Christopher Strachey
Encyclopedia
Christopher Strachey was a British
computer scientist
. He was one of the founders of denotational semantics
, and a pioneer in programming language
design. He was a member of the Strachey family
prominent in government, arts, administration and academia.
and Rachel (Ray) Costelloe in Hampstead
, England
. Oliver Strachey was the son of Richard Strachey
and the great grandson of Sir Henry Strachey, 1st Baronet
. In 1919 the family moved to 51 Gordon Square
. The Stracheys belonged to the Bloomsbury Group
whose members included Virginia Woolf
, John Maynard Keynes
and Christopher's uncle Lytton Strachey
. At 13, Christopher went to Gresham's School
, Holt
where he showed signs of brilliance but in general performed poorly. He was admitted to King's College, Cambridge
in 1935 where he continued to neglect his studies. Strachey studied mathematics and then transferred to physics. At the end of his third year at Cambridge, Strachey suffered a nervous breakdown, possibly related to coming to terms with his homosexuality. He returned to Cambridge but managed only a "lower second" in the Natural Sciences Tripos.
Unable to continue his education, Christopher joined Standard Telephone & Cables Ltd (STC) as a research physicist. His first job was providing mathematical analysis for the design of electron tubes used in radar
. The complexity of the calculations required the use of a differential analyzer. This initial experience with a computing machine sparked Strachey's interest and he began to research the topic. An application for a research degree at Cambridge was rejected and Strachey continued to work at STC throughout the Second World War. After the war he fulfilled a long-standing ambition by becoming a schoolmaster at St Edmund's School, Canterbury, teaching mathematics and physics. Three years later he was able to move to the more prestigious 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 successfully built a reduced version of Turing’s Automatic Computing Engine (ACE) the concept of which dated from 1945: the Pilot ACE
. In his spare time Strachey developed a program for the game of draughts
, which he finished in February 1951. The game completely exhausted the Pilot ACE’s memory. The draughts program ran for the first time on 30 July 1951 at NPL. When Strachey heard about the Manchester Mark 1
, which had a much bigger memory, he asked his former fellow-student Alan Turing
for the manual and transcribed his program into the operation codes of that machine by around October 1951. The program could "play a complete game of draughts at a reasonable speed". He also wrote one of the first computer music
programs, which played Baa Baa Black Sheep
.
Strachey worked for the National Research and Development Corporation (NRDC) from 1952 to 1959. While working on the St. Lawrence Seaway project, he was able to visit several computer centers in the United States and catalog their instruction set
s. Later, he worked on programming both the Elliott 401
computer and the Ferranti Pegasus
computer. He also worked on the analysis of vibration in aircraft, working briefly with Roger Penrose
, and developed the concept of time-sharing
.
In 1959, Strachey left NRDC to become a computer consultant working for NRDC, EMI
, Ferranti
and other organizations on a number of wide-ranging projects. This work included logical design for computers, providing autocode
and later the design of high-level programming languages. For a contract to produce the autocode for the Ferranti Orion
computer, Strachey hired Peter Landin who became his one assistant for the duration of Strachey's consulting period.
In 1962, while remaining a consultant, he accepted a position at Cambridge University.
In 1965, Strachey accepted a position at Oxford University as the first director of the Programming Research Group
and later the University's first Professor of Computer Science and fellow of Wolfson College, Oxford
. He collaborated with Dana Scott
.
(CPL). His influential set of lecture notes Fundamental Concepts in Programming Languages
formalized the distinction between L- and R- values
(as seen in the C programming language
). Strachey also coined the term currying
, although he did not invent the underlying concept.
He was instrumental in the design of the Ferranti
PEGASUS
computer.
The macro language m4
derives much from Strachey's GPM (General Purpose Macrogenerator), one of the earliest macro expansion languages
.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
computer scientist
Computer scientist
A computer scientist is a scientist who has acquired knowledge of computer science, the study of the theoretical foundations of information and computation and their application in computer systems....
. He was one of the founders of denotational semantics
Denotational semantics
In computer science, denotational semantics is an approach to formalizing the meanings of programming languages by constructing mathematical objects which describe the meanings of expressions from the languages...
, and a pioneer in programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
design. He was a member of the Strachey family
Strachey
-Strachey family of Sutton Court, Somerset:*John Strachey , friend of John Locke**John Strachey , British geologist, son of the above...
prominent in government, arts, administration and academia.
