Editing Dennis Ritchie

{{Short description|American computer scientist known for Unix}}
{{Use mdy dates|date=September 2017}}
{{Infobox scientist
| name              = Dennis Ritchie
| image             = Dennis Ritchie 2011.jpg
| caption           = Ritchie in 2011
| birth_name        = Dennis MacAlistair Ritchie
| birth_date        = {{birth date|1941|09|09}}
| birth_place       = [[Bronxville, New York]], U.S.
| death_date        = {{circa}} {{death date and age|2011|10|12|1941|9|9}}
| death_place       = [[Berkeley Heights, New Jersey]], U.S.
| education         = [[Harvard University]] ([[Bachelor of Science|BS]])
| doctoral_advisor  = [[Patrick C. Fischer]]
| doctoral_students = 
| known_for         = [[ALTRAN]]<br/>[[B (programming language)|B]]<br/>[[BCPL]]<br/>[[C (programming language)|C]]<br/>[[Multics]]<br/>[[Unix]]
| footnotes         = 
| field             = [[Computer science]]
| workplaces        = [[Lucent Technologies]]<br/>[[Bell Labs]]
| prizes            = [[IEEE Emanuel R. Piore Award]] (1982)<ref>{{cite web |url=http://www.ieee.org/documents/piore_rl.pdf |title=IEEE Emanuel R. Piore Award Recipients |publisher=[[IEEE]] |accessdate=March 20, 2021|archive-url=https://web.archive.org/web/20101124232834/http://ieee.org/documents/piore_rl.pdf |archive-date=November 24, 2010 |url-status=dead}}</ref><br/>[[Turing Award]] (1983)<br/>[[National Medal of Technology]] (1998)<br/>[[IEEE Richard W. Hamming Medal]] (1990)<br/>[[Computer Pioneer Award]] (1994)<br/>[[Computer History Museum]] Fellow (1997)<ref name="Computerhistory"/><br/>[[Harold Pender Award]] (2003)<br/>[[Japan Prize]] (2011)
| website           = {{URL|https://www.nokia.com/bell-labs/about/dennis-m-ritchie/}}
}}

'''Dennis MacAlistair Ritchie''' (September 9, 1941 – {{circa}} October 12, 2011) was an American [[computer scientist]].<ref name=NYTimes/> He created the [[C (programming language)|C programming language]] and the [[Unix]] [[operating system]] and [[B (programming language)|B language]] with long-time colleague [[Ken Thompson]].<ref name=NYTimes/> Ritchie and Thompson were awarded the [[Turing Award]] from the [[Association for Computing Machinery]] (ACM) in 1983, the [[IEEE Richard W. Hamming Medal]] from the [[Institute of Electrical and Electronics Engineers]] (IEEE) in 1990, and the [[National Medal of Technology]] from President [[Bill Clinton]] in 1999.

Ritchie was the head of [[Lucent|Lucent Technologies]] System Software Research Department when he retired in 2007.

== 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''<ref>{{cite book |last1=Keister |first1=William |last2=Ritchie |first2=Alistair E. |last3=Washburn |first3=Seth E. |title=The Design of Switching Circuits |date=1951 |publisher=D. Van Nostrand Co., inc. |location=Princeton, NJ |edition=eighth printing Sep. 1963 |quote=Members of the Technical Staff, Bell Telephone Laboratories}}</ref> on [[switching circuit theory]].<ref name="WSJ-2018"/> As a child, Dennis moved with his family to [[Summit, New Jersey]], where he graduated from [[Summit High School (New Jersey)|Summit High School]].<ref name="NJ-2011"/> He graduated from [[Harvard University]] with [[academic degree|degree]]s in [[physics]] and [[applied mathematics]] in 1963.<ref name="WSJ-2018"/>

== Career ==
[[File:Ken Thompson and Dennis Ritchie--1973.jpg|thumb|[[Ken Thompson]] (left) and Dennis Ritchie (right), in 1973]]
[[File:Version 7 Unix SIMH PDP11 Emulation DMR.png|thumb|[[Version 7 Unix]] for the [[PDP-11]], including Dennis Ritchie's home directory: <code>/usr/dmr</code>]]
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.<ref>{{Cite journal |last1=van Renesse |first1=Robbert |s2cid=34452214 |date=January 2014 |title=The First SIGOPS Dennis M. Ritchie Doctoral Dissertation Award |s2cid-access=free |journal=ACM SIGOPS Operating Systems Review |volume=48 |issue=1 |page=100 |doi=10.1145/2626401.2626421|doi-access=free}}</ref><ref name="computerhistory.org">{{Cite web|date=2020-06-19|title=Discovering Dennis Ritchie's Lost Dissertation|url=https://computerhistory.org/blog/discovering-dennis-ritchies-lost-dissertation/ |first1=David C. |last1=Brock |access-date=2020-06-20 |website=[[Computer History Museum]] (CHM) |language=en}}</ref> In 2020, the [[Computer History Museum]] worked with Ritchie's family and Fischer's family and found a copy of the lost dissertation.<ref name="computerhistory.org"/><ref name="lost_diss">{{Cite report |last1=Brailsford |first1=David F. |last2=Kernighan |first2=Brian W. |last3=Ritchie |first3=William A. |date=2022 |title=How did Dennis Ritchie Produce his PhD Thesis? A Typographical Mystery |url=https://www.cs.princeton.edu/~bwk/dmr/doceng22.pdf |doi=10.1145/3558100.3563839 |access-date=March 15, 2023}}</ref><!-- I will have more information about this (and another reference) when I buy the book "Go To: The Story of the Math Majors, ..." (OriumX) -->

