From Wikipedia, the free encyclopedia
Parts from four early computers, 1962. From left to right: ENIAC board,
EDVAC board, ORDVAC board, and BRLESC-I board, showing the trend toward
miniaturization.
The
history of computing hardware covers the developments from
early simple devices to aid calculation to modern day computers. Before
the 20th century, most calculations were done by humans. Early
mechanical tools to help humans with digital calculations, such as the
abacus, were called "calculating machines", called by proprietary names, or referred to as
calculators. The machine operator was called the computer.
The first aids to computation were purely mechanical devices which
required the operator to set up the initial values of an elementary
arithmetic operation, then manipulate the device to obtain the result.
Later, computers represented numbers in a continuous form, for instance
distance along a scale, rotation of a shaft, or a voltage. Numbers could
also be represented in the form of digits, automatically manipulated by
a mechanical mechanism. Although this approach generally required more
complex mechanisms, it greatly increased the precision of results. A
series of breakthroughs, such as miniaturized
transistor computers, and
the integrated circuit, caused digital computers to largely replace
analog computers. The cost of computers gradually became so low that by the 1990s,
personal computers, and then, in the 2000s, mobile computers, (
smartphones and
tablets) became ubiquitous in industrialized countries.
Early devices
Ancient era
Suanpan (the number represented on this abacus is 6,302,715,408)
Devices have been used to aid computation for thousands of years, mostly using
one-to-one correspondence with
fingers. The earliest counting device was probably a form of
tally stick. Later record keeping aids throughout the
Fertile Crescent
included calculi (clay spheres, cones, etc.) which represented counts
of items, probably livestock or grains, sealed in hollow unbaked clay
containers.
[2][3][4] The use of
counting rods is one example. The
abacus was early used for arithmetic tasks. What we now call the
Roman abacus was used in
Babylonia
as early as c. 2700–2300 BC. Since then, many other forms of reckoning
boards or tables have been invented. In a medieval European
counting house,
a checkered cloth would be placed on a table, and markers moved around
on it according to certain rules, as an aid to calculating sums of
money.
Several
analog computers were constructed in ancient and medieval times to perform astronomical calculations. These included the
south-pointing chariot (c. 1050–771 BC) from
ancient China, and the
astrolabe and
Antikythera mechanism from the
Hellenistic world (c. 150–100 BC).
[5] In
Roman Egypt,
Hero of Alexandria (c. 10–70 AD) made mechanical devices including automata and a programmable cart.
[6] Other early mechanical devices used to perform one or another type of calculations include the
planisphere and other mechanical computing devices invented by
Abu Rayhan al-Biruni (c. AD 1000); the
equatorium and universal latitude-independent astrolabe by
Abū Ishāq Ibrāhīm al-Zarqālī (c. AD 1015); the astronomical analog computers of other medieval
Muslim astronomers and engineers; and the astronomical
clock tower of
Su Song (1094) during the
Song dynasty. The
castle clock, a
hydropowered mechanical
astronomical clock invented by
Ismail al-Jazari in 1206, was the first
programmable analog computer.
[7][8][9] Ramon Llull
invented the Lullian Circle: a notional machine for calculating answers
to philosophical questions (in this case, to do with Christianity) via
logical combinatorics. This idea was taken up by
Leibniz centuries later, and is thus one of the founding elements in computing and
information science.
Renaissance calculating tools
A set of
John Napier's calculating tables from around 1680
Scottish mathematician and physicist
John Napier
discovered that the multiplication and division of numbers could be
performed by the addition and subtraction, respectively, of the
logarithms
of those numbers. While producing the first logarithmic tables, Napier
needed to perform many tedious multiplications. It was at this point
that he designed his '
Napier's bones', an abacus-like device that greatly simplified calculations that involved multiplication and division.
[10]
Since
real numbers can be represented as distances or intervals on a line, the
slide rule
was invented in the 1620s, shortly after Napier's work, to allow
multiplication and division operations to be carried out significantly
faster than was previously possible.
[11] Edmund Gunter built a calculating device with a single logarithmic scale at the
University of Oxford. His device greatly simplified arithmetic calculations, including multiplication and division.
William Oughtred
greatly improved this in 1630 with his circular slide rule. He followed
this up with the modern slide rule in 1632, essentially a combination
of two
Gunter rules,
held together with the hands. Slide rules were used by generations of
engineers and other mathematically involved professional workers, until
the invention of the
pocket calculator.
[12]
Mechanical calculators
Wilhelm Schickard, a German
polymath,
designed a calculating machine in 1623 which combined a mechanised form
of Napier's rods with the world's first mechanical adding machine built
into the base. Because it made use of a single-tooth gear there were
circumstances in which its carry mechanism would jam.
[13] A fire destroyed at least one of the machines in 1624 and it is believed Schickard was too disheartened to build another.
In 1642, while still a teenager,
Blaise Pascal started some pioneering work on calculating machines and after three years of effort and 50 prototypes
[14] he invented a
mechanical calculator.
[15][16] He built twenty of these machines (called
Pascal's calculator or Pascaline) in the following ten years.
[17] Nine Pascalines have survived, most of which are on display in European museums.
[18]
A continuing debate exists over whether Schickard or Pascal should be
regarded as the "inventor of the mechanical calculator" and the range of
issues to be considered is discussed elsewhere.
[19]
Gottfried Wilhelm von Leibniz invented the
stepped reckoner and his
famous stepped drum mechanism
around 1672. He attempted to create a machine that could be used not
only for addition and subtraction but would utilise a moveable carriage
to enable long multiplication and division. Leibniz once said "It is
unworthy of excellent men to lose hours like slaves in the labour of
calculation which could safely be relegated to anyone else if machines
were used."
[20] However, Leibniz did not incorporate a fully successful carry mechanism. Leibniz also described the
binary numeral system,
[21] a central ingredient of all modern computers. However, up to the 1940s, many subsequent designs (including
Charles Babbage's machines of the 1822 and even
ENIAC of 1945) were based on the decimal system.
[22]
Around 1820,
Charles Xavier Thomas de Colmar created what would over the rest of the century become the first successful, mass-produced mechanical calculator, the Thomas
Arithmometer.
It could be used to add and subtract, and with a moveable carriage the
operator could also multiply, and divide by a process of long
multiplication and long division.
[23]
It utilised a stepped drum similar in conception to that invented by
Leibniz. Mechanical calculators remained in use until the 1970s.
Punched card data processing
In 1804,
Joseph-Marie Jacquard developed
a loom in which the pattern being woven was controlled by a paper tape constructed from
punched cards.
