Editing History of computing hardware (section)

==Stored-program computer==
{{Main|Stored-program computer}}
{{Further|List of vacuum-tube computers}}

[[File:von Neumann architecture.svg|thumb|Design of the [[von Neumann architecture]], 1947]]

The theoretical basis for the stored-program computer was proposed by [[Alan Turing]] in his 1936 paper ''On Computable Numbers''.<ref name=Turing-1937-1938/> Whilst Turing was at [[Princeton University]] working on his PhD, [[John von Neumann]] got to know him and became intrigued by his concept of a universal computing machine.{{sfn|Copeland|2004|pp=21-22}}

Early computing machines executed the set sequence of steps, known as a '[[computer program|program]]', that could be altered by changing electrical connections using switches or a [[patch panel]] (or [[plugboard]]). However, this process of 'reprogramming' was often difficult and time-consuming, requiring engineers to create flowcharts and physically re-wire the machines.{{sfn|Copeland|2006|p=104}} Stored-program computers, by contrast, were designed to store a set of instructions (a [[computer program|program]]), in memory – typically the same memory as stored data.

[[ENIAC]] inventors [[John Mauchly]] and [[J. Presper Eckert]] proposed, in August 1944, the construction of a machine called the Electronic Discrete Variable Automatic Computer ([[EDVAC]]) and design work for it commenced at the [[University of Pennsylvania]]'s [[Moore School of Electrical Engineering]], before the ENIAC was fully operational.  The design implemented a number of important architectural and logical improvements conceived during the ENIAC's construction, and a high-speed [[Delay-line memory|serial-access memory]].<ref name=Wilkes>{{cite book | last=Wilkes | first=M. V. | author-link=Maurice Vincent Wilkes | title=Automatic Digital Computers | publisher=John Wiley & Sons | year=1956 | location=New York | pages=305 pages | id=QA76.W5 1956 }}</ref> However, Eckert and Mauchly left the project and its construction floundered.

In 1945, von Neumann visited the Moore School and wrote notes on what he saw, which he sent to the project. The U.S. Army liaison there had them typed and  circulated as the ''[[First Draft of a Report on the EDVAC]]''. The draft did not mention Eckert and Mauchly and, despite its incomplete nature and questionable lack of attribution of the sources of some of the ideas,<ref name="stanf"/> the computer architecture it outlined became known as the '[[von Neumann architecture]]'.

In 1945, Turing joined the [[National Physical Laboratory (United Kingdom)|UK National Physical Laboratory]] and began work on developing an electronic stored-program digital computer. His late-1945 report 'Proposed Electronic Calculator' was the first reasonably detailed specification for such a device. Turing presented a more detailed paper to the [[National Physical Laboratory, UK|National Physical Laboratory]] (NPL) Executive Committee in March 1946, giving the first substantially complete design of a [[stored-program computer]], a device that was called the [[Automatic Computing Engine]] (ACE).

Turing considered that the speed and the size of [[computer memory]] were crucial elements,<ref name=turing1945>{{cite report|url=https://www.npl.co.uk/getattachment/about-us/History/Famous-faces/Alan-Turing/turing-proposal-Alan-LR.pdf?lang=en-GB|title=Proposed Electronic Calculator|author=Alan Turing|date=1945|access-date=August 24, 2023}}</ref>{{rp|p.4}} so he proposed a high-speed memory of what would today be called 25 [[Kibibyte|KB]], accessed at a speed of 1 [[Hertz|MHz]]. The ACE implemented [[subroutine]] calls, whereas the EDVAC did not, and the ACE also used ''Abbreviated Computer Instructions,'' an early form of [[programming language]].

