The history of computing hardware covers the history of
computer hardware, its architecture, and its impact on software. Originally calculations were computed by humans, who were called computers,
[1] as a job title. See the
history of computing article for methods intended for pen and paper, with or without the aid of tables. For a detailed timeline of events, see the
computing timeline article.
The
von Neumann architecture unifies our current computing hardware implementations.
[2] The major elements of computing hardware are input,
[3] output,
[4] control
[5] and datapath (which together make a
processor),
[6] and memory.
[7] They have undergone successive refinement or improvement over the history of computing hardware. Beginning with mechanical mechanisms, the hardware then started using analogs for a computation, including water and even air as the analog quantities:
analog computers have used
lengths,
pressures,
voltages, and
currents to represent the results of calculations.
[8] Eventually the voltages or currents were
standardized and
digital computers were developed over a period of evolution dating back centuries. Digital computing elements have ranged from mechanical gears, to electromechanical relays, to vacuum tubes, to transistors, and to integrated circuits, all of which are currently implementing the von Neumann architecture.
[9]Since digital computers rely on digital storage, and tend to be limited by the size and speed of memory, the history of
computer data storage is tied to the development of computers. The degree of improvement in computing hardware has triggered world-wide use of the technology. Even as performance has improved, the price has declined,
[10] until computers have become commodities, accessible to ever-increasing sectors
[11] of the world's population. Computing hardware thus became a platform for uses other than computation, such as automation, communication, control, entertainment, and education. Each field in turn has imposed its own requirements on the hardware, which has evolved in response to those requirements.
[12][
edit] Earliest calculators
Main article:
calculatorSuanpan (the number represented on this abacus is 6,302,715,408)
Devices have been used to aid computation for thousands of years, using
one-to-one correspondence with our fingers.
[13] The earliest counting device was probably a form of
tally stick. Later record keeping aids throughout the
Fertile Crescent included clay shapes, which represented counts of items, probably livestock or grains, sealed in containers.
[14] The
abacus was used for arithmetic tasks. The
Roman abacus was used in
Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval
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.
A number of
analog computers were constructed in ancient and medieval times to perform astronomical calculations. These include the
Antikythera mechanism and the
astrolabe from
ancient Greece (c. 150-100 BC), and are generally regarded as the first mechanical computers.
[15] Other early versions of mechanical devices used to perform some type of calculations include the
planisphere; some of the inventions of
AbÅ« RayhÄn al-BÄ«rÅ«nÄ« (c. AD 1000); the
equatorium of
AbÅ« IshÄq IbrÄhÄ«m al-ZarqÄlÄ« (c. AD 1015); the astronomical analog computers of other medieval Muslim astronomers and engineers, and the astronomical
clock tower of
Su Song during the
Song Dynasty.
Scottish mathematician and physicist
John Napier noted multiplication and division of numbers could be performed by addition and subtraction, respectively, of logarithms of those numbers. While producing the first logarithmic tables Napier needed to perform many multiplications, and it was at this point that he designed
Napier's bones, an abacus-like device used for multiplication and division.
[16] Since
real numbers can be represented as distances or intervals on a line, the
slide rule was invented in the 1620s to allow multiplication and division operations to be carried out significantly faster than was previously possible.
[17] Slide rules were used by generations of engineers and other mathematically inclined professional workers, until the invention of the
pocket calculator. The engineers in the
Apollo program to send a man to the moon made many of their calculations on slide rules, which were accurate to three or four significant figures.
[18]A mechanical calculator from 1914. Note the lever used to rotate the gears.
German polymath
Wilhelm Schickard built the first digital mechanical calculator in 1623, and thus became the father of the computing era.
[19] Since his calculator used techniques such as cogs and gears first developed for clocks, it was also called a 'calculating clock'. It was put to practical use by his friend
Johannes Kepler, who revolutionized astronomy when he condensed decades of astronomical observations into algebraic
expressions. An original calculator by
Pascal (1640) is preserved in the
Zwinger Museum. Machines by
Blaise Pascal (the
Pascaline, 1642) and
Gottfried Wilhelm von Leibniz (1671) followed. 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]Around 1820,
Charles Xavier Thomas created the first successful, mass-produced mechanical calculator, the Thomas Arithmometer, that could add, subtract, multiply, and divide. It was mainly based on Leibniz' work. Mechanical calculators, like the base-ten
addiator, the
comptometer, the
Monroe, the
Curta and the Addo-X remained in use until the 1970s. 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 1800s and even
ENIAC of 1945) were based on the decimal system;
[22] ENIAC's ring counters emulated the operation of the digit wheels of a mechanical adding machine.
