Co-inventor Of Harwell Dekatron Computer Dies

The United Kingdom has lost another of the men who cemented this country’s computing credentials in the 1940s and 1950s.

Richard “Dick” Barnes, co-designer of the Harwell Dekatron computer, died aged 98 on 8 April, according to the National Museum of Computing (TMNOC).

In 2012 the Harwell Dekatron computer, which is the oldest original digital computer, went on display at the National Museum of Computing, after a three-year restoration project.

Computing pioneer

Alongside co-designers Ted Cooke-Yarborough and Gurney Thomas, Barnes had designed the Harwell Dekatron (WITCH) computer whilst working at Harwell Atomic Energy Research Establishment in Oxfordshire in 1949.

The computer was first run in 1951 where it automated calculations that were previously performed with hand calculators.

The 2.5 tonne computer has 828 Dekatron valves, 480 relays and banks of paper tape readers and was brought back into working order in the presence of two of the original designers in 2012 (namely Barnes and Cooke-Yarborough).

It should be remembered that in 1951 the Harwell Dekatron was one of perhaps a dozen computers in the world.

As the world’s oldest original working digital computer, it provides a wonderful contrast to the wartime Colossus, which is the world’s first semi-programmable electronic computer.

Slow but steady

Speaking on video at the reboot, Barnes recalled why dekatrons were used in the computer.

“All the early computer designers faced the problems of storing data, so we selected dekatrons, a ready-made storage device for one decimal digit,” said Barnes.

According to the TMNOC, using telephone relays for control and sequencing, and the Dekatron tubes for storage and arithmetic, most program instructions are read from paper tape.

The computer is slow, but very reliable and capable of operating continuously for long periods.

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