===Manchester Baby===
{{Main|Manchester Baby}}
[[File:SSEM Manchester museum close up.jpg|thumb|left|alt=Three tall racks containing electronic circuit boards|A section of the rebuilt [[Manchester Baby]], the first electronic stored-program computer]]
The [[Manchester Baby]] (Small Scale Experimental Machine, SSEM) was the world's first electronic [[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=https://www.cs.man.ac.uk/CCS/res/res20.htm#d |issn=0958-7403 |access-date=19 April 2008 |url-status=dead |archive-url=https://web.archive.org/web/20120109142655/http://www.cs.man.ac.uk/CCS/res/res20.htm#d |archive-date=9 January 2012}}</ref>

The machine was not intended to be a practical computer but was instead designed as a [[testbed]] for the [[Williams tube]], the first [[random-access memory|random-access]] digital storage device.<ref>{{citation |title=Early computers at Manchester University |journal=Resurrection |volume=1 |issue=4 |publisher=The Computer Conservation Society |date=Summer 1992 |url=https://www.cs.man.ac.uk/CCS/res/res04.htm#g |issn=0958-7403 |access-date=7 July 2010 |archive-url=https://web.archive.org/web/20170828010743/http://www.cs.man.ac.uk/CCS/res/res04.htm#g |archive-date=28 August 2017 |url-status=dead}}</ref> Invented by [[Frederic Calland Williams|Freddie Williams]] and [[Tom Kilburn]]<ref>{{cite web |website=Computer 50 |url=https://www.computer50.org/mark1/notes.html |archive-url=https://web.archive.org/web/20130606122154/http://www.computer50.org/mark1/notes.html |archive-date=2013-06-06 |title=Why Williams-Kilburn Tube is a Better Name for the Williams Tube}}</ref><ref>{{Citation |last=Kilburn |first=Tom |author-link=Tom Kilburn |title=From Cathode Ray Tube to Ferranti Mark I |journal=Resurrection |publisher=The Computer Conservation Society |volume=1 |issue=2 |year=1990 |url=https://www.cs.man.ac.uk/CCS/res/res02.htm#e |issn=0958-7403 |access-date=15 March 2012 |archive-date=2020-06-27 |archive-url=https://web.archive.org/web/20200627165410/http://www.cs.man.ac.uk/CCS/res/res02.htm#e |url-status=live }}</ref> at the University of Manchester in 1946 and 1947, it was a [[cathode-ray tube]] that used an effect called [[secondary emission]] to temporarily store electronic [[binary data]], and was used successfully in several early computers.

Described as small and primitive in a 1998 retrospective, the Baby was the first working machine to contain all of the elements essential to a modern electronic computer.<ref name=EarlyComputers /> As soon as it had demonstrated the feasibility of its design, a project was initiated at the university to develop the design 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 |website=Computer 50 |url=https://www.computer50.org/mark1/mark1intro.html |publisher=The University of Manchester |access-date=4 November 2008 |url-status=dead |archive-url=https://web.archive.org/web/20081026080604/http://www.computer50.org/mark1/mark1intro.html |archive-date=26 October 2008 }}</ref>

The Baby had a [[32-bit computing|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 [[Computer hardware|hardware]] were [[subtraction]] and [[negation]]; other arithmetic operations were implemented in software. The first of three programs written for the machine found the highest [[proper divisor]] of 2<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 Baby had performed 3.5&nbsp;million operations (for an effective CPU speed of 1.1 [[instructions per second|kIPS]]). The successive approximations to the answer were displayed as a pattern of dots on the output [[cathode-ray tube|CRT]] which mirrored the pattern held on the Williams tube used for storage.

===Manchester Mark 1===
The SSEM led to the development of the [[Manchester Mark 1]] at the University of Manchester.{{sfn|Lavington|1998|p=20}} Work began in August 1948, and the first version was operational by April 1949; a program written to search for [[Mersenne prime]]s ran error-free for nine hours on the night of 16/17 June 1949. The machine's successful operation was widely reported in the British press, which used the phrase "electronic brain" in describing it to their readers.

The computer is especially historically significant because of its pioneering inclusion of [[index register]]s, an innovation which made it easier for a program to read sequentially through an array of [[Word (data type)|words]] in memory. Thirty-four patents resulted from the machine's development, and many of the ideas behind its design were incorporated in subsequent commercial products such as the {{nowrap|[[IBM 701]]}} and [[IBM 702|702]] as well as the Ferranti Mark 1. The chief designers, [[Frederic Calland Williams|Frederic C. Williams]] and [[Tom Kilburn]], concluded from their experiences with the Mark&nbsp;1 that computers would be used more in scientific roles than in pure mathematics. In 1951 they started development work on [[Meg (computer)|Meg]], the Mark&nbsp;1's successor, which would include a [[floating-point unit]].

