Editing Charles Babbage (section)

==Computing pioneer==
[[File:BabbageDifferenceEngine.jpg|thumb|Part of Charles Babbage's [[Difference Engine]] (#1), assembled after his death by his son, Henry Prevost Babbage (1824–1918), using parts found in Charles' laboratory. [[Whipple Museum of the History of Science]], Cambridge, England.]]

Babbage's machines were among the first mechanical computers. That they were not actually completed was largely because of funding problems and clashes of personality, most notably with George Biddell Airy, the Astronomer Royal.<ref name="Swade">{{cite book |last=Swade |first=Doron |author-link=Doron Swade |title=The Cogwheel Brain |publisher=Little, Brown and Company |location=London |isbn=978-0-316-64847-9 |year=2000 |page=186 }}</ref>

Babbage directed the building of some steam-powered machines that achieved some modest success, suggesting that calculations could be mechanised. For more than ten years he received government funding for his project, which amounted to £17,000, but eventually the Treasury lost confidence in him.<ref name="Gleick">{{cite book |author=Gleick, J. |title=The Information: A History, a Theory, a Flood |publisher=Fourth Estate |location=London |year=2011 |page=104 |title-link=The Information: A History, a Theory, a Flood }}</ref>

While Babbage's machines were mechanical and unwieldy, their basic architecture was similar to that of a modern computer. The data and program memory were separated, operation was instruction-based, the control unit could make conditional jumps, and the machine had a separate [[Input/output|I/O]] unit.<ref name="Gleick" />

===Background on mathematical tables===
In Babbage's time, printed [[mathematical table]]s were calculated by [[human computer]]s; in other words, by hand. They were central to navigation, science and engineering, as well as mathematics. Mistakes were known to occur in transcription as well as calculation.<ref name="Th35"/>

At Cambridge, Babbage saw the fallibility of this process, and the opportunity of adding mechanisation into its management. His own account of his path towards mechanical computation references a particular occasion: {{blockquote|In 1812 he was sitting in his rooms in the Analytical Society looking at a table of logarithms, which he knew to be full of mistakes, when the idea occurred to him of computing all tabular functions by machinery. The French government had produced several tables by a new method. Three or four of their mathematicians decided how to compute the tables, half a dozen more broke down the operations into simple stages, and the work itself, which was restricted to addition and subtraction, was done by eighty computers who knew only these two arithmetical processes. Here, for the first time, mass production was applied to arithmetic, and Babbage was seized by the idea that the labours of the unskilled computers [people] could be taken over completely by machinery which would be quicker and more reliable.<ref>[[B. V. Bowden]], ''Faster than Thought'', Pitman (1953), p. 8.</ref>}}

There was another period, seven years later, when his interest was aroused by the issues around computation of mathematical tables. The French official initiative by [[Gaspard de Prony]], and its problems of implementation, were familiar to him. After the [[Napoleonic Wars]] came to a close, scientific contacts were renewed on the level of personal contact: in 1819 [[Charles Blagden]] was in Paris looking into the printing of the stalled de Prony project, and lobbying for the support of the Royal Society. In works of the 1820s and 1830s, Babbage referred in detail to de Prony's project.<ref>{{cite book|author=Martin Campbell-Kelly|title=The History of Mathematical Tables: From Sumer to Spreadsheets|url=https://books.google.com/books?id=O170gWPZ7M8C&pg=PA110|year=2003|publisher=Oxford University Press|isbn=978-0-19-850841-0|page=110}}</ref><ref>{{cite book|author=Charles Coulston Gillispie|title=Science and Polity in France: The End of the Old Regime|url=https://books.google.com/books?id=EPgIpRIvaSAC&pg=PA485|year=2009|publisher=Princeton University Press|isbn=978-1-4008-2461-8|page=485}}</ref>

===Difference engine===
{{main|Difference engine}}
[[File:Babbage Difference Engine.jpg|thumb|The Science Museum's Difference Engine No. 2, built from Babbage's design]]
[[File:Babbage difference engine drawing.gif|thumb|Portion of Babbage's difference engine]]

