair/Apple Era.

3/2 Paitll 1970-s--TheAltair/Apple

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Figure 3.1: R graphical history of personal compul
the 1970' s, the MIT3 Rltair and Apple Computer

Microprocessors in the 1970's 3/3

Figure 3.2: Andrew 3. Grove, Robert X. [I.?yce and Gordon

1

Figure 3.3: Marcian E. "Ted" Hoff.
ographs are courtesy of Intel Corpora

3/4 Paitll 1970's--TheAltair/Apple

Figure 3.4: The Intel MC3-4 (Micro Computer Sys"

y of Intel Corpoi

Chapter 3 Microprocessors in the 1970's

The creation of the tcansistoc in 1947 and the
development of the integrated circuit in 1958/59, is the
technology that formed the basis for the microprocessor.
Initially the technology only enabled a restricted
number of components on a single chip. However this
changed significantly in the following years. The
technology evolved from Small Scale Integration (SSI) in
the early 1960's to Medium Scale Integration (MSI) with
a few hundred components in the mid 1960's. By the late
1960's LSI (Large Scale Integration) chips with
thousands of components had occurred.

This rapid increase in the number of components
in an integrated circuit led to what became known as
Moore's Law. The concept of this law was described by
Gordon Moore in an article entitled "Cramming More
Components Onto Integrated Circuits" in the April 1965
issue of Electronics magazine [338| . Moore' s Law
initially stated that the number of transistors on a
semiconductor chip would keep doubling every year. This
was later changed to every 18 to 24 months. The "law"
has held up remarkably well since 19 65 and has had a
profound effect on computer technology.

Advanced chip technology enabled Texas
Instruments to develop the first electronic calculator
in 1967. Then they worked with the Canon company to
produce the worlds first pocket calculator, the
Pocketronic in April 1971. During this period another
company called Intel had entered the semiconductor

3.1 ... Intel

The Beginuing

Gordon E . Moore and Robert N . Noyce resigned from
Fairchild Semiconductor and founded a company called N M
Electronics that they incorporated in July 1968. Noyce

3/6 Part II 1970's -- The Altair/Apple era

the integrated circuit at Fairchild, Moore the director
of the research and development laboratory. Rrthur Rock
and other investors provided venture capital for the
company startup. Shortly after, they changed the company
name to Intel Corporation, signifying Integrated
electronics. Andrew S. Grove who was assistant director
of research and development at Fairchild joined Intel
shortly after the founding as director of operations.
The company became a public corporation in October 1971.

The initial focus of the company was to develop
large scale integrated (LSI) memory chips to replace
magnetic core memory. Intel introduced the 1101, a 256
bit MOS static random access memory in September 1969.
Then Intel started producing the 1103 chip, the worlds
first IK bit dynamic random access memory (DRRM) in
October 1970. This provided significant reductions in
the cost of computer memory. However a request for logic
chips would change the focus of the company to include

The First Microprocessor (4-Bi0

In April 1969, a Japanese calculator company
called Busicom asked Intel to develop a set of at least
twelve custom logic chips for a new low cost desk top
calculator. Marcian E. "Ted" Hoff evaluated this request
and determined that the design configuration proposed by
the customer was too complex. Hoff had experience with
the DEC PDP-8 architecture and proposed that Intel
develop a four-chip set incorporating a general-purpose

calculator BCD (Binary Coded Decimal] requirements and
possibly other applications. Intel's executive staff
approved the proposal and design proceeded with

the Intel proposal for a general processor and
associated chips in October 1969.

Busicom paid Intel 560,000 to produce the chip
family configuration for use in their calculators in
early 1970. Federico Faggin who joined Intel in April
1970, did the detailed circuit design and layout of the
chips. The final configuration consisted of four 16 pin

Microprocessors in the 1970's 3/7

(CPU) , a 256 by 8-bit read only memory (ROM) , a 320-bit
random access memory (RAM) and a shift register for
input/output (l/O) . The CPU chip measured one-eighth of
an inch wide by one-sixth of an inch long and had about
2, 300 transistors. The CPU included a 4-bit parallel

push-down stack on one chip. This CPU chip became known
as the 4004 4-bit microprocessor. It had a set of forty
five instructions, operated at 108 kilohertz and could
execute 60,000 operations a second. Faggin produced
working samples in nine months and Intel delivered sets
of chips to Busicom in March 1571.

