Editing History of computing hardware (section)

===The electronic programmable computer===
{{Main|Colossus computer|ENIAC}}
[[File:Colossus.jpg|thumb|Colossus was the first [[electronics|electronic]] [[Digital electronics|digital]] [[Computer programming|programmable]] computing device, and was used to break German ciphers during World War II. It remained unknown, as a military secret, well into the 1970s.]]
During World War II, British codebreakers at [[Bletchley Park]], {{convert|40|mi|km}} north of London, achieved a number of successes at breaking encrypted enemy military communications. The German encryption machine, [[Enigma (machine)|Enigma]], was first attacked with the help of the electro-mechanical [[bombe]]s.{{sfn|Welchman|1984|pp=138–145, 295–309}} 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, code-named "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 developed the [[Heath Robinson (codebreaking machine)|Heath Robinson]], a fixed-function machine to aid in code breaking.{{sfn|Copeland|2006|p=182}} [[Tommy Flowers]], a senior engineer at the [[Post Office Research Station]]{{sfn|Randell|1980|p=9}} was recommended to Max Newman by Alan Turing{{sfn|Budiansky|2000|p=314}} and spent eleven months from early February 1943 designing and building the more flexible [[Colossus computer]] (which superseded the [[Heath Robinson (codebreaking machine)|Heath Robinson]]).<ref>{{cite news |title=Bletchley's code-cracking Colossus |newspaper=BBC News |date=2 February 2010 |url=https://news.bbc.co.uk/1/hi/technology/8492762.stm |access-date=19 October 2012 |url-status=live |archive-date=2020-03-08 |archive-url=https://web.archive.org/web/20200308163851/http://news.bbc.co.uk/2/hi/technology/8492762.stm}}</ref><ref>{{Citation |last=Fensom|first=Jim|title=Harry Fensom obituary |newspaper=The Guardian |date=8 November 2010 |url=https://www.theguardian.com/theguardian/2010/nov/08/harry-fensom-obituary|access-date=17 October 2012|archive-date=2013-09-17 |archive-url=https://web.archive.org/web/20130917220225/http://www.theguardian.com/theguardian/2010/nov/08/harry-fensom-obituary |url-status=live}}</ref> After a functional test in December 1943, Colossus was shipped to Bletchley Park, where it was delivered on 18 January 1944<ref>{{cite web |last=Sale |first=Tony |title=Colossus - The Rebuild Story |publisher=The National Museum of Computing |url=https://www.tnmoc.org/colossus-rebuild-story |archive-url=https://web.archive.org/web/20150418230306/http://www.tnmoc.org/colossus-rebuild-story |archive-date=2015-04-18 |url-status=dead}}</ref> and attacked its first message on 5 February.{{sfn|Copeland|2006|p=75}} By the time Germany surrendered in May 1945, there were ten [[Colossus computer|Colossi]] working at Bletchley Park.{{sfn|Copeland|2006|p=2}}

[[File:Wartime photo of Colossus 10.png|thumb|left|Wartime photo of Colossus No. 10]]
Colossus was the world's first [[electronics|electronic]] [[digital electronics|digital]] [[Computer programming|programmable]] [[computer]].<ref name="stanf" /> 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,<ref>{{Citation |last=Small |first=Albert W. |title=The Special Fish Report |publisher=The American National Archive (NARA) |location=College Campus Washington |date=December 1944 |url=https://www.codesandciphers.org.uk/documents/small/smallix.htm |access-date=2019-01-11 |archive-date=2011-05-15 |archive-url=https://web.archive.org/web/20110515021436/http://www.codesandciphers.org.uk/documents/small/smallix.htm |url-status=live}}</ref> but it was not [[Turing-complete]]. Data input to Colossus was by [[photoelectric sensor|photoelectric]] reading of a paper tape transcription of the enciphered intercepted message. This was arranged in a continuous loop so that it could be read and re-read multiple times – there being no internal store for the data. The reading mechanism ran at 5,000 characters per second with the paper tape moving at {{cvt|40|ft/s|m/s mph|sigfig=3}}. Colossus Mark 1 contained 1500 thermionic valves (tubes), but Mark 2 with 2400 valves and five processors in parallel, was both 5 times faster and simpler to operate than Mark 1, greatly speeding the decoding process. Mark 2 was designed while Mark 1 was being constructed. [[Allen Coombs]] took over leadership of the Colossus Mark 2 project when [[Tommy Flowers]] moved on to other projects.<ref>{{Citation |last1=Randell |first1=Brian |author-link=Brian |last2=Fensom |first2=Harry |last3=Milne |first3=Frank A. |title=Obituary: Allen Coombs |newspaper=The Independent |date=15 March 1995 |url=https://www.independent.co.uk/news/people/obituary-allen-coombs-1611270.html |access-date=18 October 2012 |archive-date=2012-02-03 |archive-url=https://web.archive.org/web/20120203042657/http://www.independent.co.uk/news/people/obituary-allen-coombs-1611270.html |url-status=dead}}</ref> The first Mark 2 Colossus became operational on 1 June 1944, just in time for the Allied [[Invasion of Normandy]] on [[Normandy landings|D-Day]].