Babbage began in 1822 with what he called the difference engine, made to compute values of [[polynomial function]]s. It was created to calculate a series of values automatically. By using the method of finite differences, it was possible to avoid the need for multiplication and division.<ref>{{Cite web|url=https://www.britannica.com/technology/Difference-Engine|title=Difference Engine {{!}} calculating machine|website=Encyclopædia Britannica|access-date=13 May 2019}}</ref>

For a prototype difference engine, Babbage brought in [[Joseph Clement]] to implement the design, in 1823. Clement worked to high standards, but his [[machine tool]]s were particularly elaborate. Under the standard terms of business of the time, he could charge for their construction, and would also own them. He and Babbage fell out over costs around 1831.<ref>{{cite ODNB|id=37291|title=Clement, Joseph|first=Anita|last=McConnell}}</ref>

Some parts of the prototype survive in the [[Museum of the History of Science, Oxford]].<ref>{{Cite journal | first = Denis | last = Roegel | title = Prototype Fragments from Babbage's First Difference Engine | journal=IEEE Annals of the History of Computing | volume = 31 | pages = 70–75 | date = April–June 2009 | issue = 2 | doi = 10.1109/MAHC.2009.31 | s2cid = 45564453 }}</ref> This prototype evolved into the "first difference engine". It remained unfinished and the finished portion is located at the Science Museum in London. This first difference engine would have been composed of around 25,000 parts, weighed {{Convert|15|short ton|kg|spell=in|lk=in|sigfig=3}}, and would have been {{Convert|8|ft|m|1|abbr=on}} tall. Although Babbage received ample funding for the project, it was never completed. He later (1847–1849) produced detailed drawings for an improved version,"Difference Engine No. 2", but did not receive funding from the British government. His design was finally constructed in 1989–1991, using his plans and 19th-century manufacturing tolerances. It performed its first calculation at the Science Museum, London, returning results to 31 digits.<ref>{{Cite web |title=Babbage's Difference Engine No 2, 2002. {{!}} Science Museum Group Collection |url=https://collection.sciencemuseumgroup.org.uk/objects/co62748/babbages-difference-engine-no-2-2002 |access-date=2025-03-25 |website=collection.sciencemuseumgroup.org.uk |language=en}}</ref>

Nine years later, in 2000, the Science Museum completed the [[computer printer|printer]] Babbage had designed for the difference engine.<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/710950.stm |title=SCI/TECH &#124; Babbage printer finally runs |work=BBC News |date=13 April 2000 |access-date=27 April 2012}}</ref> His printers were the first computer printers invented.<ref name=":2" />

====Completed models====
The Science Museum has constructed two Difference Engines according to Babbage's plans for the Difference Engine No 2. One is owned by the museum. The other, owned by the technology multimillionaire [[Nathan Myhrvold]], went on exhibition at the [[Computer History Museum]]<ref>{{cite web | url = http://www.computerhistory.org/babbage/ | title = Overview&nbsp;– The Babbage Engine | publisher=Computer History Museum | access-date =29 January 2009 }}</ref> in [[Mountain View, California]] on 10 May 2008.<ref>{{cite news | last = Shiels | first = Maggie | title = Victorian 'supercomputer' is reborn | url = http://news.bbc.co.uk/2/hi/technology/7391593.stm | access-date =11 May 2008 |work=BBC News  | date = 10 May 2008 }}</ref> The two models that have been constructed are not replicas.