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".<ref name="Evolution">{{Cite report |last1=Ritchie |first1=Dennis M. |date=October 1984 |title=The Evolution of the Unix Time-sharing System |url=https://www.bell-labs.com/usr/dmr/www/hist.html |website=Bell Laboratories |access-date=October 31, 2016}}</ref> To supplement assembly language with a system-level programming language, Thompson created [[B (programming language)|B]]. Later, B was replaced by [[C (programming language)|C]], created by Ritchie, who continued to contribute to the development of Unix and C for many years.<ref name="c">{{Cite report |last1=Ritchie |first1=Dennis |date=April 1993 |title=The Development of the C Language |url=https://www.bell-labs.com/usr/dmr/www/chist.html |publisher=[[Bell Labs]] |access-date=October 31, 2016}}</ref>

During the 1970s, Ritchie collaborated with James Reeds and [[Robert Morris (cryptographer)|Robert Morris]] on a [[ciphertext-only attack]] on the [[M-209]] US cipher machine that could solve messages of at least 2000–2500 letters.<ref name="ritchiec">{{Cite web |title=Dabbling in Cryptography |url=https://www.bell-labs.com/usr/dmr/www/crypt.html |date=May 5, 2000 |website=Bell Labs |access-date=November 14, 2016}}</ref> 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.<ref name="ritchiec"/>

Ritchie was also involved with the development of the operating systems [[Plan 9 from Bell Labs|Plan 9]] and [[Inferno (operating system)|Inferno]], and the programming language [[Limbo (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.<ref>{{Cite news |first1=Steven |last1=Musil |date=October 13, 2011 |title=Dennis Ritchie, father of C programming language, dies |url=https://www.cnet.com/news/dennis-ritchie-father-of-c-programming-language-dies/ |publisher=cnet |url-status=live |archive-url= https://web.archive.org/web/20211209192037/https://www.cnet.com/news/dennis-ritchie-father-of-c-programming-language-dies/ |archive-date= Dec 9, 2021}}</ref>

== C and Unix ==
{{Multiple image
| direction = vertical
| width = 230
| header = [[Usenix]] conference, 1984
| image1 = Dennis Ritchie in a chalet in the mountains surrounding Salt Lake City, Utah--Summer 1984, Usenix conference.jpg
| caption1 = Ritchie conversing in a [[chalet]] in the mountains surrounding [[Salt Lake City]]
| image2 = Usenix84 1.jpg
| caption2 = Ritchie, standing in middle, in a striped sweater, behind [[Steven Bellovin]] in a baseball cap
}}
Ritchie created the [[C (programming language)|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.<ref>"Pioneer Programmer Shaped the Evolution of Computers", ''Wall Street Journal'', October 14, 2011, p.A7</ref> 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."<ref name="reader">{{Cite tech report |first1=M. D. |last1=McIlroy |author-link1=Doug McIlroy |year=1987 |url=http://www.cs.dartmouth.edu/~doug/reader.pdf |archive-url=https://web.archive.org/web/20140504225225/http://www.cs.dartmouth.edu/~doug/reader.pdf |archive-date=2014-05-04 |url-status=live |title=A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 |series=CSTR |number=139 |institution=Bell Labs}}</ref>

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.<ref>"The C Programming Language, Second Edition", Bell Telephone Laboratories, Inc., 1988, p.xi</ref> Moreover, C is a [[high-level programming language]] with constructs mapping to [[data structure]]s in [[application software]].

