World's first stored program computer to be recreated

The Computer Conservation Society (CCS) has commissioned a working replica of the world's first fully operational stored-program computer.

When completed, the Electronic Delay Storage Automatic Calculator (Edsac) will go on display at The National Museum of Computing at Bletchley Park.

The CCS said it commissioned the replica in recognition of the achievements of the pioneering computer scientists at Cambridge University in the 1940s.

It also wants the public to know more about Britain's illustrious computer heritage and to inspire future engineering and computing students.

David Hartley, CCS chairman and a former president of the BCS, the Chartered Institute for IT, said: "The Edsac was a brilliant achievement that laid the foundations for general purpose computing and introduced programming methods adopted worldwide and still in use.

"By recreating it where the public can watch the process, we aim to enthuse a new generation of computer science and engineering students with the genius of those post-war pioneers at Cambridge University."

Edsac was originally built by a team led by Professor Sir Maurice Wilkes who died last November aged 97. At the time he created Edsac, Wilkes was director of Cambridge University's Mathematical Laboratory. His objective was to produce a practical and reliable computer using proven hardware and imaginative software programming techniques.

The computer was so successful that in the nine years following 1949 it was used by Cambridge University researchers in studies of genetics, meteorology and X-ray crystallography.

Edsac even helped two researchers win Nobel prizes. It eventually led directly to the first commercially applied computer, the Leo. This computer enabled the catering company J Lyons & Co Ltd to perform payroll calculations in 1953.

It won't be easy to recreate the computer but the result is expected to be as authentic as possible. The original computer had more than 3,000 electronic tubes (or 'valves') used for logic, mercury-filled tubes for memory, data input via paper tape and output on a teleprinter.

Only the mercury-filled tubes are expected not to be recreated – in compliance with modern safety requirements – and will be substituted with a similar technology.

The project, which is being funded by a consortium led by computing entrepreneur Hermann Hauser, will take about three to four years to complete.

Kevin Murrell, a director and trustee of the museum, said: "Recreating a fully-functioning Edsac computer is quite a challenge, but our experience in rebuilding the Colossus computer gives us confidence and insight.

"The project is fortunate in having the advice and support of Chris Burton who managed the reconstruction of the Manchester Baby, another CCS project. Professor Martin Campbell-Kelly, computer historian at the University of Warwick, will provide an historical and academic perspective for the recreation of Edsac."

When Edsac goes on show at the museum, it will occupy a floor area of 20 square metres.