Alan Turing

Alan Turing, along with figures such as Shannon and Von Neumann, is one of the "fathers of the computer age".

     life 

Turing was born in London on 23 June 1912. Like George Orwell his family was embedded within the colonial civil service in India and returned to the subcontinent when he was a child, leaving the boy behind. After Hazlehurst Preparatory School he went to Sherborne School where he was distinguished as a mathematician and athlete (long distance running and cycling 60 miles from home during the 1926 General Strike).

He entered King's College, Cambridge in 1931 on a mathematics scholarship and graduated in 1934. He was elected a fellow of King's - a milieux that included Ludwig Wittgenstein, Maynard Keynes and EM Forster - in 1935 for a probability theory dissertation On the Gaussian error function. In 1936 Turing was a Smith's Prizeman.

In 1936 he published On Computable Numbers, with an application to the Entscheidungsproblem, a paper that introduced the 'Turing Machine' - an abstraction that moved from one state to another using a single symbol it read from a tape interpreted through a precise and finite set of rules. In principle the machine could perform any mathematical calculation. He was a graduate student at Princeton University in 1936 under logician Alonzo Church, returning to the UK in 1938 after turning down a position as John von Neumann's assistant at the Institute for Advanced Studies (IAS). His doctorate from Princeton was reflected in Systems of Logic Based on Ordinals, published in 1939.

Turing joined the cryptologists at the Government Code & Cypher School (Bletchley Park) in 1939. He visited the US from November 1942 to March 1943 for work on decryption and radio/telephone speech encryption. He was awarded the OBE in 1945.

In 1948 he moved to the University of Manchester as Reader in Mathematics, having presented a proposal for an Automatic Computing Engine (ACE) while employed by the National Physical Laboratory after leaving Bletchley Park. In 1950 Turing published a paper in Mind on Computing Machinery & Intelligence. He was elected a Fellow of the Royal Society of London in 1951.

Turing was convicted of homosexual behaviour in 1952 - consensual activity remained illegal until the Wolfenden reforms (1967) and beyond. His security clearance was revoked and, amid hysteria about the homintern, Turing's treatment by surveillance agencies appears to have been more than usually shabby. He died on 7 June 1954, presumably a suicide by eating an apple laced with potassium cyanide.

     biographies 

The best biography of Turing remains the quirky Alan Turing: The Enigma (New York: Simon & Schuster 83) by Alan Hodges. 

Sara Turing's  Alan M Turing (Cambridge: Heffers 59) is a slight but charming collectors item by his mother. He features in most studies of Bletchley Park. There's a fictional treatment in Hugh Whitemore's play Breaking The Code, later made into a film with Derek Jacobi.

Hodges has a rich but somewhat polemical Turing site; there's a short biography on John Kowalik's site.

     writings 

Publication of a multivolume Collected Works of A M Turing (London: North-Holland) under the general editorship of P. N. Furbank - Turing's literary executor and biographer of EM Forster - commenced in 1992.

The Turing Digital Archive project at Cambridge is digitising unpublished correspondence, papers and other documents for access over the web.

     other

For Turing at Bletchley see David Kahn's The Code Breakers (London: Weidenfeld & Nicolson 90), essays in Action This Day (London: Bantam 01) edited by Ralph Erskine & Michael Smith or the less impressive The Code Book (New York: Doubleday 99) by Simon Singh. The broader context is provided by studies such as Harry Hinsley's British Intelligence in the Second World War (London: HMSO 93).

For an overview of computing history see the Evolution of the Web profile on this site. Introductions are provided in Computer: A History of the Information Machine (New York: Basic Books 96) by William Aspray & Martin Campbell-Kelly or Paul Ceruzzi's A History of Modern Computing (Cambridge: MIT Press 98), with a more detailed treatment John Von Neumann & The Origins Of Modern Computing (Cambridge: MIT 90) by Aspray.

A perspective on Turing's work at Manchester and the National Physical Laboratory is provided by John Hendry's Innovating for Failure: Government Policy & the Early British Computer Industry (Cambridge: MIT Press 90) and The First Computers: History & Architectures (Cambridge: MIT Press 00) edited by Raul Rojas & Ulf Hashagen.
 


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