History of Computer 计算机发展史5 Computer Systems

Chapter 4
Computer Systems

239
Introduction
• The evolution of digital computing is
often divided into generations. Each
generation is characterized by dramatic
improvements over the previous
generation in the technology used to build
computers, the internal organization of
computer systems, and programming
languages.

240
The Five Generations
• The first generation of computers used
vacuum tubes (1937-1953)
• The second generation of computers used
transistors (1954-1962)
• The third generation of computers used
integrated circuits (1963-1972)
• The fourth generation of computers used
microprocessors (1972-1984)
• The fifth generation of computers used
parallel processing (1984-1990)

241
4.1 First Generation Computers
• The first generation of computers is said by
some to have started in 1946 with ENIAC, the
first computer to use electronic valves (ie.
vacuum tubes). Others would say it started in
May 1949 with the introduction of EDSAC, the
first stored program computer. Whichever, the
distinguishing feature of the first generation
computers was the use of electronic valves.
1946，我国处于民国三十五年， 国共“停战协议”签
字；政治协商会议在重庆召开；李闻血案在昆明发生；
制宪国民大会在南京召开；全国学生抗议美军暴行的爱
国运动爆发。

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• The operating instructions or programs
were specifically built for the task for
which computer was manufactured.
• The machine language was the only way
to tell these machines to perform the
operations.
• First Generation computers used
Vacuum tubes and magnetic drums (for
data storage).

243
Vacuum Tube
• In 1879, the legendary American inventor Thomas
Alva Edison publicly exhibited his incandescent（白
炽的） electric light bulb for the first time.
• Edison did not develop this particular finding any
further, but an English physicist, John Ambrose
Fleming, discovered that the Edison Effect could also
be used to detect radio waves and to convert them to
electricity. Fleming went on to develop a two-element
vacuum tube known as diode(二极管).
1879，我国处于清朝光绪五年，国内无大事。

244
Vacuum Tube
• In 1906, the American inventor Lee de Forest
introduced a third electrode（电极） called the grid
into the vacuum tube. The resulting triode（三极管）
could be used as both an amplifier and a switch, and
many of the early radio transmitters were built by de
Forest using these triodes (he also presented the first
live opera broadcast and the first news report on radio).
• De Forest's triodes revolutionized the field of
broadcasting and were destined to do much more,
because their ability to act as switches was to have a
tremendous impact on digital computing.
1906，我国处于清朝光绪三十二年，清廷发布
谕旨，宣布“预备仿行宪政”（预备立宪）。

245
Three Preceding Technologies
• Like all great inventions, the ENIAC
built on existing concepts. Here are
three that played a large role in the
development of the ENIAC:
---- Mechanical Brains
---- The Vacuum Tube
---- The Punched Card

246
Mechanical Brains
• Abacus
• Slide Rule
• Difference Engine
• Mechanical Calculators
• Differential Analyzer

247
The Vacuum Tube
• Faster Switches mean Faster Computers
• Electromagnetic Relays
• Tube is like a “valve（真空管）"

248
The Punched Card
• Jacquard Loom
• The US Census of 1890
• Tabulating Machines grow in popularity
1890，我国处于清朝光绪十六年，张之洞在汉
阳兴建铁厂。

249
John Mauchly
• John Mauchly designed the
ENIAC. He was a professor of
Physics at Ursinus College. In
1943 he attended a workshop at
Penn. There, he saw the
Differential Analyzer producing
firing tables. Mauchly realized
that he could build an electronic
machine that could be much
faster.
1943，我国处于民国三十二年， 蒋介石《中国之命
运》出版，毛泽东任中共中央政治局和书记处主席， 蒋
介石任国民政府主席，中美英首脑举行开罗会议。

250
J. Presper Eckert
• J. Presper Eckert solved
the engineering
challenges. The chief
challenge was tube
reliability. Eckert was
able to get good
reliability by running the
tubes at 1/4 power.

251
The creation of ENIAC
• Together, they proposed the ENIAC to the
Army in 1943. Construction was finished in
1946. For the next nine years, the ENIAC
served as the primary computing engine for the
Army.
• It was 10 feet tall, occupied 1,000 square feet of
floor- space, weighed in at approximately 30
tons, and used more than 70,000 resistors,
10,000 capacitors, 6,000 switches, and 18,000
vacuum tubes. The final machine required 150
kilowatts of power, which was enough to light a
small town.

