computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...

Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

C programming language ''The C Programming Language'' (sometimes termed ''K&R'', after its authors' initials) is a computer programming book written by Brian Kernighan and Dennis Ritchie, the latter of whom originally designed and implemented the language, as well as ...

Plan 9 Plan 9 or Plan Nine may refer to: Music * Plan 9 (band), a psychedelic rock band from Rhode Island * ''Plan 9'', an album by Big Guitars From Memphis with Rick Lindy * "Plan 9", a song on the 1993 album ''Gorgeous'' by electronica band 808 Stat ...

Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...

Go programming language Go is a statically typed, compiled programming language designed at Google by Robert Griesemer, Rob Pike, and Ken Thompson. It is syntactically similar to C, but with memory safety, garbage collection, structural typing, and CSP-style conc ...

regular expression A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" ...

UTF-8 UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''. UTF-8 is capable of ...

Turing Award The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery (ACM) for contributions of lasting and major technical importance to computer science. It is generally recognized as the highest distinction in compu ...

New Orleans, Louisiana New Orleans ( , ,New Orleans

Thompson received a

Bachelor of Science A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University o ...

in 1965 and a

master's degree A master's degree (from Latin ) is an academic degree awarded by universities or colleges upon completion of a course of study demonstrating mastery or a high-order overview of a specific field of study or area of professional practice.

in 1966, both in electrical engineering and computer science, from the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

, where his master's thesis advisor was Elwyn Berlekamp.

Career and research

Thompson was hired by

Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

in 1966. In the 1960s at Bell Labs, Thompson and Dennis Ritchie worked on the

Multics Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...

operating system. While writing Multics, Thompson created the Bon programming language. He also created a video game called '' Space Travel''. Later, Bell Labs withdrew from the MULTICS project. In order to go on playing the game, Thompson found an old PDP-7 machine and rewrote ''Space Travel'' on it. Eventually, the tools developed by Thompson became the

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

: Working on a PDP-7, a team of Bell Labs researchers led by Thompson and Ritchie, and including

Rudd Canaday Rudd Canaday is an American computer systems engineer and a previous member of the technical staff at the Bell Telephone Laboratories in Murray Hill, New Jersey, credited to co-develop the initial design of the Unix file system. In 2015 he join ...

, developed a hierarchical file system, the concepts of computer processes and device files, a

command-line interpreter A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive command (computing), commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invokin ...

,

pipes Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circul ...

for easy inter-process communication, and some small utility programs. In 1970,

Brian Kernighan Brian Wilson Kernighan (; born 1942) is a Canadian computer scientist. He worked at Bell Labs and contributed to the development of Unix alongside Unix creators Ken Thompson and Dennis Ritchie. Kernighan's name became widely known through co ...

suggested the name "Unix", in a pun on the name "Multics". After initial work on Unix, Thompson decided that Unix needed a system programming language and created B, a precursor to Ritchie's C. In the 1960s, Thompson also began work on

regular expression A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" ...

s. Thompson had developed the CTSS version of the editor QED, which included regular expressions for searching text. QED and Thompson's later editor ed (the standard text editor on Unix) contributed greatly to the eventual popularity of regular expressions, and regular expressions became pervasive in Unix text processing programs. Almost all programs that work with regular expressions today use some variant of Thompson's notation. He also invented

Thompson's construction algorithm In computer science, Thompson's construction algorithm, also called the McNaughton–Yamada–Thompson algorithm, is a method of transforming a regular expression into an equivalent nondeterministic finite automaton (NFA). This NFA can be used ...

used for converting regular expressions into nondeterministic finite automata in order to make expression matching faster.

1970s

Throughout the 1970s, Thompson and Ritchie collaborated on the Unix operating system; they were so prolific on

Research Unix The term "Research Unix" refers to early versions of the Unix operating system for DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC). History The term ''Resear ...

that Doug McIlroy later wrote, "The names of Ritchie and Thompson may safely be assumed to be attached to almost everything not otherwise attributed." In a 2011 interview, Thompson stated that the first versions of Unix were written by him, and that Ritchie began to advocate for the system and helped to develop it: Feedback from Thompson's Unix development was also instrumental in the development of the C programming language. Thompson would later say that the C language "grew up with one of the rewritings of the system and, as such, it became perfect for

writing systems A writing system is a method of visually representing verbal communication, based on a script and a set of rules regulating its use. While both writing and speech are useful in conveying messages, writing differs in also being a reliable form ...

