Dennis M. Ritchie
Dennis MacAlistair Ritchie (September 9, 1941 – c. October 12, 2011) was an American computer scientist. He created, together with long-time colleague Ken Thompson, the Unix operating system, C programming language, and B programming language.
Also recorded as Dennis MacAlistair Ritchie · A. Ritči · dmr · Dennis Ritchie
Dennis M. Ritchie

Denise Panyik-Dale · CC BY 2.0
- Name
- Dennis Ritchie
- Birth Name
- Dennis MacAlistair Ritchie
- Born
- 9 September 1941
- Birthplace
- Bronxville, New York, U.S.
- Died
- c. 12 October 2011
- Place of death
- Berkeley Heights, New Jersey, U.S.
- Education
- Harvard University (BS)
- Known for
- ALTRAN B BCPL C Multics Unix
- Field
- Computer science
- Awards
- IEEE Emanuel R.
- Full name
- Dennis MacAlistair Ritchie.
- Nationality
- United States.
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Dennis MacAlistair Ritchie (September 9, 1941 – c. October 12, 2011) was an American computer scientist. He created, together with long-time colleague Ken Thompson, the Unix operating system, C programming language, and B programming language.
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wikidata · Q45575 · wikipedia · Dennis Ritchie
In this article
Biography
Biography
Ritchie studied at Harvard University and Summit High School. The recorded working language is English. The field of work recorded is computer science. Employment is recorded with Bell Labs. Works named in the authority record are The C Programming Language, ALTRAN, B, BCPL, Multics and Plan 9. Distinctions recorded are Turing Award, National Medal of Technology and Innovation, Harold Pender Award and IEEE Emanuel R.
Key facts
Key facts
• Name — Dennis Ritchie • Birth Name — Dennis MacAlistair Ritchie • Born — 9 September 1941 • Birthplace — Bronxville, New York, U.S. • Died — c. 12 October 2011 • Place of death — Berkeley Heights, New Jersey, U.S. • Education — Harvard University (BS) • Doctoral Advisor — Patrick C. Fischer • Known for — ALTRAN B BCPL C Multics Unix • Field — Computer science • Workplaces — Lucent Technologies Bell Labs • Awards — IEEE Emanuel R. Piore Award (1982) Turing Award (1983) National Medal of Technology (1998) IEEE Richard W. Hamming Medal (1990) Computer Pioneer Award (1994) Computer History Museum Fellow (1997) Harold Pender Award (2003) Japan Prize (2011) • Website — www.nokia.com/bell-labs/about/dennis-m-ritchie/
Early life and education
Early life and education
Dennis Ritchie was born in Bronxville, New York. His father was Alistair E. Ritchie, a longtime Bell Labs scientist and co-author of The Design of Switching Circuits on switching circuit theory. As a child, Dennis moved with his family to Summit, New Jersey, where he graduated from Summit High School. He graduated from Harvard University with degrees in physics and applied mathematics in 1963.
Career
Career
• Illustration — Ken Thompson (left) and Dennis Ritchie (right), in 1973 • Illustration — Version 7 Unix for the PDP-11, including Dennis Ritchie's home directory: /usr/dmr In 1967, Ritchie began working at the Bell Labs Computing Science Research Center. In 1968, he completed a draft of his PhD thesis on "Computational Complexity and Program Structure" at Harvard under the supervision of Patrick C. Fischer. However, Ritchie never officially received his PhD degree. In 2020, the Computer History Museum worked with Ritchie's family and Fischer's family and found a copy of the lost dissertation. During the 1960s, Ritchie and Ken Thompson worked on the Multics operating system at Bell Labs. Thompson then found an old PDP-7 machine and developed his own application programs and operating system from scratch, aided by Ritchie and others. In 1970, Brian Kernighan suggested the name "Unix", a pun on the name "Multics". To supplement assembly language with a system-level programming language, Thompson created B. Later, B was replaced by C, created by Ritchie, who continued to contribute to the development of Unix and C for many years. During the 1970s, Ritchie collaborated with James Reeds and Robert Morris on a ciphertext-only attack on the M-209 US cipher machine that could solve messages of at least 2000–2500 letters. Ritchie relates that, after discussions with the National Security Agency, the authors decided not to publish it, as they were told that the principle applied to machines still in use by foreign governments. Ritchie was also involved with the development of the operating systems Plan 9 and Inferno, and the programming language Limbo. As part of an AT&T restructuring in the mid-1990s, Ritchie was transferred to Lucent Technologies, where he retired in 2007 as head of System Software Research Department.
