Editing LEO (computer) (section)

== Origins and initial design ==

[[J. Lyons and Co.]] was one of the UK's leading catering and food manufacturing companies in the first half of the 20th century.  In 1947, two of its senior managers, Oliver Standingford and Raymond Thompson, were sent to the United States to look at new business methods developed during [[World War II]]. During the visit, they met [[Herman Goldstine]] who was one of the original developers of [[ENIAC]], the first general-purpose electronic computer. Standingford and Thompson saw the potential of computers to help solve the problem of administering a major business enterprise.  They also learned from Goldstine that, back in the UK, [[Douglas Hartree]] and [[Maurice Wilkes]] were actually building another such machine, the pioneering [[EDSAC]] computer, at the [[University of Cambridge]].<ref>Ferry (2003), Chapter 2</ref>

On their return to the UK, Standingford and Thompson visited Hartree and Wilkes in Cambridge and were favourably impressed with their technical expertise and vision. Hartree and Wilkes estimated that EDSAC was 12–18 months from completion, but said that this interval could be shortened by additional funding. Standingford and Thompson wrote a report to the Lyons' board recommending that Lyons should acquire or build a computer to meet their business needs.  The board agreed that, as a first step, Lyons would provide Hartree and Wilkes with £2,500 for the EDSAC project, and would also provide them with the services of a Lyons electrical engineer, Ernest Lenaerts. EDSAC was completed and ran its first program in May 1949.<ref>Ferry (2003), Chapter 3</ref>

Following the successful completion of EDSAC, the Lyons board agreed to start the construction of their own machine, expanding on the EDSAC design. The LEO computer room, which took up around 2,500 square feet of floor space, was at [[Cadby Hall]] in Hammersmith.<ref name=":1">{{Cite web|last=Speed|first=Richard|date=30 November 2021|title=70 years ago, 'computer for business' LEO ran first biz app|url=https://www.theregister.com/2021/11/30/leo_70/|access-date=2021-11-30|website=[[The Register]]|language=en}}</ref>

The Lyons machine was christened Lyons Electronic Office, or LEO. On the recommendation of Wilkes, Lyons recruited [[John Pinkerton (computer designer)|John Pinkerton]], a radar engineer and research student at Cambridge, as team leader for the project. Lenaerts returned to Lyons to work on the project, and Wilkes provided training for Lyons' engineer Derek Hemy, who would be responsible for writing LEO's programs. On 15 February 1951 the computer, carrying out a simple test program, was shown to [[Royal Highness|HRH]] [[Elizabeth II|Princess Elizabeth]].<ref name=":0">{{Cite book |url=https://books.google.com/books?id=O4VPAAAAMAAJ |title=LEO: The First Business Computer |author-last=Bird |author-first=Peter John |year=1994 |publisher=Hasler |isbn=9780952165101 |pages=84, 86, 228}}</ref> The first business application to be run on LEO was Bakery Valuations, which computed the costs of ingredients used in bread and cakes.<ref name=":2">{{Cite web|date=9 November 2018|title=Meet LEO, the world's first business computer|url=https://www.sciencemuseum.org.uk/objects-and-stories/meet-leo-worlds-first-business-computer|access-date=2021-11-30|website=Science Museum|language=en}}</ref> This was successfully run on 5 September 1951,<ref name=":0" /> and LEO took over Bakery Valuations calculations completely on 29–30 November 1951.<ref>Ferry (2003), Chapter 4</ref><ref name=":0" />

[[Mary Coombs]] was employed in 1952 as the first female programmer to work on LEO, and as such she is recognized as the first female commercial programmer.<ref>{{cite web|url=http://www.bl.uk/voices-of-science/interviewees/mary-coombs|title=Mary Coombs|work=The British Library}}</ref><ref name="computingheritage">{{Citation|last=computingheritage|title=Mary Coombs shares her story|date=5 September 2013|url=https://www.youtube.com/watch?v=C6DRr0Dhn4Q|publisher=YouTube|access-date=26 July 2018}}</ref><ref>{{Cite news|url=https://www.telegraph.co.uk/women/womens-life/10299904/Bletchley-Park-celebrates-women-in-computing.html|title=Bletchley Park celebrates women in computing|journal=The Daily Telegraph|last=Douglas|first=Ian|date=11 September 2013|access-date=26 July 2018|language=en-GB|issn=0307-1235}}</ref><ref>{{Cite news|url=https://artsandculture.google.com/exhibit/ARmIoOoP|title=Women in Computing: a British Perspective – Google Arts & Culture|work=Google Cultural Institute|access-date=26 July 2018|language=en}}</ref><ref>{{Cite web|url=http://www.computinghistory.org.uk/det/45796/Mary-Coombs/|title=Mary Coombs – Computing History|website=www.computinghistory.org.uk|access-date=26 July 2018}}</ref>

Five files of archive material on the LEO Computer patent are held at the [[British Library]] and can be accessed through the British Library Archives catalogue.<ref>[http://searcharchives.bl.uk/IAMS_VU2:IAMS032-003391654 LEO Computer Patent], archives and manuscripts catalogue, the British Library. Retrieved 2 June 2020</ref>