In early 1971, Busicom got into financial
difficulties and Intel obtained the design rights for
applications other than calculators in return for a
lower price on the chips. In mid-November 1971, the
first advertisement for a commercially available
microprocessor, the Intel 4004 appeared in Electronic
News. Intel advertised it as the MCS-4 {Micro Computer
System 4-bit) family of four integrated chips. The
advertisement stated it was "Announcing a new era of
integrated electronics... A micro-programmable computer
on a chip!" The 4004 CPU chip sold for S200. It was
indeed the beginning of a new era, but the 8-bit
microprocessor is what started the microcomputer
industry.

S-Bit Mtcropro cessors

In late 19 69, concurrent with the Busicom
development. Computer Terminal Corporation (GTC) , which
later became Datapoint , contracted with Intel and Texas

intelligent terminal. Ted Hoff and Stan Mazor analyzed

integrated chip could contain all the logic. Intel
initially assigned the chip design to Hal Feeney. Then
at the end of 1970 Federico Faggin directed the
development of the chip that became the Intel 1201.
During the summer of 1971 Datapoint agreed to let Intel
use this architecture in exchange for a release from the
development charges . Experience with the Intel 4004

3/8 Part II 1970's -- The Altair/Apple era

1201 chip to 8008 .

Intel introduced the first 8-bit 8008

microprocessor in April 1972 as a family of products,
the MCS-8 (Micro Computer System 8-Bit) . The 16 pin 8008
had 3,500 transistors and operated at about 0.2 MHz. The
microprocessor had a set of 66 instructions, with 4 5

six 8-bit general registers and could address 16K bytes
of memory. The chip implemented interrupts, however the
interrupts worked poorly. This chip with its 8-bit

processing as compared to the 4004 4-bit microprocessor.
It was the first true general purpose microprocessor.

microcomputer industry. The e

as the French Micral in 1973

8 in 1974 used the Intel 8008 microprocessor.

The 4004 and the 8008 chips had started the
technology, but a new chip, the 8080 had a more
significant impact on the microcomputer market. Federico
Faggin proposed the new faster chip and its use of high-
performance NM03 (H-channel Metal Oxide Semiconductor)
technology as compared to PMOS (P-channel Metal Oxide
Semiconductor) used on the 4004 and 8008

microprocessors. Masatoshi Shima who had moved from
Busicom headed the design team. Intel approved
development in the summer of 1972 and introduced the 8-
bit 8080 chip in April 1974.

This new 40 pin chip with 5, 000 transistors,
operated at 2-3 MHz, could execute 290,000 operations a
second, had 111 instructions and could address 64K bytes
of memory. The chip offered a tenfold increase in
throughput compared to the 8008. It also required only 6
support chips for operation as compared to 20 for the
8008. Intel had an initial price of 5360 for the chip in

MITS used this chip on the Rltair 8800 in 1975.
The microprocessor had a significant impact on the early
development of microcomputers. However Motorola and

Microprocessors in the 1970's 3/9

The Motorola MC6800 had a single +5-volt powe i: supply
requirement and the Zilog Z-80 was faster with more
features.

The competitive pressure from Motorola and Zilog
resulted in the release of a faster 8-bit

microprocessor, the 8085 in November 1576. It had more
functions integrated, a 113 instruction set and only
required a single 5-volt power supply.

The 8085 was faster but National Semiconductor

in 1974. Intel had started a 16-bit microprocessor
project but was having problems that resulted in a
conservative development schedule.