Life
Christopher Strachey was born on 16 November 1916 to Oliver StracheyOliver Strachey
Oliver Strachey , a British civil servant in the Foreign Office was a cryptographer from World War I to World War II....
and Rachel (Ray) Costelloe in Hampstead
Hampstead
Hampstead is an area of London, England, north-west of Charing Cross. Part of the London Borough of Camden in Inner London, it is known for its intellectual, liberal, artistic, musical and literary associations and for Hampstead Heath, a large, hilly expanse of parkland...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. Oliver Strachey was the son of Richard Strachey
Richard Strachey
Lieutenant-General Sir Richard Strachey, GCSI, FRS , British soldier and Indian administrator, third son of Edward Strachey and grandson of Sir Henry Strachey, 1st Baronet was born on 24 July 1817, at Sutton Court, Stowey, Somerset...
and the great grandson of Sir Henry Strachey, 1st Baronet
Sir Henry Strachey, 1st Baronet
Sir Henry Strachey, 1st Baronet was a British civil servant and politician.Strachey was the eldest son of Henry Strachey, of Sutton Court, Somerset, and his first wife Helen, daughter of Robert Clerk, a Scottish physician. His grandfather was the geologist John Strachey and his great-grandfather...
. In 1919 the family moved to 51 Gordon Square
Gordon Square
Gordon Square is in Bloomsbury, in the London Borough of Camden, London, England . It was developed by Thomas Cubitt in the 1820s, as one of a pair with Tavistock Square, which is a block away and has the same dimensions...
. The Stracheys belonged to the Bloomsbury Group
Bloomsbury Group
The Bloomsbury Group or Bloomsbury Set was a group of writers, intellectuals, philosophers and artists who held informal discussions in Bloomsbury throughout the 20th century. This English collective of friends and relatives lived, worked or studied near Bloomsbury in London during the first half...
whose members included Virginia Woolf
Virginia Woolf
Adeline Virginia Woolf was an English author, essayist, publisher, and writer of short stories, regarded as one of the foremost modernist literary figures of the twentieth century....
, John Maynard Keynes
John Maynard Keynes
John Maynard Keynes, Baron Keynes of Tilton, CB FBA , was a British economist whose ideas have profoundly affected the theory and practice of modern macroeconomics, as well as the economic policies of governments...
and Christopher's uncle Lytton Strachey
Lytton Strachey
Giles Lytton Strachey was a British writer and critic. He is best known for establishing a new form of biography in which psychological insight and sympathy are combined with irreverence and wit...
. At 13, Christopher went to Gresham's School
Gresham's School
Gresham’s School is an independent coeducational boarding school in Holt in North Norfolk, England, a member of the HMC.The school was founded in 1555 by Sir John Gresham as a free grammar school for forty boys, following King Henry VIII's dissolution of the Augustinian priory at Beeston Regis...
, Holt
Holt, Norfolk
Holt is a market town and civil parish in the English county of Norfolk. The town is north of the city of Norwich, west of Cromer and east of King's Lynn. The town is on the route of the A148 King's Lynn to Cromer road. The nearest railway station is in the town of Sheringham where access to the...
where he showed signs of brilliance but in general performed poorly. He was admitted to King's College, Cambridge
King's College, Cambridge
King's College is a constituent college of the University of Cambridge, England. The college's full name is "The King's College of our Lady and Saint Nicholas in Cambridge", but it is usually referred to simply as "King's" within the University....
in 1935 where he continued to neglect his studies. Strachey studied mathematics and then transferred to physics. At the end of his third year at Cambridge, Strachey suffered a nervous breakdown, possibly related to coming to terms with his homosexuality. He returned to Cambridge but managed only a "lower second" in the Natural Sciences Tripos.
Unable to continue his education, Christopher joined Standard Telephone & Cables Ltd (STC) as a research physicist. His first job was providing mathematical analysis for the design of electron tubes used in radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
. The complexity of the calculations required the use of a differential analyzer. This initial experience with a computing machine sparked Strachey's interest and he began to research the topic. An application for a research degree at Cambridge was rejected and Strachey continued to work at STC throughout the Second World War. After the war he fulfilled a long-standing ambition by becoming a schoolmaster at St Edmund's School, Canterbury, teaching mathematics and physics. Three years later he was able to move to the more prestigious Harrow School
Harrow School
Harrow School, commonly known simply as "Harrow", is an English independent school for boys situated in the town of Harrow, in north-west London.. The school is of worldwide renown. There is some evidence that there has been a school on the site since 1243 but the Harrow School we know today was...
in 1949, where he stayed for three years.
In January 1951, a friend introduced him to Mike Woodger of the National Physical Laboratory
National Physical Laboratory, UK
The National Physical Laboratory is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England. It is the largest applied physics organisation in the UK.-Description:...
