Explore our LEO Computers Collection

Discover more about our LEO Computers collection through these topics. 

Click on the blue links or the blue arrows at the bottom of the page to see all the items that have been tagged with each topic. Information on the individual LEO machines produced can be found on our How Many LEOs page.

CLEO (Clear Language for Expressing Orders) was a second generation Autocode for LEO. It combined features of COBOL and Algol.

David Caminer
As head of Lyons' Systems Research Office, David Caminer was the system designer behind the Lyons Electronic Office (LEO). He has been described as the inventor of systems analysis and his methodological approach was a key factor in the success of LEO.

Early computers and their interrelationships
There was a lot of cross-fertilisation of ideas amongst the various people who developed the early (1940s/1950s) computer systems, LEO included.

The first LEO computer was based on the Electronic Delay Storage Automatic Calculator (EDSAC) developed at the University of Cambridge by Maurice Wilkes.

Ernest Lenaerts
On the inauguration of the collaboration between Cambridge University and Lyons on the EDSAC/LEO project, Lyons employee Ernest Lenaerts was sent to Cambridge both to learn about computer technology and to help in the design of EDSAC. When Lyons commenced building LEO in 1949 he joined John Pinkerton in the design team.

John Pinkerton
Maurice Wilkes recommended John Pinkerton to J. Lyons & Co as the engineer to design and develop LEO. He joined Lyons in January 1949 and started to build the small team of engineers which succeeded in building LEO I.

LEO were early pioneers in reading original documents directly into computers, eliminating problems of data preparation and making possible dynamic large scale data processing.

We have tagged original documents that refer to the first three iterations of the LEO computer. Although there was only one of the first LEO computers, installed at Lyons HQ in Cadby Hall in London, there were 11 LEO II computers and many LEO IIIs. Machines after LEO I are referred to by their numerical place in the production cycle, i.e. LEO II/2 was the second LEO II, which was installed at tobacco company WD & HO Wills. All of the LEOs are listed on our How Many LEOs page.

Although everything about the early LEOs is about J. Lyons & Co, this tag is applied to documents that include specific detail on Lyons. J. Lyons & Co was one of the UK's largest catering companies in the early part of the twentieth century.

This tag applies to items that highlight the roles women have played in computing history, including LEO.
As we make more images from our collections available over the coming months, we will add more topics in a systematic and consistent manner. If you would like to suggest a topic for inclusion on this page, please let us know.

Date : Unknown

This exhibit has a reference ID of CH55802. Please quote this reference ID in any communication with the Centre for Computing History.

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