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[[File:Information processing system (english).svg|thumb|400px|[[Computing hardware]] is a platform for [[information processing]].]]
{{History of computing}}

[[Computing hardware]] evolved from machines that needed separate manual action to perform each arithmetic operation, to punched card machines, and then to [[stored-program computer]]s. The history of stored-program computers relates first to computer architecture, that is, the organization of the units to perform input and output, to store data and to operate as an integrated mechanism.

Before the development of the general-purpose computer, most calculations were done by humans. Mechanical tools to help humans with digital calculations were then called "calculating machines", by proprietary names, or even as they are now, [[calculator]]s. It was those humans who used the machines who were then called computers. Aside from written numerals, 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. A sophisticated (and comparatively recent) example is the [[slide rule]] in which numbers are represented as lengths on a logarithmic scale and computation is performed by setting a cursor and aligning sliding scales, thus adding those lengths. Numbers could be represented in a continuous "analog" form, for instance a voltage or some other physical property was set to be proportional to the number. Analog computers, like those designed and built by [[Vannevar Bush]] before World War II were of this type. Numbers could be represented in the form of digits, automatically manipulated by a mechanical mechanism. Although this last approach required more complex mechanisms in many cases, it made for greater precision of results.

The invention of electronic amplifiers made calculating machines much faster than their mechanical or electromechanical predecessors. [[Vacuum tube|Vacuum tube (thermionic valve)]] amplifiers gave way to solid state [[transistor]]s, and then rapidly to [[integrated circuit]]s which continue to improve, placing millions of electrical switches (typically transistors) on a single elaborately manufactured piece of semi-conductor the size of a fingernail. By defeating the [[tyranny of numbers]], integrated circuits made high-speed and low-cost digital computers a widespread commodity. There is an ongoing effort to make computer hardware faster, cheaper, and capable of storing more data.

Computing hardware has become a platform for uses other than mere computation, such as process automation, electronic communications, equipment control, entertainment, education, etc. Each field in turn has imposed its own requirements on the hardware, which has evolved in response to those requirements, such as the role of the [[touch screen]] to create a more intuitive and [[natural user interface]].

As all 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.

==Earliest true hardware==
Devices have been used to aid computation for thousands of years, mostly using [[one-to-one correspondence]] with our [[finger counting|finger]]s. 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 containers.<ref>According to {{harvnb|Schmandt-Besserat|1981}}, these clay containers contained tokens, the total of which were the count of objects being transferred. The containers thus served as something of a [[bill of lading]] or an accounts book. In order to avoid breaking open the containers, marks were placed on the outside of the containers, for the count. Eventually ([http://www.laits.utexas.edu/ghazal/Chap1/dsb/chapter1.html Schmandt-Besserat estimates it took 4000 years]) the marks on the outside of the containers were all that were needed to convey the count, and the clay containers evolved into clay tablets with marks for the count.
</ref><ref>{{Citation |first=Eleanor |last=Robson |author-link=Eleanor Robson |year=2008 |title=Mathematics in Ancient Iraq |publisher= |isbn=978-0-691-09182-2}}. p.5: these calculi were in use in Iraq for primitive accounting systems as early as 3200–3000 BCE, with commodity-specific counting representation systems. Balanced accounting was in use by 3000–2350 BCE, and a [[sexagesimal number system]] was in use 2350–2000 BCE.</ref> 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 2400 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 computer]]s 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), which are generally regarded as the earliest known mechanical analog computers.<ref>{{harvnb|Lazos|1994}}</ref> [[Hero of Alexandria]] (c. 10–70 AD) made many complex mechanical devices including automata and a programmable cart.<ref>{{citation |title=A programmable robot from 60 AD |author=Noel Sharkey|publisher=New Scientist|url=http://www.newscientist.com/blog/technology/2007/07/programmable-robot-from-60ad.html|date= July 4, 2007 |volume=2611}}</ref> Other early versions of mechanical devices used to perform one or another type of calculations include the [[planisphere]] and other mechanical computing devices invented by [[Abū Rayhān al-Bīrūnī]] (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 [[Islamic astronomy|Muslim astronomers]] and engineers; and the [[astronomical clock]] [[Clock tower|tower]] of [[Su Song]] (c. AD 1090) during the [[Song Dynasty]].

[[File:Abacus 6.png|thumb|left|[[Suanpan]] (the number represented on this abacus is 6,302,715,408)]]
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.<ref>A Spanish implementation of [[Napier's bones]] (1617), is documented in {{harvnb|Montaner|Simon|1887|pp=19–20}}.</ref> Since [[real number]]s 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.<ref>{{harvnb|Kells|Kern|Bland|1943|p=92}}</ref> Slide rules were used by generations of engineers and other mathematically involved professional workers, until the invention of the [[pocket calculator]].<ref>{{harvnb|Kells|Kern|Bland|1943|p=82}}</ref>

[[File:Patented Yazu Arithmometer.jpg|thumb|[[Ryōichi Yazu|Yazu]] Arithmometer. Patented in Japan in 1903. Note the lever for turning the gears of the calculator.]]
[[Wilhelm Schickard]], a German [[polymath]], designed a calculating clock in 1623. It made use of a single-tooth gear that was not an adequate solution for a general carry mechanism.<ref>"...the single-tooth gear, like that used by Schickard, would not do for a general carry mechanism. The single-tooth gear works fine if the carry is only going to be propagated a few places but, if the carry has to be propagated several places along the accumulator, the force needed to operate the machine would be of such magnitude that it would do damage to the delicate gear works." {{harvnb|Williams|1997|p=128}}</ref> A fire destroyed the machine during its construction in 1624 and Schickard abandoned the project. Two sketches of it were discovered in 1957, too late to have any impact on the development of mechanical calculators.<ref>{{harvnb|Taton|1969|p=81}}</ref>

In 1642, while still a teenager, [[Blaise Pascal]] started some pioneering work on calculating machines and after three years of effort and 50 prototypes<ref>[http://fr.wikisource.org/wiki/La_Machine_d%E2%80%99arithm%C3%A9tique (fr) La Machine d’arithmétique, Blaise Pascal], Wikisource</ref> he invented the [[mechanical calculator]].<ref>{{harvnb|Marguin|1994|p=48}}</ref><ref>[[#DOCA|Maurice d'Ocagne (1893)]], p. 245 [http://cnum.cnam.fr/CGI/fpage.cgi?8KU54-2.5/248/150/369/363/369 Copy of this book found on the CNAM site]</ref> He built twenty of these machines (called [[Pascal's Calculator]] or Pascaline) in the following ten years.<ref>{{harvnb|Mourlevat|1988|p=12}}</ref> Nine Pascalines have survived, most of which are on display in European museums.<ref>All nine machines are described in {{harvnb|Vidal|Vogt|2011}}.</ref>

[[Gottfried Leibniz|Gottfried Wilhelm von Leibniz]] invented the [[Stepped Reckoner]] and his [[Leibniz wheel|famous cylinders]] around 1672 while adding direct multiplication and division to the Pascaline. 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."<ref>As quoted in {{harvnb|Smith|1929|pp=180–181}}</ref>

Around 1820, [[Charles Xavier Thomas]] created the first successful, mass-produced mechanical calculator, the Thomas [[Arithmometer]], that could add, subtract, multiply, and divide.<ref>[http://www.cis.cornell.edu/boom/2005/ProjectArchive/arithometer/ Discovering the Arithmometer], [[Cornell University]]</ref> It was mainly based on Leibniz' work. Mechanical calculators, like the base-ten [[addiator]], the [[comptometer]], the [[Monroe calculator|Monroe]], the [[Curta]] and the [[Addo-X]] remained in use until the 1970s.
Leibniz also described the [[binary numeral system]],<ref>{{harvnb|Leibniz|1703}}</ref> 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;<ref>[[Binary-coded decimal]] (BCD) is a numeric representation, or [[character encoding]], which is still widely used.</ref> ENIAC's ring counters emulated the operation of the digit wheels of a mechanical adding machine.

