Production begins on recreation of EDSAC


This week sees the production of the first replica components for the recreation of EDSAC, the computer that 63 years ago made general purpose computing available to users for the first time.

The highly ambitious project to build of a working replica of EDSAC was first announced twelve months ago and is scheduled for completion in 2015. A display of original EDSAC artefacts can now be seen by visitors to The National Museum of Computing where the EDSAC recreation is to take place.

See BBC's video of the production and interviews with Hermann Hauser, Andrew Herbert and David Hartley.

EDSAC project manager, Andrew Herbert, explained: "EDSAC marks a hugely important early milestone in computing. Until EDSAC, general purpose computers had been purely experimental systems locked away in research laboratories. But the late Professor Sir Maurice Wilkes, now widely regarded as the father of British computing, had the vision and the drive to realise the potential of computers to take on the mathematical calculations that underpin scientific research. He led the team that built the original EDSAC for the Mathematical Laboratory at Cambridge University. The impact of that new facility contributed quickly and directly to Nobel prize-winning scientific research, and to LEO, the first computer used in business. The impact of EDSAC has been profound, so we aim to celebrate the achievements of its creators and to inspire future generations of engineers and computer scientists."

EDSAC (Electronic Delay Storage Automatic Calculator) was first operational on 6 May 1949 and, continuously expanded throughout its lifetime, ran for a further nine years. It was then scrapped and only three of its 140 "chassis" have survived. This week one of these chassis was used as the model for the production of the first 20 replica chassis at Teversham Engineering Ltd in Cambridge. Today's computer-aided techniques, running on direct descendants of EDSAC, are used to model the replica chassis so that they look exactly like the originals but can be manufactured using modern processes.

Andrew Herbert continued: "Over the past year we have researched EDSAC's design and original construction, so this week marks the exciting transition from research to production. It has been inspiring to see in detail the chassis design and manufacture using computer techniques that EDSAC effectively paved the way for. With this important step accomplished we are confident that we can complete the daunting task of replicating EDSAC as it was in 1949."

The recreation of EDSAC will be as authentic as possible and will happen in full public view at The National Museum of Computing. An original chassis will soon be included in the display at TNMOC along with an original mercury delay line store and other smaller components from EDSAC.

David Hartley, Museum Director, at TNMOC said: "We are delighted to have the EDSAC Project at TNMOC. The educational value of this machine to our many visiting education groups will be enormous. Pupils and students, so-called 'digital natives', who have grown up almost casually using computers as part of their everyday lives will gain an understanding of where general purpose computing started out -- and how far it has come in less than a lifetime. EDSAC will be an enormously important addition to our other displays of historic working computers."

The EDSAC recreation is being undertaken by EDSAC Project volunteers at The National Museum of Computing in association with the Computer Conservation Society. Funding is being provided by a consortium led by computing entrepreneur Hermann Hauser, and includes a contribution from Google UK.

To follow the developments of the project, see and watch out for announcements of developments of the EDSAC display at The National Museum of Computing.

For visiting times at TNMOC, see

Notes to Editors

1 EDSAC facts
• EDSAC was based on the ideas of John von Neumann and others who in 1945 suggested that the future of computing lay in computers which could store sets of instructions (programs) as well as data in a memory.
• EDSAC was over two metres high and occupied a ground area of four metres by five metres.
• Pre-dating the transistor, its 3000+ thermionic valves / vacuum tubes used as logic were arranged on 12 racks containing just over 140 chassis in total.
• Mercury-filled tubes were used for the main memory, comprising 512 words initially, later 1024 word (equivalent to 2KB/4KB of PC storage)
• It performed 650 instructions per second, effectively computing more than 1500 times faster than the mechanical calculators it replaced.
• EDSAC read in programs from paper tape and printed its results on a teleprinter.
• EDSAC ran its first program on 6 May 1949 and soon began nine years of regular service for scientific users across the University of Cambridge and other institutions, ending in July 1958 when it was dismantled to enable the re-use of precious space. By then it had been superseded by the faster and much larger EDSAC 2.

2 Sir Maurice Wilkes
Sir Maurice Wilkes, the principal designer and creator of EDSAC and now widely regarded as the 'father' of British Computing, died in November 2010 at the age of 97. He continued to take a great interest in computing and was the first President of BCS and a great supporter of CCS right up until his death.

3 About the Computer Conservation Society
Founded in 1989, the Computer Conservation Society (CCS) is a joint venture between the BCS, The Chartered Institute for IT, the Science Museum and the Museum of Science and Industry in Manchester. The primary mission of CCS is to preserve historic computers, develop awareness of the history of computing, and encourage research. CCS runs many specialised working groups, organises a public lecture series, and publishes a regular bulletin Resurrection. Other CCS restoration and rebuild projects include a replica of the Turing Bombe and a rebuild of Colossus Mark II at Bletchley Park, the Manchester Small-Scale Electronic Machine in the Manchester Museum of Science and Industry, the restored Pegasus in the Science Museum in London and in 2012 the world’s oldest working original computer, the 1951 Harwell Dekatron computer / WITCH now on display at The National Museum of Computing.

4 About The National Museum of Computing
The National Museum of Computing, located at Bletchley Park, is an independent charity housing the largest collection of functional historic computers in the world, including a rebuilt Colossus, the world’s first electronic, semi-programmable computer, and the Harwell Dekatron / WITCH computer , the world's oldest original working digital computer. The Museum enables visitors to follow the development of computing from the ultra-secret pioneering efforts of the 1940s through the mainframes of the 1960s and 1970s, the rise of personal computing in the 1980s and beyond. For more information, see

Media Contact

Stephen Fleming of Palam Communications on behalf of the EDSAC Project at The National Museum of Computing
t 01635 299116