[
edit] 1801: punched card technology
Main article:
analytical engineSee also:
logic pianoAs early as 1725
Basile Bouchon used a perforated paper loop in a loom to establish the pattern to be reproduced on cloth, and in 1726 his co-worker Jean-Baptiste Falcon improved on his design by using perforated paper cards attached to one another for efficiency in adapting and changing the program. The Bouchon-Falcon loom was semi-automatic and required manual feed of the program. In 1801,
Joseph-Marie Jacquard developed a
loom in which the pattern being woven was controlled by
punched cards. The series of cards could be changed without changing the mechanical design of the loom. This was a landmark point in programmability.
Punched card system of a music machine. Also referred to as
Book music, a one-stop European medium for organs
In 1833,
Charles Babbage moved on from developing his
difference engine to developing a more complete design, the analytical engine, which would draw directly on Jacquard's punched cards for its programming.
[23] In 1835, Babbage described his
analytical engine. It was the plan of a general-purpose programmable computer, employing punch cards for input and a steam engine for power. One crucial invention was to use gears for the function served by the beads of an abacus. In a real sense, computers all contain automatic abacuses (the datapath,
arithmetic logic unit, or
floating-point unit). His initial idea was to use punch-cards to control a machine that could calculate and print logarithmic tables with huge precision (a specific purpose machine). Babbage's idea soon developed into a general-purpose programmable computer, his analytical engine. While his design was sound and the plans were probably correct, or at least
debuggable, the project was slowed by various problems. Babbage was a difficult man to work with and argued with anyone who didn't respect his ideas. All the parts for his machine had to be made by hand. Small errors in each item can sometimes sum up to large discrepancies in a machine with thousands of parts, which required these parts to be much better than the usual tolerances needed at the time. The project dissolved in disputes with the artisan who built parts and was ended with the depletion of government funding.
Ada Lovelace,
Lord Byron's daughter, translated and added notes to the "Sketch of the Analytical Engine" by
Federico Luigi, Conte Menabrea.
[24]A reconstruction of the
Difference Engine II, an earlier, more limited design, has been operational since 1991 at the
London Science Museum. With a few trivial changes, it works as Babbage designed it and shows that Babbage was right in theory. The museum used computer-operated machine tools to construct the necessary parts, following tolerances which a machinist of the period would have been able to achieve. The failure of Babbage to complete the engine can be chiefly attributed to difficulties not only related to politics and financing, but also to his desire to develop an increasingly sophisticated computer.
[25] Following in the footsteps of 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.
IBM 407
tabulating machine, (1961).
Punched card with the extended alphabet.
In 1890, the
United States Census Bureau used
punched cards, sorting machines, and
tabulating machines designed by
Herman Hollerith to handle the flood of data from the decennial
census mandated by the
Constitution.
[26] Hollerith's company eventually became the core of
IBM. IBM developed punch card technology into a powerful tool for business data-processing and produced an extensive line of specialized
unit record equipment. By 1950, the IBM card had become ubiquitous in industry and government. The warning printed on most cards intended for circulation as documents (checks, for example), "Do not fold,
spindle or mutilate," became a motto for the post-
World War II era.
[27]Leslie Comrie's articles on punched card methods and
W.J. Eckert's publication of Punched Card Methods in Scientific Computation in 1940, described techniques which were sufficiently advanced to solve differential equations
[28] or perform multiplication and division using floating point representations, all on punched cards and
unit record machines. In the image of the tabulator (see left), note the
patch panel, which is visible on the right side of the tabulator. A row of
toggle switches is above the patch panel. The
Thomas J. Watson Astronomical Computing Bureau,
Columbia University performed astronomical calculations representing the state of the art in
computing.
[29]Computer programming in the punch card era revolved around the computer center. The computer users, for example, science and engineering students at universities, would submit their programming assignments to their local computer center. in the form of a stack of cards, one card per program line. They then had to wait for the program to be queued for processing, compiled, and executed. In due course a printout of any results, marked with the submitter's identification, would be placed in an output tray outside the computer center. In many cases these results would comprise solely a printout of error messages regarding program syntax etc., necessitating another
edit-compile-run cycle.