===EDSAC===
[[File:EDSAC (19).jpg|right|thumb|EDSAC]]
The other contender for being the first recognizably modern digital stored-program computer<ref>{{cite web |first=Mark |last=Ward |date=13 January 2011 |work=BBC News |title=Pioneering Edsac computer to be built at Bletchley Park |url=https://www.bbc.co.uk/news/technology-12181153 |access-date=2018-06-21 |archive-date=2018-06-20 |archive-url=https://web.archive.org/web/20180620162103/https://www.bbc.co.uk/news/technology-12181153 |url-status=live }}</ref> was the [[EDSAC]],<ref>{{cite journal |last1=Wilkes |first1=W. V. |author-link=Maurice Wilkes |last2=Renwick |first2=W. |title=The EDSAC (Electronic delay storage automatic calculator) |journal=Math. Comp. |year=1950 |volume=4 |issue=30 |pages=61–65 |doi=10.1090/s0025-5718-1950-0037589-7|doi-access=free }}</ref> designed and constructed by [[Maurice Wilkes]] and his team at the [[University of Cambridge Mathematical Laboratory]] in [[England]] at the [[University of Cambridge]] in 1949. The machine was inspired by [[John von Neumann]]'s seminal ''[[First Draft of a Report on the EDVAC]]'' and was one of the first usefully operational electronic digital [[Von Neumann architecture|stored-program]] computers.{{efn|The Manchester Baby predated EDSAC as a [[stored-program computer]], but was built as a test bed for the [[Williams tube]] and not as a machine for practical use.<ref>{{cite web |title=A brief informal history of the Computer Laboratory |work=EDSAC 99 |url=https://www.cl.cam.ac.uk/events/EDSAC99/history.html |access-date=2020-12-01 |publisher=University of Cambridge Computer Laboratory |archive-url=https://web.archive.org/web/20130506195233/http://www.cl.cam.ac.uk/events/EDSAC99/history.html |archive-date=2013-05-06 |url-status=live}}</ref> However, the Manchester Mark 1 of 1949 (not to be confused with the 1948 prototype, the Baby) was available for university research in April 1949 despite being still under development.<ref>{{cite web |title=The Manchester Mark 1 |website=Computer 50 |url=https://www.computer50.org/mark1/MM1.html |access-date=2014-01-05 |url-status=dead |archive-url=https://web.archive.org/web/20140209155638/http://www.computer50.org/mark1/MM1.html |archive-date=2014-02-09}}</ref>}}

EDSAC ran its first programs on 6&nbsp;May 1949, when it calculated a table of squares<ref>{{cite journal|title=Pioneer computer to be rebuilt|journal=Cam|volume=62|date=2011|page=5}} To be precise, EDSAC's first program printed a list of the [[square number|square]]s of the [[integer (computer science)|integer]]s from 0 to 99 inclusive.</ref> and a list of [[prime number]]s.The EDSAC also served as the basis for the first commercially applied computer, the [[LEO (computer)|LEO I]], used by food manufacturing company [[J. Lyons and Co.|J. Lyons & Co. Ltd.]]  EDSAC 1 was finally shut down on 11 July 1958, having been superseded by EDSAC 2 which stayed in use until 1965.<ref>{{citation |title=EDSAC 99: 15–16 April 1999 |publisher=University of Cambridge Computer Laboratory |date=1999-05-06 |pages=68–69 |url=https://www.cl.cam.ac.uk/events/EDSAC99/booklet.pdf |access-date=2013-06-29 |archive-date=2020-09-26 |archive-url=https://web.archive.org/web/20200926061030/https://www.cl.cam.ac.uk/events/EDSAC99/booklet.pdf |url-status=live }}</ref>