". In 1975, Thompson took a

sabbatical A sabbatical (from the Hebrew: (i.e., Sabbath); in Latin ; Greek: ) is a rest or break from work. The concept of the sabbatical is based on the Biblical practice of ''shmita'' (sabbatical year), which is related to agriculture. According to ...

from Bell Labs and went to his alma mater, UC Berkeley. There, he helped to install

Version 6 Unix Sixth Edition Unix, also called Version 6 Unix or just V6, was the first version of the Unix operating system to see wide release outside Bell Labs. It was released in May 1975 and, like its direct predecessor, targeted the DEC PDP-11 family of m ...

on a PDP-11/70. Unix at Berkeley would later become maintained as its own system, known as the

Berkeley Software Distribution The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Ber ...

(BSD). In early 1976, Thompson wrote the initial version of Berkeley Pascal at the Computer Science Division, Department of Electrical Engineering and Computer Science, UC Berkeley (with extensive modifications and additions following later that year by

William Joy William Joy ( fl. 1310 – 1348) was an English master mason, or architect, of the Decorated Gothic style, known for his work on several English cathedrals. Joy's cathedral work shows influences of Bristol Cathedral, and he may have originated ...

, Charles Haley and faculty advisor Susan Graham). Thompson wrote a chess-playing program called "chess" for the first version of Unix (1971). Later, along with Joseph Condon, Thompson created the hardware-assisted program Belle, a world champion chess computer. He also wrote programs for generating the complete enumeration of

chess Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to dist ...

endings, known as endgame tablebases, for all 4, 5, and 6-piece endings, allowing chess-playing computer programs to make "perfect" moves once a position stored in them is reached. Later, with the help of chess endgame expert John Roycroft, Thompson distributed his first results on CD-ROM. In 2001, the '' ICGA Journal'' devoted almost an entire issue to Thompson's various contributions to computer chess.

1980s

In 1983, Thompson and Ritchie jointly received the

Turing Award The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery (ACM) for contributions of lasting and major technical importance to computer science. It is generally recognized as the highest distinction in compu ...

"for their development of generic operating systems theory and specifically for the implementation of the UNIX operating system". His acceptance speech, "Reflections on Trusting Trust", presented the persistent compiler backdoor attack now known as the '' Thompson hack'' or trusting trust attack, and is widely considered a seminal

computer security Computer security, cybersecurity (cyber security), or information technology security (IT security) is the protection of computer systems and networks from attack by malicious actors that may result in unauthorized information disclosure, t ...

work in its own right. Throughout the 1980s, Thompson and Ritchie continued revising Research Unix, which adopted a BSD codebase for the 8th, 9th, and 10th editions. In the mid-1980s, work began at Bell Labs on a new operating system as a replacement for Unix. Thompson was instrumental in the design and implementation of the Plan 9 from Bell Labs, a new operating system utilizing principles of Unix, but applying them more broadly to all major system facilities. Some programs that were part of later versions of Research Unix, such as mk and rc, were also incorporated into Plan 9. Thompson tested early versions of the C++ programming language for

Bjarne Stroustrup Bjarne Stroustrup (; ; born 30 December 1950) is a Danish computer scientist, most notable for the invention and development of the C++ programming language. As of July 2022, Stroustrup is a professor of Computer Science at Columbia Universit ...

by writing programs in it, but later refused to work in C++ due to frequent incompatibilities between versions. In a 2009 interview, Thompson expressed a negative view of C++, stating, "It does a lot of things half well and it's just a garbage heap of ideas that are mutually exclusive."

1990s

In 1992, Thompson developed the

UTF-8 UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''. UTF-8 is capable of ...

encoding scheme together with Rob Pike. UTF-8 encoding has since become the dominant character encoding for the

World Wide Web The World Wide Web (WWW), commonly known as the Web, is an information system enabling documents and other web resources to be accessed over the Internet. Documents and downloadable media are made available to the network through web se ...

, accounting for more than 90% of all web pages in 2019. In the 1990s, work began on the Inferno operating system, another research operating system that was based around a portable

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...

. Thompson and Ritchie continued their collaboration with Inferno, along with other researchers at Bell Labs.

2000s

In late 2000, Thompson retired from Bell Labs. He worked at Entrisphere, Inc. as a

fellow A fellow is a concept whose exact meaning depends on context. In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements. Within the context of higher education ...

until 2006 and now works at

Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...

as a Distinguished Engineer. Recent work has included the co-design of the Go programming language. Referring to himself along with the other original authors of Go, he states:

Programming setup

According to a 2009 interview, Thompson now uses a

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which i ...

-based operating system.