The paper tape could be changed without changing the mechanical design
of the loom. This was a landmark achievement in programmability. His
machine was an improvement over similar weaving looms. Punched cards
were preceded by punch bands, as in the machine proposed by
Basile Bouchon. These bands would inspire information recording for automatic pianos and more recently
numerical control machine tools.
IBM punched card Accounting Machines, pictured in 1936
In the late 1880s, the American
Herman Hollerith invented data storage on
punched cards that could then be read by a machine.
[24] To process these punched cards he invented the
tabulator, and the
keypunch machine. His machines used electromechanical
relays and
counters.
[25] Hollerith's method was used in the
1890 United States Census. That census was processed two years faster than the prior census had been.
[26] Hollerith's company eventually became the core of
IBM.
By 1920, electromechanical tabulating machines could add, subtract and print accumulated totals.
[27] Machine functions were directed by inserting dozens of wire jumpers into removable
control panels. When the United States instituted
Social Security in 1935, IBM punched card systems were used to process records of 26 million workers.
[28] Punched cards became ubiquitous in industry and government for accounting and administration.
Leslie Comrie's articles on punched card methods and
W.J. Eckert's publication of
Punched Card Methods in Scientific Computation in 1940, described punched card techniques sufficiently advanced to solve some differential equations
[29] or perform multiplication and division using floating point representations, all on punched cards and
unit record machines.
Such machines were used during World War II for cryptographic
statistical processing, as well as a vast number of administrative uses.
The Astronomical Computing Bureau,
Columbia University, performed astronomical calculations representing the state of the art in
computing.
[30][31]
The book
IBM and the Holocaust by
Edwin Black outlines the ways in which IBM's technology helped facilitate
Nazi genocide through generation and tabulation of
punch cards based upon national
census data.
See also: Dehomag
Calculators
The
Curta calculator could also do multiplication and division.
By the 20th century, earlier mechanical calculators, cash registers,
accounting machines, and so on were redesigned to use electric motors,
with gear position as the representation for the state of a variable.
The word "computer" was a job title assigned to primarily women who used
these calculators to perform mathematical calculations.
[32] By the 1920s, British scientist
Lewis Fry Richardson's interest in weather prediction led him to propose
human computers and
numerical analysis to model the weather; to this day, the most powerful computers on
Earth are needed to adequately model its weather using the
Navier–Stokes equations.
[33]
Companies like
Friden,
Marchant Calculator and
Monroe made desktop mechanical calculators from the 1930s that could add, subtract, multiply and divide.
[34] In 1948, the
Curta was introduced by Austrian inventor
Curt Herzstark. It was a small, hand-cranked mechanical calculator and as such, a descendant of
Gottfried Leibniz's
Stepped Reckoner and
Thomas's
Arithmometer.
The world's first
all-electronic desktop calculator was the British
Bell Punch ANITA, released in 1961.
[35][36] It used
vacuum tubes, cold-cathode tubes and
Dekatrons in its circuits, with 12 cold-cathode
"Nixie" tubes for its display. The
ANITA
sold well since it was the only electronic desktop calculator
available, and was silent and quick. The tube technology was superseded
in June 1963 by the U.S. manufactured
Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch (13 cm)
CRT, and introduced
reverse Polish notation (RPN).
First general-purpose computing device
Charles Babbage, an English mechanical engineer and
polymath, originated the concept of a programmable computer. Considered the "
father of the computer",
[37] he conceptualized and invented the first
mechanical computer in the early 19th century. After working on his revolutionary
difference engine, designed to aid in navigational calculations, in 1833 he realized that a much more general design, an
Analytical Engine, was possible. The input of programs and data was to be provided to the machine via
punched cards, a method being used at the time to direct mechanical
looms such as the
Jacquard loom.
For output, the machine would have a printer, a curve plotter and a
bell. The machine would also be able to punch numbers onto cards to be
read in later. It employed ordinary
base-10 fixed-point arithmetic.
The Engine incorporated an
arithmetic logic unit,
control flow in the form of
conditional branching and
loops, and integrated
memory, making it the first design for a general-purpose computer that could be described in modern terms as
Turing-complete.
[38][39]
There was to be a store, or memory, capable of holding 1,000 numbers of 40 decimal digits each (ca. 16.7
kB). An
arithmetical unit, called the "mill", would be able to perform all four
arithmetic operations, plus comparisons and optionally
square roots. Initially it was conceived as a
difference engine curved back upon itself, in a generally circular layout,
[40] with the long store exiting off to one side. (Later drawings depict a regularized grid layout.)
[41] Like the
central processing unit (CPU) in a modern computer, the mill would rely upon its own internal procedures, roughly equivalent to
microcode
in modern CPUs, to be stored in the form of pegs inserted into rotating
drums called "barrels", to carry out some of the more complex
instructions the user's program might specify.
[42]
The programming language to be employed by users was akin to modern day
assembly languages. Loops and conditional branching were possible, and so the language as conceived would have been
Turing-complete as later defined by
Alan Turing.
Three different types of punch cards were used: one for arithmetical
operations, one for numerical constants, and one for load and store
operations, transferring numbers from the store to the arithmetical unit
or back. There were three separate readers for the three types of
cards.
The machine was about a century ahead of its time. However, the
project was slowed by various problems including disputes with the chief
machinist building parts for it. All the parts for his machine had to
be made by hand—this was a major problem for a machine with thousands of
parts. Eventually, the project was dissolved with the decision of the
British Government to cease funding. Babbage's failure to complete the
analytical engine can be chiefly attributed to difficulties not only of
politics and financing, but also to his desire to develop an
increasingly sophisticated computer and to move ahead faster than anyone
else could follow.
Ada Lovelace,
Lord Byron's daughter, translated and
added notes to the "
Sketch of the Analytical Engine" by
Luigi Federico Menabrea.
This appears to be the first published description of programming, so
Ada Lovelace is widely regarded as the first computer programmer.
[43]
Following Babbage, although unaware of his earlier work, was
Percy Ludgate,
an accountant from Dublin, Ireland. He independently designed a
programmable mechanical computer, which he described in a work that was
published in 1909.
[44]
Analog computers
In the first half of the 20th century,
analog computers
were considered by many to be the future of computing. These devices
used the continuously changeable aspects of physical phenomena such as
electrical,
mechanical, or
hydraulic quantities to
model the problem being solved, in contrast to
digital computers
that represented varying quantities symbolically, as their numerical
values change. As an analog computer does not use discrete values, but
rather continuous values, processes cannot be reliably repeated with
exact equivalence, as they can with
Turing machines.