{{blockquote|The "brain" [computer] may one day come down to our level [of the common people] and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far.|British newspaper ''The Star'' in a June 1949 news article about the [[EDSAC]] computer, long before the era of the personal computers.<ref>{{Cite web |first=Martin |last=Campbell-Kelly |date=July 2001 |title=Tutorial Guide to the EDSAC Simulator |publisher=Department of Computer Science, University of Warwick |url=https://www.dcs.warwick.ac.uk/~edsac/Software/EdsacTG.pdf |access-date=2016-11-18 |archive-url=https://web.archive.org/web/20151222132057/http://www.dcs.warwick.ac.uk/~edsac/Software/EdsacTG.pdf |archive-date=2015-12-22 |url-status=dead }}<br/>{{*}}{{Cite web |date=March 2018 |title=Tutorial Guide to the EDSAC Simulator |publisher=The EDSAC Replica Project, The National Museum of Computing |url=https://www.dcs.warwick.ac.uk/~edsac/Software/EdsacTG.pdf |access-date=2020-12-02 |archive-date=2015-12-22 |archive-url=https://web.archive.org/web/20151222132057/http://www.dcs.warwick.ac.uk/~edsac/Software/EdsacTG.pdf |url-status=live }}</ref>}}

===EDVAC===
[[File:Edvac.jpg|right|thumb|upright|EDVAC]]
[[ENIAC]] inventors [[John Mauchly]] and [[J. Presper Eckert]] proposed the [[EDVAC]]'s construction in August 1944, and design work for the EDVAC commenced at the [[University of Pennsylvania]]'s [[Moore School of Electrical Engineering]], before the [[ENIAC]] was fully operational.  The design implemented a number of important architectural and logical improvements conceived during the ENIAC's construction, and a high-speed [[Delay-line memory|serial-access memory]].<ref name="Wilkes" /> However, Eckert and Mauchly left the project and its construction floundered.

It was finally delivered to the [[United States Army|U.S. Army]]'s [[Ballistics Research Laboratory]] at the [[Aberdeen Proving Ground]] in August 1949, but due to a number of problems, the computer only began operation in 1951, and then only on a limited basis.

===Commercial computers===
The first commercial electronic computer was the [[Ferranti Mark 1]], built by [[Ferranti]] and delivered to the [[University of Manchester]] in February 1951. It was based on the [[Manchester Mark 1]]. The main improvements over the Manchester Mark 1 were in the size of the [[primary storage]] (using [[Random-access 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).{{sfn|Lavington|1998|p=25}} 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 |publisher=Computer Conservation Society |title=Our Computer Heritage Pilot Study: Deliveries of Ferranti Mark I and Mark I Star computers. |url=https://www.ourcomputerheritage.org/wp/ |archive-url=https://web.archive.org/web/20161211201840/http://www.ourcomputerheritage.org/wp/ |url-status=dead |archive-date=11 December 2016 |access-date=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 (Lyons Electronic Office) 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? | access-date = 10 January 2010 | archive-date = 2010-07-05 | archive-url = https://web.archive.org/web/20100705050757/http://www.bcs.org/server.php | url-status = dead }}</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 – the first business [[:Category:Application software|application]] to go live on a stored-program computer.{{efn|{{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. LEO would calculate an employee's pay, handle billing, and other office automation tasks.}}

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 {{US$|1 million}} each (${{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 {{val|125|ul=kW}} of power. Its primary storage was [[Sequential access|serial-access]] mercury delay lines capable of storing 1,000 words of 11 decimal digits plus sign (72-bit words).

In 1952, [[Groupe Bull|Compagnie des Machines Bull]] released the [[Bull Gamma 3|Gamma 3]] computer, which became a large success in Europe, eventually selling more than 1,200 units, and the first computer produced in more than 1,000 units.<ref name=":1">{{Cite journal |last=Leclerc |first=Bruno |date=January 1990 |title=From Gamma 2 to Gamma E.T.: The Birth of Electronic Computing at Bull |url=https://ieeexplore.ieee.org/document/4637512 |journal=Annals of the History of Computing |volume=12 |issue=1 |pages=5–22 |doi=10.1109/MAHC.1990.10010 |s2cid=15227017 |issn=0164-1239}}</ref> The Gamma 3 had innovative features for its time including a dual-mode, software switchable, BCD and binary ALU, as well as a hardwired floating-point library for scientific computing.<ref name=":1" /> In its E.T configuration, the Gamma 3 drum memory could fit about 50,000 instructions for a capacity of 16,384 words (around 100&nbsp;kB), a large amount for the time.<ref name=":1" />

