The next time you feel frustrated with your aging personal computer, just watch the video above. In these fifty seconds, the National Museum of Computing fires up the Harwell Dekatron, also known as the Wolverhampton Instrument for Teaching Computation — or, naturally, the WITCH. Holder of the title of the world's oldest working original digital computer, the WITCH, first built in 1951, went into retirement from Wolverhampton's Staffordshire Technical College in 1973. A three-year restoration of the computer — all two-and-a-half tons, 828 flashing Dekatron valves, and 480 relays of it — began in 2008. Now, having just finished returning the machine to tip-top shape, they've actually booted it up, as you can see. "In 1951 the Harwell Dekatron was one of perhaps a dozen computers in the world," The National Museum of Computing's press release quotes its trustee Kevin Murrell as saying, "and since then it has led a charmed life surviving intact while its contemporaries were recycled or destroyed."
The Harwell Atomic Energy Research Establishment provided the Dekatron its first tasks, cranking out calculations formerly done by hand. When it passed into obsolescence there in 1957, Staffordshire Technical College took the massive computer off Harwell's hands, and there it became the WITCH, used for teaching purposes over the next sixteen years. When it outlived even its educational use, the WITCH went on display at the Birmingham Museum of Science and Industry, and finally to dismantlement and storage. Now it offers a whirring, clattering, flashing, retro-technological spectacle to new generations of computer enthusiasts. Some of them may be shocked to learn that, by virtue of sheer age, it doesn't adhere to some of the very qualities of digital computing they take for granted: it doesn't calculate in binary code, but decimal code, hence the name "Dekatron." Though its practical applications would seem limited in the modern world, rest assured that some young hobbyist is even now pondering how to get the thing onto the web.