World’s Oldest Digital Computer Still Works
Posted by Ram Kumar Shrestha on December 14, 2012
The Harwell Dekatron computer is as big as a SUV and has the computational power of a drugstore pocket calculator. However, it’s also 60 years old. And, unlike my laptop from 2006, this relic from the 1950s is still working.
The National Museum of Computing recently restored the Harwell Dekatron to original operating condition with 95% original parts (parts that include valves, tubes and rolls of paper tape).
The Dekatron digital computer was named the Most Durable Computer in the world by the Guinness Book of World Records in 1973. The most recent restoration means it’ll be still doing basic math for years to come.
The 2.5 ton Dekatron was built in 1951 by the UK Atomic Energy Research Establishment to perform basic calculations accurately and repeatedly, computing at a rate of 0.1 flops, a snail’s pace by today’s standards.
Technological advances quickly made the Dekatron obsolete, but no one told the computer. Instead, it made its rounds as a teaching tool.
The project to restore the computer was initiated by Kevin Murrell, a trustee of the National Museum of Computing. He says, “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.”
The Harwell Dekatron is a computer dear to Murrell’s heart:
“I first encountered the Harwell Dekatron as a teenager in the 1970s when it was on display in the Birmingham Museum of Science and Industry – and I was captivated by it. When that Museum closed, it disappeared from public view, but four years ago quite by chance I caught a glimpse of its control panel in a photograph of stored equipment. That sparked our ideas to rescue it and we hunted it down.”
“The TNMOC 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,” Murrell continues, “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 project of the ancient machine proved to be difficult for contemporary computing engineers and designers used to newer, and much smaller, technologies like microchips.
“The restoration was quite a challenge requiring work with components like valves, relays and paper tape readers that are rarely seen these days and are certainly not found in modern computers,” claims Delwyn Holroyd, leader of the restoration team, “Older members of the team had to brush up on old skills while younger members had to learn from scratch!”