[[File:IBM-650-panel.jpg|thumb|right|Front panel of the [[IBM 650]] ]]
Compared to the UNIVAC, IBM introduced a smaller, more affordable computer in 1954 that proved very popular.{{efn|For example, Kara Platoni's article on [[Donald Knuth]] stated that "there was something special about the IBM 650".<ref>{{cite magazine |first=Kara |last=Platoni |title=Love at First Byte |magazine=Stanford Magazine |url=https://www.stanfordalumni.org/news/magazine/2006/mayjun/features/knuth.html |date=May–June 2006 |archive-url= https://web.archive.org/web/20060925022700/http://www.stanfordalumni.org/news/magazine/2006/mayjun/features/knuth.html |archive-date=2006-09-25 |url-status=dead}}</ref>}}<ref>
V. M. Wolontis (18 August 1955) "A Complete Floating-Decimal Interpretive System for the I.B.M. 650 Magnetic Drum Calculator—Case 20878" Bell Telephone Laboratories Technical Memorandum MM-114-37, Reported in IBM Technical Newsletter No. 11, March 1956, as referenced in {{cite journal |title=Wolontis-Bell Interpreter |publisher=IEEE |journal=Annals of the History of Computing |volume=8 |issue=1 |date=January–March 1986 |pages=74–76 |doi=10.1109/MAHC.1986.10008 |s2cid=36692260}}
</ref> The [[IBM 650]] weighed over {{val|900|u=kg}}, the attached power supply weighed around {{val|1350|u=kg}} and both were held in separate cabinets of roughly 1.5{{times}}0.9{{times}}{{val|1.8|u=meters}}. The system cost {{US$|500000}}<ref>{{cite book |last=Dudley |first=Leonard |title=Information Revolution in the History of the West |year=2008 |url= https://books.google.com/books?id=jLnPi5aYoJUC&pg=PA266 |isbn=978-1-84720-790-6 |publisher=Edward Elgar Publishing |page=266 |access-date=2020-08-30}}</ref> (${{Formatprice|{{Inflation|US|500000|1954|r=-4}}|0}} as of {{CURRENTYEAR}}) or could be leased for {{US$|3500}} a month (${{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 |id=C24-4000-0 |url= http://www.bitsavers.org/pdf/ibm/650/24-4000-0_SOAPII.pdf |access-date=2009-05-25 |archive-date=2009-09-20 |archive-url=https://web.archive.org/web/20090920081523/http://www.bitsavers.org/pdf/ibm/650/24-4000-0_SOAPII.pdf |url-status=live}}</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 reduced.

===Microprogramming===
In 1951, British scientist [[Maurice Wilkes]] developed the concept of [[microcode|microprogramming]] from the realisation that the [[central processing unit]] of a computer could be controlled by a miniature, highly specialized [[computer program]] in high-speed [[Read-only memory|ROM]]. Microprogramming allows the base instruction set to be defined or extended by built-in programs (now called [[firmware]] or [[microcode]]).{{sfn|Horowitz|Hill|1989|p=743}} This concept greatly simplified CPU development. He first described this at the [[University of Manchester]] Computer Inaugural Conference in 1951, then published in expanded form in ''[[IEEE Spectrum]]'' in 1955.{{citation needed|date=April 2013}}

It was widely used in the CPUs and [[floating-point]] units of [[mainframe computer|mainframe]] and other computers; it was implemented for the first time in [[EDSAC 2]],<ref name="edsac2">{{Cite journal |last1=Wilkes |first1=M. V. |author-link1=Maurice Wilkes| title=Edsac 2 |doi=10.1109/85.194055 |journal=IEEE Annals of the History of Computing| volume=14 |issue=4 |pages=49–56 |year=1992 |s2cid=11377060}}</ref> which also used multiple identical "bit slices" to simplify design. Interchangeable, replaceable tube assemblies were used for each bit of the processor.{{efn|The microcode was implemented as ''extracode'' on Atlas.<ref>{{cite web |title=The Atlas Supervisor |author1=T. Kilburn |author2=R. B. Payne |author3=D. J. Howarth |year=1962 |work=Atlas Computer |url=https://www.chilton-computing.org.uk/acl/technology/atlas/p019.htm |access-date=2010-02-09 |archive-date=2009-12-31 |archive-url=https://web.archive.org/web/20091231062425/http://www.chilton-computing.org.uk/acl/technology/atlas/p019.htm |url-status=live }}</ref>}}