THE WORLD'S OLDEST working digital computer, the Harwell Dekatron or 'Witch' will be rebooted today at the National Museum of Computing at Bletchley Park.
The Witch is being rebooted at Bletchley Park after a three year restoration project. It was originally built in 1951, is 2 metres high and weighs 2.5 tonnes.
Unlike today's computers the Witch is something of an event machine, and its fitting that you can go and see it in a museum. It has 828 flashing Dekatron valves, 480 relays and a bank of paper tape readers.
"In 1951 the Harwell Dekatron was one of perhaps a dozen computers in the world, and since then it has led a charmed life surviving intact while its contemporaries were recycled or destroyed," said Kevin Murrell, trustee of the museum.
"As the world's oldest original working digital computer, it provides a wonderful contrast to our Rebuild of the wartime Colossus, the world's first semi-programmable electronic computer."
When it was built the Witch worked at the Harwell Atomic Energy Research Establishment and automated calculations made by humans.
A workhorse, it would clatter away on its calculations, always delivering their results correctly. It was retired after six years, but is now back, ready to distracts kids and adults away from their Pokemon and cloud music services.
"The [museum] restoration team has done a superb job to get it working again and it is already proving to be a fascination to young and old alike," added Murrell.
"To see it in action is to watch the inner workings of a computer -- something that is impossible on the machines of today. The restoration has been in full public view and even before it was working again the interest from the public was enormous." µ