Konrad Zuse (1910-1995)
In 1936 Konrad Zuse, absolutely set apart from the academic world, started constructing an automatic machine to solve calculation problems for designing plane wings; these analyses forcing him to long and repetitive calculations. In his living-room and with the mere aid of few tools, he first produced a binary mechanical memory, to which he soon connected a mechanical calculation unit as well as a programming unit controlled from old movie films punched by hand. He called this model V1 (Versuchsmodell 1), but subsequently changed this name into Z1 in order not to confuse it with the flying bombs having the same name! Having become aware of the poor liability and slowness of this machine, in 1939, Zuse prepared a second one, called Z2, characterized from a still mechanical memory but with a relay-operated electromechanical calculating unit.
In the following years, Zuse accomplished a real electromechanical working computer, Z3, which was submitted in 1941 to an audience of engineers and scientists, raising great interest. Not yet satisfied, living in a Berlin continuously bombed and in which it was difficult to find even food, Zuse constructed Z4 with a mechanical memory (relays were now unfindable): the machine was ended in 1944. Zuse arrived in protecting Z4 from the destructions of war and from the hands of Allies, hiding it in a cellar in the small Bavarian village of Hindelang. Once tranquillity returned again, Zuse transferred in to the Swiss Federal Institute of Technology (ETH), in Zurich, were it remained working for 15 years. Up to 1951, this machine remained the only working computer in continental Europe.
The history of Zuse is emblematic for at least five reasons: 1) his contribution was completely original, as he was very isolated from the rest of the world but even from the German research activity; 2) the fact that he has conceived a binary representation of figures which is that adopted from all the modern computers; 3) the fact that he has independently achieved an architecture which was already suggested by Babbage; the invention of the first programming language (Plankalkul, 1943-45); 5) the extremely practical and simple way of facing the problem: the estimated cost of Z2 is 6.500 US $, only.