252

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The main parts
• Cycling Unit
• Master Programmer Unit
• Function Table
• Accumulator
• Digit Trays(盘）
• Punch Card Reader
• Card Puncher
• Card Printer
• Division Unit
• Square-root Unit

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The ENIAC in Action
• After construction, the ENIAC was shipped to the
Aberdeen Proving Ground in Aberdeen MD. There, it
produced firing tables.
• In addition to ballistics（弹道学）, the ENIAC‘s field
of application included weather prediction, atomicenergy
calculations, cosmic-ray studies, thermal
ignition（热点火）, random-number studies, windtunnel
design, and other scientific uses. It is recalled
that no electronic computers were being applied to
commercial problems until about 1951.
• With the ability to perform math at blinding speed,
the ENIAC gave scientists a tool unlike any calculator
that had come before.

255
4.2 Second Generation Computers
• The invention of transistors marked the
start of the second generation. These
transistors took place of the vacuum
tubes used in the first generation
computers.

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• Memory technology was based on magnetic
cores which could be accessed in random order,
as opposed to mercury delay lines, in which
data was stored as an acoustic wave（声波）
that passed sequentially through the medium
and could be accessed only when the data
moved by the I/O interface.
• Important innovations in computer
architecture included index registers for
controlling loops and floating point units for
calculations based on real numbers.

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• During this second generation many high level
programming languages were introduced,
including FORTRAN (1956), ALGOL (1958),
and COBOL (1959).
• The second generation also saw the first two
supercomputers designed specifically for
numeric processing in scientific applications.
The Livermore Atomic Research Computer
(LARC) and the IBM 7030 were early examples
of machines that overlapped memory
operations with processor operations and had
primitive forms of parallel processing.

258
Transistors
• The vacuum tube, used to amplify music and voice,
made long-distance calling practical, but the tubes
consumed power, created heat and burned out
rapidly, requiring high maintenance.
• John Bardeen, William Shockley, and Walter
Brattain, scientists at the Bell Telephone
Laboratories in Murray Hill, New Jersey, were
researching the behavior of crystals (germanium
锗) as semi-conductors in an attempt to replace
vacuum tubes as mechanical relays in
telecommunications.

259
Transistors
• The team‘s research was about to come
to a fruitless end（无果而终） when a
last attempt to try a purer substance as a
contact point lead to the invention of the
"point-contact" transistor amplifier. In
1956, the team received the Nobel Prize
in Physics for the invention of the
transistor.

260
Transistors
• A transistor is a device composed of semiconductor
material that can both conduct
and insulate (e.g. germanium and silicon).
• Transistors switch and modulate（调制）
electronic current.
• The transistor was the first device
designed to act as both a transmitter,
converting sound waves into electronic
waves, and resistor, controlling electronic
current.

261
4.3 Third Generation Computers
• Despite the fact that transistors were
clearly an improvement over the vacuum
tube, they still generated a great deal of
heat, which damaged the computer's
sensitive internal parts.
• The development of integrated circuits
(IC) signaled the beginning of the third
generation.

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• The use of integrated circuits, or ICs
(semiconductor devices with several
transistors built into one physical
component),
• semiconductor memories begun to be
used instead of magnetic cores
• microprogramming as a technique for
efficiently designing complex processors

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• the coming of age of pipelining and other
forms of parallel processing
• Introduced the operating systems and
time-sharing.
• A new concept was that of a family of
computers, which allowed computers to
be upgraded and expanded as necessary.

264
The Brief History of Integrated Circuits
• Transistors were much smaller than their
vacuum tube predecessors, but designers
desired still smaller electronic switches.
• The first public discussion of integrated
circuits is credited to a British radar
expert, G.W.A. Dummer, in a paper
presented in 1952.

265
• Individually packaged transistors were much
smaller than their vacuum tube predecessors,
but designers desired still smaller electronic
switches. To a large extent the demand for
miniaturization was driven by the demands of
the American space program. For some time
people had been thinking that it would be a
good idea to be able to fabricate（制造） entire
circuits on a single piece of semiconductor.

266
• The first public discussion of this idea is credited to a
British radar expert, G.W.A. Dummer, in a paper
presented in 1952. However, it was not until the
summer of 1958, that Jack Kilby, working for Texas
Instruments, succeeded in fabricating multiple
components on a single piece of semiconductor. Kilby’s
first prototype was a phase shift （相移）oscillator
（振荡器） and, although manufacturing techniques
subsequently took different paths to those used by
Kilby, he is still credited with the creation of the first
true integrated circuit.

267
• By 1961, Fairchild and Texas Instruments had
announced the availability of the first
commercial planar(平面) integrated circuits
comprising simple logic functions. This
announcement marked the beginning of the
mass production of integrated circuits. In 1963,
Fairchild produced a device called the 907
containing two logic gates, each of which
consisted of four bipolar transistors and four
resistors. The 907 also made use of isolation
layers and buried layers（埋层）, both of
which were to become common features in
modern integrated circuits.