(NPL). The lab had successfully built a reduced version of Turing’s Automatic Computing Engine (ACE) the concept of which dated from 1945: the Pilot ACE
Pilot ACE
The Pilot ACE was one of the first computers built in the United Kingdom, at the National Physical Laboratory in the early 1950s.It was a preliminary version of the full ACE, which had been designed by Alan Turing. After Turing left NPL , James H...
. In his spare time Strachey developed a program for the game of draughts
Draughts
Draughts is a group of abstract strategy board games between two players which involve diagonal moves of uniform pieces and mandatory captures by jumping over the enemy's pieces. Draughts developed from alquerque...
, which he finished in February 1951. The game completely exhausted the Pilot ACE’s memory. The draughts program ran for the first time on 30 July 1951 at NPL. When Strachey heard about the Manchester Mark 1
Manchester Mark 1
The Manchester Mark 1 was one of the earliest stored-program computers, developed at the Victoria University of Manchester from the Small-Scale Experimental Machine or "Baby" . It was also called the Manchester Automatic Digital Machine, or MADM...
, which had a much bigger memory, he asked his former fellow-student Alan Turing
Alan Turing
Alan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
for the manual and transcribed his program into the operation codes of that machine by around October 1951. The program could "play a complete game of draughts at a reasonable speed". He also wrote one of the first computer music
Computer music
Computer music is a term that was originally used within academia to describe a field of study relating to the applications of computing technology in music composition; particularly that stemming from the Western art music tradition...
programs, which played Baa Baa Black Sheep
Baa, Baa, Black Sheep (nursery rhyme)
Baa, Baa, Black Sheep is an English nursery rhyme, sung to a variant of the 1761 French melody Ah! Vous dirai-je, Maman. The original form of the tune is used for Twinkle Twinkle Little Star and the Alphabet song. The words have changed little in two and a half centuries...
.
Strachey worked for the National Research and Development Corporation (NRDC) from 1952 to 1959. While working on the St. Lawrence Seaway project, he was able to visit several computer centers in the United States and catalog their instruction set
Instruction set
An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...
s. Later, he worked on programming both the Elliott 401
Elliott Brothers (computer company)
-Elliott Brothers Ltd:Elliott Brothers Ltd was an early computer company of the 1950s–60s in the United Kingdom, tracing its descent from a firm of instrument makers founded by William Elliott in London around 1804. The research laboratories were based at Borehamwood, originally set up in...
computer and the Ferranti Pegasus
Pegasus (computer)
Pegasus was an early thermionic valve computer built by Ferranti, Ltd of Great Britain.The Pegasus 1 was first delivered in 1956 and the Pegasus 2 was delivered in 1959...
computer. He also worked on the analysis of vibration in aircraft, working briefly with Roger Penrose
Roger Penrose
Sir Roger Penrose OM FRS is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College...
, and developed the concept of time-sharing
Time-sharing
Time-sharing is the sharing of a computing resource among many users by means of multiprogramming and multi-tasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major technological shift in the history of computing.By allowing a large...
.
In 1959, Strachey left NRDC to become a computer consultant working for NRDC, EMI
EMI
The EMI Group, also known as EMI Music or simply EMI, is a multinational music company headquartered in London, United Kingdom. It is the fourth-largest business group and family of record labels in the recording industry and one of the "big four" record companies. EMI Group also has a major...
, Ferranti
Ferranti
Ferranti or Ferranti International plc was a UK electrical engineering and equipment firm that operated for over a century from 1885 until it went bankrupt in 1993. Known primarily for defence electronics, the Company was once a constituent of the FTSE 100 Index but ceased trading in 1993.The...
and other organizations on a number of wide-ranging projects. This work included logical design for computers, providing autocode
Autocode
Autocode is the name of a family of "simplified coding systems", later called programming languages, devised in the 1950s and 1960s for a series of digital computers at the Universities of Manchester and Cambridge...
and later the design of high-level programming languages. For a contract to produce the autocode for the Ferranti Orion
Ferranti Orion
The Orion was a mid-range mainframe computer introduced by Ferranti in 1959 and installed for the first time in 1961. Ferranti positioned Orion to be their primary offering during the early 1960s, complementing their high-end Atlas and smaller systems like the Sirius and Argus...
computer, Strachey hired Peter Landin who became his one assistant for the duration of Strachey's consulting period.
In 1962, while remaining a consultant, he accepted a position at Cambridge University.
In 1965, Strachey accepted a position at Oxford University as the first director of the Programming Research Group
Programming Research Group
The Programming Research Group is part of the Oxford University Computing Laboratory . It was founded by Christopher Strachey in 1965 and after his death, C.A.R. Hoare, FRS took over the leadership in 1977...
and later the University's first Professor of Computer Science and fellow of Wolfson College, Oxford
Wolfson College, Oxford
Wolfson College is a constituent college of the University of Oxford in England. Located in north Oxford along the River Cherwell, Wolfson is an all-graduate college with over sixty governing body fellows, in addition to both research and junior research fellows. It caters to a wide range of...