[45]
The first modern analog computer was a
tide-predicting machine, invented by
Sir William Thomson,
later Lord Kelvin, in 1872. It used a system of pulleys and wires to
automatically calculate predicted tide levels for a set period at a
particular location and was of great utility to navigation in shallow
waters. His device was the foundation for further developments in analog
computing.
[46]
The
differential analyser,
a mechanical analog computer designed to solve differential equations
by integration using wheel-and-disc mechanisms, was conceptualized in
1876 by
James Thomson,
the brother of the more famous Lord Kelvin. He explored the possible
construction of such calculators, but was stymied by the limited output
torque of the
ball-and-disk integrators.
[47] In a differential analyzer, the output of one integrator drove the input of the next integrator, or a graphing output.
A Mk. I Drift Sight. The lever just in front of the bomb aimer's
fingertips sets the altitude, the wheels near his knuckles set the wind
and airspeed.
An important advance in analog computing was the development of the first
fire-control systems for long range
ship gunlaying.
When gunnery ranges increased dramatically in the late 19th century it
was no longer a simple matter of calculating the proper aim point, given
the flight times of the shells. Various spotters on board the ship
would relay distance measures and observations to a central plotting
station. There the fire direction teams fed in the location, speed and
direction of the ship and its target, as well as various adjustments for
Coriolis effect,
weather effects on the air, and other adjustments; the computer would
then output a firing solution, which would be fed to the turrets for
laying. In 1912, British engineer
Arthur Pollen developed the first electrically powered mechanical
analogue computer (called at the time the Argo Clock).
[citation needed] It was used by the
Imperial Russian Navy in
World War I.
[citation needed] The alternative
Dreyer Table fire control system was fitted to British capital ships by mid-1916.
Mechanical devices were also used to aid the
accuracy of aerial bombing.
Drift Sight was the first such aid, developed by
Harry Wimperis in 1916 for the
Royal Naval Air Service; it measured the
wind speed
from the air, and used that measurement to calculate the wind's effects
on the trajectory of the bombs. The system was later improved with the
Course Setting Bomb Sight, and reached a climax with
World War II bomb sights,
Mark XIV bomb sight (
RAF Bomber Command) and the
Norden[48] (
United States Army Air Forces).
The art of mechanical analog computing reached its zenith with the
differential analyzer,
[49] built by H. L. Hazen and
Vannevar Bush at
MIT starting in 1927, which built on the mechanical integrators of
James Thomson and the
torque amplifiers
invented by H. W. Nieman. A dozen of these devices were built before
their obsolescence became obvious; the most powerful was constructed at
the
University of Pennsylvania's
Moore School of Electrical Engineering, where the
ENIAC was built.
A fully electronic analog computer was built by
Helmut Hölzer in 1942 at
Peenemünde Army Research Center .
[50][51][52]
By the 1950s the success of digital electronic computers had spelled the end for most analog computing machines, but
hybrid analog computers,
controlled by digital electronics, remained in substantial use into the
1950s and 1960s, and later in some specialized applications.
Advent of the digital computer
The principle of the modern computer was first described by
computer scientist Alan Turing, who set out the idea in his seminal 1936 paper,
[53] On Computable Numbers. Turing reformulated
Kurt Gödel's
1931 results on the limits of proof and computation, replacing Gödel's
universal arithmetic-based formal language with the formal and simple
hypothetical devices that became known as
Turing machines.
He proved that some such machine would be capable of performing any
conceivable mathematical computation if it were representable as an
algorithm. He went on to prove that there was no solution to the
Entscheidungsproblem by first showing that the
halting problem for Turing machines is
undecidable: in general, it is not possible to decide algorithmically whether a given Turing machine will ever halt.
He also introduced the notion of a 'Universal Machine' (now known as a
Universal Turing machine),
with the idea that such a machine could perform the tasks of any other
machine, or in other words, it is provably capable of computing anything
that is computable by executing a program stored on tape, allowing the
machine to be programmable.
Von Neumann acknowledged that the central concept of the modern computer was due to this paper.
[54] Turing machines are to this day a central object of study in
theory of computation. Except for the limitations imposed by their finite memory stores, modern computers are said to be
Turing-complete, which is to say, they have
algorithm execution capability equivalent to a
universal Turing machine.
Electromechanical computers
The
era of modern computing began with a flurry of development before and
during World War II. Most digital computers built in this period were
electromechanical – electric switches drove mechanical relays to perform
the calculation. These devices had a low operating speed and were
eventually superseded by much faster all-electric computers, originally
using
vacuum tubes.
The
Z2 was one of the earliest examples of an electromechanical relay
computer, and was created by German engineer
Konrad Zuse in 1940. It was an improvement on his earlier
Z1; although it used the same mechanical
memory, it replaced the arithmetic and control logic with electrical
relay circuits.
[55]
Replica of
Zuse's
Z3, the first fully automatic, digital (electromechanical) computer
In the same year, electro-mechanical devices called
bombes were built by British
cryptologists to help decipher
German Enigma-machine-encrypted secret messages during
World War II. The bombes' initial design was created in 1939 at the UK
Government Code and Cypher School (GC&CS) at
Bletchley Park by
Alan Turing,
[56] with an important refinement devised in 1940 by
Gordon Welchman.
[57] The engineering design and construction was the work of
Harold Keen of the
British Tabulating Machine Company. It was a substantial development from a device that had been designed in 1938 by
Polish Cipher Bureau cryptologist
Marian Rejewski, and known as the "
cryptologic bomb" (
Polish:
"bomba kryptologiczna").
In 1941, Zuse followed his earlier machine up with the
Z3,
[58] the world's first working
electromechanical programmable, fully automatic digital computer.
[59] The Z3 was built with 2000
relays, implementing a 22
bit word length that operated at a
clock frequency of about 5–10
Hz.
[60] Program code and data were stored on punched
film. It was quite similar to modern machines in some respects, pioneering numerous advances such as
floating point numbers. Replacement of the hard-to-implement decimal system (used in
Charles Babbage's earlier design) by the simpler
binary
system meant that Zuse's machines were easier to build and potentially
more reliable, given the technologies available at that time.
[61] The Z3 was probably a complete
Turing machine. In two 1936
patent
applications, Zuse also anticipated that machine instructions could be
stored in the same storage used for data—the key insight of what became
known as the
von Neumann architecture, first implemented in the British
SSEM of 1948.
[62]
Zuse suffered setbacks during World War II when some of his machines were destroyed in the course of
Allied
bombing campaigns. Apparently his work remained largely unknown to
engineers in the UK and US until much later, although at least IBM was
aware of it as it financed his post-war startup company in 1946 in
return for an option on Zuse's patents.
