Discovery: user manual of the oldest surviving computer in the world

The Zuse Z4 is considered the oldest preserved computer in the world. Manufactured in 1945 and overhauled and expanded in 1949/1950, the relay machine was in operation on loan at the ETH Zurich from 1950 to 1955. Today the huge digital computer is located in the Deutsches Museum in Munich. The operating instructions for the Z4 were lost for a long time. In 1950, ETH Zurich was the only university in continental Europe with a functioning tape-controlled computer. From the 1940s, only one other computer survived: the Csirac vacuum tube computer (1949). It is in the Melbourne Museum, Carlton, Victoria, Australia.


Evelyn Boesch from the ETH Zurich University archives let me know in early March 2020 that her father René Boesch (born in 1929), who had been working under Manfred Rauscher at the Institute for Aircraft Statics and Aircraft Construction at ETH Zurich since 1956, had kept rare historical documents. Boesch’s first employment was with the Swiss Aeronautical Engineering Association, which was housed and affiliated to the above-mentioned institute. The research revealed that the documents included a user manual for the Z4 and notes on flutter calculations.

What an astonishing discovery. Stories like this make me wonder just how many rare, valuable, irreplaceable hardware, software, and documentation is rotting away in old attics, waiting to be thrown in a dumpster after someone’s death.


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