In Japan, [[Ryōichi Yazu]] patented a mechanical calculator called the Yazu Arithmometer in 1903. It consisted of a single cylinder and 22 gears, and employed the mixed base-2 and base-5 number system familiar to users to the [[soroban]] (Japanese abacus). Carry and end of calculation were determined automatically.<ref>{{citation |title=Biquinary mechanical calculating machine,"Jido-Soroban" (automatic abacus), built by Ryoichi Yazu |publisher=[[National Science Museum of Japan]] |page=8| first=Akihiko |last=Yamada |url=http://sts.kahaku.go.jp/temp/5.pdf |format=|archiveurl=http://web.archive.org/web/20090327145540/http://sts.kahaku.go.jp/temp/5.pdf|archivedate=2009-03-27|deadurl=yes}}</ref>
More than 200 units were sold, mainly to government agencies such as the Ministry of War and agricultural experiment stations.<ref>{{cite web|url=http://www.xnumber.com/xnumber/japanese_calculators.htm |title=The History of Japanese Mechanical Calculating Machines |publisher=Xnumber.com |date=2000-04-10 |accessdate=2010-01-30}}</ref><ref>[http://www.jsme.or.jp/kikaiisan/data/no_030.html Mechanical Calculator, "JIDOSOROBAN"], The Japan Society of Mechanical Engineers (in Japanese)</ref>

==1801: punched card technology==
:''Main article: [[Analytical Engine]]. See also: [[Logic piano]]''
[[File:Lochkarte Tanzorgel.jpg|thumb|Punched card system of a music machine, also referred to as [[Book music]]]]

In 1801, [[Joseph Marie Jacquard|Joseph-Marie Jacquard]] developed [[Jacquard loom|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 achievement in programmability. His machine was an improvement over similar weaving looms. Punch 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 NC machine-tools.

In 1833, [[Charles Babbage]] moved on from developing his [[difference engine]] (for navigational calculations) to a general purpose design, the Analytical Engine, which drew directly on Jacquard's punched cards for its program storage.<ref>{{harvnb|Jones}}</ref> In 1837, Babbage described his [[analytical engine]]. It was a general-purpose programmable computer, employing punch cards for input and a steam engine for power, using the positions of gears and shafts to represent numbers.<ref>[http://www.nytimes.com/2011/11/08/science/computer-experts-building-1830s-babbage-analytical-engine.html?hpw John Markoff (7 November 2011) "It started digital wheels turning" ] ''[[New York Times]]'' description of Babbage's Analytical Engine</ref> His initial idea was to use punch-cards to control a machine that could calculate and print logarithmic tables with huge precision (a special purpose machine). Babbage's idea soon developed into a general-purpose programmable computer. While his design was sound and the plans were probably correct, or at least [[debug]]gable, the project was slowed by various problems including disputes with the chief machinist building parts for it. Babbage was a difficult man to work with and argued with everyone. All the parts for his machine had to be made by hand. Small errors in each item might sometimes sum to cause 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, this was a major problem. The project dissolved in disputes with the artisan who built parts and ended with the decision of the British Government to cease funding. [[Ada Lovelace]], [[George Gordon Byron, 6th Baron Byron|Lord Byron]]'s daughter, translated and [[Ada Byron's notes on the analytical engine|added notes]] to the "''Sketch of the Analytical Engine''" by [[Federico Luigi, Conte Menabrea]]. This appears to be the first published description of programming.<ref>{{harvnb|Menabrea|Lovelace|1843}}</ref>

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 exactly as Babbage designed it and shows that Babbage's design ideas were correct, merely too far ahead of his time. The museum used computer-controlled machine tools to construct the necessary parts, using tolerances a good machinist of the period would have been able to achieve. 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.

A machine based on Babbage's difference engine was built in 1843 by [[Per Georg Scheutz]] and his son Edward. An improved Scheutzian calculation engine was sold to the British government and a later model was sold to the American government and these were used successfully in the production of logarithmic tables.<ref>{{cite book|title=Glory and failure: the difference engines of Johann Müller, Charles Babbage and Georg and Edward Scheutz |year=1990 |isbn=0-262-12146-8 |name1=Michael |name2=Lindgren |pages=116–123}}</ref><ref>For an explanation of the technique of interpolation used in calculating the logarithm tables, see, for example {{harvnb|Feynman|Leighton|Sands|1965|pp=22-3 to 22-10}}.</ref>

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.

==1880s: punched card data storage==
[[File:Early SSA accounting operations.jpg|thumb|left|IBM punched card Accounting Machines at the U.S. Social Security Administration in 1936.]]
In the late 1880s, the American [[Herman Hollerith]] invented data storage on a medium that could then be read by a machine. Prior uses of machine readable media had been for control ([[automaton]]s such as [[piano roll]]s or [[Jacquard loom|looms]]), not data. "After some initial trials with paper tape, he settled on [[punched card]]s..."<ref>{{cite web|url=http://www.columbia.edu/acis/history/hollerith.html |title=Columbia University Computing History — Herman Hollerith |publisher=Columbia.edu |date= |accessdate=2010-01-30}}</ref> Hollerith came to use punched cards after observing how [[railroad conductor]]s encoded personal characteristics of each passenger with punches on their tickets. To process these punched cards he invented the [[tabulating machine|tabulator]], and the [[key punch]] machine. These three inventions were the foundation of the modern information processing industry. His machines used mechanical [[relay]]s (and [[solenoid]]s) to increment [[mechanical counter]]s. Hollerith's method was used in the [[1890 United States Census]] and the completed results were "... finished months ahead of schedule and far under budget".<ref>[http://www.census.gov/history/www/innovations/technology/tabulation_and_processing.html U.S. Census Bureau: Tabulation and Processing]</ref> Indeed, the census was processed years faster than the prior census had been. Hollerith's company eventually became the core of [[International Business Machines|IBM]]. IBM developed punch card technology into a powerful tool for business data-processing and produced an extensive line of [[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 (stationery)|spindle]] or mutilate," became a catch phrase for the post-World War II era.<ref>{{harvnb|Lubar|1991}}</ref>
[[File:Ibm407 tabulator 1961 01.redstone.jpg|thumb|left|Punch card Tabulator]]
[[File:Blue-punch-card-front.png|thumb|upright|[[Punched card]] with the extended alphabet]]
[[Leslie Comrie]]'s articles on punched card methods and [[W.J. Eckert]]'s publication of ''Punched Card Methods in Scientific Computation'' in 1940, described punch card techniques sufficiently advanced to solve some differential equations<ref>{{harvnb|Eckert|1935}}</ref> or perform multiplication and division using floating point representations, all on punched cards and [[unit record equipment|unit record machines]]. Those same machines had been used during World War II for cryptographic statistical processing. In the image of the tabulator (see left), note the [[plugboard|control panel]], which is visible on the right side of the tabulator. A row of [[toggle switch]]es is above the control panel. The [http://www.columbia.edu/acis/history/ Thomas J. Watson Astronomical Computing Bureau], [[Columbia University]] performed astronomical calculations representing the state of the art in [[computing]].<ref>{{harvnb|Eckert|1940|pp=101=114}}. Chapter XII is "The Computation of Planetary Perturbations".</ref>

[[Computer programming in the punch card era]] was centered in the "computer center". 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 deck of punched cards, one card per program line. They then had to wait for the program to be read in, 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, typically in the computer center lobby. In many cases these results would be only a series of error messages, requiring yet another [[Code and fix|edit-punch-compile-run cycle]].<ref>{{harvnb|Fisk|2005}}</ref> Punched cards are still used and manufactured to this day, and their distinctive dimensions (and 80-column capacity) can still be recognized in forms, records, and programs around the world. They are the size of American paper currency in Hollerith's time, a choice he made because there was already equipment available to handle bills.