In 1944, the
Harvard Mark I was constructed at IBM's Endicott laboratories;
[63] it was a similar general purpose electro-mechanical computer to the Z3, but was not quite Turing-complete.
Digital computation
The
term digital is suggested by George Stibitz and refers to all
applications based on signals with two states – low (0) and high (1).
That is why the decimal and binary computing are two ways to implement
digital computing. A mathematical basis of digital computing is
Boolean algebra, developed by the British mathematician
George Boole in his work
The Laws of Thought, published in 1854. His Boolean algebra was further refined in the 1860s by
William Jevons and
Charles Sanders Peirce, and was first presented systematically by
Ernst Schröder and
A. N. Whitehead.
[64] In 1879 Gottlob Frege develops the formal approach to logic and proposes the first logic language for logical equations.
[65]
In the 1930s and working independently, American
electronic engineer Claude Shannon and Soviet
logician Victor Shestakov[66] both showed a
one-to-one correspondence between the concepts of
Boolean logic and certain electrical circuits, now called
logic gates, which are now ubiquitous in digital computers.
[67] They showed
[68] that electronic relays and switches can realize the
expressions of
Boolean algebra. This thesis essentially founded practical
digital circuit design.
Electronic data processing
Purely
electronic circuit
elements soon replaced their mechanical and electromechanical
equivalents, at the same time that digital calculation replaced analog.
Machines such as the first IBM electronic accounting machine (US
2,580,740), the NCR electronic calculating machine (US 2,595,045), the
Z3, the
Atanasoff–Berry Computer, the
Colossus computers, and the
ENIAC were built by hand, using circuits containing relays or valves (vacuum tubes), and often used
punched cards or
punched paper tape for input and as the main (non-volatile) storage medium.
[69]
The engineer
Tommy Flowers joined the telecommunications branch of the
General Post Office in 1926. While working at the
research station in
Dollis Hill in the 1930s, he began to explore the possible use of electronics for the
telephone exchange. Experimental equipment that he built in 1934 went into operation 5 years later, converting a portion of the
telephone exchange network into an electronic data processing system, using thousands of
vacuum tubes.
[46]
In the US, in the period summer 1937 to the fall of 1939 Arthur Dickinson (IBM) invented the first digital electronic computer.
[70] This calculating device was fully electronic – control, calculations and output (the first electronic display).
[71] John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed the
Atanasoff–Berry Computer (ABC) in 1942,
[72] the first binary electronic digital calculating device.
[73]
This design was semi-electronic (electro-mechanical control and
electronic calculations), and used about 300 vacuum tubes, with
capacitors fixed in a mechanically rotating drum for memory. However,
its paper card writer/reader was unreliable and the regenerative drum
contact system was mechanical. The machine's special-purpose nature and
lack of changeable,
stored program distinguish it from modern computers.
[74]
The tests of the ABC computer in June 1942 were not successful. Instead
of solving system of equations with 29 unknowns, the computer could
solve system of equations with no more than three to five unknowns. The
ABC computer was not completed and was abandoned.
[75]
In 1942 – 1943 Joseph Desch from NCR developed with the help from Allan
Turing the first mass-produced electronic computer N530 for breaking
the four-wheel Enigma. From August 1943 to the end of the WWII 180
machines were manufactured, and one third of them were sent to Bletchley
Park, UK.
[76]
The electronic programmable computer
Colossus was the first
electronic digital programmable
computing device, and was used to break German ciphers during World War
II. It remained unknown, as a military secret, well into the 1970s
During World War II, the British at
Bletchley Park
(40 miles north of London) achieved a number of successes at breaking
encrypted German military communications. The German encryption machine,
Enigma, was first attacked with the help of the electro-mechanical
bombes.
[77]
They ruled out possible Enigma settings by performing chains of logical
deductions implemented electrically. Most possibilities led to a
contradiction, and the few remaining could be tested by hand.
The Germans also developed a series of teleprinter encryption systems, quite different from Enigma. The
Lorenz SZ 40/42
machine was used for high-level Army communications, termed "Tunny" by
the British. The first intercepts of Lorenz messages began in 1941. As
part of an attack on Tunny,
Max Newman and his colleagues helped specify the Colossus.
[78]
Tommy Flowers, still a senior engineer at the
Post Office Research Station[79] was recommended to Max Newman by Alan Turing
[80] and spent eleven months from early February 1943 designing and building the first Colossus.
[81][82] After a functional test in December 1943, Colossus was shipped to Bletchley Park, where it was delivered on 18 January 1944
[83] and attacked its first message on 5 February.
[74]
Colossus rebuild seen from the rear of the device.
Colossus was the world's first
electronic digital programmable computer.
[46]
It used a large number of valves (vacuum tubes). It had paper-tape
input and was capable of being configured to perform a variety of
boolean logical operations on its data, but it was not
Turing-complete.
Nine Mk II Colossi were built (The Mk I was converted to a Mk II making
ten machines in total). Colossus Mark I contained 1500 thermionic
valves (tubes), but Mark II with 2400 valves, was both 5 times faster
and simpler to operate than Mark 1, greatly speeding the decoding
process. Mark 2 was designed while Mark 1 was being constructed.
Allen Coombs took over leadership of the Colossus Mark 2 project when
Tommy Flowers moved on to other projects.
[84]
Colossus was able to process 5,000 characters per second with the
paper tape moving at 40 ft/s (12.2 m/s; 27.3 mph). Sometimes, two or
more Colossus computers tried different possibilities simultaneously in
what now is called
parallel computing, speeding the decoding process by perhaps as much as double the rate of comparison.
Colossus included the first ever use of
shift registers and
systolic arrays, enabling five simultaneous tests, each involving up to 100
Boolean calculations,
on each of the five channels on the punched tape (although in normal
operation only one or two channels were examined in any run). Initially
Colossus was only used to determine the initial wheel positions used for
a particular message (termed wheel setting). The Mark 2 included
mechanisms intended to help determine pin patterns (wheel breaking).
Both models were programmable using switches and plug panels in a way
their predecessors had not been.
ENIAC was the first Turing-complete electronic device, and performed ballistics trajectory calculations for the
United States Army.
[85]
W
ithout the use of these machines, the
Allies would have been deprived of the very valuable
intelligence that was obtained from reading the vast quantity of
encrypted high-level
telegraphic messages between the
German High Command (OKW) and their
army commands throughout occupied Europe. Details of their existence, design, and use were kept secret well into the 1970s.