1 6-Bit Microprocessors

Management had approved development of a unique
16-bit architecture in late 1974 . Then in mid 1975,
William W. Lattin who had been the manager of memory and
microprocessor products at Motorola, moved to Intel and

multiprocessing architecture that became the 32-bit iRPX
432 (Intel Advanced Processor architecture) product.
However due to product development delays and
competitive pressures, Intel released the 8-bit 8085 in
1976 and began a second 16-bit project that became the
8086.

Development of the 8086 microprocessor with a 16-
bit architecture started in 1976. Jean Claude Cornet was
assigned to manage the project and William B . Pohlman
who had managed the 8085 design was also the leader for
the 8086 design team. Stephen P. Morse defined the
microprocessor architecture and created it as an
extension of the 8080 architecture to provide software
compatibility, Intel introduced the 8086 with ten times
the performance of the 8080 in June 1978.

The chip has 29,000 transistors with a minimum
feature size of 3 microns and at a clock speed of 5 MHz
it has a rating of 0.33 MIPS (million instructions per
second) . The instruction set is an expanded version of
the 8080 with 133 instructions. Memory addressability is

3/10 Part II 1970's -- The Altaii/Apple era

frequencies of 5, 8 and 10 MHz. The price at launch was
$360.

Intel introduced the 8088 microprocessor in June
1979. It has a 16-bit internal architecture with an 8-
bit external data bus. This 8-bit external data bus
allowed for a simpler interfacing to the rest of the

characteristics is similar to the 8086. The memory
addressability is 1 megabyte and the microprocessor is
available at clock frequencies of 5 and 8 MHz.

IBM selected this microprocessor for the PC
computer announced in Rugust 1981. This computer became
a dominant product in the personal computer marketplace
of the early 1980' s, and was crucial in helping to

fln IEEE Micro article entitled "A History of
Microprocessor Development at Intel" [342] and s^n Intel
publication entitled "R Revolution in Progress: A
History of Intel to Date" [48] provide additional
details on Intel microprocessors and a history of the
company. Intel had pioneered the introduction of
microprocessors. However other companies had entered the
marketplace with competing products. One of the other
dominant companies was Motorola.

3.2 ... Motorola

Paul V. Galvin founded the Galvin Manufacturing
Corporation in Chicago, in 1928. Then the company name
changed to Motorola, Inc., in 1947. Following the name
change and the invention of the transistor in 1947, the
company opened a research laboratory in 1950, in
Phoenix, Arizona to explore solid-state electronics.
Motorola is now a major supplier of discreet

Motorola introduced the 8-bit MC6800 MPU (Micro
Processor Unit) in mid-1974. Principals in the design of
the microprocessor and peripheral chips were Charles
Melear and Chuck Peddle. The MC6800 used six-micron NMOS

technology, contained 4,000 transistors and was the

6800.

Motor

-ol

a

world'

3

f

ir;

microcomputi

Br.

RSM,

I/O,

ti

me

Microprocessors in the 1970's 3/11

first microprocessor to require a single 5-volts power
supply. This simplification of the power supply
requirements and the related Motorola family of chips
lowered product costs. Some early microcomputers using
this chip were the MIT3 Rltair 680B, Sphere and SwTPC

luced the MC680i in 1978, as "the
35, 00-transistor single-chip

licrocomputer system had ROM/ E PROM,
ock and CPU. The MC6809 was a
microprocessor with an 8-bit external bus that processed
data internally in 16-bit words. Motorola announced the
microprocessor in 1978. ftpple Computer selected this
chip for the initial Macintosh computer design in 1979.

The MC68000 was the first of the MC68000 family
of 16/32-bit microprocessors. Principals in the design
were Tom Gunter and Gene Schriber. The MC68000 has 61
instructions and a capability of two million
instructions per second (MIPS). The chip had 68,000
transistors. It can address 16 megabytes directly and 64
megabytes through functional segmentation. It has a 16-
bit data bus that processed data internally in 32-bit
words. Motorola introduced the MC68000 in 1979. Motorola

68008.