==Desktop calculators==
{{Main|Calculator}}
[[File:Curta01.JPG|thumb|The [[Curta]] calculator can 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 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 computer]]s 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]].<ref>{{harvnb|Hunt|1998|pp=xiii–xxxvi}}</ref>

Companies like [[Friden, Inc.|Friden]], [[Marchant Calculator]] and [[Monroe Calculator Company|Monroe]] made desktop mechanical [http://www.oldcalculatormuseum.com/fridenstw.html calculators] from the 1930s that could add, subtract, multiply and divide. During the [[Manhattan project]], future Nobel laureate [[Richard Feynman]] was the supervisor of human computers who understood the use of [[differential equations]] which were being solved for the war effort.

In 1948, the [[Curta calculator|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 calculators appeared on the market. The first all-electronic desktop calculator was the British [[Sumlock ANITA calculator|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 {{convert|5|in|mm|sing=on}} [[Cathode ray tube|CRT]], and introduced [[Reverse Polish notation]] (RPN) to the calculator market at a price of $2200. The EC-132 model 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 [[logarithm]]s.

In the early days of binary vacuum-tube computers, their reliability was poor enough to justify marketing a mechanical octal version ("Binary Octal") of the Marchant desktop calculator. It was intended to check and verify calculation results of such computers.

==Advanced analog computers==
{{Main|Analog computer}}
[[File:Cambridge differential analyser.jpg|thumb|Cambridge differential analyzer, 1938]]
Before World War II, mechanical and electrical [[analog computer]]s 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, for example, ballistic trajectories, inertia, resonance, energy transfer, momentum, and so forth. They model physical phenomena with electrical [[voltage]]s and [[Electric current|currents]]<ref>{{harvnb|Chua|1971|pp=507–519}}</ref> as the analog quantities.

Centrally, these analog systems work by creating electrical '[[analogy|analog]]s' of other systems, allowing users to predict behavior of the systems of interest by observing the electrical analogs.<ref>
See, for example,{{harvnb|Horowitz|Hill|1989|pp=1–44}}</ref> 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. Unlike modern digital computers, analog computers are not very flexible, and need to be rewired 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.

Some of the most widely deployed analog computers included devices for aiming weapons, such as the [[Norden bombsight]],<ref>{{harvnb|Norden}}</ref> and [[fire-control system]]s,<ref>{{harvnb|Singer|1946}}</ref> such as [[Arthur Pollen]]'s Argo system for naval vessels. Some stayed in use for decades after World War II; the [[Mark I Fire Control Computer]] was deployed by the [[United States Navy]] on a variety of ships from [[destroyer]]s to [[battleship]]s. Other analog computers included the [[Heathkit]] EC-1, and the hydraulic [[MONIAC Computer]] which modeled econometric flows.<ref>{{harvnb|Phillips||}}</ref>

The art of mechanical analog computing reached its zenith with the [[differential analyzer]],<ref>{{harvnb|Coriolis|1836|pp=5–9}}</ref> built by H. L. Hazen and [[Vannevar Bush]] at [[MIT]] starting in 1927, which in turn built on the mechanical integrators invented in 1876 by [[James Thomson (engineer)|James Thomson]] and the torque amplifiers invented by H. W. Nieman. A dozen of these devices were built before their obsolescence was obvious; 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.

==Early electronic digital computation==
[[File:Punched tape puncher.JPG|thumb|right|Friden paper tape punch. [[Punched tape]] programs would be much longer than the short fragment of yellow paper tape shown.]]
The era of modern computing began with a flurry of development before and during World War II.

At first electromechanical components such as relays were employed. [[George Stibitz]] is internationally recognized as one of the fathers of the modern digital computer. While working at Bell Labs in November 1937, Stibitz invented and built a relay-based calculator that he dubbed the "Model K" (for "kitchen table", on which he had assembled it), which was the first to calculate using [[Binary numeral system|binary form]].<ref>{{Citation|title=Inventor Profile: George R. Stibitz|publisher=National Inventors Hall of Fame Foundation, Inc.|url=http://www.invent.org/hall_of_fame/140.html}}</ref>

However [[electronic circuit]] elements replaced their mechanical and electromechanical equivalents, and digital calculations replaced analog calculations. Machines such as the [[Z3 (computer)|Z3]], the [[Atanasoff–Berry Computer]], the [[Colossus computer]]s, and the [[ENIAC]] were built by hand using circuits containing relays or valves (vacuum tubes), and often used [[punched card]]s or [[punched tape|punched paper tape]] for input and as the main (non-volatile) storage medium. 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).

===Turing===
[[Alan Turing]]'s 1936 paper<ref>{{harvnb|Turing|1937|pp=230–265}}. Online versions: [http://plms.oxfordjournals.org/cgi/reprint/s2-42/1/230 Proceedings of the London Mathematical Society] [http://www.thocp.net/biographies/papers/turing_oncomputablenumbers_1936.pdf Another version online.]
</ref> 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]].<ref>[[Kurt Gödel]] (1964), p. 71, "Postscriptum" in [[Martin Davis]] (ed., 2004),''[http://books.google.com/books?id=qW8x7sQ4JXgC&dq=%23+%23+Martin+Davis+editor,+The+Undecidable,+Basic+Papers+on+Undecidable+Propositions,+Unsolvable+Problems+And+Computable+Functions,&printsec=frontcover&source=bn&hl=en&ei=Cf1cStGfN6TIMrmbgZIH&sa=X&oi=book_result&ct=result&resnum=4 The Undecidable]'' Fundamental papers by papers by Gödel, Church, Turing, and Post on this topic and the relationship to computability. ISBN 0-486-43228-9, as summarized in [[Church-Turing thesis]].</ref> 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]].

[[File:Largetape.jpg|thumb|Half-inch (12.7 mm) [[magnetic tape]], originally written with [[IBM 7 track|7 tracks]] and later [[9 track tape|9-tracks]].]]
For a computing machine to be a practical general-purpose computer, there must be some convenient read-write mechanism, punched tape, for example. With knowledge of Alan Turing's theoretical 'universal computing machine' [[John von Neumann]] defined an architecture which uses the same [[computer memory|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, but some of the technology led, via Turing and others, to the first commercial electronic computer. The third stream of computer development was Eckert and Mauchly's ENIAC and EDVAC, which was widely publicized.<ref>{{harvnb|Moye|1996}}</ref><ref>{{harvnb|Bergin|1996}}</ref>

===Zuse===
{{Main|Konrad Zuse}}
[[File:Zuse Z1.jpg|thumb|A 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 (computer)|Z1]], finished in 1938, never worked reliably due to problems with the precision of parts.

Zuse's later machine, the [[Z3 (computer)|Z3]],<ref>{{harvnb|Zuse}}</ref> was finished in 1941. It was based on telephone relays and did work satisfactorily. The Z3 thus became the world's 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 number]]s. Replacement of the hard-to-implement decimal system (used in [[Charles Babbage]]'s earlier design) by the simpler [[binary numeral system|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 (computer)|Z3]] on punched films. Conditional jumps were missing, but since the 1990s it has been proved theoretically that Z3 was still a [[Turing machine|universal computer]] (as always, ignoring physical storage 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]], first implemented in the British [[Manchester Small-Scale Experimental Machine|SSEM]] of 1948.<ref>{{citation |title=Electronic Digital Computers |journal=Nature |date=25&nbsp;September 1948 |volume=162 |page=487 |url=http://www.computer50.org/kgill/mark1/natletter.html |accessdate=2009-04-10|bibcode = 1948Natur.162..487W |doi = 10.1038/162487a0 }}</ref> Zuse also claimed to have designed the first higher-level [[programming language]], which he named [[Plankalkül]], in 1945 (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 [[Allies of World War II|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.

