LEO (computer)

1947

In 1947, they sent two of its senior managers, Oliver Standingford and Raymond Thompson, to the US to look at new business methods developed during World War II.

1949

EDSAC was completed and ran its first program in May 1949. Following the successful completion of EDSAC, the Lyons' board agreed to start the construction of their own machine, expanding on the EDSAC design.

1951

LEO I ran its first business application in 1951.

On 15 February 1951 the computer, carrying out a simple test program, was shown to HRH Princess Elizabeth.

This was successfully run on 5 September 1951, and LEO took over Bakery Valuations calculations completely on 29–30 November 1951. Five files of archive material on the LEO Computer patent are held at the British Library and can be accessed through the British Library catalogue. ==Technical description== LEO I's clock speed was 500 kHz, with most instructions taking about 1.5 ms to execute.

1954

In 1954 Lyons formed LEO Computers Ltd to market LEO I and its successors LEO II and LEO III to other companies.

Met Office staff used a LEO I before the Met Office bought its own computer, a Ferranti Mercury, in 1959. In 1954, with the decision to proceed with LEO II and interest from other commercial companies, Lyons formed LEO Computers Ltd. ===Leo III=== The first LEO III was completed in 1961.

1956

The LEO project was also a pioneer in outsourcing: in 1956, Lyons started doing the payroll calculations for Ford UK and others on the LEO I machine.

1959

Met Office staff used a LEO I before the Met Office bought its own computer, a Ferranti Mercury, in 1959. In 1954, with the decision to proceed with LEO II and interest from other commercial companies, Lyons formed LEO Computers Ltd. ===Leo III=== The first LEO III was completed in 1961.

1961

Met Office staff used a LEO I before the Met Office bought its own computer, a Ferranti Mercury, in 1959. In 1954, with the decision to proceed with LEO II and interest from other commercial companies, Lyons formed LEO Computers Ltd. ===Leo III=== The first LEO III was completed in 1961.

1963

In 1963, LEO Computers Ltd was merged into English Electric Company and this led to the breaking up of the team that had inspired LEO computers.

1968

Another quirk was that many intermittent faults were due to faulty connectors and could be temporarily fixed by briskly strumming the card handles. English Electric LEO Computers, later English Electric Leo Marconi (EELM), eventually merged with International Computers and Tabulators (ICT) and others to form International Computers Limited (ICL) in 1968.

1980

In the 1980s, there were still ICL 2900 mainframes running LEO programs, using an emulator written in ICL 2960 microcode at the Dalkeith development centre.

1981

It then passed to International Computers Limited (ICL) and ultimately Fujitsu. LEO series computers were still in use until 1981. ==Origins and initial design== J.

1996

Resurrection, Summer issue 1996. Land, F.

Resurrection, Summer issue 1996. Aris, J.

2001

Lyons and Company, English Electric, and International Computers Ltd. About LEO — From Business Computing: the Second 50 Years, The Guildhall conference for business leaders, 2001.

2012

Archived in The Internet Archive on 2012-02-10. J.

2018

Lyons to subsidise it. In 2018, The Centre for Computing History along with LEO Computers Society were awarded funding from the Heritage Lottery Fund for their project aiming to bring together, preserve, archive and digitise a range of LEO Computers artefacts, and documents.

Accessed 2018-01-13.




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