Rebooting the WITCH - third life anniversary

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On 20 November 2012, the Harwell Dekatron / WITCH computer was rebooted to become the world's oldest working digital computer. Today, it is marvelled at by everyone from students to long-term programmers and is hailed by many as a "proper computer" with flashing lights and fascinating noises.

The machine has led a charmed life and on three occasions has been brought back from the brink of destruction.

Design of the computer began in 1949 at Harwell, Oxfordshire, where there wanted to automate the calculations then being performed on Facit hand calculators by human "computors" (as they were then known). Construction was completed in 1952 and it was passed to the mathematicians to exploit its reliability -- when required it ran for more than 90 hours a week in its first year, although its speed of performance was that of a tortoise rather than a hare.

By 1957 it was becoming obsolete at Harwell and was offered in a competition to an educational establishment proposing its most appropriate use. It was won by the Wolverhampton and Staffordshire College of Technology who used it as the Wolverhampton Instrument for the Teaching of Computation from Harwell (hence its later name: the WITCH).

In 1973, it was recognised by Guinness World Records as "the world's most durable computer" and was again retired, this time to the Birmingham Museum of Science and Industry. When that Museum closed in 1997, it was put into storage, but was rediscovered by TNMOC in 2009 and a successful proposal was made to move it to TNMOC for restoration.

Restoration was completed in November 2012 and and in 2013 it was again recognised by Guinness World Records, this time as the world's oldest original working digital computer. Today it is one of the Museum's most popular exhibits and has been visited by its original designers at Harwell and a group of former students who took their first steps in computing with the machine at Wolverhampton.

The full story of the WITCH is told in a book by Kevin Murrell and Delwyn Holroyd available in the Museum coffee shop.

Of course, the restoration of the WITCH could never have been possible without the skilled and dedicated work of the TNMOC Volunteer team. And don't miss the moment when the famous man versus machine race was rerun on reboot day.

The story of the WITCH continues ... just this summer we've been in search of its portrait and this year it has even had its own emulator created in the USA and musical composition by Matt Parker.

Below are:

  • a 40-second video clip of the reboot
  • a 20-minute video of the reboot event with contributions from the original design team.

Short version

Full version (20 minutes)

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