===Colossus===
{{Main|Colossus computer}}
[[File:Colossus.jpg|thumbnail|right|Colossus 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 (machine)|Enigma]], was attacked with the help of electro-mechanical machines called ''[[bombe]]s''. The bombe, designed by [[Alan Turing]] and [[Gordon Welchman]], after the Polish cryptographic ''[[bomba (cryptography)|bomba]]'' by [[Marian Rejewski]] (1938), came into productive use in 1941.<ref>
{{harvnb|Welchman|1984|pp=138–145, 295–309}}</ref> 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.<ref>{{harvnb|Copeland|2006}}</ref> 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 world's first electronic programmable computing device. 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 logic]]al 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, to keep secret that the British were capable of cracking Lorenz 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. A reconstructed working copy of one of the Colossus machines is now on display at Bletchley Park.

===American developments===
In 1937, [[Claude Shannon]] showed there is a [[one-to-one correspondence]] between the concepts of [[Boolean logic]] and certain electrical circuits, now called [[logic gate]]s, which are now ubiquitous in digital computers.<ref>[[Claude Shannon]], "[[A Symbolic Analysis of Relay and Switching Circuits]]", ''Transactions of the American Institute of Electrical Engineers'', Vol. '''57''',(1938), pp. 713–723</ref> In his master's thesis<ref>{{harvnb|Shannon|1940}}</ref> at [[Massachusetts Institute of Technology|MIT]], for the first time in history, Shannon showed that electronic relays and switches can realize the [[expression (mathematics)|expression]]s of [[Boolean algebra (logic)|Boolean algebra]]. Entitled ''[[A Symbolic Analysis of Relay and Switching Circuits]]'', Shannon's thesis essentially founded practical [[digital circuit]] design. George Stibitz completed a relay-based computer he dubbed the "Model K" at [[Bell Labs]] in November 1937. Bell Labs authorized a full research program in late 1938 with Stibitz at the helm. Their ''[[Complex Number Calculator]]'',<ref>
[[George Stibitz]], {{Ref patent |country=US |number=2668661|status=patent|title=Complex Computer|gdate=1954-02-09 |assign1 =[[AT&T]]}}, 102 pages.</ref> completed January 8, 1940, was able to calculate [[complex numbers]]. In a demonstration to the [[American Mathematical Society]] conference at [[Dartmouth College]] on September 11, 1940, Stibitz was able to send the Complex Number Calculator remote commands over telephone lines by a [[teletype]]. It was the first computing machine ever used remotely, in this case over a phone line. Some participants in the conference who witnessed the demonstration were [[John von Neumann]], John Mauchly, and [[Norbert Wiener]], who wrote about it in their memoirs.

[[File:Atanasoff-Berry Computer at Durhum Center.jpg|thumb|[[Atanasoff–Berry Computer]] replica at 1st floor of Durham Center, [[Iowa State University]] ]]
In 1939, John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed the [[Atanasoff–Berry Computer]] (ABC),<ref>January 15, 1941 notice in the ''Des Moines Register''.</ref> The Atanasoff-Berry Computer was the world's first electronic digital computer.<ref>The First Electronic Computer By Arthur W. Burks</ref> The design used over 300 vacuum tubes and employed capacitors fixed in a mechanically rotating drum for memory. Though the ABC machine was not programmable, it was the first to use electronic tubes in an adder. ENIAC co-inventor John Mauchly examined the ABC in June 1941, and its influence on the design of the later ENIAC machine is a matter of contention among computer historians. The ABC was largely forgotten until it became the focus of the lawsuit ''[[Honeywell v. Sperry Rand]]'', the ruling of which invalidated the ENIAC patent (and several others) as, among many reasons, having been anticipated by Atanasoff's work.

In 1939, development began at IBM's Endicott laboratories on the [[Harvard Mark I]]. Known officially as the Automatic Sequence Controlled Calculator,<ref>{{harvnb|Da Cruz|2008}}</ref> the Mark I was a general purpose electro-mechanical computer built with IBM financing and with assistance from IBM personnel, under the direction of Harvard mathematician [[Howard Aiken]]. Its design was influenced by Babbage's Analytical Engine, using decimal arithmetic and storage wheels and rotary switches in addition to electromagnetic relays. It was programmable via punched paper tape, and contained several calculation units working in parallel. Later versions contained several paper tape readers and the machine could switch between readers based on a condition. Nevertheless, the machine was not quite Turing-complete. The Mark I was moved to [[Harvard University]] and began operation in May 1944.

===ENIAC===
{{Main|ENIAC}}
[[File:Eniac.jpg|thumb|[[ENIAC]] performed ballistics trajectory calculations with 160 kW of power]]
The US-built ENIAC (Electronic Numerical Integrator and Computer) was the first electronic general-purpose computer. It combined, for the first time, 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, and contained over 18,000 vacuum tubes. One of the major engineering feats was to minimize tube burnout, which was a common problem at that time. The machine was in almost constant use for the next ten years.

ENIAC was unambiguously a Turing-complete device. It could compute any problem (that would fit in memory). A "program" on the ENIAC, however, 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.
[[ENIAC#Programming|Six women did most of the programming of ENIAC.]] (Improvements completed in 1948 made it possible to execute stored programs set in function table memory, which made programming less a "one-off" effort, and more systematic).

===Manchester "baby"===
{{main|Manchester Small-Scale Experimental Machine}}
[[File:SSEM Manchester museum.jpg|thumb|300px|alt=A series of seven tall metal racks filled with electronic equipment standing in front of a brick wall. Signs above each rack describe the functions carried out by the electronics they contain. Three visitors read from information stands to the left of the image.|Replica of the Small-Scale Experimental Machine (SSEM) at the [[Museum of Science and Industry (Manchester)|Museum of Science and Industry]] in [[Castlefield]], [[Manchester]]]]
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 Calland Williams|Frederic C. Williams]], [[Tom Kilburn]] and Geoff Tootill, and ran its first program on 21&nbsp;June 1948.<ref>{{citation |last=Enticknap |first=Nicholas |title=Computing's Golden Jubilee |journal=Resurrection |issue=20 |publisher=The Computer Conservation Society |date=Summer 1998 |url=http://www.cs.man.ac.uk/CCS/res/res20.htm#d |issn=0958-7403 |accessdate=19&nbsp;April 2008}}</ref>

The machine was not intended to be a practical computer but was instead designed as a [[testbed]] for the [[Williams tube]], an early form of computer memory. Although 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.<ref name=EarlyComputers /> 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.<ref name=NapperMK1>{{citation |last=Napper |first=R. B. E. |title=Introduction to the Mark 1 |url=http://www.computer50.org/mark1/mark1intro.html |publisher=The University of Manchester |accessdate=4&nbsp;November 2008}}</ref>

The SSEM had a 32-[[bit]] [[word (data type)|word]] length and a [[computer memory|memory]] of 32&nbsp;words. As it was designed to be the simplest possible stored-program computer, the only arithmetic operations implemented in hardware were [[subtraction]] and [[negation (algebra)|negation]]; other arithmetic operations were implemented in software. The first of three programs written for the machine found the highest [[proper divisor]] of 2<sup>18</sup> (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<sup>18</sup>&nbsp;−&nbsp;1 downwards, as division was implemented by repeated subtraction of the divisor. The program consisted of 17&nbsp;instructions and ran for 52&nbsp;minutes before reaching the correct answer of 131,072, after the SSEM had performed 3.5&nbsp;million operations (for an effective CPU speed of 1.1 [[instructions per second|kIPS]]).

