Germans claim first programmable computer

Z3 goes head-to-head with Colossus

The Brits may have beaten the Americans, but it seems we were both pipped by the Germans. No, not football. Computers.

Colossus was not, in fact, the world's first programmable computer: that particular distinction belongs to the Z3, built in 1941 by Konrad Zuse, a German civil engineer.

When Zuse met with the Colossus team in the 1980 and the two groups compared notes, they found they had all been working along very similar lines.

The Z3 was based on a binary floating-point number and switching system. It could perform between three and four additions per second, and could multiply in around five seconds. The program was fed in on a old movie film punched with holes, as paper was in short supply. It could perform basic arithmetic: addition, subtraction, multiplication and division and it could calculate square roots.

His early experiments building a mechanical computer were based on telephone relays: the most widely available and reliable 'yes/no' devices available to him at the time. Although he was aware of vacuum tubes, he opted to use relays in the Z3 because they were more reliable.

Zuse's machine saw use during the war, but not as a codebreaker. Instead it was used to perform statistical analysis of the stresses on aircraft wings, and in particular, a problem known as wing-flutter. This vibration of an aircraft's wing can cause a critical instability during flight. The calculations needed to overcome this design issue were incredibly complex, and it was this problem that the Z3 solved.

The Z3 was destroyed during bombing raids in the war, but Zuse managed to escape to Switzerland with its successor - the Z4 - which can now now be seen at the Deutsches Museum in Munich. ®

Related links

Konrad Zuse's story
The construction of Z1 and Z3
More about Zuse

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