[30] Punched cards are still used and manufactured to this day, and their distinctive dimensions
[31] (and 80-column capacity) can still be recognized in forms, records, and programs around the world.
[
edit] 1930s–1960s: desktop calculators
Main article:
Post–Turing machineFurther information:
category:computational modelsThe
Curta calculator can also do multiplication and division
By the 1900s, 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 people who used these calculators to perform mathematical calculations. By the 1920s
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.
[32]Companies like
Friden,
Marchant Calculator and
Monroe made desktop mechanical
calculators from the 1930s that could add, subtract, multiply and divide. During the
Manhattan project, future Nobel laureate
Richard Feynman was the supervisor of the roomful of human computers, many of them women mathematicians, who understood the
differential equations which were being solved for the war effort. Even the renowned
Stanisław Ulam was pressed into service to translate the mathematics into computable approximations for the
hydrogen bomb, after the war.
In 1948, the
Curta was introduced. This was a small, portable, mechanical calculator that was about the size of a
pepper grinder. Over time, during the 1950s and 1960s a variety of different brands of mechanical calculator appeared on the market. The first all-electronic desktop calculator was the British
ANITA Mk.VII, which used a
Nixie tube display and 177 subminiature
thyratron tubes. In June 1963, Friden introduced the four-function EC-130. It had an all-transistor design, 13-digit capacity on a 5-inch (130 mm)
CRT, and introduced reverse Polish notation (
RPN) to the calculator market at a price of $2200. The model EC-132 added square root and reciprocal functions. In 1965,
Wang Laboratories produced the LOCI-2, a 10-digit transistorized desktop calculator that used a Nixie tube display and could compute
logarithms.
[
edit] Advanced analog computers
Main article:
analog computerCambridge differential analyzer, 1938
Before
World War II, mechanical and electrical
analog computers were considered the "state of the art", and many thought they were the future of computing. Analog computers take advantage of the strong similarities between the mathematics of small-scale properties — the position and motion of wheels or the voltage and current of electronic components — and the mathematics of other physical phenomena,
[33] e.g. ballistic trajectories, inertia, resonance, energy transfer, momentum, etc. They model physical phenomena with electrical
voltages and
currents[34][35] as the analog quantities.
Centrally, these analog systems work by creating electrical
analogs of other systems, allowing users to predict behavior of the systems of interest by observing the electrical analogs.
[36] The most useful of the analogies was the way the small-scale behavior could be represented with integral and differential equations, and could be thus used to solve those equations. An ingenious example of such a machine, using
water as the analog quantity, was the
water integrator built in 1928; an electrical example is the
Mallock machine built in 1941. A
planimeter is a device which does integrals, using
distance as the analog quantity. Until the 1980s,
HVAC systems used
air both as the analog quantity and the controlling element. Unlike modern digital computers, analog computers are not very flexible, and need to be reconfigured (i.e., reprogrammed) manually to switch them from working on one problem to another. Analog computers had an advantage over early digital computers in that they could be used to solve complex problems using behavioral analogues while the earliest attempts at digital computers were quite limited.
A
Smith Chart is a well-known
nomogram.
Since computers were rare in this era, the solutions were often hard-coded into paper forms such as
graphs and
nomograms,
[37] which could then produce analog solutions to these problems, such as the distribution of pressures and temperatures in a heating system. Some of the most widely deployed analog computers included devices for aiming weapons, such as the
Norden bombsight[38] and the
fire-control systems,
[39] such as
Arthur Pollen's Argo system for naval vessels. Some stayed in use for decades after WWII; the
Mark I Fire Control Computer was deployed by the
United States Navy on a variety of ships from
destroyers to
battleships. Other analog computers included the
Heathkit EC-1, and the hydraulic
MONIAC Computer which modeled econometric flows.
[40]The art of analog computing reached its zenith with the
differential analyzer,
[41] invented in 1876 by
James Thomson and built by H. W. Nieman and
Vannevar Bush at
MIT starting in 1927. Fewer than a dozen of these devices were ever built; the most powerful was constructed at the
University of Pennsylvania's Moore School of Electrical Engineering, where the
ENIAC was built. Digital electronic computers like the ENIAC 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. But like all digital devices, the decimal
precision of a digital device is a limitation,
[42] as compared to an analog device, in which the
accuracy is a limitation.
