Following my earlier post on the legacy of computer pioneer Alan M Turing (Turing’s Legacy), Turing’s achievements have again hit the headlines with the news last week that members of the Institution of Mechanical Engineers (IMechE) have voted the Bombe at Bletchley Park as their favourite Engineering Heritage Award winner from the past 30 years.
The Bombe was an electromechanical code-breaking device which emulated the rotors of an Enigma machine, the typewriter-like device used by the German military to encrypt radio messages during World War II. It employed a motorised mechanism to step rapidly through every possible combination of rotor settings and apply a logical test to each one to determine if it met the conditions for a possible solution which had been wired into the machine before operation. The Bombe was closely based on an earlier device developed by the Polish Cipher Bureau in 1938. Alan Turing improved the Polish design by incorporating 36 sets of rotors to allow multiple checks to be made in parallel. Turing’s design was then turned into a fully-engineered device by the British Tabulating Machine Company under the direction of chief engineer Harold H Keen.
I must confess to being somewhat surprised by the result of the IMechE vote, as the Bombe was a workmanlike device which employed a brute force approach to cryptanalysis and lacks the sophistication and ingenuity of later developments at Bletchley Park (although these later developments employed electronic technology which probably renders them ineligible). It also ranks low in terms of Alan Turing’s achievements, as the concept was not entirely his.
There have been 100 winners of the Engineering Heritage Award to date, so the IMechE members had many other remarkable examples of engineering excellence to choose from, including the world’s first supersonic airliner, Concorde, which came second in the vote. The fact that they chose something designed by Alan Turing may be due in part to the high level of media attention he is receiving at the moment. This attention is likely to increase further with the release next month of the Hollywood film The Imitation Game, a dramatised account of Turing’s cryptanalysis work at Bletchley Park during World War II. Let’s hope the filmmakers have done their research and that Turing’s achievements are portrayed accurately. I certainly plan to go see it and will report back in a future post.
It was good to hear the recent news that computer pioneer Alan M Turing has been granted a posthumous royal pardon for his 1952 conviction for gross indecency (as a result of a homosexual act, which at that time was illegal in the UK). His punishment, for which he chose chemical castration rather than a prison sentence, and subsequent loss of security clearance for his cryptanalysis work are thought to have led to his untimely death by suicide two years later in 1954. However, Turing’s pardon has also caused considerable controversy, as the thousands of other men who were convicted of homosexual acts during the same period are unlikely to receive the same treatment. It seems that Turing has been singled out for a pardon as a result of his status as a national hero rather than for the degree of injustice that he suffered.
Alan Turing is one of the few British computer pioneers who is a household name. This is well-deserved and an accurate reflection of the magnitude of his achievements. However, many of the comments made in the media in the wake of the royal pardon announcement credit Turing with having a much greater influence on the development of the computer than is perhaps deserved. Turing’s greatest achievements were in the field of mathematical logic and relate to the theory of computation rather than the practical development of computers. His philosophy on the design of computers was to keep the hardware as simple as possible and rely on clever programming instead. Consequently, his only computer design, for the NPL ACE (Automatic Computing Engine), made very little impact.
Alan Turing’s influence on the development of the computer is discussed in an excellent article by Professor Simon Lavington written last year as part of the celebration to mark the centenary of Turing’s birth. The article, which is entitled Alan Turing: Is he really the father of computing?, questions how influential Turing’s pioneering work on early computers proved to be in their later development. Lavington sums this up as follows:-
“… his codebreaking work at Bletchley Park, and indeed Turing’s Ace design, exerted little influence on commercially viable computers as markets began to open up in the late 1950s. Nevertheless, Alan Turing’s ideas remain to this day embedded in the theories of both codebreaking and computing.“
Like Charles Babbage a century earlier, Alan Turing’s achievements went largely unrecognised during his lifetime and can only be fully appreciated when put into the context of later developments. However, we must be careful not to place credit where it is not due. Turing didn’t invent the modern computer anymore than Babbage did but his work did provide a solid theoretical foundation for later developments and for this he deserves to be honoured.