C and Unix
C and Unix
Ritchie created the C programming language and was one of the developers of the Unix operating system. With Brian Kernighan, he co-wrote the book The C Programming Language, which is often referred to as K&R after their initials. Ritchie worked together with Ken Thompson, who is credited with writing the original version of Unix; one of Ritchie's contributions to Unix was its porting to different machines and platforms. They were so influential on Research Unix that Doug McIlroy later wrote, "The names of Ritchie and Thompson may safely be assumed to be attached to almost everything not otherwise attributed." Nowadays, the C language is widely used in application, operating system, and embedded system development, and its influence is seen in most modern programming languages. C is a low-level language with constructs closely translating to the hardware's instruction set. However, it is not tied to any given hardware, making it easy to write programs on any machine that supports C. Moreover, C is a high-level programming language with constructs mapping to data structures in application software. C influenced several other languages and derivatives, such as C++, Objective-C used by Apple, C# used by Microsoft, and Java used in corporate environments extensively and by Android. Ritchie and Thompson used C to write Unix, which has been influential in establishing many computing concepts and principles that are adopted widely. In an interview from 1999, Ritchie clarified that he saw Linux and Berkeley Software Distribution (BSD) operating systems as a continuation of the basis of the Unix operating system, and as derivatives of Unix: I think the Linux phenomenon is quite delightful, because it draws so strongly on the basis that Unix provided. Linux seems to be among the healthiest of the direct Unix derivatives, though there are also the various BSD systems as well as the more official offerings from the workstation and mainframe manufacturers. In the same interview, he stated that he viewed Unix and Linux as "the continuation of ideas that were started by Ken and me and many others, many years ago."
Death
Death
• Illustration — Dennis Ritchie (right) with Doug McIlroy (left) in May 2011 Ritchie was found dead on October 12, 2011, at the age of 70 at his home in Berkeley Heights, New Jersey, where he lived alone. First news of his death came from his former colleague, Rob Pike. He had been in frail health for several years following treatment for prostate cancer and heart disease.
Notable works
Notable works
• B language • C language on which many succeeding languages and technologies are based. • Unix multiuser operating system. Several workalikes (commonly referred to as Unix-like systems) have been developed based on Unix's design. Some follow POSIX standards, again based on Unix. • Unix Programmer's Manual (1971) • The C Programming Language (sometimes referred to as K&R; 1978 with Brian Kernighan)
Identity
Identity
What the record establishes about Dennis M. Ritchie is recorded as having received Turing Award, National Medal of Technology and Innovation and Harold Pender Award. Ritchie is recorded at birth as Dennis MacAlistair Ritchie. The identifiers under which Dennis M. Ritchie may be traced in institutional catalogues.
Life and career
Dated record
Life and career
Explore 1941–2011
The full dated record · 3 entries
1941
Dennis M. Ritchie born at Bronxville.
2011
Dennis M. Ritchie died at Berkeley Heights.
2011
Dennis Ritchie Official Homepage Mirror (2011) is digitised and catalogued by Internet Archive.
Places
Named by the record
Places
Only places the record itself states, plotted where the house gazetteer settles their coordinates. Nothing is inferred from a name or a nationality.
Bronxville.
Birth place
Berkeley Heights.
Death place
Publications and academic papers
Ritchie has been the author or contributor to about 50 academic papers, books, and textbooks which have had over 15,000 citations. Here are some of his most cited works: • The C Programming Language, BW Kernighan, DM Ritchie, Prentice Hall, Englewood Cliffs, New Jersey (1978) • Programming languages, D Ritchie (1978) • The UNIX time-sharing system, DM Ritchie, K Thompson, Classic operating systems, 195-220 (2001) • Advanced Programming in the Unix Environment, WR Stevens, SA Rago, DM Ritchie, Addison-Wesley (1992, 2008)
Legacy
Following Ritchie's death, computer historian Paul E. Ceruzzi stated: Ritchie was under the radar. His name was not a household name at all, but... if you had a microscope and could look in a computer, you'd see his work everywhere inside. In an interview shortly after Ritchie's death, long-time colleague Brian Kernighan said Ritchie never expected C to be so significant. Kernighan told The New York Times "The tools that Dennis built—and their direct descendants—run pretty much everything today." Kernighan reminded readers of how important a role C and Unix had played in the development of later high-profile projects, such as the iPhone. Other testimonials to his influence followed. Reflecting upon his death, a commentator compared the relative importance of Steve Jobs and Ritchie, concluding that "[Ritchie's] work played a key role in spawning the technological revolution of the last forty years—including technology on which Apple went on to build its fortune." Another commentator said, "Ritchie, on the other hand, invented and co-invented two key software technologies which make up the DNA of effectively every single computer software product we use directly or even indirectly in the modern age. It sounds like a wild claim, but it really is true." Another said, "many in computer science and related fields knew of Ritchie's importance to the growth and development of, well, everything to do with computing,..." The Fedora 16 Linux distribution, which was released about a month after he died, was dedicated to his memory. FreeBSD 9.0, released January 12, 2012, was also dedicated in his memory. Asteroid 294727 Dennisritchie, discovered by astronomers Tom Glinos and David H. Levy in 2008, was named in his memory. The official naming citation was published by the Minor Planet Center on 7 February 2012 (Minor Planet Circulars (M.P.C.) 78272).