===Analytical Engine===
{{main|Analytical Engine}}
[[File:Babbages Analytical Engine, 1834-1871. (9660574685).jpg|thumb|Portion of the mill with a printing mechanism of the Analytical Engine, built by Charles Babbage, as displayed at the Science Museum (London)]]
After the attempt at making the first difference engine fell through, Babbage worked to design a more complex machine called the Analytical Engine. He hired C. G. Jarvis, who had previously worked for Clement as a draughtsman.<ref name="CollierMacLachlan2000">{{cite book|author1=Bruce Collier|author2=James MacLachlan|title=Charles Babbage: And the Engines of Perfection|url=https://books.google.com/books?id=-vzMEwf-bHEC&pg=PA65|year=2000|publisher=Oxford University Press|isbn=978-0-19-514287-7|page=65}}</ref> The Analytical Engine marks the transition from mechanised arithmetic to fully-fledged general purpose computation. It is largely on it that Babbage's standing as computer pioneer rests.<ref>{{cite web|title=The Baggage Engine|url=http://www.computerhistory.org/babbage/|publisher=Computer History Museum|access-date=6 March 2013}}</ref>

The major innovation was that the Analytical Engine was to be programmed using [[punched card]]s: the Engine was intended to use loops of [[Jacquard loom|Jacquard's]] punched cards to control a mechanical calculator, which could use as input the results of preceding computations.<ref name="Ceruzzi, Paul">{{cite book|last=Ceruzzi|first=Paul|title=Computing: A Concise History|year=2012|publisher=Smithsonian Institution|location=United States|isbn=978-0-262-51767-6|pages=7–8}}</ref><ref name="Gross">{{cite journal|last1=Gross|first1=Benjamin|title=The French connection|journal=Distillations Magazine|date=Fall 2015|volume=1|issue=3|pages=10–13|url=https://www.sciencehistory.org/distillations/magazine/the-french-connection|access-date=22 March 2018}}</ref> The machine was also intended to employ several features subsequently used in modern computers, including sequential control, branching and looping. It would have been the first mechanical device to be, in principle, [[Turing-complete]]. Charles Babbage wrote a series of programs for the Analytical Engine from 1837 to 1840.<ref name="IEEE2021">{{Cite journal | last1 = Rojas | first1 = R. | title = The Computer Programs of Charles Babbage | journal = IEEE Annals of the History of Computing | volume = 43 | issue = 1 | pages = 6–18 | year = 2024 | doi = 10.1109/MAHC.2020.3045717}}</ref> The first program was finished in 1837.<ref name="IEEE2024">{{Cite journal | last1 = Rojas | first1 = R. | title = The First Computer Program | journal = Communications of the ACM | volume = 67 | issue = 6 | pages = 78–81 | year = 2024 | doi = 10.1145/3624731| doi-access = free }}</ref> The Engine was not a single physical machine, but rather a succession of designs that Babbage tinkered with until his death in 1871.<ref>{{Cite journal |last=Ashworth |first=William J. |date=March 2002 |title=Bruce Collier; James MacLachlan. ''Charles Babbage and the Engines of Perfection''. 123 pp., illus., figs., tables, apps., bibl., index. New York/Oxford: Oxford University Press, 2000. $11.95 (paper). |url=https://doi.org/10.1086/343300 |journal=Isis |volume=93 |issue=1 |pages=127–128 |doi=10.1086/343300 |issn=0021-1753}}</ref>
[[File:Opening George III museum.jpg|thumb|Part of the Analytical Engine on display, in 1843, left of centre in this engraving of the [[King George III Museum]] in [[King's College, London]]]]

