Zuse Z3 Computer (1941)

Completed May 1941

Who made the world’s first programmable digital computer? The Americans? The British? The Japanese? Well, in what is perhaps a forgotten part of history it was quite possibly the Germans with the Zuse Z3 which was completed in May 1941.

The electronics of the time were not sophisticated, the Z3 relied mostly on relays and the whole machine ran at a little over 5 hertz (no, not megahertz.. just 5 cycles per second). It weighed a ton and drew 4000 watts of power, but it was actually remarkably capable.

Zuse Z3 detail

Floating point numbers were supported, the Z3 could not only add and subtract, but divide, multiply and calculated the square root. Many of the computer’s operations were actually implemented in microcode rather than being hard wides. A keyboard and row of lights formed the basis of the operator console, and the Z3 could store data on punched celluloid tape.

Sometimes considered a design flaw, the Z3 was incapable of performing a conditional jump – i.e. the program couldn’t take a different path depending on different circumstances, an essential feature of a multipurpose computer. Still, the Z3 could perform complex calculations more quickly and accurately than a human, which is pretty much all early computers were used for.

It might not have escaped your attention that a lot was going on in Germany in 1941. Designer Konrad Zuse struggled to get resources for his project, but the much simpler predecessors of the Z3 (the Z1 and Z2) persuaded the Nazi government to support it in a limited way. Despite commissioning the Z3, the authorities were not convinced of its value and it was not used to its full capabilities. A bombing raid in 1943 destroyed the computer, and by this time Zuse had gone on the design the Z4 – arguably the world’s first commercially available computer - which was released a few years after the end of the war. Zuse continued to develop computers into the 1960s.

Zuse Z3

It is perhaps fortunate that the Nazis didn’t see the potential of the computer – in Britain the Colossus computer was breaking high-level German codes produced by the Lorenz cipher. This allowed the Allies to read communications from German high-command, including some from Adolf Hitler himself.

The Z3 ended up being largely forgotten, although a reconstruction was made after the war which now resides in the Deutsches Museum. In different circumstances – probably not very good circumstances considering – the Zuse Z3 might have been the progenitor of modern computing. But it wasn’t, instead the Zuse company was taken over by Brown Boveri in 1964 and then was sold on to Siemens in 1966, eventually disappearing in 1971. In 1999 the computer division of Siemens merged into a joint venture with Fujitsu, eventually being wholly taken over by the Japanese firm in 2009. Perhaps somewhere in there a little bit of Zuse DNA lives on.

Image credits:
DKsen via Wikimedia Commons – CC0
Floheinstein via Flickr - CC BY-SA 2.0