World Library  
Flag as Inappropriate
Email this Article

Dennis Ritchie

Dennis MacAlistair Ritchie
Dennis Ritchie, 2011
Born (1941-09-09)September 9, 1941
Bronxville, New York, U.S.
Died c. October 12, 2011(2011-10-12) (aged 70)
Berkeley Heights, New Jersey, U.S.
Nationality American
Fields Computer science
Institutions Lucent Technologies
Bell Labs
Alma mater Harvard University (Ph.D., 1968)
Known for ALTRAN
Notable awards Turing Award (1983)
National Medal of Technology (1998)
IEEE Richard W. Hamming Medal (1990)
Computer Pioneer Award (1994)
Computer History Museum Fellow (1997)[1]
Harold Pender Award (2003)
Japan Prize (2011)

Dennis MacAlistair Ritchie (September 9, 1941 – c. October 12, 2011)[2][3][4][5] was an American computer scientist.[2] He created the C programming language and, with long-time colleague Ken Thompson, the Unix operating system.[2] Ritchie and Thompson received the Turing Award from the ACM in 1983, the Hamming Medal from the IEEE in 1990 and the National Medal of Technology from President Clinton in 1999. Ritchie was the head of Lucent Technologies System Software Research Department when he retired in 2007. He was the "R" in K&R C and commonly known by his username dmr.


  • Personal life 1
  • Career 2
  • Views on computing 3
  • Awards 4
  • Death and legacy 5
  • Notable work 6
  • References 7
  • External links 8

Personal life

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. He moved with his family to Summit, New Jersey, as a child, where he graduated from Summit High School.[6] He graduated from Harvard University with degrees in physics and applied mathematics.


Ken Thompson (left) and Dennis Ritchie (right)
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 Sciences Research Center, and in 1968, he defended his PhD thesis on "Program Structure and Computational Complexity" at Harvard under the supervision of Patrick C. Fischer. However, Ritchie never officially received his PhD degree.[7]

Ritchie was best known as the creator of the C programming language, a key developer of the Unix operating system, and co-author of the book The C Programming Language, and was the 'R' in K&R (a common reference to the book's authors Kernighan and Ritchie). Ritchie worked together with Ken Thompson, the scientist credited with writing the original Unix; one of Ritchie's most important contributions to Unix was its porting to different machines and platforms.[8] 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."[9]

The C language is widely used today in application, operating system, and embedded system development, and its influence is seen in most modern programming languages. Unix has also been influential, establishing concepts and principles that are now precepts of computing.

Ritchie has described a 1970s collaboration 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.[10] Ritchie relates that, after discussions with the NSA, the authors decided not to publish it, as they were told the principle was applicable to machines then still in use by foreign governments.[10]

Views on computing

In an interview from 1999, Dennis Ritchie clarifies that he sees Linux and BSD operating systems as a continuation of the basis of the Unix operating system, and as derivatives of Unix:[11]

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 states that he views both Unix and Linux as "the continuation of ideas that were started by Ken and me and many others, many years ago."[11]


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".[12] 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".[13]

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."[14]

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".[15][16]

In 2005, the Industrial Research Institute awarded Ritchie with its Achievement Award in recognition of his contribution to science and technology, and to society generally, with his development of the Unix operating system.[17]

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.[18]

Death and legacy

Dennis Ritchie 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.[2] First news of his death came from his former colleague, Rob Pike.[3][4] The cause and exact time of death have not been disclosed.[19] He had been in frail health for several years following treatment for prostate cancer and heart disease.[2][3][20][21] His death came a week after the death of Steve Jobs but did not receive as much media coverage.[22][23][24] Following Ritchie's death, computer historian Paul E. Ceruzzi stated:[25]

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.[26] Kernighan reminded readers of how important a role C and UNIX had played in the development of later high-profile projects, like the iPhone.[27][28]

Other testimonials to his influence followed.[29][30][31][32]

The Fedora 16 Linux distribution, which was released about a month after he died, was dedicated to his memory.[33] FreeBSD 9.0, released January 12, 2012 was also dedicated in his memory.[34]

Notable work


  1. ^ Dennis Ritchie 1997 Fellow
  2. ^ a b c d e
  3. ^ a b c
  4. ^ a b
  5. ^
  6. ^ Keill, Liz. "Berkeley Heights man wins Japan Prize for inventing UNIX operating system", Independent Press, February 1, 2011. Accessed October 17, 2011. "Ritchie, 69, has lived in Berkeley Heights for 15 years. He was born in Bronxville, New York, grew up in Summit and attended Summit High School before going to Harvard University."
  7. ^
  8. ^ [Pioneer Programmer Shaped the Evolution of Computers, Wall Street Journal, October 14, 2011, p.A7]
  9. ^
  10. ^ a b Dennis M. Ritchie, Dabbling in the Cryptographic World — A Story
  11. ^ a b
  12. ^
  13. ^
  14. ^ [1]
  15. ^ Ritchie and Thompson [to] Get National Medal of Technology Bell Labs pre-announcement
  16. ^ Ritchie and Thompson Receive National Medal of Technology from President Clinton Bell Labs press release
  17. ^ "Dennis Ritchie, Bell Labs Researcher and Co-Inventor of Unix, Receives 2005 Industrial Research Institute Achievement Award", Alcatel-Lucent Press Release, Nov. 15, 2005, accessed Feb. 8, 2012.
  18. ^ Evangelista, Benny, "Ken Thompson, Dennis Ritchie win Japan Prize", San Francisco Chronicle, January 25, 2011
  19. ^
  20. ^ mirror
  21. ^ mirror
  22. ^
  23. ^
  24. ^
  25. ^ mirror
  26. ^ mirror
  27. ^ mirror
  28. ^ mirror
  29. ^ mirror
  30. ^ mirror
  31. ^ mirror
  32. ^ mirror
  33. ^
  34. ^

External links

  • Dennis Ritchie's home page at Bell Labs
  • "The C Family of Languages: Interview with Dennis Ritchie, Bjarne Stroustrup, and James Gosling" – article in Java Report, 5(7), July 2000 and C++ Report, 12(7), July/August 2000
  • "The Guru" – article in Linux Magazine, June 2001
  • Dennis Ritchie's video interview June 2011
  • Works by or about Dennis Ritchie in libraries (WorldCat catalog)
  • Dennis Ritchie at Find a Grave
  • Dennis Ritchie at DMOZ
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.