The document summarizes key developments in computer memory and processor technology from 1947 to 1986. It describes the invention of the Williams tube, the point-contact transistor, core memory, the first silicon transistor, the first integrated circuit, early microprocessors like the Intel 4004 and 8008, and the introduction of optical computing technologies. These innovations drove improvements in computer performance, size, cost, power consumption, and capabilities.

1. 1947
The Williams tube won the race for a practical random-
access memory. Sir Frederick Williams of Manchester
University modified a cathode-ray tube to paint dots and
dashes of phosphorescent electrical charge on the screen,
representing binary ones and zeros. Vacuum tube
machines, such as the IBM 701, used the Williams tube as
primary memory.
Williams tube
On December 23, William Shockley, Walter Brattain, and
John Bardeen successfully tested this point-contact
transistor, setting off the semiconductor revolution.
Improved models of the transistor, developed at AT&T Bell
Laboratories, supplanted vacuum tubes used on computers
at the time.
Point-contact transistor
1953
At MIT, Jay Forrester installed magnetic core memory on
the Whirlwind computer. Core memory made computers
more reliable, faster, and easier to make. Such a system of
storage remained popular until the development of
semiconductors in the 1970s.
Core memory
1954

2. A silicon-based junction transistor, perfected by Gordon
Teal of Texas Instruments Inc., brought the price of this
component down to $2.50. A Texas Instruments news
release from May 10, 1954, read, "Electronic "brains"
approaching the human brain in scope and reliability came
much closer to reality today with the announcement by
Texas Instruments Incorporated of the first commercial
production of silicon transistors kernel-sized substitutes
for vacuum tubes."
The company became a household name when the first
transistor radio incorporated Teal´s invention. The radio,
First production silicon junction sold by Regency Electronics for $50, launched the world
into a global village of instant news and pop music.
transistors
1955
Felker and Harris program TRADIC, AT&T Bell Laboratories
announced the first fully transistorized computer, TRADIC.
It contained nearly 800 transistors instead of vacuum
tubes. Transistors — completely cold, highly efficient
amplifying devices invented at Bell Labs — enabled the
machine to operate on fewer than 100 watts, or one-
twentieth the power required by comparable vacuum tube
computers.
In this photograph, J. H. Felker (left) gives instructions to
the TRADIC computer by means of a plug-in unit while J. R.
Harris places numbers into the machine by flipping simple
switches. The computer occupied only 3 cubic feet.
Felker and Harris program TRADIC
1958
Jack Kilby created the first integrated circuit at Texas
Instruments to prove that resistors and capacitors could
exist on the same piece of semiconductor material. His
circuit consisted of a sliver of germanium with five
components linked by wires.
Kilby integrated circuit
1959

3. Jean Hoerni's Planar process, invented at Fairchild Camera
and Instrument Corp., protects transistor junctions with a
layer of oxide. This improves reliability and, by allowing
printing of conducting channels directly on the silicon
surface, enabled Robert Noyce's invention of the
monolithic integrated circuit.
First Planar transistor
1961
Fairchild Camera and Instrument Corp. invented the
resistor-transistor logic (RTL) product, a set/reset flip-flop
and the first integrated circuit available as a monolithic
chip.
RTL integrated circuit
1962
Fairchild Camera and Instrument Corp. produced the first
widely accepted epitaxial gold-doped NPN transistor. The
NPN transistor served as the industry workhouse for
discrete logic.
Fairchild NPN transistor
1967

4. Fairchild Camera and Instrument Corp. built the first
standard metal oxide semiconductor product for data
processing applications, an eight-bit arithmetic unit and
accumulator. In a MOS chip, engineers treat the
semiconductor material to produce either of two varieties
of transistors, called n-type and p-type.
MOS semiconductor
Using integrated circuits, Medtronics constructed the first
internal pacemaker.
1971
The first advertisement for a microprocessor, the Intel
4004, appeared in Electronic News. Developed for
Busicom, a Japanese calculator maker, the 4004 had 2250
transistors and could perform up to 90,000 operations per
second in four-bit chunks. Federico Faggin led the design
and Ted Hoff led the architecture.
Intel 4004
1972

5. Intel´s 8008 microprocessor made its debut. A vast
improvement over its predecessor, the 4004, its eight-bit
word afforded 256 unique arrangements of ones and zeros.
For the first time, a microprocessor could handle both
uppercase and lowercase letters, all 10 numerals,
punctuation marks, and a host of other symbols.
Intel 8008
1976
Intel and Zilog introduced new microprocessors. Five
times faster than its predecessor, the 8008, the Intel 8080
could address four times as many bytes for a total of 64
kilobytes. The Zilog Z-80 could run any program written for
the 8080 and included twice as many built-in machine
instructions.
Zilog Z-80
1979
The Motorola 68000 microprocessor exhibited a
processing speed far greater than its contemporaries. This
high performance processor found its place in powerful
work stations intended for graphics-intensive programs
common in engineering.
Motorola 68000

