As key parts of the reconstruction of one the most influential computers ever built were commissioned, the sights, sounds, heat and sheer size of computing in the late 1940s were brought to life. Already the machine is proving to be a very popular exhibit and is a marvel and an inspiration to visiting educational groups.
EDSAC, the Electronic Delay Storage Automatic Calculator, was originally built in the University of Cambridge immediately after World War II by a team led by Sir Maurice Wilkes. It was the first practical general purpose computer and marked the beginning of computer programming as a distinct profession. EDSAC was so successful that it was used in Nobel prize-winning scientific research and its design was later developed to create LEO, the world's first business computer.
After two years of research and re-engineering by a team of about 20 volunteers, the EDSAC reconstruction is now becoming a reality that is already fascinating visitors to the Museum.
At the official opening of the exhibit, several key elements of EDSAC were demonstrated. Bill Purvis showed how a program would be input before the advent of keyboards and how the result would be output before screens became commonplace. Peter Linnington revealed how, at the start of the computer age, delay lines were used as stores. As the climax, Chris Burton switched on of the EDSAC clock, the beating heart of the machine.
The three-year project is on schedule for completion late next year and computer historian Martin Campbell-Kelly gave a preview of what is in store by outlining the importance of EDSAC in marking the beginnings of computer programming. He revealed plans for young people to create and run their own programs on one of the world’s most influential early computers.
Andrew Herbert, leader of the EDSAC Project, said: “Reconstructing EDSAC is proving to be a fascinating challenge with lots of surprises. We are incredibly fortunate to be able to call of a volunteer team with an extraordinarily rare skill set. The team includes students of the original computer pioneers and members of the last generation to be trained in the use of thermionic valves, the key component of EDSAC which has 3,000 of them!
“But even with those rare skills, the task is not straightforward. Our skilled team has to forget knowledge that it painstakingly acquired in the development of later landmark machines like the 1950’s Ferranti Pegasus and the 1960’s Elliott computers. We don’t have blueprints to follow, so to create an authentic EDSAC we have to adopt a 1940’s mind-set to re-engineer, redesign the machine. We face the same challenges as those remarkable pioneers who succeeded in building a machine that transformed computing.”
Doron Swade, co-founder of the Computer Conservation Society and a hands-on pioneer of computer restoration, said: “This is truly a remarkable project that brings history to life for its participants and for the viewing public. EDSAC provided, for the first time, reliable computing capability for scientists. It could be said that EDSAC invented the user as a distinct class of practitioner. To have a working reconstruction of the computer that trail-blazed both programming practices and computational services for scientific research cannot fail to interest casual observers and more importantly inspire young people with their careers ahead of them. It shows that computer conservation is flourishing and contributing real value in the modern world.”
About EDSAC
EDSAC, the Electronic Delay Storage Automatic Calculator, was built immediately after World War II by a team led by Sir Maurice Wilkes in the Mathematical Laboratory of the University of Cambridge. It was the first practical general purpose computers and was used by scientific researchers across the University. The EDSAC design was later developed to create LEO, the world's first business computer.
- EDSAC was based on the ideas of J Presper Eckert, John Mauchley and John von Neumann 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 and demonstrated early computing circuits in the ENIAC electronic calculator.
- 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 after that 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.
The EDSAC Reconstruction Project
The EDSAC Reconstruction Project which began in 2011 is expected to be completed in late 2015. The reconstructed EDSAC, which will occupy 20 square metres, is being built at The National Museum of Computing, where visitors can see the work in progress. The EDSAC Replica Project has been funded by a consortium of corporate and private donors led by Hermann Hauser.
The ongoing reconstruction story featuring videos of progress can be seen at www.edsac.org
About The National Museum of Computing
The National Museum of Computing, located on Bletchley Park, is an independent charity housing the world's largest collection of functional historic computers, including the rebuilt Colossus, the world’s first electronic computer, and the WITCH, the world's oldest working digital computer. The Museum enables visitors to follow the development of computing from the ultra-secret pioneering efforts of the 1940s through the large systems and mainframes of the 1950s, 60s and 70s, and the rise of personal computing in the 1980s and beyond.
A pledge by an individual benefactor of £1 million if matched funding is found means that every pound or dollar donated to the Museum will count double. Previous funders of the Museum have included Bletchley Park Capital Partners, Bloomberg, CreateOnline, Ceravision, InsightSoftware.com, Ocado Technology, 4 Links, Google UK, IBM, NPL, HP Labs, BCS.
The whole Museum is currently open to the public on Thursdays, Saturdays and Sundays from 12 noon, spring and summer Bank Holidays and increasingly during school holidays. Colossus and Tunny galleries are open almost every day. Guided tours are available at 2pm on Tuesdays. There are often additional opening times for the public -- see the website or the iPhone app for updates. Educational and corporate groups are very welcome and may be on any day or evening by prior arrangement.
For more information, see www.tnmoc.org and follow @tnmoc on Twitter and The National Museum of Computing on Facebook and Google+. A TNMOC iPhone App is also now available from the iPhone App Store.
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Media Contact
Stephen Fleming of Palam Communications for the EDSAC Project and TNMOC
+44 (0)1635 299116
s.fleming@palam.co.uk