. He collaborated with Dana Scott
Dana Scott
Dana Stewart Scott is the emeritus Hillman University Professor of Computer Science, Philosophy, and Mathematical Logic at Carnegie Mellon University; he is now retired and lives in Berkeley, California...
.
Work
He developed the Combined Programming LanguageCombined Programming Language
CPL was a multi-paradigm programming language, that was developed in the early 1960s.- Design :...
(CPL). His influential set of lecture notes Fundamental Concepts in Programming Languages
Fundamental Concepts in Programming Languages
Fundamental Concepts in Programming Languages were an influential set of lecture notes written by Christopher Strachey for the International Summer School in Computer Programming at Copenhagen in August, 1967. It introduced much programming language terminology still in use today, including...
formalized the distinction between L- and R- values
Value (computer science)
In computer science, a value is an expression which cannot be evaluated any further . The members of a type are the values of that type. For example, the expression "1 + 2" is not a value as it can be reduced to the expression "3"...
(as seen in the C programming language
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
). Strachey also coined the term currying
Currying
In mathematics and computer science, currying is the technique of transforming a function that takes multiple arguments in such a way that it can be called as a chain of functions each with a single argument...
, although he did not invent the underlying concept.
He was instrumental in the design of the Ferranti
Ferranti
Ferranti or Ferranti International plc was a UK electrical engineering and equipment firm that operated for over a century from 1885 until it went bankrupt in 1993. Known primarily for defence electronics, the Company was once a constituent of the FTSE 100 Index but ceased trading in 1993.The...
PEGASUS
Pegasus (computer)
Pegasus was an early thermionic valve computer built by Ferranti, Ltd of Great Britain.The Pegasus 1 was first delivered in 1956 and the Pegasus 2 was delivered in 1959...
computer.
The macro language m4
M4 (computer language)
m4 is a general purpose macro processor designed by Brian Kernighan and Dennis Ritchie. m4 is an extension of an earlier macro processor m3, written by Ritchie for the AP-3 minicomputer.-Use:...
derives much from Strachey's GPM (General Purpose Macrogenerator), one of the earliest macro expansion languages
General Purpose Macro Processor
A general purpose macro processor is a macro processor that is not tied to or integrated with a particular language or piece of software.A macro processor is a program that copies a stream of text from one place to another, making a systematic set of replacements as it does so. Macro processors...
.
See also
- Pegasus computerPegasus (computer)Pegasus was an early thermionic valve computer built by Ferranti, Ltd of Great Britain.The Pegasus 1 was first delivered in 1956 and the Pegasus 2 was delivered in 1959...
- Lytton StracheyLytton StracheyGiles Lytton Strachey was a British writer and critic. He is best known for establishing a new form of biography in which psychological insight and sympathy are combined with irreverence and wit...
, the writer and critic - John St Loe StracheyJohn St Loe StracheyEvelyn John St Loe Strachey PC was a British Labour politician and writer.-Background and education:Born in Guildford, Surrey, the son of John Strachey, editor of The Spectator, he was educated at Eton College and Magdalen College, Oxford. At Oxford, he was editor, with Robert Boothby, of the...
, writer and member of Parliament
Further reading
- Copeland, B.J. A Brief History of Computing, AlanTuring.net, June 2000.
- Lavington, S. The Pegasus Story, Science MuseumScience museumA science museum or a science centre is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in museology have broadened the range of...
, 2000. ISBN 1-900747-40-5. - C. Strachey, An impossible program, The Computer JournalThe Computer JournalThe Computer Journal is a journal published by the Oxford University Press on behalf of the British Computer Society. It contains peer-reviewed articles and other contributions on computer science and information systems. Its first issue appeared in 1958, and it has been published continually since...
, 7(4):313, January 1965.
External links
- Christopher Strachey (1916–1975) at the Virtual Museum of ComputingVirtual Museum of ComputingThe Virtual Museum of Computing is an eclectic collection of links and online resources concerning the history of computers and computer science. It includes links to other related museums, both real and virtual, around the world, as well as having its own virtual galleries of information...
- A simulator of the Manchester Mark 1, executing Christopher Strachey's Love letter algorithm from 1952
- A web based version of Christopher Strachey's Love letter algorithm showing word lists
- Higher-Order and Symbolic Computation Volume 13, Issue 1/2 (April 2000) Special Issue in memory of Christopher Strachey