Winston Churchill
personally issued an order for their destruction into pieces no larger
than a man's hand, to keep secret that the British were capable of
cracking
Lorenz SZ cyphers
(from German rotor stream cipher machines) during the oncoming Cold
War. Two of the machines were transferred to the newly formed
GCHQ and the others were destroyed. As a result, the machines were not included in many histories of computing.
[86] A reconstructed working copy of one of the Colossus machines is now on display at Bletchley Park.
The US-built
ENIAC
(Electronic Numerical Integrator and Computer) was the first electronic
programmable computer built in the US. Although the ENIAC was similar
to the Colossus it was much faster and more flexible. It was
unambiguously a Turing-complete device and could compute any problem
that would fit into its memory. Like the Colossus, a "program" on the
ENIAC was defined by the states of its patch cables and switches, a far
cry from the
stored program
electronic machines that came later. Once a program was written, it had
to be mechanically set into the machine with manual resetting of plugs
and switches.
It combined the high speed of electronics with the ability to be
programmed for many complex problems. It could add or subtract 5000
times a second, a thousand times faster than any other machine. It also
had modules to multiply, divide, and square root. High-speed memory was
limited to 20 words (about 80 bytes). Built under the direction of
John Mauchly and
J. Presper Eckert
at the University of Pennsylvania, ENIAC's development and construction
lasted from 1943 to full operation at the end of 1945. The machine was
huge, weighing 30 tons, using 200 kilowatts of electric power and
contained over 18,000 vacuum tubes, 1,500 relays, and hundreds of
thousands of resistors, capacitors, and inductors.
[87]
One of its major engineering feats was to minimize the effects of tube
burnout, which was a common problem in machine reliability at that time.
The machine was in almost constant use for the next ten years.
Stored-program computer
Early computing machines had fixed programs. For example, a desk
calculator is a fixed program computer. It can do basic
mathematics, but it cannot be used as a
word processor
or a gaming console. Changing the program of a fixed-program machine
requires re-wiring, re-structuring, or re-designing the machine. The
earliest computers were not so much "programmed" as they were
"designed". "Reprogramming", when it was possible at all, was a
laborious process, starting with
flowcharts
and paper notes, followed by detailed engineering designs, and then the
often-arduous process of physically re-wiring and re-building the
machine.
[88] With the proposal of the stored-program computer this changed. A stored-program computer includes by design an
instruction set and can store in memory a set of instructions (a
program) that details the
computation.
Theory
The theoretical basis for the stored-program computer had been composed by
Alan Turing in his 1936 paper. In 1945 Turing joined the
National Physical Laboratory
and began his work on developing an electronic stored-program digital
computer. His 1945 report ‘Proposed Electronic Calculator’ was the first
specification for such a device.
Meanwhile,
John von Neumann at the
Moore School of Electrical Engineering,
University of Pennsylvania, circulated his
First Draft of a Report on the EDVAC
in 1945. Although substantially similar to Turing's design and
containing comparatively little engineering detail, the computer
architecture it outlined became known as the "
von Neumann architecture". Turing presented a more detailed paper to the
National Physical Laboratory (NPL) Executive Committee in 1946, giving the first reasonably complete design of a
stored-program computer, a device he called the
Automatic Computing Engine (ACE). However, the better-known
EDVAC design of
John von Neumann,
who knew of Turing's theoretical work, received more publicity, despite
its incomplete nature and questionable lack of attribution of the
sources of some of the ideas.
[46]
Turing thought that the speed and the size of
computer memory were crucial elements, so he proposed a high-speed memory of what would today be called 25
KB, accessed at a speed of 1
MHz. The ACE implemented
subroutine calls, whereas the EDVAC did not, and the ACE also used
Abbreviated Computer Instructions, an early form of
programming language.
Manchester "Baby"
The Manchester Small-Scale Experimental Machine, nicknamed
Baby, was the world's first
stored-program computer. It was built at the
Victoria University of Manchester by
Frederic C. Williams,
Tom Kilburn and Geoff Tootill, and ran its first program on 21 June 1948.
[89]
The machine was not intended to be a practical computer but was instead designed as a
testbed for the
Williams tube, the first
random-access digital storage device.
[90] Invented by
Freddie Williams and
Tom Kilburn[91][92] at the University of Manchester in 1946 and 1947, it was a
cathode ray tube that used an effect called
secondary emission to temporarily store electronic
binary data, and was used successfully in several early computers.
Although the computer was considered "small and primitive" by the
standards of its time, it was the first working machine to contain all
of the elements essential to a modern electronic computer.
[93]
As soon as the SSEM had demonstrated the feasibility of its design, a
project was initiated at the university to develop it into a more usable
computer, the
Manchester Mark 1. The Mark 1 in turn quickly became the prototype for the
Ferranti Mark 1, the world's first commercially available general-purpose computer.
[94]
The SSEM had a 32-
bit word length and a
memory
of 32 words. As it was designed to be the simplest possible
stored-program computer, the only arithmetic operations implemented in
hardware were
subtraction and
negation;
other arithmetic operations were implemented in software. The first of
three programs written for the machine found the highest
proper divisor of 2
18
(262,144), a calculation that was known would take a long time to
run—and so prove the computer's reliability—by testing every integer
from 2
18 - 1 downwards, as division was implemented by
repeated subtraction of the divisor. The program consisted of
17 instructions and ran for 52 minutes before reaching the correct
answer of 131,072, after the SSEM had performed 3.5 million operations
(for an effective CPU speed of 1.1
kIPS).
Manchester Mark 1
The Experimental machine led on to the development of the
Manchester Mark 1 at the University of Manchester.
[95] Work began in August 1948, and the first version was operational by April 1949; a program written to search for
Mersenne primes
ran error-free for nine hours on the night of 16/17 June 1949. The
machine's successful operation was widely reported in the British press,
which used the phrase "electronic brain" in describing it to their
readers.
The computer is especially historically significant because of its pioneering inclusion of
index registers, an innovation which made it easier for a program to read sequentially through an array of
words
in memory. Thirty-four patents resulted from the machine's development,
and many of the ideas behind its design were incorporated in subsequent
commercial products such as the
IBM 701 and
702 as well as the Ferranti Mark 1. The chief designers,
Frederic C. Williams and
Tom Kilburn,
concluded from their experiences with the Mark 1 that computers would
be used more in scientific roles than in pure mathematics. In 1951 they
started development work on Meg, the Mark 1's successor, which would
include a
floating point unit.
EDSAC
The other contender for being the first recognizably modern digital stored-program computer
[96] was the
EDSAC,
[97] designed and constructed by
Maurice Wilkes and his team at the
University of Cambridge Mathematical Laboratory in
England at the
University of Cambridge in 1949. The machine was inspired by
John von Neumann's seminal
First Draft of a Report on the EDVAC and was one of the first usefully operational electronic digital
stored-program computer.