Awards

National Academies

In 1980, Thompson was elected to the

National Academy of Engineering The National Academy of Engineering (NAE) is an American nonprofit, non-governmental organization. The National Academy of Engineering is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of ...

for "designing UNIX, an operating system whose efficiency, breadth, power, and style have guided a generation's exploitation of

minicomputer A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...

s". In 1985 he was elected a

Member of the National Academy of Sciences Membership of the National Academy of Sciences is an award granted to scientists that the National Academy of Sciences (NAS) of the United States judges to have made “distinguished and continuing achievements in original research”. Membership i ...

.

Turing Award

In 1983, Thompson and Ritchie jointly received the

Turing Award The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery (ACM) for contributions of lasting and major technical importance to computer science. It is generally recognized as the highest distinction in compu ...

"for their development of generic operating systems theory and specifically for the implementation of the UNIX operating system". His acceptance speech, "Reflections on Trusting Trust", presented the backdoor attack now known as the '' Thompson hack'' or trusting trust attack, and is widely considered a seminal

computer security Computer security, cybersecurity (cyber security), or information technology security (IT security) is the protection of computer systems and networks from attack by malicious actors that may result in unauthorized information disclosure, t ...

work in its own right.

IEEE Richard W. Hamming Medal

In 1990, both Thompson and Dennis Ritchie received the IEEE Richard W. Hamming Medal from the

Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operat ...

(IEEE), "for the origination of the UNIX operating system and the C programming language".

Fellow of the Computer History Museum

In 1997, both Thompson and Ritchie were inducted as

Fellow A fellow is a concept whose exact meaning depends on context. In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements. Within the context of higher education ...

s of the

Computer History Museum The Computer History Museum (CHM) is a museum of computer history, located in Mountain View, California. The museum presents stories and artifacts of Silicon Valley and the information age, and explores the computing revolution and its impact ...

for "the co-creation of the UNIX operating system, and for development of the C programming language".

National Medal of Technology

On April 27, 1999, Thompson and Ritchie jointly received the 1998

National Medal of Technology The National Medal of Technology and Innovation (formerly the National Medal of Technology) is an honor granted by the President of the United States to American inventors and innovators who have made significant contributions to the development ...

from President

Bill Clinton William Jefferson Clinton (Birth name, né Blythe III; born August 19, 1946) is an American politician who served as the 42nd president of the United States from 1993 to 2001. He previously served as governor of Arkansas from 1979 to 1981 ...

for co-inventing the UNIX operating system and the C programming language which together have "led to enormous advances in computer hardware, software, and networking systems and stimulated growth of an entire industry, thereby enhancing American leadership in the Information Age".

Tsutomu Kanai Award

In 1999, the

Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operat ...

chose Thompson to receive the first Tsutomu Kanai Award "for his role in creating the UNIX operating system, which for decades has been a key platform for distributed systems work".

Japan Prize

In 2011, Thompson, along with Dennis Ritchie, was awarded the Japan Prize for Information and Communications for the pioneering work in the development of the Unix operating system.

Personal life

Ken Thompson is married and has a son.

References

Sources *

External links

Ken Thompson
Bell Labs
Reflections on Trusting Trust
1983

Turing Award The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery (ACM) for contributions of lasting and major technical importance to computer science. It is generally recognized as the highest distinction in compu ...

Lecture
Unix and Beyond: An Interview with Ken ThompsonIEEE Computer Society
The Linux Information Project (LINFO) *Computer Chess Comes of Age
PhotosComputer History Museum
*Computer Chess Comes of Age
Video of Interview with Ken ThompsonComputer History MuseumReading Chess paper by HS Baird and Ken Thompson
on

optical character recognition Optical character recognition or optical character reader (OCR) is the electronic or mechanical conversion of images of typed, handwritten or printed text into machine-encoded text, whether from a scanned document, a photo of a document, a sc ...

{{DEFAULTSORT:Thompson, Ken Members of the United States National Academy of Sciences American computer scientists American computer programmers American technology writers Turing Award laureates Multics people Unix people Plan 9 people Inferno (operating system) people Scientists at Bell Labs National Medal of Technology recipients UC Berkeley College of Engineering alumni Programming language designers Google employees 1943 births Living people Members of the United States National Academy of Engineering 20th-century American inventors People from New Orleans

Early life and education

Career and research

1970s

1980s

1990s

2000s

Programming setup

Awards

National Academies

Turing Award

IEEE Richard W. Hamming Medal

Fellow of the Computer History Museum

National Medal of Technology

Tsutomu Kanai Award

Japan Prize

Personal life

See also

References

External links