Christopher Strachey

From Chessprogramming wiki
Jump to: navigation, search

Home * People * Christopher Strachey

Christopher Strachey [1]

Christopher Strachey, (November 16, 1916 – May 18, 1975)
was a British computer scientist and pioneer in computer and programming language design, between 1952 and 1959 ‎technical officer in the National Research Development Corporation, between 1962 and 1965 fellow of Churchill College, Cambridge, and from 1966 ‎leader of the Programming Research Group, Oxford University [2], where he worked with Dana Scott and Joe Stoy, constituting the Scott-Strachey approach to denotational semantics [3].

Strachey had a major role in the development of the Elliot 401 and Ferranti Pegasus computers, being responsible for its logical design. In the early 1960s, along with Maurice Wilkes at the University of Cambridge Computer Laboratory, he was involved in the development of the Titan or Atlas 2 [4] , and developed the Combined Programming Language (CPL) [5] . His influential fundamental concepts in programming languages formalized the distinction between L- and R- values [6] . In 1959, Strachey wrote one of the first seminal papers on Time-sharing [7] [8] [9]. In his 1961 paper Bitwise operations [10] he already proposed a parallel prefix bit reversal algorithm [11].


Strachey wrote the first successful AI program, his checkers (draughts) program for the Ferranti Mark 1 at the University of Manchester, after first trials on Turing's Pilot ACE at National Physical Laboratory in 1950/1951 exhausted its memory. By the summer of 1952 the program could play a complete game of checkers at a reasonable speed [12] [13] [14], and also played “God Save the King” on completion [15] [16], and already featured Bitboards for White, Black and Kings to represent the board [17]. His checkers program from 1966 [18] written in CPL is available on-line, in a corrected version with courtesy of Peter Norvig [19] [20].

Love Letters

In 1952, Christopher Strachey used the built-in random number generator of the Ferranti Mark 1 [21] to generate texts that are intended to express and arouse emotions, the Strachey love letters by M.U.C. (Manchester University Computer), recently broached by David Link [22] [23] [24]. One sample from Matt Sephton's [25] Loveletter Generator, a reimplementation of Strachey 's algorithm from 1952 [26]:

Beloved Dear,

My anxious rapture clings to your craving

infatuation. My unsatisfied hunger impatiently longs
for your winning ardour. You are my anxious heart, my
burning rapture, my tender little liking.

Yours curiously,
Loves Messenger Stillman DAM.jpg

Selected Publications

[27] [28]

External Links

Lytton Strachey from Wikipedia (uncle of Christopher Strachey)


  1. Pioneer Profiles - Christopher Strachey by David Barron, Resurrection - The Bulletin of the Computer Conservation Society
  2. Christopher Strachey - I13799 - Individual Information - PhpGedView
  3. Joe Stoy (1981). Denotational Semantics: The Scott-Strachey Approach to Programming Language Theory. MIT Press, ISBN 978-0262690768
  4. Ferranti Computing Systems Atlas 2 Brochure: August 1963 from Atlas Computer Laboratory, Chilton: 1961-1975
  5. CPL also dubbed as Cambridge + London or Christopher's (Strachey) Private Language, London Atlas, Additional Material from Atlas Computer Laboratory
  6. Christopher Strachey (1967, 2000). Fundamental Concepts in Programming Languages. Higher-Order and Symbolic Computation, Vol. 13: 11–49
  7. Christopher Strachey (1959). Time sharing in large, fast computers. IFIP Congress 1959
  8. Reminiscences on the History of Time Sharing by John McCarthy, 1983
  9. Origins of Timesharing by Bob Bemer
  10. Christopher Strachey (1961). Bitwise operations. Communications of the ACM, Vol. 4, No. 3
  11. reverse.c from C code for most of the programs that appear in Hacker's Delight by Henry S. Warren, Jr.
  12. B. Jack Copeland, Diane Proudfoot (2011-2012). Turing, Father of the Modern Computer. The Rutherford Journal - The New Zealand Journal for the History and Philosophy of Science and Technology, Vol. 4 » with photos of Alan Turing, John von Neumann, Dietrich Prinz, Christopher Strachey, Jack Good, Arthur Samuel, Herbert Simon, Allen Newell, ...
  13. artificial intelligence (AI) :: Early milestones in AI from Britannica Online Encyclopedia
  14. The “Modern” History of Artificial Intelligence and Programs from Neuroscience Of Intelligence
  15. Pioneer Profiles - Christopher Strachey by David Barron, Resurrection - The Bulletin of the Computer Conservation Society
  16. Oldest' computer music unveiled by Jonathan Fildes, BBC News, June 17, 2008
  17. On Bitboards for White, Black and Kings to represent the checkers board, see David Link Video at 1:04:02
  18. Christopher Strachey (1966). System Analysis and Programming. Scientific American, September 1966, republished August 23, 2011
  19. Complete Annotated Strachey Checkers Program by Peter Norvig
  20. Prescient but Not Perfect: A Look Back at a 1966 Scientific American Article on Systems Analysis by Peter Norvig, August 23, 2011
  21. The function /W puts random digits into the twenty least significant digits of the accumulator. (The randomness is derived from a resistance noise generator) - Alan Turing (1952). Programmers' Handbook for the Manchester Electronic Computer Mark II. 2nd edition, revised by R.A. Brooker
  22. The Archaeology of Very Early Algorithms, 1948-58 - Christopher Strachey's Love Letter Generator by David Link, Computer Conservation Society, March 12, 2009
  23. LoveLetters_1.0, 2009—...: by David Link
  24. Strachey Love Letters from Gnoetry Daily
  25. Websites, widgets and other wonderful things. By Matt Sephton
  26. Christopher Strachey "Loveletters" (1952)
  27. The National Archives - Catalogue of the papers and correspondence of Christopher Strachey (1916 - 1975)
  28. DBLP: Christopher Strachey
  29. reverse.c from C code for most of the programs that appear in Hacker's Delight by Henry S. Warren, Jr.
  30. J.N. Buxton: Software Engineering Techniques 1969

Up one level