[98]
EDSAC ran its first programs on 6 May 1949, when it calculated a table of squares
[99] and a list of
prime numbers.The EDSAC also served as the basis for the first commercially applied computer, the
LEO I, used by food manufacturing company
J. Lyons & Co. Ltd. EDSAC 1 and was finally shut down on 11 July 1958, having been superseded by EDSAC 2 which stayed in use until 1965.
[100]
The “brain” [computer] may one day come down to our level [of the
common people] and help with our income-tax and book-keeping
calculations. But this is speculation and there is no sign of it so far.
—
British newspaper The Star in a June 1949 news article about the EDSAC computer, long before the era of the personal computers.[101]
EDVAC
ENIAC inventors
John Mauchly and
J. Presper Eckert proposed the
EDVAC's construction in August 1944, and design work for the EDVAC commenced at the
University of Pennsylvania's
Moore School of Electrical Engineering, before the
ENIAC
was fully operational. The design implemented a number of important
architectural and logical improvements conceived during the ENIAC's
construction, and a high speed
serial access memory.
[102] However, Eckert and Mauchly left the project and its construction floundered.
It was finally delivered to the
U.S. Army's
Ballistics Research Laboratory at the
Aberdeen Proving Ground in August 1949, but due to a number of problems, the computer only began operation in 1951, and then only on a limited basis.
Commercial computers
The first commercial computer was the
Ferranti Mark 1, built by
Ferranti and delivered to the
University of Manchester in February 1951. It was based on the
Manchester Mark 1. The main improvements over the Manchester Mark 1 were in the size of the
primary storage (using
random access Williams tubes),
secondary storage (using a
magnetic drum),
a faster multiplier, and additional instructions. The basic cycle time
was 1.2 milliseconds, and a multiplication could be completed in about
2.16 milliseconds. The multiplier used almost a quarter of the machine's
4,050 vacuum tubes (valves).
[103] A second machine was purchased by the
University of Toronto, before the design was revised into the
Mark 1 Star. At least seven of these later machines were delivered between 1953 and 1957, one of them to
Shell labs in Amsterdam.
[104]
In October 1947, the directors of
J. Lyons & Company,
a British catering company famous for its teashops but with strong
interests in new office management techniques, decided to take an active
role in promoting the commercial development of computers. The
LEO I computer became operational in April 1951
[105] and ran the world's first regular routine office computer
job.
On 17 November 1951, the J. Lyons company began weekly operation of a
bakery valuations job on the LEO (Lyons Electronic Office). This was the
first business
application to go live on a stored program computer.
[106]
In June 1951, the
UNIVAC I (Universal Automatic Computer) was delivered to the
U.S. Census Bureau. Remington Rand eventually sold 46 machines at more than US$1 million each ($9.43 million as of 2018).
[107]
UNIVAC was the first "mass produced" computer. It used 5,200 vacuum
tubes and consumed 125 kW of power. Its primary storage was
serial-access mercury delay lines capable of storing 1,000 words of 11 decimal digits plus sign (72-bit words).
IBM introduced a smaller, more affordable computer in 1954 that proved very popular.
[108] The
IBM 650
weighed over 900 kg, the attached power supply weighed around 1350 kg
and both were held in separate cabinets of roughly 1.5 meters by 0.9
meters by 1.8 meters. It cost US$500,000
[109] ($4.56 million as of 2018) or could be leased for US$3,500 a month ($30 thousand as of 2018).
[107] Its drum memory was originally 2,000 ten-digit words, later expanded to
4,000 words. Memory limitations such as this were to dominate
programming for decades afterward. The program instructions were fetched
from the spinning drum as the code ran. Efficient execution using drum
memory was provided by a combination of hardware architecture: the
instruction format included the address of the next instruction; and
software: the Symbolic Optimal Assembly Program, SOAP,
[110]
assigned instructions to the optimal addresses (to the extent possible
by static analysis of the source program). Thus many instructions were,
when needed, located in the next row of the drum to be read and
additional wait time for drum rotation was not required.
Microprogramming
In 1951, British scientist
Maurice Wilkes developed the concept of
microprogramming from the realisation that the
central processing unit of a computer could be controlled by a miniature, highly specialised
computer program in high-speed
ROM. Microprogramming allows the base instruction set to be defined or extended by built-in programs (now called
firmware or
microcode).
[111] This concept greatly simplified CPU development. He first described this at the
University of Manchester Computer Inaugural Conference in 1951, then published in expanded form in
IEEE Spectrum in 1955.
[citation needed]
It was widely used in the
CPUs and
floating-point units of
mainframe and other computers; it was implemented for the first time in
EDSAC 2,
[112]
which also used multiple identical "bit slices" to simplify design.
Interchangeable, replaceable tube assemblies were used for each bit of
the processor.
[113]
Magnetic memory
Magnetic
drum memories were developed for the US Navy during WW II with the work continuing at
Engineering Research Associates (ERA) in 1946 and 1947. ERA, then a part of Univac included a drum memory in its
1103, announced in February 1953. The first mass-produced computer, the
IBM 650, also announced in 1953 had about 8.5 kilobytes of drum memory.
The first use of
magnetic core was demonstrated for the
Whirlwind computer in August 1953.
[114]
Commercialization followed quickly. Magnetic core was used in
peripherals of the IBM 702 delivered in July 1955, and later in the 702
itself. The
IBM 704 (1955) and the Ferranti Mercury (1957) used magnetic-core memory. It went on to dominate the field through the mid-1970s.
[115]
As late as 1980, PDP-11/45 machines using magnetic core main memory
and drums for swapping were still in use at many of the original UNIX
sites
Early digital computer characteristics
Transistor computers
The bipolar
transistor was invented in 1947. From 1955 onwards transistors replaced
vacuum tubes in computer designs,
[117] giving rise to the "second generation" of computers. Initially the only devices available were
germanium point-contact transistors.
[118]
Compared to vacuum tubes, transistors have many advantages: they are
smaller, and require less power than vacuum tubes, so give off less
heat. Silicon junction transistors were much more reliable than vacuum
tubes and had longer, indefinite, service life. Transistorized computers
could contain tens of thousands of binary logic circuits in a
relatively compact space. Transistors greatly reduced computers' size,
initial cost, and
operating cost. Typically, second-generation computers were composed of large numbers of
printed circuit boards such as the
IBM Standard Modular System[119] each carrying one to four
logic gates or
flip-flops.