===Early computer characteristics===

{| class="wikitable" style="margin-left:auto; margin-right:auto;"
|+Defining characteristics of some early digital computers of the 1940s {{Small| (In the [[history of computing hardware]])}}
|-
! Name !! First operational !! Numeral system !! Computing mechanism !! [[Computer program|Programming]] !! [[Turing completeness|Turing complete]]
|-
|{{rh}}| [[Konrad Zuse|Zuse]] [[Z3 (computer)|Z3]] {{small|(Germany)}} ||align=right| May 1941 || [[Binary numeral system|Binary]] [[floating point]] || [[Electromechanics|Electro-mechanical]] || Program-controlled by punched 35 mm [[film stock]] (but no conditional branch) || In theory {{small|([[Z3 (computer)#Relation to the concept of a universal Turing machine|1998]])}}
|-
|{{rh}}| [[Atanasoff–Berry Computer]] {{small|(US)}} ||align=right| 1942|| Binary || [[Electronics|Electronic]] || Not programmable—single purpose || No
|-
|{{rh}}| [[Colossus computer|Colossus]] Mark 1 {{small|(UK)}} ||align=right| February 1944 || Binary || Electronic || Program-controlled by patch cables and switches || No
|-
|{{rh}}| [[Harvard Mark I|Harvard Mark I – IBM ASCC]] {{small|(US)}} || align=right|May 1944 || [[Decimal]] || Electro-mechanical || Program-controlled by 24-channel [[Punched tape|punched paper tape]] (but no conditional branch) || Debatable
|-
|{{rh}}| Colossus Mark 2 {{small|(UK)}} || align=right|June 1944 || Binary || Electronic || Program-controlled by patch cables and switches || In theory {{small|(2011)}}<!--Benjamin Wells: Unwinding performance and power on Colossus, an unconventional computer. Natural Computing 10(4): 1383-1405 (2011)-->
|-
|{{rh}}| Zuse [[Z4 (computer)|Z4]] {{small|(Germany)}} ||align=right| March 1945 || Binary floating point || Electro-mechanical || Program-controlled by punched 35 mm film stock || Yes
|-
|{{rh}}| [[ENIAC]] {{small|(US)}} || align=right|July 1946|| Decimal || Electronic || Program-controlled by patch cables and switches || Yes
|-
|{{rh}}| [[Manchester Small-Scale Experimental Machine]] (Baby) {{small|(UK)}} ||align=right| June 1948 || Binary || Electronic || [[Stored-program]] in [[Williams tube|Williams cathode ray tube memory]] || Yes
|-
|{{rh}}| [[ENIAC|Modified ENIAC]] {{small|(US)}} ||align=right| September 1948 || Decimal || Electronic || Read-only stored programming mechanism using the Function Tables as program [[Read-only memory|ROM]] || Yes
|-
|{{rh}}| [[EDSAC]] {{small|(UK)}} ||align=right| May 1949 ||Binary || Electronic || Stored-program in mercury [[delay line memory]] || Yes
|-
|{{rh}}| [[Manchester Mark 1]] {{small|(UK)}} || align=right|October 1949 || Binary || Electronic || Stored-program in Williams cathode ray tube memory and [[Drum memory|magnetic drum]] memory|| Yes
|-
|{{rh}}| [[CSIRAC]] {{small|(Australia)}} || align=right|November 1949 || Binary || Electronic || Stored-program in mercury delay line memory || Yes
|}

==First-generation machines==
{{See|List of vacuum tube computers}}
[[File:von Neumann architecture.svg|right|thumb|Design of the [[von Neumann architecture]] (1947)]]
Even before the ENIAC was finished, Eckert and Mauchly recognized its limitations and started the design of a [[stored-program computer]], EDVAC. [[John von Neumann]] was credited with a [[First Draft of a Report on the EDVAC|widely circulated report]] describing the [[EDVAC]] design in which both the programs and working data were stored in a single, unified store. This basic design, denoted the [[von Neumann architecture]], would serve as the foundation for the worldwide development of ENIAC's successors.<ref>{{harvnb|von Neumann|1945|p=1}}. The title page, as submitted by Goldstine, reads: "First Draft of a Report on the EDVAC by John von Neumann, Contract No. W-670-ORD-4926, Between the United States Army Ordnance Department and the University of Pennsylvania Moore School of Electrical Engineering".</ref> In this generation of equipment, temporary or working storage was provided by [[acoustic delay line]]s, which used the propagation time of sound through a medium such as liquid [[mercury (element)|mercury]] (or through a wire) to briefly store data. A series of [[acoustics|acoustic]] pulses is sent along a tube; after a time, as the pulse reached the end of the tube, the circuitry detected whether the pulse represented a 1 or 0 and caused the oscillator to re-send the pulse. Others used [[Williams tube]]s, which use the ability of a small cathode-ray tube (CRT) to store and retrieve data as charged areas on the phosphor screen. By 1954, [[magnetic core memory]]<ref>[[An Wang]] filed October 1949, {{Ref patent |country=US|number=2708722|status=patent|gdate=1955-05-17|title=Pulse transfer controlling devices}}</ref> was rapidly displacing most other forms of temporary storage, and dominated the field through the mid-1970s.

[[File:Magnetic core.jpg|left|thumb|250|[[Magnetic core memory]]. Each [[Magnetic core|core]] is one [[bit]].]]
EDVAC was the first stored-program computer designed; however it was not the first to run. Eckert and Mauchly left the project and its construction floundered. The first working von Neumann machine was the Manchester "Baby" or [[Small-Scale Experimental Machine]], developed by [[Frederic Calland Williams|Frederic C. Williams]] and [[Tom Kilburn]] at the [[University of Manchester]] in 1948 as a test bed for the [[Williams tube]];<ref>{{harvnb|Enticknap|1998|p=1}}; Baby's 'first good run' was June 21, 1948.</ref> it was followed in 1949 by the [[Manchester Mark 1]] computer, a complete system, using Williams tube and [[magnetic drum]] memory, and introducing [[index register]]s.<ref>{{harvnb|Manchester|1999}}, by [http://www.computer50.org/mark1/acknowledge.mark1.html R.B.E. Napper, et al.]</ref> The other contender for the title "first digital stored-program computer" had been [[EDSAC]], designed and constructed at the [[University of Cambridge]]. Operational less than one year after the Manchester "Baby", it was also capable of tackling real problems. EDSAC was actually inspired by plans for EDVAC (Electronic Discrete Variable Automatic Computer), the successor to ENIAC; these plans were already in place by the time ENIAC was successfully operational. Unlike ENIAC, which used parallel processing, EDVAC used a single processing unit. This design was simpler and was the first to be implemented in each succeeding wave of miniaturization, and increased reliability.
Some view Manchester Mark 1 / EDSAC / EDVAC as the "Eves" from which nearly all current computers derive their architecture. Manchester University's
machine became the prototype for the [[Ferranti Mark 1]]. The first Ferranti Mark 1 machine was delivered to the University in February 1951 and at least nine others were sold between 1951 and 1957.

