Historic computer restored

A British computer known as the Harwell Dekatron, which was put into service in 1951, used 828 Dekatron tubes to calculate in decimal rather than binary. It was designed for the Atomic Energy Research Establishment at Harwell, in Oxfordshire, and was intended to count in decimal, exactly as humans do with their ten fingers.

Design and function of the Dekatron tubes

The Harwell Dekatron used Dekatron tubes, which could represent a digit from 0 to 9 through a visible electrical discharge, moving from one electrode to another. With 828 of these tubes associated with 480 electromechanical relays, the machine had sufficient memory and computational capacity to process the mathematical operations related to nuclear energy research programs.

Transition from research to education

Once it became obsolete for Harwell's scientific needs, the computer could have ended up as scrap like so many other machines of that generation. However, in 1957, the managers had the original idea of proposing the machine as a prize to the educational institution presenting the best reuse project.

Rediscovery and restoration

Retired from service, the device had a brief exhibition at the Birmingham Museum of Science and Industry before sinking into a long sleep. Disassembled and stored for several decades, it could have remained a dusty memory if a team from the National Museum of Computing had not rediscovered it in 2008.

Recognition and significance

In 2013, Guinness World Records officially certified the Harwell Dekatron, also known as WITCH, as the oldest original digital computer still in working condition in the world. This title takes on full meaning when one knows how capricious the machines of that generation had a reputation for being.