This microprocessor had a significant impact in
the marketplace. Rpple Computer selected the MC68000 for
the Lisa computer, with the processor operating at 5

Motoro

la and Intel

became

two dominant desigr

and

supplier:

3 of micropr<

jcessor:

; for microcomputers

the

1970's.

However the

other

company that playec

sign

ificant

role in

the

introduction of

3/12 Pai1 II 1970's -- The Altau/Apple era
3.3 ... Texas Instruments

J. Clarence Karcher and Eugene McDermott founded
Geophysical Service as a partnership in May 1930. The
company name changed to Coronado Corporation, with
Geophysical Service, Inc., (GSI) as a subsidiary in
January 1939. Cecil H. Green, J. Erik Jonsson, Eugene
McDermott, H. B. Peacock and others purchased the GSI
subsidiary in 1941. The Coronado Corporation dissolved
in 1545 and GSI's narae changed to Texas Instruments,
Inc. , in 1951 .

Texas Instruments (TI) obtained a license for the
manufacture of transistors in May 1952 and aggressively
expanded its semiconductor business during the 1950's.
Jack St. Claire Kilby of TI co-developed the integrated
circuit in 1958. During the 1960's TI was a significant
supplier of chips for consumer products such as
calculators, watches and toys.

Computer Terminal Corporation (CTC) , which later

Intel) to evaluate a set of chips for a new intelligent
terminal in late 19 69 . This requirement resulted in TI

developing and submitting a single-chip microprocessor
to CTC.

TI has stated in company literature that it

company applied for a patent in 1971 with the invention
being credited to Gary W. Boone an Michael Cochran (the
patent was approved in February 1978). The company
described their invention as a "microcomputer --the

complete computer on a single chip of silicon" [178]. TI
advertised the integrated circuit developed for the

caption "GPU on a chip" in June 1971. This was the first

functional problems with the chip and never marketed it.
However, it did lead to the subsequent development of
the TMSIOOO microprocessor.

TI released the TMSIOOO 4-bit microprocessor in
1974. The chip had a set of 43 instructions and included

a 2

56-bit RAM foi:

da

pro

gram storage.

Th€

emb

edded applicat:

Lon

of

16-bit micropr

oce

the

TI 9980 in the

■ 1,

ext

ernal bus but

Pt

in

the TI-99/4 mi

■urn.

the

^computer was

not

Texas Instru

mic

rocomputer ma

rkt

app

lications. Texa

3 :

Microprocessors in the 1970's 3/13

:a storage and an 8,192-tait ROM for
chip was used mainly in low-cost
;. TI announced the TMS9000 series
ssors in the spring of 1976, then
te 1970's. The TI 9980 had an 8-bit
acessed data internally in 16-bit
nts used the TMS9900 microprocessor
computer released in 1979. However
successful and TI discontinued it

lents failed to penetrate the
t and concentrated in other
nstruments is a leading supplier of

3.4... Other Companies

R number of other compan

ies

pro(

>rocessors in the 1970's. However

two

compi

:ed products that had a significant

imp a

ct on

computer market. Those two compar

lies

were

>logy and Zilog.

MOS Technology

In July 1975, MOS Technology, Inc., started

compatible with the Motorola MC6800 and would cost only
$20. Chuck Peddle who had left Motorola and joined MOS
Technology was a principal in the design of the
microprocessor. Motorola subsequently forced the company
to withdraw the 6501 because of technology

However MOS was also developing another chip, the
8-bit 6502 with additional features that would only cost
$25. The chip had approximately 9,000 transistors. This
pricing had a significant effect on the lowering of
prices for microprocessors at both Intel and Motorola.
This reduction in the cost of microprocessors resulted

3/14 Part II 1970's -- The Altaii/Apple era

the WE3C0N show in September 1975.

The MOS 6502 miccoprocessoi: had a significant
impact on the early miccocomputer market. The Apple II,
Atari 400 and 800 and Commodote PET microcomputets used
the chip. Commode te International purchased MOS
Technology in October 1976.