268
• In 1967, Fairchild introduced a device called the
Micromosaic, which contained a few hundred
transistors. The key feature of the Micromosaic was
that the transistors were not initially connected to
each other. A designer used a computer program to
specify the function the device was required to
perform, and the program determined the necessary
transistor interconnections and constructed the
photo-masks required to complete the device. The
Micromosaic is credited as the forerunner of the
modern application-specific integrated circuit
(ASIC), and also as the first real application of
computer aided design.

269
• In 1970, Fairchild introduced the first
256-bit static RAM called the 4100, while
Intel announced the first 1024-bit
dynamic RAM, called the 1103, in the
same year.

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4.4 Fourth Generation Computers
• Marcian Hoff invented a device which
could replace several of the components
of earlier computers, the microprocessor.
The microprocessor is the characteristic
of fourth generation computers, capable
of performing all of the functions of a
computer's central processing unit.

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• Semiconductor memories replaced core
memories as the main memory in most
systems until this time the use of
semiconductor memory in most systems was
limited to registers and cache.
• Developments in software include very high
level languages such as FP (functional
programming) and Prolog (programming in
logic). These languages tend to use a
declarative programming style as opposed to
the imperative style of Pascal, C, FORTRAN,
et al.

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• The continued improvement allowed the
networking of computers for the sharing
of data. Local Area Networks(LAN) and
Wide Area Network(WAN), were
potential benefits, in that they could be
implemented in corporations and
everybody could share data over it. Soon
the internet and World Wide Web
appeared on the computer scene and
formed the Hi-Tech revolution of 90's.

273
The development of Integration
• After the invention of the integrated circuit,
the next step in the computer design process
was to reduce the overall size.
• Large scale integration (LSI) could fit
hundreds of components onto one chip.
• very large scale integration (VLSI) squeezed
hundreds of thousands of components onto a
chip.
• Ultra-large scale integration (ULSI) increased
that number into the millions.

274
Intel 4004
The Intel 4004 chip, developed in
1971, took the integrated circuit
one step further by locating all the
components of a computer (central
processing unit, memory, and
input and output controls) on a
minute chip. Whereas previously
the integrated circuit had had to be
manufactured to fit a special
purpose, now one microprocessor
could be manufactured and then
programmed to meet any number
of demands.

275
The First Personal Computer
• The reduced size, reduced cost, and
increased speed of the microprocessor led
to the creation of the first personal
computers.
• In 1976, Steve Jobs and Steve Wozniak
built the Apple II, the first personal
computer in a garage in California.
• In 1981, IBM introduced personal
computers for home and office use

276
Original Apple Machintosh Screenshot

277
The First Microprocessors
• With the benefit of hindsight (the one exact
science), the advent of the microprocessor
appears to have been an obvious development.
But this was less than self-evident at the time
for a number of reasons, not the least that
computers of the day were big, expensive, and a
complete pain to use. Although these
arguments would appear to support the
development of the microprocessor, by some
strange quirk of fate they actually managed to
work to its disfavor.

278
The First Microprocessors
• Due to the fact that computers were so big and
expensive, only large institutions could afford
them and they were only used for
computationally intensive tasks. Thus,
following a somewhat circular argument,
popular opinion held that only large
institutions needed computers in the first place.
Similarly, due to the fact that computers were
few and far between, only the chosen few had
any access to them, which meant that only a
handful of people had the faintest clue as to
how they worked.

279
The First Microprocessors
• Coupled with the fact that the early computers
were difficult to use in the first place, this
engendered the belief that only heroes (and
heroines) with size-16 turbo-charged brains
had any chance of being capable of using them
at all. Last but not least, computers of the day
required many thousands of transistors and the
thrust was toward yet more powerful
computers in terms of raw number-crunching
capability, but integrated circuit technology
was in its infancy and it wasn't possible to
construct even a few thousand transistors on a
single integrated circuit until the late 1960s.

280
The First Microprocessors
• The end result was that the (potential) future of
the (hypothetical) microprocessor looked
somewhat bleak, but fortunately other forces
were afoot. Although computers were
somewhat scarce in the 1960s, there was a large
and growing market for electronic desktop
calculators. In 1970, the Japanese calculator
company Busicom approached Intel with a
request to design a set of twelve integrated
circuits for use in a new calculator.