At the
University of Manchester, a team under the leadership of
Tom Kilburn designed and built a machine using the newly developed
transistors instead of valves. Initially the only devices available were
germanium point-contact transistors, less reliable than the valves they replaced but which consumed far less power. Their first
transistorised computer and the first in the world, was
operational by 1953,
[121] and a second version was completed there in April 1955. The 1955 version used 200 transistors, 1,300
solid-state diodes,
and had a power consumption of 150 watts. However, the machine did make
use of valves to generate its 125 kHz clock waveforms and in the
circuitry to read and write on its magnetic
drum memory, so it was not the first completely transistorized computer.
That distinction goes to the
Harwell CADET of 1955,
[123] built by the electronics division of the
Atomic Energy Research Establishment at
Harwell. The design featured a 64-kilobyte magnetic
drum memory store with multiple moving heads that had been designed at the
National Physical Laboratory, UK. By 1953 this team had transistor circuits operating to read and write on a smaller magnetic drum from the
Royal Radar Establishment. The machine used a low clock speed of only 58 kHz to avoid having to use any valves to generate the clock waveforms.
[124][125]
CADET used 324
point-contact transistors provided by the UK company
Standard Telephones and Cables; 76
junction transistors were used for the first stage amplifiers for data read from the drum, since
point-contact transistors
were too noisy. From August 1956 CADET was offering a regular computing
service, during which it often executed continuous computing runs of 80
hours or more.
[126][127] Problems with the reliability of early batches of point contact and alloyed junction transistors meant that the machine's
mean time between failures was about 90 minutes, but this improved once the more reliable
bipolar junction transistors became available.
[128]
The Transistor Computer's design was adopted by the local engineering firm of
Metropolitan-Vickers in their
Metrovick 950, the first commercial transistor computer anywhere.
[129]
Six Metrovick 950s were built, the first completed in 1956. They were
successfully deployed within various departments of the company and were
in use for about five years. A second generation computer, the
IBM 1401, captured about one third of the world market. IBM installed more than ten thousand 1401s between 1960 and 1964.
Transistorized peripherals
Transistorized electronics improved not only the
CPU (Central Processing Unit), but also the
peripheral devices. The second generation
disk data storage units were able to store tens of millions of letters and digits. Next to the
fixed disk storage units, connected to the CPU via high-speed data transmission, were removable disk data storage units. A removable
disk pack
can be easily exchanged with another pack in a few seconds. Even if the
removable disks' capacity is smaller than fixed disks, their
interchangeability guarantees a nearly unlimited quantity of data close
at hand.
Magnetic tape provided archival capability for this data, at a lower cost than disk.
Many second-generation CPUs delegated peripheral device
communications to a secondary processor. For example, while the
communication processor controlled
card reading and punching, the main CPU executed calculations and binary
branch instructions. One
databus would bear data between the main CPU and core memory at the CPU's
fetch-execute cycle rate, and other databusses would typically serve the peripheral devices. On the
PDP-1,
the core memory's cycle time was 5 microseconds; consequently most
arithmetic instructions took 10 microseconds (100,000 operations per
second) because most operations took at least two memory cycles; one for
the instruction, one for the
operand data fetch.
During the second generation
remote terminal units (often in the form of
Teleprinters like a
Friden Flexowriter) saw greatly increased use.
[130]
Telephone connections provided sufficient speed for early remote
terminals and allowed hundreds of kilometers separation between
remote-terminals and the computing center. Eventually these stand-alone
computer networks would be generalized into an interconnected
network of networks—the Internet.
[131]
Supercomputers
The University of Manchester Atlas in January 1963
The early 1960s saw the advent of
supercomputing. The
Atlas Computer was a joint development between the
University of Manchester,
Ferranti, and
Plessey, and was first installed at Manchester University and officially commissioned in 1962 as one of the world's first
supercomputers – considered to be the most powerful computer in the world at that time.
[132] It was said that whenever Atlas went offline half of the United Kingdom's computer capacity was lost.
[133] It was a second-generation machine, using
discrete germanium transistors. Atlas also pioneered the
Atlas Supervisor, "considered by many to be the first recognisable modern
operating system".
[134]
In the US, a series of computers at
Control Data Corporation (CDC) were designed by
Seymour Cray to use innovative designs and parallelism to achieve superior computational peak performance.
[135] The
CDC 6600, released in 1964, is generally considered the first supercomputer.
[136][137] The CDC 6600 outperformed its predecessor, the
IBM 7030 Stretch, by about a factor of three. With performance of about 1
megaFLOPS, the CDC 6600 was the world's fastest computer from 1964 to 1969, when it relinquished that status to its successor, the
CDC 7600.
Integrated circuit
The next great advance in computing power came with the advent of the
integrated circuit. The idea of the integrated circuit was conceived by a radar scientist working for the
Royal Radar Establishment of the
Ministry of Defence,
Geoffrey W.A. Dummer.
Dummer presented the first public description of an integrated circuit
at the Symposium on Progress in Quality Electronic Components in
Washington, D.C. on 7 May 1952:
[138]
- With the advent of the transistor and the work on semi-conductors
generally, it now seems possible to envisage electronic equipment in a
solid block with no connecting wires.[139] The block may consist of layers of insulating, conducting, rectifying and amplifying materials, the electronic functions being connected directly by cutting out areas of the various layers”.
The first practical ICs were invented by
Jack Kilby at
Texas Instruments and
Robert Noyce at
Fairchild Semiconductor.
[140]
Kilby recorded his initial ideas concerning the integrated circuit in
July 1958, successfully demonstrating the first working integrated
example on 12 September 1958.
[141]
In his patent application of 6 February 1959, Kilby described his new
device as “a body of semiconductor material ... wherein all the
components of the electronic circuit are completely integrated.”
[142] The first customer for the invention was the
US Air Force.
[143]
Noyce also came up with his own idea of an integrated circuit half a year later than Kilby.
[144] His chip solved many practical problems that Kilby's had not. Produced at Fairchild Semiconductor, it was made of
silicon, whereas Kilby's chip was made of
germanium.
Post-1960 (integrated circuit based)
Intel 8742 eight-bit microcontroller IC
The explosion in the use of computers began with "third-generation"
computers, making use of Jack St. Clair Kilby's and Robert Noyce's
independent invention of the
integrated circuit (or microchip). This led to the invention of the
microprocessor.
While the subject of exactly which device was the first microprocessor
is contentious, partly due to lack of agreement on the exact definition
of the term "microprocessor", it is largely undisputed that the first
single-chip microprocessor was the Intel 4004,
[145] designed and realized by
Ted Hoff,
Federico Faggin, and
Stanley Mazor at
Intel.
