Christopher S. Strachey (pronounced STRAY-chee; born November 16, 1916; died May 18, 1975) was a British computer scientist. He was an early leader in creating programming languages and helped develop the idea of denotational semantics and computer time-sharing. He is credited as possibly the first person to create a video game and introduced terms like polymorphism and referential transparency, which are still used by programmers today. He was part of the Strachey family, which has been well-known in government, arts, administration, and education.

Early life and education

Christopher S. Strachey was born on November 16, 1916, in Hampstead, England, to Oliver Strachey and Rachel (Ray) Costelloe. Oliver was the son of Richard Strachey and the great-grandson of Sir Henry Strachey, 1st Baronet. His older sister, Barbara Strachey, was a writer. In 1919, the family moved to 51 Gordon Square. The Stracheys were part of the Bloomsbury Group, which included famous people like Virginia Woolf, John Maynard Keynes, and Strachey's uncle, Lytton Strachey. At age 13, Strachey attended Gresham's School in Holt. He showed signs of being very bright but did not do well in school. In 1935, he was admitted to King's College, Cambridge, the same college as Alan Turing. However, he did not focus on his studies. He first studied mathematics and then switched to physics. After his third year at Cambridge, Strachey experienced mental health challenges, possibly because he was dealing with his identity as a homosexual. He returned to Cambridge but received a lower grade in the Natural Sciences Tripos.

Career

Unable to continue his education, Strachey joined Standard Telephones and Cables (STC) as a research physicist. His first job involved helping with math problems for the design of electron tubes used in radar. The math was so difficult that a special machine called a differential analyser was needed. This experience with a computing machine interested Strachey, and he began studying the topic. He tried to get a research degree at the University of Cambridge but was not accepted. He continued working at STC during World War II. After the war, he became a schoolteacher at St Edmund's School, Canterbury, where he taught math and physics. Three years later, he moved to the more famous Harrow School in 1949, where he stayed for three years.

In January 1951, a friend introduced him to Mike Woodger of the National Physical Laboratory (NPL). The lab had built a smaller version of Alan Turing's Automatic Computing Engine (ACE), called the Pilot ACE. In his spare time, Strachey created a checkers video game in May 1951. This may have been the first video game. The game used up all the memory of the Pilot ACE. The program had errors and failed when it first ran at NPL on 30 July 1951. When Strachey learned about the Manchester Mark 1, which had more memory, he asked his former classmate Alan Turing for the manual and rewrote his program using the machine's codes by October 1951. By the summer of 1952, the program could "play a complete game of Draughts at a reasonable speed." Although Strachey did not name the game, it was later called "M. U. C. Draughts" by Noah Wardrip-Fruin.

Strachey programmed the first computer music in England. The earliest recording of music played by a computer was a version of the British National Anthem "God Save the King" on the University of Manchester's Ferranti Mark 1 computer in 1951. Later that year, short parts of three songs were recorded there by a BBC team: "God Save the King," "Baa, Baa, Black Sheep," and "In the Mood." Researchers at the University of Canterbury, Christchurch, restored the original recording disc in 2016, and the recordings can be heard on SoundCloud.

During the summer of 1952, Strachey programmed a love letter generator for the Ferranti Mark 1. This is known as the first example of computer-generated literature.

In May 1952, Strachey gave a two-part talk on "the study of control in animals and machines" ("cybernetics") for the BBC Home Service's Science Survey programme.

Strachey worked for the National Research Development Corporation (NRDC) from 1952 to 1959. While working on the St. Lawrence Seaway project, he visited several computer centres in the United States and listed their instruction sets. Later, he programmed both the Elliott 401 computer and the Ferranti Pegasus computer. With Donald B. Gillies, he filed three patents in computing design, including the design of base registers for program relocation. He also studied vibration in aircraft, working briefly with Roger Penrose.

In 1959, Strachey left NRDC to become a computer consultant for NRDC, EMI, Ferranti, and other organisations. His work included designing computers, creating autocode, and later developing high-level programming languages. For a contract to create autocode for the Ferranti Orion computer, Strachey hired Peter Landin, who became his assistant for the duration of his consulting work.

Strachey developed the concept of time-sharing in 1

Legacy

The Department of Computer Science at the University of Oxford has a Christopher Strachey Professorship of Computing, which has had the following people as professors:

• Sir Tony Hoare FRS (1988–2000)
• Samson Abramsky FRS (2000–2021)
• Nobuko Yoshida (2022 onwards)

In November 2016, an event called Strachey 100 was held at Oxford University to mark the 100th anniversary of Christopher Strachey’s birth. The event included a display at the Weston Library in Oxford of the Christopher Strachey archive, which is kept in the Bodleian Library’s collection.

Publications

• Strachey, Christopher (1952). "Logical or Non-Mathematical Programmes." Proceedings of the 1952 ACM national meeting. Toronto: ACM. pp. 46– 49. doi : 10.1145/800259.808992.
• Strachey, Christopher (1954). "The 'Thinking' Machine." Encounter. pp. 25– 31.
• Strachey, Christopher (1959). "Programme-Controlled Time Sharing." Proceedings of the IEE – Part B: Electronic and Communication Engineering. 106 (29): 462. doi : 10.1049/pi-b-2.1959.0311.
• Strachey, Christopher (1959). "On Taking the Square Root of a Complex Number." The Computer Journal. 2 (2): 89. doi : 10.1093/comjnl/2.2.89.
• Strachey, Christopher (1959). "Time Sharing in Large, Fast Computers." Proceedings of the 1st International Conference on Information Processing. Paris: UNESCO. pp. 336– 341.
• Strachey, Christopher (1960). "Two Contributions to the Techniques of Queuing Problems." The Computer Journal. 3 (2): 114– 116. doi : 10.1093/comjnl/3.2.114.
• Strachey, Christopher (1961). "Bitwise Operations." Communications of the ACM. 4 (3): 146. doi : 10.1145/366199.366254. S2CID 7359297.
• Strachey, Christopher; Wilkes, Maurice (1961). "Some Proposals for Improving the Efficiency of ALGOL 60." Communications of the ACM. 4 (11): 488– 491. doi : 10.1145/366813.366816. S2CID 8757176.
• Strachey, Christopher; Francis, John (1961). "The Reduction of a Matrix to Codiagonal Form by Eliminations." The Computer Journal. 4 (2): 168– 176. doi : 10.1093/comjnl/4.2.168.
• Strachey, Christopher (1962). "Book Reviews." The Computer Journal. 5 (2): 152– 153. doi : 10.1093/comjnl/5.2.152.
• Barron, David; Buxton, John; Hartley, David; Nixon, Eric; Strachey, Christopher (1963). "The Main Features of CPL." The Computer Journal. 6 (2): 134– 143. doi : 10.1093/comjnl/6.2.134.
• Strachey, Christopher (1965). "An Impossible Program." The Computer Journal. 7 (4): 313. doi : 10.1093/comjnl/7.4.313.
• Strachey, Christopher (1965). "A General Purpose Macrogenerator." The Computer Journal. 8 (3): 225– 241. doi : 10.1093/comjnl/8.3