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The First Microprocessors
• The task was presented to one Marcian "Ted"
Hoff, a man who could foresee a somewhat
bleak and never-ending role for himself
designing sets of special-purpose integrated
circuits for one-of-a-kind tasks. However,
during his early ruminations on the project,
Hoff realized that rather than design the
special-purpose devices requested by Busicom,
he could create a single integrated circuit with
the attributes of a simple-minded, strippeddown,
general-purpose computer processor.

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The First Microprocessors
• The result of Hoff's inspiration was the world's
first microprocessor, the 4004, where the '4's
were used to indicate that the device had a 4-bit
data path. The 4004 was part of a four-chip
system which also consisted of a 256-byte ROM,
a 32-bit RAM, and a 10-bit shift register. The
4004 itself contained approximately 2,300
transistors and could execute 60,000 operations
per second. The advantage (as far as Hoff was
concerned) was that by simply changing the
external program, the same device could be
used for a multitude of future projects.

283
The First Microprocessors
• Knowing how pervasive micro- processors were to
become, you might be tempted to imagine that there
was a fanfare of trumpets and Hoff was immediately
acclaimed to be the master of the known universe, but
such was not to be the case.
• The 4004 was so radically different from what
Busicom had requested that they didn't immediately
recognize its implications (much as if they'd ordered
a Chevy Cavalier, which had suddenly
transmogrified itself into an Aston Martin), so they
politely said that they weren't really interested and
could they please have the twelve-chip set they'd
originally requested (they did eventually agree to use
the fruits of Hoff's labors).

284
The First Microprocessors
• In November 1972, Intel introduced the 8008,
which was essentially an 8-bit version of the
4004. The 8008 contained approximately 3,300
transistors and was the first microprocessor to
be supported by a high-level language compiler
called PL/M. The 8008 was followed by the
4040, which extended the 4004's capabilities by
adding logical and compare instructions, and
by supporting subroutine nesting using a small
internal stack.

285
The First Microprocessors
• However, the 4004, 4040, and 8008 were all designed
for specific applications, and it was not until April
1974 that Intel presented the first true generalpurpose
microprocessor, the 8080. This 8-bit device,
which contained around 4,500 transistors and could
perform 200,000 operations per second, was destined
for fame as the central processor of many of the early
home computers.
• Following the 8080, the microprocessor field exploded
with devices such as the 6800 from Motorola in
August 1974, the 6502 from MOS Technology in 1975,
and the Z80 from Zilog in 1976 (to name but a few).

286
4.5 Fifth Generation Computers
• The development of the fifth generation
of computer systems is characterized
mainly by the acceptance of parallel
processing.
• The Fifth Generation Computer Systems
project (FGCS) was an initiative by
Japan's Ministry of International Trade
and Industry, begun in 1982, to create a
"fifth generation computer" which was
supposed to perform much calculation
utilizing massive parallelism.

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• Until this time parallelism was limited to
pipelining and vector processing, or at
most to a few processors sharing jobs.
The fifth generation saw the introduction
of machines with hundreds of processors
that could all be working on different
parts of a single program.
• Semiconductor memories became
standard on all computers.

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• The new developments were the
widespread use of computer networks
and the increasing use of single-user
workstations.
• Intel began to connect each processor to
its own memory and used a network
interface to connect processors. This
distributed memory architecture meant
memory was no longer a bottleneck and
large systems (using more processors)
could be built.

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• In the area of computer networking, both wide
area network (WAN) and local area network
(LAN) technology developed at a rapid pace,
stimulating a transition from the traditional
mainframe computing environment toward a
distributed computing environment in which
each user has their own workstation for
relatively simple tasks (editing and compiling
programs, reading mail) but sharing large,
expensive resources such as file servers and
supercomputers.

290
Parallel Processing
• The simultaneous use of more than one CPU to
execute a program. Ideally, parallel processing
makes a program run faster because there are
more engines (CPUs) running it. In practice, it
is often difficult to divide a program in such a
way that separate CPUs can execute different
portions without interfering with each other.
• Note that parallel processing differs from
multitasking, in which a single CPU executes
several programs at once.

291
Parallel Processing
• Most computers have just one CPU, but
some models have several. There are even
computers with thousands of CPUs. With
single-CPU computers, it is possible to
perform parallel processing by
connecting the computers in a network.
However, this type of parallel processing
requires very sophisticated software
called distributed processing software.

292
Parallel Processing
• Emerging computer technology that
allows more than one computation at the
same time. Although in the 1990s this
technology enabled only a small number
of computer processor units to work in
parallel, in theory thousands or millions
of processors could be used at the same
time.

293
Parallel Processing
• Parallel processing, which involves
breaking down computations into small
parts and performing thousands of them
simultaneously, rather than in a linear
sequence, offers the prospect of a vast
improvement in working speed for
certain repetitive applications.