The Colossus is not a computer!

Having bashed the Americans yesterday for ignoring Konrad Zuse, I will take the opportunity today to bash the Germans, or more precisely Horst Zuse, Konrad’s son, and at the same time correct a commonly held myth.

23rd June is the birthday of another computer pioneer, Alan Turing. Turing of course means Bletchley Park and the breaking of the Enigma code. Now Bletchley also means one of the early computers, Colossus an electronic, binary, programmable non-Turing complete, special purpose computer designed and built in order to help the Bletchley code breakers. In a lot of popular sources Turing and Colossus are brought together as if it were obvious, Turing = computer expert, Colossus = computer, 1+1 = 3! Before the war Turing wrote one of the most important theoretical works on computing in the history of mathematics and after the War he worked on two major computer projects but in Bletchley he was responsible for the Bombe a very specialised and primitive form of computer but he was not involved in the design and construction of Colossus.

What does all this have to do with Horst Zuse? Horst is a professor for informatics who also specialises in the history of his father’s work. In one of his excellent lectures on his father’s computers, at which I was present, somebody asked him about the Colossus, his answer: “The Colossus was not a computer”. It would appear that Horst Zuse is as blind to his father’s competitors as the Americans to theirs.


Filed under History of Computing, History of Mathematics

5 responses to “The Colossus is not a computer!

  1. Pingback: The Link Purple « Evolving Thoughts

  2. I have some sympathy with this position since the Colossus was not Turing complete. I think when we say “computer” we usually mean something that would be Turing complete if it had indefinite amounts of memory.

    • As I have pointed out on my Zuse post and earlier on my Babbage post there is a very wide spectrum of the possibilities for defining the word computer and to restrict it in any of the list of possible attributes is to deny important stages in the history of computing.

      • araybold

        Indeed, but that means the context created by the question matters. If it was predicated on the assumption that the Colossus was a Turing-complete device, then Horst’s answer was sufficient, if terse (assuming that you have quoted his entire response). If the question was one in a steady stream that he may have heard over the years, suggesting that Konrad’s work was eclipsed by the Colossus, I can understand his terseness.

  3. Pingback: Monday blast from the past #5: Who invented the computer? | The Renaissance Mathematicus

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