Primary material
Documents and archives
scholarly publication
- Dennis Ritchie, father of modern computer programming, dies, 2011
Scholarly · Crossref registry · 2011
Institutional database
- Wikidata, structured authority record Q45575: Dennis M. Ritchie
Scholarly · Wikimedia Foundation
reference work
- “Dennis Ritchie”, English Wikipedia, consulted as further reading
Reputable secondary · Wikipedia
Awards
In 1983, Ritchie and Thompson received the Turing Award "for their development of generic operating systems theory and specifically for the implementation of the UNIX operating system". Ritchie's Turing Award lecture was titled "Reflections on Software Research". In 1990, both Ritchie and Thompson received the IEEE Richard W. Hamming Medal from the Institute of Electrical and Electronics Engineers (IEEE), "for the origination of the UNIX operating system and the C programming language". In 1997, both Ritchie and Thompson were made Fellows of the Computer History Museum, "for co-creation of the UNIX operating system, and for development of the C programming language." On April 21, 1999, Thompson and Ritchie jointly received the National Medal of Technology of 1998 from President Bill Clinton for co-inventing the UNIX operating system and the C programming language which, according to the citation for the medal, "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". In 2005, the Industrial Research Institute awarded Ritchie its Achievement Award in recognition of his contribution to science and technology, and to society generally, with his development of the Unix operating system. In 2011, Ritchie, along with Thompson, was awarded the Japan Prize for Information and Communications for his work in the development of the Unix operating system.
Notes from the source article
Cited by Wikipedia
Notes from the source article
These works are cited by the source article, in its own numbering. They are recorded as its citations, not as sources VALÉORINE has verified.
- 1.IEEE. IEEE Emanuel R. Piore Award Recipients.
- 2.Computer History Museum. Dennis Ritchie.
- 3.Lohr, Steve. Dennis Ritchie, Programming Trailblazer, Dies at 70. The New York Times. October 12, 2011.
- 4.Keister, William. The Design of Switching Circuits. D. Van Nostrand Co., inc. 1951.
- 5.Miller, Stephen. Pioneer Programmer Shaped the Evolution of Computers. Wall Street Journal. 2011-10-14. 0099-9660.
- 6.Keill, Liz. Berkeley Heights man wins Japan Prize for inventing UNIX operating system. Independent Press. February 1, 2011.
- 7.van Renesse, Robbert. The First SIGOPS Dennis M. Ritchie Doctoral Dissertation Award. ACM SIGOPS Operating Systems Review. 48. 1. 100. January 2014. 10.1145/2626401.2626421.
- 8.Brock, David C. Discovering Dennis Ritchie's Lost Dissertation. Computer History Museum (CHM). 2020-06-19.
- 9.Brailsford, David F. How did Dennis Ritchie Produce his PhD Thesis? A Typographical Mystery. 2022. 10.1145/3558100.3563839.
- 10.Ritchie, Dennis M. The Evolution of the Unix Time-sharing System. Bell Laboratories. October 1984.
- 11.Ritchie, Dennis. The Development of the C Language. Bell Labs. April 1993.
- 12.Dabbling in Cryptography. Bell Labs. May 5, 2000.
- 13.Musil, Steven. Dennis Ritchie, father of C programming language, dies. cnet. October 13, 2011.
- 14."Pioneer Programmer Shaped the Evolution of Computers", Wall Street Journal, October 14, 2011, p.A7
- 15.McIlroy, M. D. A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986. Bell Labs. 139. 1987.
- 16."The C Programming Language, Second Edition", Bell Telephone Laboratories, Inc., 1988, p.xi
- 17.Benet, Manuel. Interview With Dennis M. Ritchie. LinuxFocus.org. 1999.
- 18.Association for Computing Machinery (ACM). A.M. Turing Award Laureate - Dennis M. Ritchie. amturing.acm.org.
- 19.Ritchie, Dennis M. ACM Turing Award Lectures: The First Twenty Years 1666–1985. Addison-Wesley Publishing Company. 163–169. 1987. 9781450310499.
- 20.IEEE. IEEE Richard W. Hamming Medal Recipients. 1990.
- 21.Dennis Ritchie: 1997 Fellow. Computer History Museum (CHM).
- 22.Bell Labs. Ritchie and Thompson Get National Medal of Technology. December 8, 1998.
- 23.Bell Labs. Ritchie and Thompson Receive National Medal of Technology from President Clinton. April 27, 1999.