The first universal programmable computer in the Soviet Union was created by a team of scientists under direction of [[Sergei Alekseyevich Lebedev]] from [[Kiev Institute of Electrotechnology]], [[Soviet Union]] (now [[Ukraine]]). The computer [[History of computer hardware in communist countries#MESM|MESM]] (''МЭСМ'', ''Small Electronic Calculating Machine'') became operational in 1950. It had about 6,000 vacuum tubes and consumed 25&nbsp;kW of power. It could perform approximately 3,000 operations per second. Another early machine was [[CSIRAC]], an Australian design that ran its first test program in 1949. CSIRAC is the oldest computer still in existence and the first to have been used to play digital music.<ref>{{harvnb|CSIRAC|2005}}</ref>

==Commercial computers==
The first commercial computer was the [[Ferranti Mark 1]], which was 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 memory|random access]] [[Williams tubes]]), [[secondary storage]] (using a [[drum memory|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).<ref>{{Harvnb|Lavington|1998|p=25}}</ref> A second machine was purchased by the [[University of Toronto]], before the design was revised into the [[Ferranti Mark 1#Mark 1 Star|Mark 1 Star]]. At least seven of these later machines were delivered between 1953 and 1957, one of them to [[Royal Dutch Shell|Shell]] labs in [[Amsterdam]].<ref>{{Citation | last = Computer Conservation Society | author-link = Computer Conservation Society | title = Our Computer Heritage Pilot Study: Deliveries of Ferranti Mark I and Mark I Star computers. | url = http://www.ourcomputerheritage.org/wp/ | accessdate = 9 January 2010 }}</ref>

In October 1947, the directors of [[J. Lyons and Co.|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 computer|LEO I]] computer became operational in April 1951 <ref>{{cite web | last = Lavington | first = Simon | title = A brief history of British computers: the first 25 years (1948–1973). | publisher = [[British Computer Society]] | url = http://www.bcs.org/server.php? | accessdate = 10 January 2010 }}</ref> and ran the world's first regular routine office computer [[job (software)|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 [[:Category:Application software|application]] to go live on a stored program computer.<ref>{{harvnb|Martin|2008|p=24}} notes that David Caminer (1915–2008) served as the first corporate electronic systems analyst, for this first business computer system, a Leo computer, part of J. Lyons & Company. LEO would calculate an employee's pay, handle billing, and other office automation tasks.</ref>

In June 1951, the [[UNIVAC I]] (Universal Automatic Computer) was delivered to the [[United States Census Bureau|U.S. Census Bureau]]. Remington Rand eventually sold 46 machines at more than $1 million each (${{Formatprice|{{Inflation|US|1000000|1951|r=-4}}|0}} as of {{CURRENTYEAR}}).{{Inflation-fn|US}} UNIVAC was the first "mass produced" computer. It used 5,200 vacuum tubes and consumed 125&nbsp;kW of power. Its primary storage was [[Sequential access|serial-access]] mercury delay lines capable of storing 1,000 words of 11&nbsp;decimal digits plus sign (72-bit words). A key feature of the UNIVAC system was a newly invented type of metal magnetic tape, and a high-speed tape unit, for non-volatile storage. Magnetic tape is still used in many computers.<ref>Magnetic tape will be the primary data storage mechanism when [[CERN]]'s [[Large Hadron Collider]] comes online in 2008.</ref>
In 1952, IBM publicly announced the [[IBM 701]] Electronic Data Processing Machine, the first in its successful [[IBM 700/7000 series|700/7000 series]] and its first [[IBM mainframe]] computer. The [[IBM 704]], introduced in 1954, used magnetic core memory, which became the standard for large machines. The first implemented high-level general purpose [[programming language]], [[Fortran]], was also being developed at IBM for the 704 during 1955 and 1956 and released in early 1957. (Konrad Zuse's 1945 design of the high-level language [[Plankalkül]] was not implemented at that time.) A volunteer [[user group]], which exists to this day, was founded in 1955 to [[SHARE (computing)|share]] their software and experiences with the IBM 701.

[[File:IBM-650-panel.jpg|thumb|IBM 650 front panel]]
IBM introduced a smaller, more affordable computer in 1954 that proved very popular.<ref>For example, Kara Platoni's article on [[Donald Knuth]] [http://www.stanfordalumni.org/news/magazine/2006/mayjun/features/knuth.html stated that "there was something special about the] [[IBM 650]]", ''Stanford Magazine'', May/June 2006</ref> The [[IBM 650]] weighed over 900&nbsp;kg, the attached power supply weighed around 1350&nbsp;kg and both were held in separate cabinets of roughly 1.5 meters by 0.9 meters by 1.8 meters. It cost $500,000<ref>{{Citation | last = Dudley | first=Leonard | title = Information Revolution in the History of the West | year = 2008 | url = http://books.google.com/?id=jLnPi5aYoJUC&pg=PA266&lpg=PA266&dq=ibm+650+$500,000#v=onepage&q=ibm%20650%20%24500%2C000&f=false | isbn = 978-1-84720-790-6 | publisher=Edward Elgar Publishing | page=266}}</ref> (${{Formatprice|{{Inflation|US|500000|1954|r=-4}}|0}} as of {{CURRENTYEAR}}) or could be leased for $3,500 a month (${{Formatprice|{{Inflation|US|3500|1954|r=-4}}|0}} as of {{CURRENTYEAR}}).{{Inflation-fn|US}} 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,<ref>{{Citation | last = IBM | title = SOAP II for the IBM 650 | year = 1957 | url = http://www.bitsavers.org/pdf/ibm/650/24-4000-0_SOAPII.pdf | id = C24-4000-0 |format=PDF}}</ref> 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.

In 1955, [[Maurice Wilkes]] invented [[microprogram]]ming,<ref>{{harvnb|Wilkes|1986|pp=115–126}}</ref> which allows the base instruction set to be defined or extended by built-in programs (now called [[firmware]] or [[microcode]]).<ref>{{harvnb|Horowitz|Hill|1989|p=743}}</ref> It was widely used in the [[Central processing unit|CPUs]] and [[floating-point]] units of [[mainframe computer|mainframe]] and other computers, such as the [[Manchester University|Manchester]] [[Atlas Computer|Atlas]] <ref>[http://www.chilton-computing.org.uk/acl/technology/atlas/p019.htm The microcode was implemented as ''extracode'' on Atlas] accessdate=20100209</ref> and the [[IBM 360]] series.<ref>{{harvnb|Patterson|Hennessy|1998|p=424}}</ref>

IBM introduced its [[Early IBM disk storage|first magnetic disk system]], [[IBM 350#Early IBM HDDs|RAMAC]] (Random Access Method of Accounting and Control) in 1956. Using fifty {{convert|24|in|mm|sing=on}} metal disks, with 100&nbsp;tracks per side, it was able to store 5&nbsp;[[megabyte]]s of data at a cost of $10,000 per megabyte (${{Formatprice|{{Inflation|US|10000|1956|r=-4}}|0}} as of {{CURRENTYEAR}}).{{Inflation-fn|US}}<ref>{{harvnb|IBM|1956}}</ref>

==Second generation: transistors==
{{Main|Transistor computer}}
{{See|List of transistorized computers}}
[[File:Transistor-die-KSY34.jpg|thumb|A [[bipolar junction transistor]]]]
The bipolar [[transistor]] was invented in 1947. From 1955 onwards transistors replaced [[vacuum tube]]s in computer designs,<ref>{{harvnb|Feynman|Leighton|Sands|1966|pp=14-11 to 14–12}}</ref> giving rise to the "second generation" of computers. Initially the only devices available were [[germanium]] [[point-contact transistor]]s, which although less reliable than the vacuum tubes they replaced had the advantage of consuming far less power.<ref>{{Harvnb|Lavington|1998|pp=34–35}}</ref> The first [[transistor computer|transistorised computer]] was built at the [[University of Manchester]] and was operational by 1953;<ref name=LavingtonP37>{{Harvnb|Lavington|1998|p=37}}</ref> a second version was completed there in April 1955. The later machine used 200&nbsp;transistors and 1,300&nbsp;[[Solid-state (electronics)|solid-state]] [[diode]]s and had a power consumption of 150&nbsp;watts. However, it still required valves to generate the clock waveforms at 125&nbsp;kHz and to read and write on the magnetic [[drum memory]], whereas the [[Harwell CADET]] operated without any valves by using a lower clock frequency, of 58&nbsp;kHz when it became operational in February 1955.<ref>{{Citation|last= Cooke-Yarborough |first= E.H. |title= Some early transistor applications in the UK. |journal= Engineering and Science Education Journal |volume= 7 |issue= 3 |pages= 100–106 |publisher= IEE |location= London, UK |date = June 1998|url= http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=00689507 |issn= 0963-7346 |accessdate= 2009-06-07|doi= 10.1049/esej:19980301 }}</ref> 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&nbsp;minutes, but this improved once the more reliable [[bipolar junction transistor]]s became available.<ref>{{Harvnb|Lavington|1998|pp=36–37}}</ref>

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 board]]s such as the [[IBM Standard Modular System]]<ref name=IBM_SMS>{{harvnb|IBM_SMS|1960}}</ref>
each carrying one to four [[logic gate]]s or [[Flip-flop (electronics)|flip-flops]].

