1948-1950
1948-1950 |
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Max Newman, after 1945 Professor of Pure Mathematics at Manchester University, created a place for Turing there. He enjoyed a somewhat uncertain status, with the official title of Deputy Director of the Computing Laboratory in connection with the successful computer development that Newman had initiated in 1946.
The prototype computer looked like this:
Turing worked on this machine between 1948 and 1950, when it was superseded by the Mark 1. Go here for more and better photographs of it, maintained by Thomas Thomas, one of the engineers of the project.
There is a history of Manchester computers from 1948 to 1975, with pages on F. C. Williams, the electronic engineer in charge of the early work, and of the Williams tube which converted the cathode-ray-tube into the first working electronic computer storage medium.
The Manchester computer of 1948 is being reconstructed for its fiftieth anniversary in 1998. See this
announcement.
After taking up the post in October 1948 Turing supervised programming work, but he lost interest in software development as his own focus moved towards the use of the computer for his own mathematical research. Somewhat incredibly, he continued writing directly in machine code, happily doing base-32 arithmetic as required. His vision of the future of programming, however, was absorbed by Christopher Strachey. Jonathan Bowen (Virtual Museum of Computing) has an introduction to Algebra and computing which puts this in context.
At this period the great rival to the Manchester computer development was the EDSAC computer at Cambridge, England, inaugurated in September 1949. Turing gave a talk at its inauguration which anticipated modern ideas of program proof. There is a description and simulator of the EDSAC by Martin Campbell-Kelly.
At that time the largest known prime was 2^127 - 1, and had been so since 1876, when Lucas discovered a test for primality of numbers of this type, a test which was extremely well suited to a computer. They ran a program successfully, and then Turing coded a faster version of it, but even so did not discover the next prime, which was out of range at 2^521 - 1, and found only in 1952.
The largest known prime now is again a Mersenne prime: 2^1398269 - 1. It was announced on 13 November 1996 and found by exactly the same method, only on a somewhat larger and faster computer).
The 1949 programme gained newspaper publicity for the Manchester computer, although (or because) readers of the day would have assumed prime numbers to be the epitome of pure mathematical uselessness. Today, of course, prime numbers are a hot topic because of the connection with cryptography.
In 1950 Turing used the same prototype Manchester computer for a more demanding calculation of the Riemann Zeta-function, also associated with the properties of prime numbers.
You are welcome to play with my little Java applet for factorisation and finding primes!
He also gave a talk on the BBC radio Third Programme:
although the producer had strong doubts about his talents as a media performer.
Meanwhile, by 1951 Alan Turing had said almost everything he had to say about Artificial Intelligence, and had moved on with a completely new idea: a theory of biological growth and the beginning of computer-aided non-linear dynamics.
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Last updated 21 September 1997.