In the USA a number of teams worked on ideas contained in von Neumann’s Draft Report. Von Neumann himself worked on one, but the first to produce an operational machine was the National Bureau of Standards, where the SEAC (Standards Eastern Automatic Computer) came into being in the summer of 1950. SEAC was a very well engineered machine with many of the latest techniques for memory storage, including some pioneering ones, all used successfully in its construction.

In the UK meanwhile, again with Hartree’s encouragement, at the National Physical Laboratory (NPL), Turing had been working on the design of the pilot ACE (Automatic Computing Engine) in 1946. He produced a report on the ACE in which he acknowledged some influences from the EDVAC report (his was to be read in conjunction with the EDVAC report), but which had a much greater founding in his own Universal Turing Machine.

The ACE was about 5 to 7 times faster in operation than most other early machines (particularly those at Manchester and Cambridge), but this was at the expense of increased difficulty in programming. Because Turing had made no attempt to make the programmer’s life easy, ACE was quite unlike EDSAC (which was designed to ease the difficulty of programming a machine). In fact, ACE’s programmer (like early programmers at Manchester) had to write everything in binary notation, backwards! The Pilot ACE first worked on May 10th 1950 and started doing useful work in the summer of that year, shortly after SEAC. Because of the difficulty in programming ACE, it was EDSAC and not the Pilot ACE which set the standards for operation and programming for future machines.

Though Turing designed the ACE, he actually left NPL in 1948 long before its construction was complete. He moved to a readership at Manchester University, though he did not arrive there until after June, after the Manchester Baby had been constructed. However, he did do a considerable amount of work on programming the subsequent machines and also assisted with the design of the paper tape input, although Williams and Kilburn did not allow any interference with their actual machine design and construction.

Turing himself, a great mathematician and philosopher, refused to behave within the then perceived confines of his class. In the 1950’s homosexuality was a crime and as a result Turing was tried for committing an act of gross sexual indecency with a young man from Manchester. However, his spirit was not broken and he continued his research in earnest. His death two years after the trial, aged 41, was therefore a shock to his close friends. The coroner recorded a verdict of suicide.

His achievements are so remarkable, not only because they are so numerous, but also because they are so profound. In different ways he was involved with three of the first six computers ever built. He was so remarkable because he designed the computer first as a thought exercise, and then helped to do the same as a reality. This is an amazing feat if we consider, for example, the first steam engine which was built in 1712. The actual theory of the way in which it worked was not described until 1824! His achievements are then surely among the more outstanding feats science has seen and it is for this reason that we remember him specially here.


Alan Turing