6. California Institute of Technology professor Carver Mead
and Xerox Corp. computer scientist Lynn Conway wrote a
manual of chip design, "Introduction to VLSI Systems."
Demystifying the planning of very large scale integrated
(VLSI) systems, the text expanded the ranks of engineers
capable of creating such chips. The authors had observed
that computer architects seldom participated in the
specification of the standard integrated circuits with
which they worked. The authors intended "Introduction to
VLSI Systems" to fill a gap in the literature and introduce
all electrical engineering and computer science students
to integrated system architecture.
Introduction to VLSI Systems
1986
David Miller of AT&T Bell Labs patented the optical
transistor, a component central to digital optical
computing. Called Self-ElectroOptic-Effect Device, or SEED,
the transistor involved a light-sensitive switch built with
layers of gallium arsenide and gallium aluminum arsenide.
Beams of light triggered electronic events that caused the
light either to be transmitted or absorbed, thus turning the
switch on or off.
Within a decade, research on the optical transistor led to
successful work on the first all-optical processor and the
first general-purpose all-optical computer. Bell Labs
researchers first demonstrated the processor there in 1990.
A computer using the SEED also contained lasers, lenses,
and fast light switches, but it still required programming by
a separate, non-optical computer. In 1993, researchers at
the University of Colorado unveiled the first all-optical
computer capable of being programmed and of
manipulating instructions internally.
Compaq beat IBM to the market when it announced the
Deskpro 386, the first computer on the market to use
Intel´s new 80386 chip, a 32-bit microprocessor with
275,000 transistors on each chip. At 4 million operations
per second and 4 kilobytes of memory, the 80386 gave PCs
as much speed and power as older mainframes and
minicomputers.
The 386 chip brought with it the introduction of a 32-bit
architecture, a significant improvement over the 16-bit
architecture of previous microprocessors. It had two
operating modes, one that mirrored the segmented
memory of older x86 chips, allowing full backward
Compaq compatibility, and one that took full advantage of its more
advanced technology. The new chip made graphical

7. operating environments for IBM PC and PC-compatible
computers practical. The architecture that allowed
Windows and IBM OS/2 has remained in subsequent chips.
1987
Motorola unveiled the 68030 microprocessor. A step up
from the 68020, it built on a 32-bit enhanced
microprocessor with a central processing unit core, a data
cache, an instruction cache, an enhanced bus controller,
and a memory management unit in a single VLSI device —
all operating at speeds of at least 20 MHz.
Motorola 68030
1988
Compaq and other PC-clone makers developed enhanced
industry standard architecture — better than microchannel
and retained compatibility with existing machines. EISA
used a 32-bit bus, or a means by which two devices can
communicate. The advanced data-handling features of the
EISA made it an improvement over the 16-bit bus of
industry standard architecture. IBM´s competitors
developed the EISA as a way to avoid paying a fee to IBM
for its MCA bus.
1989
Intel released the 80486 microprocessor and the i860
RISC/coprocessor chip, each of which contained more than
1 million transistors. The RISC microprocessor had a 32-bit
integer arithmetic and logic unit (the part of the CPU that
performs operations such as addition and subtraction), a
64-bit floating-point unit, and a clock rate of 33 MHz.
The 486 chips remained similar in structure to their
predecessors, the 386 chips. What set the 486 apart was
its optimized instruction set, with an on-chip unified
Intel 80486 instruction and data cache and an optional on-chip
floating-point unit. Combined with an enhanced bus
interface unit, the microprocessor doubled the
performance of the 386 without increasing the clock rate.

8. Motorola announced the 68040 microprocessor, with about
1.2 million transistors. Due to technical difficulties, it
didn´t ship until 1991, although promised in January 1990.
A 32-bit, 25-MHz microprocessor, the 68040 integrated a
floating-point unit and included instruction and data
caches. Apple used the third generation of 68000 chips in
Macintosh Quadra computers.
Motorola 68040
1993
The Pentium microprocessor is released. The Pentium was
the fifth generation of the ‘x86’ line of microprocessors
from Intel, the basis for the IBM PC and its clones. The
Pentium introduced several advances that made programs
run faster such as the ability to execute several
instructions at the same time and support for graphics and
music.
Intel Pentium Processor diagram