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.

[[File:IBM 350 RAMAC.jpg|thumb|left|This [[IBM 350#Early IBM HDDs|RAMAC]] [[Direct access storage device|DASD]] is being restored at the [[Computer History Museum]]]]
Transistorized electronics improved not only the [[Central processing units|CPU]] (Central Processing Unit), but also the [[peripheral|peripheral devices]]. The [[IBM 350]] RAMAC was introduced in 1956 and was the world's first disk drive. The second generation [[disk storage|disk data storage units]] were able to store tens of millions of letters and digits. Next to the [[Hard disk drive|fixed disk storage units]], connected to the CPU via high-speed data transmission, were removable disk data storage units. A removable disk stack can be easily exchanged with another stack 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 data storage|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 [[Unit record equipment|card reading and punching]], the main CPU executed calculations and binary [[branch (computer science)|branch instructions]]. One [[Bus (computing)|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 Digital Terminal|remote terminal]] units (often in the form of [[Teleprinter|teletype machines]] like a [[Friden Flexowriter]]) saw greatly increased use.<ref>[[Alan Newell]] used remote terminals to communicate cross-country with the [[RAND]] computers, as noted in {{harvnb|Simon|1991}}</ref> 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 ''[[history of the Internet|network of networks]]''—the Internet.<ref> [[Robert Taylor (computer scientist)|Bob Taylor]] conceived of a generalized protocol to link together multiple networks to be viewed as a single session regardless of the specific network: "Wait a minute. Why not just have one terminal, and it connects to anything you want it to be connected to? And, hence, the Arpanet was born."—{{harvnb|Mayo|Newcomb|2008}}</ref>

==Post-1960: third generation and beyond==
{{Main|History of computing hardware (1960s–present)|History of general purpose CPUs}}
[[File:153056995 5ef8b01016 o.jpg|right|thumb|Intel [[integrated circuit|8742 eight-bit microcontroller IC]]]]
The explosion in the use of computers began with "third-generation" computers, making use of [[Jack Kilby|Jack St. Clair Kilby]]'s<ref>{{harvnb|Kilby|2000}}</ref> and [[Robert Noyce]]'s<ref>[[Robert Noyce]]'s Unitary circuit, {{Ref patent |country=US |number=2981877|status=patent|gdate=1961-04-25|title=Semiconductor device-and-lead structure |assign1 =[[Fairchild Semiconductor Corporation]]}}</ref> independent invention of the [[integrated circuit]] (or microchip), which 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,<ref>{{harvnb|Intel_4004|1971}}</ref> designed and realized by [[Marcian Hoff|Ted Hoff]], [[Federico Faggin]], and Stanley Mazor at [[Intel]].<ref>The Intel 4004 (1971) die was 12&nbsp;mm<sup>2</sup>, composed of 2300 transistors; by comparison, the Pentium Pro was 306&nbsp;mm<sup>2</sup>, composed of 5.5 million transistors, according to {{harvnb|Patterson|Hennessy|1998|pp=27–39}}.</ref>

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&nbsp;MHz, 128 bytes of [[RAM]], 2048 bytes of [[EPROM]], and [[Input/output|I/O]] in the same chip.

During the 1960s there was considerable overlap between second and third generation technologies.<ref>In the defense field, considerable work was done in the computerized implementation of equations such as {{harvnb|Kalman|1960|pp= 35–45}}</ref> IBM implemented its [[IBM Solid Logic Technology]] modules in [[hybrid circuit]]s 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 machine]]s, which allowed for simpler programming. These [[pushdown automaton]]s 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.<ref>{{harvnb|Eckhouse|Morris|1979|pp= 1–2}}</ref> 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 ([[:Category:Electronic design automation software|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.

In April 1975 at the Hannover Fair, was presented the [[P6060]] produced by [[Olivetti]], the world's first personal computer with built-in floppy disk: Central Unit on two plates, code names PUCE1/PUCE2, [[Transistor–transistor logic|TTL]] components made, 8" single or double [[floppy disk]] driver, 32 alphanumeric characters [[plasma display]], 80 columns graphical [[thermal printer]], 48 Kbytes of [[RAM]], [[BASIC]] language, 40 kilograms of weight. He was in competition with a similar product by IBM but with an external floppy disk.

[[KIM-1|MOS Technology KIM-1]] and [[Altair 8800]], were sold as kits for do-it-yourselfers, as was the [[Apple I]], soon afterward. The first Apple computer with graphic and sound capabilities came out well after the [[Commodore PET]]. Computing has evolved with microcomputer architectures, with features added from their larger brethren, now dominant in most market segments.

Systems as complicated as computers require very high [[reliability engineering|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 plugging|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 farm]]s are the delivery platform.<ref>"Since 2005, its [Google's] data centers have been composed of standard shipping containers—each with 1,160 servers and a power consumption that can reach 250 kilowatts."&nbsp;— Ben Jai of Google, as quoted in {{harvnb|Shankland|2009}}</ref> 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.<ref>"If you're running 10,000 machines, something is going to die every day." —Jeff Dean of Google, as quoted in {{harvnb|Shankland|2008}}.</ref><ref>[https://groups.google.com/group/google-appengine/browse_thread/thread/a7640a2743922dcf?pli=1 However, when an entire server farm fails today, the recovery procedures are currently still manual procedures, with the need for training the recovery team, even for the most advanced facilities. The initial failure was a power failure; the recovery procedure cited an inconsistent backup site, and the inconsistent backup site was outdated. Accessdate=2010-03-08]</ref>

In the 21st century, [[multi-core]] CPUs became commercially available.<ref>Intel has unveiled a [http://www.pcper.com/article.php?aid=825 single-chip version of a 48-core CPU] for software and circuit research in cloud computing: accessdate=2009-12-02. [http://news.bbc.co.uk/2/hi/technology/8392392.stm Intel has loaded Linux on each core; each core has an X86 architecture]: accessdate=2009-12-3</ref> [[Content-addressable memory]] (CAM)<ref>{{harvnb|Kohonen|1980|pp=1–368}}</ref> has become inexpensive enough to be used in networking, 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<!--ref>{{harvnb|Mead |Conway|1980|pp= 0}}</ref-->, except for leakage.

