A home workshop in Reading, England is today playing a vital role in the reconstruction of EDSAC, the Cambridge University machine that sixty-five years ago led the world’s computing revolution and today is being reconstructed and assembled at The National Museum of Computing (TNMOC) on Bletchley Park, where the process can be watched by museum visitors.
The Reading workshop, affectionately named Edshack, belongs to James Barr, who not only has the rare skills required to help in the reconstruction of EDSAC, but also has a computing pedigree that can be traced directly to the machine that first ran before he was even born.
EDSAC, full name the Electronic Delay Storage Automatic Calculator, was built in Cambridge, England in the years following the Second World War and was the first high-speed electronic computer ever to go into service at a University. Because of its remarkable speed, it enabled new approaches to scientific research, which were previously impossible, and was used in at least two Nobel-Prize winning research breakthroughs.
In Barr’s workshop, key components of EDSAC’s central control system are being reconstructed. He is one of the very few people in the country who could attempt such a task. It requires a knowledge of thermionic valves that were used for wartime RADAR and preceded the invention of transistors and silicon chips. They were the only devices at that time fast enough for high-speed computing technology. He also has had to research and re-discover the ways that 1940’s valve circuits were made to perform digital functions.