===Ada Lovelace and Italian followers===
Ada Lovelace, who corresponded with Babbage during his development of the Analytical Engine, is credited with developing an algorithm that would enable the Engine to calculate a sequence of [[Bernoulli numbers]].<ref name="Legacy">Robin Hammerman, Andrew L. Russell (2016). ''Ada's Legacy: Cultures of Computing from the Victorian to the Digital Age''. Association for Computing Machinery and Morgan & Claypool Publishers. {{ISBN|978-1-970001-51-8}}</ref> Despite documentary evidence in Lovelace's own handwriting,<ref name="Legacy" /> some scholars dispute to what extent the ideas were Lovelace's own.<ref>{{cite book |last=Bromley |first=Allan G. |author-link=Allan G. Bromley |contribution=Difference and Analytical Engines |title=Computing Before Computers |editor-first=William |editor-last=Aspray |publisher=Iowa State University Press |location=Ames |pages=59–98 |chapter-url=http://ed-thelen.org/comp-hist/CBC-Ch-02.pdf |archive-url=https://ghostarchive.org/archive/20221010/http://ed-thelen.org/comp-hist/CBC-Ch-02.pdf |archive-date=2022-10-10 |url-status=live |date=1990 |isbn=978-0-8138-0047-9}} p. 89.</ref><ref>{{cite journal |last=Stein |first=Dorothy K. |year=1984 |title=Lady Lovelace's Notes: Technical Text and Cultural Context |journal=Victorian Studies |pages=33–67 |volume=28 |issue=1}} p. 34.</ref><ref>{{cite thesis |last=Collier |first=Bruce |title=The Little Engines That Could've: The Calculating Machines of Charles Babbage |type=PhD |publisher=Harvard University |year=1970 |url=http://robroy.dyndns.info/collier |access-date=18 December 2015}} Chapter 3.</ref> For this achievement, she is often described as the first [[programmer|computer programmer]];<ref>{{cite journal |vauthors=Fuegi J, Francis J | title = Lovelace & Babbage and the creation of the 1843 'notes' | journal=Annals of the History of Computing | volume = 25 | issue = 4 | pages = 16–26 | date = October–December 2003 | doi = 10.1109/MAHC.2003.1253887 }} See pages 19, 25</ref>{{Failed verification|date=March 2019|reason="computer programmer" or similar not found in article}} though no programming language had yet been invented.<ref name="Legacy" /><ref>{{Cite encyclopedia|url=https://www.britannica.com/biography/Charles-Babbage|title=Charles Babbage {{!}} Biography & Facts|encyclopedia=Encyclopædia Britannica|access-date=21 December 2017}}</ref>

Lovelace also translated and wrote literature supporting the project.  Describing the engine's programming by punch cards, she wrote: "We may say most aptly that the Analytical Engine weaves algebraical patterns just as the [[Jacquard loom]] weaves flowers and leaves."<ref name="Gross" />

Babbage visited [[Turin]] in 1840 at the invitation of [[Giovanni Plana]], who had developed in 1831 an analog computing machine that served as a [[Cappella dei Mercanti, Turin|perpetual calendar]]. Here in 1840 in Turin, Babbage gave the only public explanation and lectures about the Analytical Engine.<ref>{{Cite web|last=Wired|title=Charles Babbage Left a Computer Program in Turin in 1840. Here It Is.|url=https://cacm.acm.org/news/217292-charles-babbage-left-a-computer-program-in-turin-in-1840-here-it-is/fulltext|access-date=24 September 2021|website=cacm.acm.org|language=en}}</ref><ref>{{Cite magazine|last=Sterling|first=Bruce|title=Charles Babbage left a computer program in Turin in 1840. Here it is.|language=en-US|magazine=Wired|url=https://www.wired.com/beyond-the-beyond/2017/05/charles-babbage-left-computer-program-turin-1840/|access-date=24 September 2021|issn=1059-1028}}</ref> In 1842 [[Charles Wheatstone]] approached Lovelace to translate a paper of [[Luigi Menabrea]], who had taken notes of Babbage's Turin talks; and Babbage asked her to add something of her own. Fortunato Prandi who acted as interpreter in Turin was an Italian exile and follower of [[Giuseppe Mazzini]].<ref>{{cite book |author=Benjamin Woolley |title=The Bride of Science |year=1999 |publisher=Macmillan |isbn=978-0-333-72436-1 |pages=258–260, 338}}</ref>