Most of the use of Colossus was in determining the start positions of the Tunny rotors for a message, which was called "wheel setting". Colossus included the first-ever use of [[shift register]]s and [[systolic array]]s, enabling five simultaneous tests, each involving up to 100 [[Boolean algebra|Boolean calculations]]. This enabled five different possible start positions to be examined for one transit of the paper tape.<ref>{{Citation |last=Flowers |first=T. H. |author-link=Tommy Flowers |title=The Design of Colossus |journal=Annals of the History of Computing |volume=5 |issue=3 |pages=239–252 |year=1983 |doi=10.1109/MAHC.1983.10079 |s2cid=39816473 |url=https://www.ivorcatt.com/47c.htm |access-date=2019-03-03 |archive-date=2006-03-26 |archive-url=https://web.archive.org/web/20060326041703/http://www.ivorcatt.com/47c.htm |url-status=live}}</ref> As well as wheel setting some later [[Colossus computer|Colossi]] included mechanisms intended to help determine pin patterns known as "wheel breaking". Both models were programmable using switches and plug panels in a way their predecessors had not been.

[[File:Glen Beck and Betty Snyder program the ENIAC in building 328 at the Ballistic Research Laboratory.jpg|thumb|[[ENIAC]] was the first Turing-complete electronic device, and performed ballistics trajectory calculations for the [[United States Army]].<ref>{{cite magazine |date=2014-11-25 |title=How the World's First Computer Was Rescued From the Scrap Heap |url=https://www.wired.com/2014/11/eniac-unearthed/ |first=Brendan I. |last=Loerner |magazine=Wired |access-date=2017-03-07 |archive-date=2017-05-02 |archive-url=https://web.archive.org/web/20170502064714/https://www.wired.com/2014/11/eniac-unearthed/ |url-status=live}}</ref>]]
Without the use of these machines, the [[Allies of World War II|Allies]] would have been deprived of the very valuable [[military intelligence|intelligence]] that was obtained from reading the vast quantity of [[encipher]]ed high-level [[telegraphy|telegraphic]] messages between the [[Oberkommando der Wehrmacht|German High Command (OKW)]] and their [[Wehrmacht|army]] commands throughout occupied Europe. Details of their existence, design, and use were kept secret well into the 1970s. [[Winston Churchill]] personally issued an order for their destruction into pieces no larger than a man's hand, to keep secret that the British were capable of cracking [[Lorenz cipher|Lorenz SZ cyphers]] (from German rotor stream cipher machines) during the oncoming Cold War. Two of the machines were transferred to the newly formed [[GCHQ]] and the others were destroyed. As a result, the machines were not included in many histories of computing.{{efn|The existence of Colossus was kept secret by the UK Government for 30 years and so was not known to American computer scientists, such as [[Gordon Bell]] and [[Allen Newell]]. And was not in {{harvp|Bell|Newell|1971}} ''Computing Structures'', a standard reference work in the 1970s.}} A reconstructed working copy of one of the Colossus machines is now on display at Bletchley Park.

The [[ENIAC]] (Electronic Numerical Integrator and Computer) was the first electronic programmable computer built in the US. Although the ENIAC used similar technology to the [[Colossus computer|Colossi]], it was much faster and more flexible and was Turing-complete. Like the Colossi, a "program" on the ENIAC was defined by the states of its patch cables and switches, a far cry from the [[stored-program computer|stored-program]] electronic machines that came later. Once a program was ready to be run, it had to be mechanically set into the machine with manual resetting of plugs and switches. The programmers of the ENIAC were women who had been trained as mathematicians.{{Sfn|Evans|2018|p=39}}

It combined the high speed of electronics with the ability to be programmed for many complex problems. It could add or subtract 5000 times a second, a thousand times faster than any other machine. It also had modules to multiply, divide, and square root. High-speed memory was limited to 20 words (equivalent to about 80 bytes). Built under the direction of [[John Mauchly]] and [[J. Presper Eckert]] at the University of Pennsylvania, ENIAC's development and construction lasted from 1943 to full operation at the end of 1945. The machine was huge, weighing 30 tons, using 200 kilowatts of electric power and contained over 18,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors.<ref name="Eniac">{{cite web|url=https://www.techiwarehouse.com/engine/a046ee08/Generations-of-Computer|title=Generations of Computer|access-date=11 August 2015|archive-url=https://web.archive.org/web/20150702211455/http://www.techiwarehouse.com/engine/a046ee08/Generations-of-Computer/|archive-date=2 July 2015|url-status=dead}}</ref> One of its major engineering feats was to minimize the effects of tube burnout, which was a common problem in machine reliability at that time. The machine was in almost constant use for the next ten years.