- 24.Alcatel-Lucent Press Release. Dennis Ritchie, Bell Labs Researcher and Co-Inventor of Unix, Receives 2005 Industrial Research Institute Achievement Award. November 15, 2005.
- 25.Evangelista, Benny. Ken Thompson, Dennis Ritchie win Japan Prize. San Francisco Chronicle. January 25, 2011.
- 26.Unix creator Dennis Ritchie dies aged 70. BBC News. October 13, 2011.
- 27.Pike, Rob. (untitled post to Google+). October 12, 2011.
- 28.Summary Box: Dennis Ritchie, pioneer in computer programming at Bell Labs, dies at 70. The Washington Post. Associated Press. October 13, 2011.
- 29.Gallagher, Sean. Dennis Ritchie, Father of C and Co-Developer of Unix, Dies. Wired. October 13, 2011.
- 30.Binstock, Andrew. Dennis Ritchie, in Memoriam. Dr. Dobb's Journal.
- 31.Langer, Emily. Dennis Ritchie, founder of Unix and C, dies at 70. Washington Post. October 14, 2011.
- 32.Prasad, Shishir. No one thought 'C' would become so big: Brian Kernighan. Forbes India. November 4, 2011.
- 33.Lohroct, Steve. Dennis Ritchie, 70, Dies, Programming Trailblazer. The New York Times. October 13, 2011.
- 34.Myths of Steve Jobs. Deccan Herald. November 28, 2011.
- 35.Datta, Subhajit. The tale of three deeply different technologists. The Hindu. November 14, 2011.
- 36.Cardinal, David. Dennis Ritchie, creator of C, bids "goodbye, world". Extreme Tech. November 2, 2011.
- 37.Dennis Ritchie and John McCarthy: Dennis Ritchie and John McCarthy, machine whisperers, died on October 8th and 24th respectively, aged 70 and 84. The Economist. November 5, 2011.
- 38.Newswise. The Strange Birth and Long Life of Unix. November 23, 2011.
- 39.Das, Shyamanuja. The forgotten tech luminaries: The new generation of the digital age owe a part of their numeric souls to Dennis Ritchie and John McCarthy. Ciol.com. November 1, 2011.
- 40.Duncan, Geoff. Was Dennis Ritchie more important than Steve Jobs?. Digital Trends. October 13, 2011.
- 41.Perlow, Jason. Without Dennis Ritchie, there would be no Steve Jobs. ZDNet.com. October 9, 2015.
- 42.Biggs, John. What Can We Learn From Dennis Ritchie?. TechCrunch. October 15, 2011.
- 43.Larabel, Michael. Red Hat Releases Fedora 16 "Verne". Phoronix. 8 November 2011.
- 44.Jude, Allan. FreeBSD-9.0 Announcement. FreeBSD.org. January 12, 2012.
- 45.294727 Dennisritchie (2008 BV41). Minor Planet Center.
- 46.MPC/MPO/MPS Archive. Minor Planet Center.
- 47.Kernighan, Brian W. The C Programming Language. Prentice-Hall. 1978. 978-0131101630.
- 48.Dennis Ritchie. scholar.google.com.
- 49.Kernighan, Brian W. C Programming Language: C PROGRAMMING LANG _p2. Prentice Hall. 1988-03-22. 978-0-13-308621-8.
- 50.Dennis Ritchie. scholar.google.com.
- 51.Ritchie, Dennis M. Classic Operating Systems: From Batch Processing to Distributed Systems. Springer. 195–220. 2001. 978-1-4757-3510-9.
- 52.Stevens, W. Richard. Advanced Programming in the UNIX Environment. Addison-Wesley. 2008. 978-0-321-52594-9.
- 53.Campbell-Kelly, Martin. Dennis Ritchie obituary. The Guardian. October 13, 2011.
References
Citations
References
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scholarly publication
Dennis Ritchie, father of modern computer programming, dies, 2011Crossref registry
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Wikidata, structured authority record Q45575: Dennis M. RitchieWikimedia Foundation
Verifiedreference work
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Open the remaining particulars
Ritchie worked in computer science. He was employed by Bell Labs. He belonged to National Academy of Engineering. Ritchie received Turing Award, National Medal of Technology and Innovation, Harold Pender Award, IEEE Emanuel R. Piore Award, Computer History Museum Fellow and Computer Pioneer Award.
Career and activity
Recognition and collections
The Encyclopedia exists whether or not anything is for sale. Corrections are recorded rather than overwritten, and every version of this record is kept. Published 14 August 2026.
Elsewhere in Books
38,960 published records in this field, each with its sources named.
- Dennis Feltham JonesAuthor
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- Dennis LehaneAuthor
- Dennis ListAuthor
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- Dennis O'DriscollAuthor
- Dennis OsadebayAuthor
- Dennis PhillipsAuthor
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