Oldest working computer restoration project starts

The 50-year-old Harwell computer has been removed from storage to The National Museum of Computing at Bletchley Park for 12-month restoration to full working condition.

Once restored by Museum volunteers at the Museum, it will be the oldest original functioning electronic stored program computer in the world, it’s claimed, and will be housed alongside the rebuild of Colossus Mk II, the world’s first electronic computer.

The National Museum of Computing is inviting industry and the public to sponsor the restoration of the Harwell computer by purchasing one of 25 shares at £4500 each to fund the restoration.

The Harwell Computer dates back to 1949, when plans were drawn up for a machine to perform calculations then done by a team of graduates using mechanical calculators. The machine first ran in 1951.
“The machine was a relay-based computer using 900 Dekatron gas-filled tubes that could each hold a single digit in memory - similar to RAM in a modern computer - and paper tape for both input and program storage,” explains National Museum of Computing trustee Kevin Murrell. “Its promises for reliability over speed were certainly met – in a race with a human mathematician using a mechanical calculator, the human kept pace for 30 minutes, but then had to retire exhausted as the machine carried on. The machine once ran for ten days unattended over a Christmas/New Year holiday period.”

The computer was operational at Harwell until 1957, when it was offered in a competition for colleges to see who could make best use of it. Wolverhampton and Staffordshire Technical College (later becoming Wolverhampton University) won and, then becoming known as the WITCH (Wolverhampton Instrument for Teaching Computing from Harwell), it was used in computer education until 1973. After a period on display at Birmingham Science Museum, it was disassembled and put in storage at Birmingham City Council Museums’ Collection Centre. 

Insight Software has become the first sponsor of the Harwell/WITCH computer restoration project. The current earliest-functioning computer is the 1956 Pegasus machine at The Science Museum in London.

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