[146]
While the earliest microprocessor ICs literally contained only the
processor, i.e. the central processing unit, of a computer, their
progressive development naturally led to chips containing most or all of
the internal electronic parts of a computer. The integrated circuit in
the image on the right, for example, an
Intel 8742, is an
8-bit microcontroller that includes a
CPU running at 12 MHz, 128 bytes of
RAM, 2048 bytes of
EPROM, and
I/O in the same chip.
During the 1960s there was considerable overlap between second and third generation technologies.
[147] IBM implemented its
IBM Solid Logic Technology modules in
hybrid circuits
for the IBM System/360 in 1964. As late as 1975, Sperry Univac
continued the manufacture of second-generation machines such as the
UNIVAC 494. The
Burroughs large systems such as the B5000 were
stack machines, which allowed for simpler programming. These
pushdown automatons
were also implemented in minicomputers and microprocessors later, which
influenced programming language design. Minicomputers served as
low-cost computer centers for industry, business and universities.
[148] It became possible to simulate analog circuits with the
simulation program with integrated circuit emphasis, or
SPICE (1971) on minicomputers, one of the programs for electronic design automation (
EDA). The microprocessor led to the development of the
microcomputer,
small, low-cost computers that could be owned by individuals and small
businesses. Microcomputers, the first of which appeared in the 1970s,
became ubiquitous in the 1980s and beyond.
While which specific system is considered the first microcomputer is a
matter of debate, as there were several unique hobbyist systems
developed based on the
Intel 4004 and its successor, the
Intel 8008, the first commercially available microcomputer kit was the
Intel 8080-based
Altair 8800, which was announced in the January 1975 cover article of
Popular Electronics. However, this was an extremely limited system in its initial stages, having only 256 bytes of
DRAM
in its initial package and no input-output except its toggle switches
and LED register display. Despite this, it was initially surprisingly
popular, with several hundred sales in the first year, and demand
rapidly outstripped supply. Several early third-party vendors such as
Cromemco and
Processor Technology soon began supplying additional
S-100 bus hardware for the Altair 8800.
In April 1975 at the
Hannover Fair,
Olivetti presented the
P6060,
the world's first complete, pre-assembled personal computer system. The
central processing unit consisted of two cards, code named PUCE1 and
PUCE2, and unlike most other personal computers was built with
TTL components rather than a microprocessor. It had one or two 8"
floppy disk drives, a 32-character
plasma display, 80-column graphical
thermal printer, 48 Kbytes of
RAM, and
BASIC
language. It weighed 40 kg (88 lb). As a complete system, this was a
significant step from the Altair, though it never achieved the same
success. It was in competition with a similar product by IBM that had an
external floppy disk drive.
From 1975 to 1977, most microcomputers, such as the
MOS Technology KIM-1, the
Altair 8800, and some versions of the
Apple I,
were sold as kits for do-it-yourselfers. Pre-assembled systems did not
gain much ground until 1977, with the introduction of the
Apple II, the
Tandy TRS-80, the first
SWTPC computers, and the
Commodore PET.
Computing has evolved with microcomputer architectures, with features
added from their larger brethren, now dominant in most market segments.
A NeXT Computer and its
object-oriented development tools and libraries were used by
Tim Berners-Lee and
Robert Cailliau at
CERN to develop the world's first
web server software,
CERN httpd, and also used to write the first
web browser,
WorldWideWeb.
These facts, along with the close association with Steve Jobs, secure
the 68030 NeXT a place in history as one of the most significant
computers of all time.
[citation needed]
Systems as complicated as computers require very high
reliability.
ENIAC remained on, in continuous operation from 1947 to 1955, for eight
years before being shut down. Although a vacuum tube might fail, it
would be replaced without bringing down the system. By the simple
strategy of never shutting down ENIAC, the failures were dramatically
reduced. The vacuum-tube SAGE air-defense computers became remarkably
reliable – installed in pairs, one off-line, tubes likely to fail did so
when the computer was intentionally run at reduced power to find them.
Hot-pluggable
hard disks, like the hot-pluggable vacuum tubes of yesteryear, continue
the tradition of repair during continuous operation. Semiconductor
memories routinely have no errors when they operate, although operating
systems like Unix have employed memory tests on start-up to detect
failing hardware. Today, the requirement of reliable performance is made
even more stringent when
server farms are the delivery platform.
[149]
Google has managed this by using fault-tolerant software to recover
from hardware failures, and is even working on the concept of replacing
entire server farms on-the-fly, during a service event.
[150][151]
In the 21st century,
multi-core CPUs became commercially available.
[152] Content-addressable memory (CAM)
[153] has become inexpensive enough to be used in networking, and is frequently used for on-chip
cache memory
in modern microprocessors, although no computer system has yet
implemented hardware CAMs for use in programming languages. Currently,
CAMs (or associative arrays) in software are
programming-language-specific. Semiconductor memory cell arrays are very
regular structures, and manufacturers prove their processes on them;
this allows price reductions on memory products. During the 1980s, CMOS
logic gates
developed into devices that could be made as fast as other circuit
types; computer power consumption could therefore be decreased
dramatically. Unlike the continuous current draw of a gate based on
other logic types, a
CMOS gate only draws significant current during the 'transition' between logic states, except for leakage.
This has allowed computing to become a
commodity which is now ubiquitous, embedded in
many forms, from greeting cards and
telephones to
satellites. The
thermal design power
which is dissipated during operation has become as essential as
computing speed of operation. In 2006 servers consumed 1.5% of the total
energy budget of the U.S.
[154] The energy consumption of computer data centers was expected to double to 3% of world consumption by 2011. The
SoC (system on a chip) has compressed even more of the
integrated circuitry into a single chip; SoCs are enabling phones and PCs to converge into single hand-held wireless
mobile devices.
[155]
MIT Technology Review reported 10 November 2017 that IBM has created a 50-
qubit computer; currently its quantum state lasts 50 microseconds.
[156] See: Quantum supremacy[157]
Computing hardware and its software have even become a metaphor for the operation of the universe.
[158]
Epilogue
An
indication of the rapidity of development of this field can be inferred
from the history of the seminal 1947 article by Burks, Goldstine and von
Neumann.
[159] By the time that anyone had time to write anything down, it was obsolete. After 1945, others read John von Neumann's
First Draft of a Report on the EDVAC, and immediately started implementing their own systems. To this day, the rapid pace of development has continued, worldwide.
[160][161][162]
A 1966 article in
Time
predicted that: "By 2000, the machines will be producing so much that
everyone in the U.S. will, in effect, be independently wealthy. How to
use leisure time will be a major problem."
[163]
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