This has allowed computing to become a [[commodity]] which is now ubiquitous, embedded in [[embedded system|many forms]], from greeting cards and [[Mobile phone|telephone]]s to [[Satellite communications#History|satellites]]. Computing hardware and its software have even become a metaphor for the operation of the universe.<ref>{{harvnb|Smolin|2001|pp= 53–57}}.Pages 220–226 are annotated references and guide for further reading.</ref> Although [[DNA_computing|DNA-based computing]] and [[quantum computing]] are years or decades in the future, the infrastructure is being laid today, for example, with [[DNA origami]] on photolithography<ref>Ryan J. Kershner, Luisa D. Bozano, Christine M. Micheel, Albert M. Hung, Ann R. Fornof, Jennifer N. Cha, Charles T. Rettner, Marco Bersani, Jane Frommer, Paul W. K. Rothemund & Gregory M. Wallraff (16 August 2009) "Placement and orientation of individual DNA shapes on lithographically patterned surfaces" ''[[Nature Nanotechnology]]'' [http://www.nature.com/nnano/journal/vaop/ncurrent/suppinfo/nnano.2009.220_S1.html publication information], [http://www.nature.com/nnano/journal/vaop/ncurrent/extref/nnano.2009.220-s1.pdf supplementary information: DNA origami on photolithography] {{doi|10.1038/nnano.2009.220}}</ref> and with quantum antennae for transferring information between ion traps.<ref>[http://www.sciencedaily.com/releases/2011/02/110223133444.htm M. Harlander, R. Lechner, M. Brownnutt, R. Blatt, W. Hänsel. Trapped-ion antennae for the transmission of quantum information. ''Nature'', 2011; ] {{doi|10.1038/nature09800}}</ref> By 2011, researchers had [[Qubit#Entanglement|entangled]] [http://www.nanowerk.com/news/newsid=20823.php 14] [[qubit]]s.<ref>Thomas Monz, Philipp Schindler, Julio T. Barreiro, Michael Chwalla, Daniel Nigg, William A. Coish, Maximilian Harlander, Wolfgang Hänse, Markus Hennrich, and Rainer Blatt, (31 March 2011) "14-Qubit Entanglement: Creation and Coherence" ''[[Phys. Rev. Lett.]]'' '''106''' 13 http://link.aps.org/doi/10.1103/PhysRevLett.106.130506 {{doi|10.1103/PhysRevLett.106.130506}}
</ref> Fast [[digital circuit]]s (including those based on [[Josephson junction]]s and [[rapid single flux quantum]] technology) are becoming more nearly realizable with the discovery of [[nanoscale superconductor]]s.<ref>Saw-Wai Hla et al., ''Nature Nanotechnology'' March 31, 2010 [http://www.thinq.co.uk/news/2010/3/30/worlds-smallest-superconductor-discovered/ "World’s smallest superconductor discovered"]. Four pairs of certain molecules have been shown to form a nanoscale superconductor, at a dimension of 0.87 [[nanometer]]s. Access date 2010-03-31</ref>

Fiber-optic and photonic devices, which already have been used to transport data over long distances, are now entering the data center, side by side with CPU and semiconductor memory components. This allows the separation of RAM from CPU by optical interconnects.<ref>[http://www.technologyreview.com/computing/25924/?a=f Tom Simonite, "Computing at the speed of light", ''Technology Review'' Wed., August 4, 2010] [[MIT]]</ref>

An indication of the rapidity of development of this field can be inferred by the history of the seminal article.<ref>{{harvnb|Burks|Goldstine|von Neumann|1947|pp=1–464}} reprinted in ''[[Datamation]]'', September–October 1962. Note that ''preliminary discussion/design'' was the term later called ''system analysis/design'', and even later, called ''system architecture.''</ref> By the time that anyone had time to write anything down, so 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 pace of development has continued, worldwide.<ref>{{harvnb|IEEE_Annals|1979}} Online access to the ''[[IEEE Annals of the History of Computing]]'' here [http://csdl2.computer.org/persagen/DLPublication.jsp?pubtype=m&acronym=an]. ''[[DBLP]]'' summarizes the [http://www.informatik.uni-trier.de/~ley/db/journals/annals/ ''Annals of the History of Computing''] year by year, back to 1996, so far.</ref><ref>The fastest [[supercomputer]] of the [[top 500]] was announced at the [http://www.top500.org/lists/2012/06 2012 Supercomputing Conference], Hamburg, Germany, to be [[IBM Sequoia]], topping [[K computer]], as of Monday June 18, 2012.</ref>

== See also ==
{{Portal|Computer Science}}

* [[History of computing]]
* [[Information Age]]
* [[IT History Society]]
* [[The Secret Guide to Computers]]
* [[Timeline of computing]]

==Notes==
{{Reflist|colwidth=25em|refs=

<ref name=EarlyComputers>{{citation |url=http://www.computer50.org/mark1/contemporary.html |title=Early Electronic Computers (1946–51) |publisher=University of Manchester |accessdate=16&nbsp;November 2008}}</ref>

}}

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==Further reading==
* [[Paul E. Ceruzzi|Ceruzzi, Paul E.]], [http://books.google.com/books?id=x1YESXanrgQC&printsec=frontcover A History of Modern Computing], MIT Press, 1998

==External links==
{{Commons category|Historical computers}}
{{Commons category|Computer modules}}
{{Wikiversity|Introduction to Computers/History}}
*[http://www.oldcomputers.net/ Obsolete Technology&nbsp;— Old Computers]
*[http://museum.ipsj.or.jp/en/computer/index.html Historic Computers in Japan]
*[http://www.xnumber.com/xnumber/japanese_calculators.htm The History of Japanese Mechanical Calculating Machines]
*[http://www.trailing-edge.com/~bobbemer/HISTORY.HTM Computer History] — a collection of articles by [[Bob Bemer]]
*[http://spectrum.ieee.org/25chips 25 Microchips that shook the world] — a collection of articles by the [[Institute of Electrical and Electronics Engineers]]
*[http://www.techbites.com/200911151052/myblog/articles/z0031-the-history-of-computers-timeline.html History of Computers and Calculators]
*[http://www.svhistory.com Rao/Scaruffi's History of Silicon Valley]

{{DEFAULTSORT:History Of Computing Hardware}}
[[Category:Early computers|*History of computing hardware]]
[[Category:History of computing hardware| ]]
[[Category:One-of-a-kind computers|*History of computing hardware]]

{{Link GA|zh}}
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[[ar:تاريخ عتاد الحوسبة]]
[[az:Hesablama avadanlıqı tarixçəsi]]
[[bs:Historija računarstva]]
[[ca:Història dels ordinadors]]
[[cs:Dějiny počítačů]]
[[da:Fjerdegenerationsdatamat]]
[[dv:ކޮންޕިއުޓަރު ހާޑުވެޔަރގެ ތާރީހު]]
[[el:Ιστορία των υπολογιστών]]
[[es:Historia del hardware]]
[[fa:پیشینه سخت‌افزار رایانه]]
[[fr:Instrument de calcul]]
[[ko:컴퓨터의 역사]]
[[hi:संगणन हार्डवेयर का इतिहास]]
[[hr:Povijest računarskog sklopovlja]]
[[id:Sejarah komputer]]
[[it:Storia del computer]]
[[he:היסטוריה של המחשוב]]
[[jv:Sajarah perkomputeran]]
[[hu:A számítógép története]]
[[mk:Историја на сметачите]]
[[ml:കമ്പ്യൂട്ടറുകളുടെ ചരിത്രം]]
[[ms:Sejarah perkembangan komputer]]
[[my:ကွန်ပျူတာ သမိုင်း]]
[[nl:Geschiedenis van de computer]]
[[ja:計算機の歴史]]
[[no:Datamaskinens historie]]
[[oc:Istoric de l'informatica]]
[[pl:Komputer czwartej generacji]]
[[pt:História do hardware]]
[[ro:Istoria mașinilor de calcul]]
[[ru:История вычислительной техники]]
[[sq:Historia e kompjuterit]]
[[sk:Dejiny počítačov]]
[[sl:Generacija računalnikov]]
[[sr:Istorija računara]]
[[fi:Tietokonetekniikan historia]]
[[sv:Datorns historia]]
[[th:ประวัติฮาร์ดแวร์คอมพิวเตอร์]]
[[uk:Історія обчислювальної техніки]]
[[vi:Lịch sử phần cứng máy tính]]
[[zh:計算機硬體歷史]]

Revision as of 18:20, 10 September 2012

IBM helped Hitler by making one of the first computers. IBM made it easy to make mass murders. Hitler did not want to kill the jews its all IBM fault

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