LEO editor

Professor Paul Ceruzzi, Smithsonian Institute Washington

“Most surveys of the history of computing mark the beginning of the commercial computer age with the delivery of the first UNIVAC in 1951.  The better ones note the first delivery of a UNIVAC to a commercial, not government, customer (General Electric) in 1954.  Only the best histories mention LEO, a computer  built by the British catering company J. Lyons & Co. and first operational in September 1951, as the real beginning of commercial application of the stored-program computer.”

Professor Paul Ceruzzi: Read More »

Ferry, Georgina (2003) ‘A Computer Called LEO’, Fourth Estate, London.
‘LEO and its creators deserve their place in history not because of what it was, but because of what it did. For LEO was the first computer in the world to be harnessed to the task of running a business.

                              A paperback edition was published in 2005, by Harper Perennial

Ferry, Georgina (2003) ‘A Computer Called LEO’: Read More »

Caminer H., editor (2016) ‘LEO remembered: by the people who worked on the world’s first business computers’, LEO Computers Society. Collection of reminiscences, testifying to a sense of collective endeavour among the LEO community.

Caminer H., editor (2016): Read More »

Lenaerts, E. (1948) ‘Development of the LEO Computer: Brief Description of EDSAC’.
Peter Bird collected and had bound (September 1992) the photocopies of the handwritten description of EDSAC compiled by Ernest Lenaerts in October 1948, with contributions from David Caminer, Derek Hemy, Thomas Thompson and others.  It formed the basis of a larger publication titled The Layman’s Guide to LEO – see below.  The volume was donated to the LEO Computers Society by Philip Bird, November 2017.

Lenaerts, E. (1948) ‘Development of the LEO Computer: Read More »

Anonymous note retrieved by John Daines

ICL set up the Scottish Development Centre at Dalkeith House in late 1970 and transferred all the System 4 software support from Kidsgrove.  That would have included the System 4 Cleo compiler that, I suspect, compiled directly into native code; not via intercode.  The aim was to free up resources at Kidsgrove so that the people could work on New Range and to provide a centre for software in Scotland that could attract Scots back home to work on software.  DME / Leo was developed at Dalkeith.

Anonymous: Read More »

LEO and its early attempt to use Magnetic Tape

The LEO design team attempted to use Magnetic Tape in its early design and worked with Standard Telephone and Cables to provide the required capability.  Ernest Lenaerts reports in his diaries on the failure of the venture.

Below is the Standard Telephone and Cables own account of their collaboration with J. Lyons, the failure of the magnetic tape facility to meet LEO’s reliability standards, and STC’s own venture into building computers resulting in the launch of the STANTEC ZEBRA, an early stored program computer, which for a limited time was successfully exported. See:

http://www.stlqcc.org.uk/a-brief-history-of-stl/

The Early Years

Shortly after the end of the second world war STC had decided to re-establish research facilities. Until the middle of 1931 a laboratory which could be considered the forerunner of STL had been established within ITT operating in premises formerly occupied by the Royal Air Force on Hendon Aerodrome. This laboratory suffered the fate of many similar institutions following the depression.

The new facilities were to be established in an existing plastics and cable factory in Progress Way, Enfield as a temporary measure. The company was to be known as Standard Telecommunication Laboratories and the date of formation was 1st. December 1945.

Further on there is reference to the Leo collaboration:

Fortunately about this time STC became involved with J. Lyons in the development of LEO, (Lyons Electronic Office), a computer system for payrolls, bread delivery forecasts and similar work to release office staff for other operations. STC approached STL to design the preparation of data in a form suitable for computer operation, the input (decimal to binary conversion), the output (binary to decimal conversion) and the ultimate paper results. System design was by D.A.Weir and J.Rice backed up by E.P.G.Wright. Design of circuits, a high speed magnetic tape machine and the necessary equipment practice was dealt with by D.S.Ridler and his team. The equipment was installed for trials in Cadby Hall but, although the design proved entirely suitable, it was finally removed because the high speed gas filled counting device that was extensively used in the circuitry lacked the extremely high reliability required. The gas tube was the STL decatron.

Because of this computer experience the Transmission Division asked us to produce a system to reduce the work involved in filter design. A team consisting of J.Rice, P.W.S.Harrild and D.G.Hunter designed a computer called STEP 1 based on magnetic drum storage and the laboratory again developed the circuits and equipment. This was one of the first electronic stored programme computers to go into active service. Subsequently STC were approached by the Dutch PTT Research Laboratories (NSEM) for assistance in developing a new computer and asked STL to provide the expertise. In consequence J.Rice worked in conjunction with the PTT, who had the basic idea, to design the practical concept, later to be produced at Newport by STC, known as ZEBRA. STL also developed the required circuitry together with the magnetic drum storage system. For some years ZEBRA was the UK’s largest export – over twenty systems.

Anonymous: Read More »