[43] As
electronics progressed during the twentieth century, its problems of operation at low voltages while maintaining high
signal-to-noise ratios[44] were steadily addressed, as shown below, for a digital circuit is a specialized form of analog circuit, intended to operate at standardized settings (continuing in the same vein,
logic gates can be realized as forms of digital circuits). But as digital computers have become faster and use larger memory (e.g.,
RAM or internal storage), they have almost entirely displaced analog computers.
Computer programming, or
coding, has arisen as another human profession.
Punched tape programs would be much longer than the short fragment shown.
The era of modern computing began with a flurry of development before and during
World War II, as
electronic circuit elements
[45] replaced mechanical equivalents and digital calculations replaced analog calculations. Machines such as 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.
In this era, a number of different machines were produced with steadily advancing capabilities. At the beginning of this period, nothing remotely resembling a modern computer existed, except in the long-lost plans of Charles Babbage and the mathematical musings of
Alan Turing and others. At the end of the era, devices like the EDSAC had been built, and are universally agreed to be digital computers. Defining a single point in the series as the "first computer" misses many subtleties (see the table "Defining characteristics of some early digital computers of the 1940s" below).
Alan Turing's 1936 paper
[46] proved enormously influential in computing and
computer science in two ways. Its main purpose was to prove that there were problems (namely the
halting problem) that could not be solved by any sequential process. In doing so, Turing provided a definition of a universal computer which executes a program stored on tape. This construct came to be called a
Turing machine; it replaces
Kurt Gödel's more cumbersome universal language based on arithmetics. 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.
Design of the
von Neumann architecture (1947)
For a computing machine to be a practical general-purpose computer, there must be some convenient read-write mechanism, punched tape, for example. With a knowledge of Alan Turing's theoretical 'universal computing machine'
John von Neumann defined an architecture which uses the same
memory both to store programs and data: virtually all contemporary computers use this architecture (or some variant). While it is theoretically possible to implement a full computer entirely mechanically (as Babbage's design showed), electronics made possible the speed and later the miniaturization that characterize modern computers.
There were three parallel streams of computer development in the World War II era; the first stream largely ignored, and the second stream deliberately kept secret. The first was the
German work of
Konrad Zuse. The second was the secret development of the Colossus computers in the
UK. Neither of these had much influence on the various computing projects in the
United States. The third stream of computer development, Eckert and Mauchly's ENIAC and EDVAC, was widely publicized.
[47][48][
edit] Program-controlled computers
Main articles:
Konrad Zuse,
Z1,
Z2,
Z3, and
Z4A reproduction of Zuse's Z1 computer.
Working in isolation in
Germany,
Konrad Zuse started construction in 1936 of his first Z-series calculators featuring memory and (initially limited) programmability. Zuse's purely mechanical, but already binary
Z1, finished in 1938, never worked reliably due to problems with the precision of parts.
Zuse's subsequent machine, the
Z3[49], was finished in 1941. It was based on telephone relays and did work satisfactorily. The Z3 thus became the first functional program-controlled, all-purpose, digital computer. In many ways it was quite similar to modern machines, 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.
Programs were fed into
Z3 on punched films. Conditional jumps were missing, but since the 1990s it has been proved theoretically that Z3 was still a
universal computer (ignoring its physical storage size limitations). In two 1936
patent applications,
Konrad 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 and was first implemented in the later British EDSAC design (1949). Zuse also claimed to have designed the first higher-level
programming language, (
Plankalkül), in 1945 (which was published in 1948) although it was implemented for the first time in 2000 by a team around
Raúl Rojas at the
Free University of Berlin – five years after Zuse died.
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.
[
edit] Colossus
Main article:
Colossus computerColossus was used to break German ciphers during
World War II.
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 attacked with the help of electro-mechanical machines called
bombes. The bombe, designed by
Alan Turing and
Gordon Welchman, after the Polish cryptographic
bomba by
Marian Rejewski (1938) came into use in 1941.
[50] 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, Professor
Max Newman and his colleagues helped specify the
Colossus[51]. The Mk I Colossus was built between March and December 1943 by
Tommy Flowers and his colleagues at the
Post Office Research Station at
Dollis Hill in London and then shipped to
Bletchley Park in January 1944.
Colossus was the first totally electronic computing device. The Colossus 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). 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. Due to this secrecy the Colossi were not included in many histories of computing. A reconstructed copy of one of the Colossus machines is now on display at Bletchley Park.