Zilog Inc.

In the summei: of 1974, Federico Faggin and Ralph
Ungermann decided to leave Intel and founded Zilog Inc.,
in November. Zilog is an acronym for the "last word (Z j
in integrated (i) logic (log)." Shortly after the
founding, the powerful oil corporation Exxon, invested
$1.5 million in Zilog for a 51 percent controlling
interest in the company. Faggin and Ungermann developed
ideas for a new microprocessor and family of components
that would be compatible and more powerful than the
Intel 8080. Assisting in the design effort was Masatoshi
Shima who had also left Intel and joined Zilog. It would

instructions than the 8080.

Zilog announced the S-80 microprocessor in 1975
and it became available in February 1976. It operated at
2.5 MHz, could address 64K bytes of memory and
incorporated the 8 080 's instruction set within 158
instructions. The chip had 8,500 transistors and was
manufactured by the Mostek company. The Z-80 with a low
price of $200, became a successful alternative to the
Intel 8080. Zilog announced a faster 4 MHz version of
the chip, the Z-80A in February 1977. A number of early
microcomputers such as the Radio Shack TRS-80 used the

The Z-8000 was a 16-bit microprocessor with
17, 5 00 transistors and 110 instructions. The memory
address capability was 48 megabytes in six segments of
eight megabytes and the operating speed was 2.5 to 3.9
MHz. Zilog priced the microprocessor at $195 for small
quantities and announced it in early 1979. The
instruction set was not compatible with the Z-80 and
other design problems prevented it from becoming

lithe 1970's 3/15

Other Sources

n number of other companies became second sources
for the major suppliers. The following are some of the
more significant suppliers.

Walter Jeremiah (Jerry) Sanders was a principal
in the founding of Advanced Micro Devices (RMD) , Inc.,
with seven other Fairchild personnel in mid 19 65.
Sanders had worked for Motorola then Fairchild
Semiconductor where he became sales and marketing

source for other manufacturers chips by creating an
equivalent design or by obtaining a license agreement
from the other company. Early license agreements were
with Intel for the 8085 microprocessor and with Zilog
for the Z-8000. RMD became a public company in September
1972 and the Siemans AG company made an investment of
$30 million for nearly 20 percent of AMD in late 1977.

Hewlett-Packard developed a proprietary

was used in the company's HP-85 personal computer
released in 1980.

Mostek was founded by L. J. Sevin and
subsequently became a subsidiary of United Technologies.
It was a major supplier of semiconductor memory chips
and a second source for other company's microprocessors
such as the Zilog Z-80.

National Semiconductor Corporation was founded in
1959. Charles E. Sporck who had been at Fairchild
Semiconductor joined the company in 1968, became the
president and a significant contributor to the success
of the company. The company offered microprocessor
systems on a 8.5 by 11-inch PC card. The IMP-8 was an 8-
bit microprocessor system and the IMP-16 was a 16-bit
microprocessor system available in 1973. Then National
Semiconductor announced the first 16-bit single chip
microprocessor, called the Pace in 1974. A faster
microprocessor called the Super-Pace followed. The SC/MP

RCA introduced the 1802, the first complementary
metal oxide semiconductor (CMOS) 8-bit microprocessor in
1974, that was followed by the 1804 microprocessor.

3/16 Part II 1970's -- The Altaii/Apple era

Rockwell introduced the PPS-4 that was a 4-bit
parallel processor in late 1972. It had a 50 instruction
set. Rockwell subsequently released the PPS-8,

Signet ics Corporation was founded by four
Fairchild Semiconductor executives in 1961. The company
name is an acronym for "Signal Network Electronics . " The
company shipped an 8-bit Programmable Integrated
Processor (PIP) in 1974 that had more than 64
instructions. The Signetics 2650, is another processor
available from the company around 1978. Signetics was
also a second source for microprocessors to companies