===Swedish followers===
[[Per Georg Scheutz]] wrote about the difference engine in 1830, and experimented in automated computation. After 1834 and Lardner's ''Edinburgh Review'' article he set up a project of his own, doubting whether Babbage's initial plan could be carried out. This he pushed through with his son, Edvard Scheutz.<ref name="Lingren1990">{{cite book|author=Michael Lingren|title=Glory and Failure: The Difference Engines of Johann Müller, Charles Babbage and Georg and Edvard Scheutz|url=https://books.google.com/books?id=plgMl2yfVkwC&pg=PA98|year=1990|publisher=MIT Press|isbn=978-0-262-12146-0|pages=98–112}}</ref> Another Swedish engine was that of [[Martin Wiberg]] (1860).<ref>{{cite book|author=I. Grattan-Guinness|title=Companion encyclopedia of the history and philosophy of the mathematical sciences|url=https://books.google.com/books?id=2hDvzITtfdAC&pg=PA698|year=2003|publisher=JHU Press|isbn=978-0-8018-7396-6|page=698}}</ref>

===Legacy===
In 2011, researchers in Britain proposed a multimillion-pound project, "Plan 28",<ref>{{Cite web|url=http://blog.plan28.org/|title=Plan 28 Blog|website=Blog.plan28.org|access-date=10 June 2022}}</ref> to construct Babbage's Analytical Engine.  Since Babbage's plans were continually being refined and were never completed, they intended to engage the public in the project and [[crowdsourcing|crowd-source]] the analysis of what should be built.<ref>{{cite news | url = https://www.nytimes.com/2011/11/08/science/computer-experts-building-1830s-babbage-analytical-engine.html | title = It Started Digital Wheels Turning | newspaper=The New York Times | date = 7 November 2011 | access-date =10 November 2011 | last1 = Markoff | first1 = John }}</ref> It would have the equivalent of 675 bytes of memory, and run at a clock speed of about 7&nbsp;Hz.  They hoped to complete it by the 150th anniversary of Babbage's death, in 2021.<ref>{{cite news
 | url=https://www.bbc.co.uk/news/technology-15001514
 | title=Babbage Analytical Engine designs to be digitised
 | work=BBC News
 | date=21 September 2011
| access-date=19 March 2012 }}
</ref>

Advances in [[microelectromechanical system|MEMS]] and [[nanotechnology]] have led to recent high-tech experiments in mechanical computation. The benefits suggested include operation in high radiation or high temperature environments.<ref>{{cite web|url=http://findarticles.com/p/articles/mi_m0WVI/is_1999_Oct_11/ai_56912203/print |archive-url=https://web.archive.org/web/20071013201309/http://findarticles.com/p/articles/mi_m0WVI/is_1999_Oct_11/ai_56912203/print |url-status=dead |archive-date=13 October 2007 |title=Electronics Times: Micro-machines are fit for space |via=Find Articles |date=11 October 1999 |access-date=29 January 2009 }}</ref> These modern versions of mechanical computation were highlighted in ''[[The Economist]]'' in its special "end of the millennium" black cover issue in an article entitled "Babbage's Last Laugh".<ref>{{cite news |title=Babbage's Last Laugh |newspaper=The Economist |date=9 September 1999 |url=http://www.economist.com/node/324654?story_id=E1_PNQGVQ}}</ref>

Due to his association with the town Babbage was chosen in 2007 to appear on the 5 [[Totnes pound]] note.<ref>{{cite web|url=http://www.westernmorningnews.co.uk/Meet-new-faces-local-currency/story-21152600-detail/story.html|title=Latest Devon News |website=Devon Live|access-date=5 December 2015|archive-url=https://web.archive.org/web/20140810153519/http://www.westernmorningnews.co.uk/Meet-new-faces-local-currency/story-21152600-detail/story.html|archive-date=10 August 2014|url-status=dead}}</ref> An image of Babbage features in the [[British culture|British cultural icons]] section of the newly designed [[British passport]] in 2015.<ref>{{cite news|title=Introducing the new UK passport design|url=https://www.gov.uk/government/uploads/system/.../HMPO_magazine.pdf|publisher=Government of the United Kingdom|date=7 November 2016}}</ref>