3.S..
Patei

. Miscellaneous
It Controversy

During the I960' s

and

ea

rly

1970's,

integra

ited

circ

uit technology contin

ued

to

imp

rove the

capabil

ity

of i

ntegrating a larger ni

imber of

C±)

'cuit elei

nents. This

evol

ved to consideration

by

son

le :

in the i

ndustry

of

poss

ibly creating a central

proc

■ess

or unit

(CPU) o

sing

le chip. However the

ass

ignn

lent

of cred

it for

the

inve

ntion of the micropi

roce:

;sor

ar

Id the a

warding

of

pate

nts for it have been

con

tro\

'ers

ial. Companies s

uch

Hyatt are principals in the controversy.

Recording to Gilbert Hyatt he built his first
breadboard concept of a small computer in 1968,
trademarked the term "microcomputer" and started a
company called Micro Computer Inc (MCI) . Hyatt made
application for a broad patent with a title "Data
Processing System" in 1569. The application was rejected
by the U.S. Patent Office. This was appealed by Hyatt
and in December 1970 the Patent Office accepted a new
application with a title "Factored Data Processing
System for Dedicated applications . " Hyatt continued
working on printed circuit prototypes but did not
demonstrate or prove that his concept was practical. In
question was Hyatt's ability to implement the patent on
a single chip at the time of the patent application. At
that time the technological capabilities were just

Microprocessors in the 1970's 3/17

single integrated chip. In September 1971, Hyatt's Micro
Computer company went out of business. Hyatt continued
to have problems with his patent application that
resulted in further appeals and changes to the

application. Then in July 1950, the U.S. Patent Office
awarded Hyatt a patent that now had a title of "Single
Chip Integrated Circuit Computer Architecture . " This
immediately created significant controversy in the
industry. However in June 1996, the patent was
overturned.

Between 1969 and March 1971, Intel conceived and
developed the 4004 microprocessor as described in

extended existing technology. This rather casual
approach resulted in Intel not filing a patent
application for the microprocessor. Ted Hoff has stated
that he published an article in March 1970 describing
the feasibility of building a central processor on a
chip. This in essence placed the concept of a

a viable patent application.

single-chip microprocessor in 1970 as described in
Section 3.3. However TI withdrew their microprocessor
due to functional problems and the following products
were not accepted by any major microcomputer

The Texas Instrument patent that was approved by
the U.S. Patent Office in 1978 has not been successfully
contested. However Hyatt's patent that was approved by
the U.S. Patent Office in July 1990 was overturned in
1956. Neither of these patents has affected Intel which
became the dominant supplier of microprocessors for
personal computers .

Rn article in Byte magazine "Micro, Micro : Who

interviews of Hyatt, Hoff and Faggin [328] . Some
additional comments by Federico Faggin are in another

3/18 Part II 1970's -- The Altaii/Apple .

[331] and in a Popular Science

R further- article in Byte magazine entitlei
"Evolution of the Microprocessor" provides an informa
history [333] . The IEEE Micro article entitled "i
History of Microprocessor Development at Intel" provide:
some details of developments at other companies [342]
The Encyclopedia of Microcomputers , "Architecture o
Microprocessors," Vol. 1, pages 269-282 [236] contain:
an extensive bibliography.

Conclusion

different i

nanufacti

cs.

For i

nstar

ice Syne

rtek

ar

Rockwell Ir

iternatic

■ nal

. pr(

Jduced

the

6500 s

erie:

micr<

jprocesE

>ors des:

.gns

;d by

MOS Technc

>logy. So

lid

stal

techi

lology

had mad

e

signi

ficant

adv

ances du

iring

tt

1970'

■ s . The

Integra

ted

cir.

:uit ei

Table

d the de

velo

pmer

of 1

ow-cost

memory

ch:

.ps a

nd the

mici

roprocess.

or. '

The;

are

the de

velopmen

ts

that

resu

Ited

in the

per

son^

compi

Jting transition

tc

. micr

-ocompu

ters.