C influenced several other languages and derivatives, such as [[C++]], [[Objective-C]] used by Apple, [[C Sharp (programming language)|C#]] used by Microsoft, and [[Java (programming language)|Java]] used in corporate environments extensively and by [[Android (operating system)|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:<ref name="Interview_1999">{{Cite news |last1=Benet |first1=Manuel |date=1999 |title=Interview With Dennis M. Ritchie |url=http://www.linuxfocus.org/English/July1999/article79.html |work=LinuxFocus.org}}</ref>

{{Blockquote|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 computer|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."<ref name="Interview_1999"/>

== 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".<ref name="Ritchie">{{Cite web |title=A.M. Turing Award Laureate - Dennis M. Ritchie |url=https://amturing.acm.org/award_winners/ritchie_1506389.cfm |website=amturing.acm.org |publisher=[[Association for Computing Machinery]] (ACM) |access-date=2 April 2019}}</ref> Ritchie's Turing Award lecture was titled "Reflections on Software Research".<ref>{{Citation |last1=Ritchie |first1=Dennis M. |year=1987 |title=ACM Turing Award Lectures: The First Twenty Years 1666–1985 |pages=163–169 |series=ACM Press Anthology Series |chapter=1983 Turing Award Lecture: Reflections on Software Research |chapter-url=http://dl.acm.org/ft_gateway.cfm?id=1283939&type=pdf |publisher=Addison-Wesley Publishing Company |doi=10.1145/1283920.1283939 |isbn=9781450310499 |access-date=January 30, 2012|doi-access=free}}</ref> 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".<ref>{{Cite news |author=<!-- Unstated --> |date=1990 |title=IEEE Richard W. Hamming Medal Recipients |url=https://corporate-awards.ieee.org/wp-content/uploads/hamming-rl.pdf |archive-url=https://web.archive.org/web/20100620000223/http://ieee.org/documents/hamming_rl.pdf |archive-date=2010-06-20 |url-status=live |publisher=[[IEEE]] |access-date=May 29, 2011}}</ref>

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."<ref>{{Cite news |title=Dennis Ritchie: 1997 Fellow |url=https://computerhistory.org/profile/dennis-ritchie/ |website=[[Computer History Museum]] (CHM) |url-status=dead |archive-url=https://web.archive.org/web/20150403185444/http://www.computerhistory.org/fellowawards/hall/bios/Dennis,Ritchie/ |archive-date=April 3, 2015 |access-date=July 4, 2024}}</ref>

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".<ref name="NationalMedalAnnouncement">{{Cite news |title=Ritchie and Thompson Get National Medal of Technology |url=http://www.bell-labs.com/news/1998/december/9/1.html |date=December 8, 1998 |publisher=Bell Labs |url-status=dead |archive-url=https://web.archive.org/web/20060327052807/http://www.bell-labs.com/news/1998/december/9/1.html |archive-date=March 27, 2006 |access-date=September 6, 2006}}</ref><ref name="NationalMedalPressRelease">{{Cite web |title=Ritchie and Thompson Receive National Medal of Technology from President Clinton |url=http://www.bell-labs.com/news/1999/april/28/1.html |date=April 27, 1999 |publisher=Bell Labs |url-status=dead |archive-url=https://web.archive.org/web/20031011075017/http://www.bell-labs.com/news/1999/april/28/1.html |archive-date=October 11, 2003 |access-date=November 4, 2003}}</ref>

In 2005, the [[Industrial Research Institute]] awarded Ritchie its [[IRI Achievement Award|Achievement Award]] in recognition of his contribution to science and technology, and to society generally, with his development of the Unix operating system.<ref>{{Cite web |title=Dennis Ritchie, Bell Labs Researcher and Co-Inventor of Unix, Receives 2005 Industrial Research Institute Achievement Award |url=http://www.alcatel-lucent.com/wps/portal/!ut/p/kcxml/04_Sj9SPykssy0xPLMnMz0vM0Y_QjzKLd4x3cg_SL8h2VAQAv8HY9g!!?LMSG_CABINET=Docs_and_Resource_Ctr&LMSG_CONTENT_FILE=News_Releases_LU_2005/LU_News_Article_005372.xml |date=November 15, 2005 |publisher=Alcatel-Lucent Press Release |url-status=dead |archive-url=https://web.archive.org/web/20140204000724/http://www3.alcatel-lucent.com/wps/portal/%21ut/p/kcxml/04_Sj9SPykssy0xPLMnMz0vM0Y_QjzKLd4x3cg_SL8h2VAQAv8HY9g%21%21?LMSG_CABINET=Docs_and_Resource_Ctr&LMSG_CONTENT_FILE=News_Releases_LU_2005%2FLU_News_Article_005372.xml |archive-date=February 4, 2014 |access-date=February 8, 2012}}</ref>

In 2011, Ritchie, along with Thompson, was awarded the [[Japan Prize|Japan Prize for Information and Communications]] for his work in the development of the Unix operating system.<ref>{{Cite news |last1=Evangelista |first1=Benny |date=January 25, 2011 |title=Ken Thompson, Dennis Ritchie win Japan Prize |url=https://www.sfgate.com/business/article/Ken-Thompson-Dennis-Ritchie-win-Japan-Prize-2478569.php |work=San Francisco Chronicle}}</ref>

==Death==
[[File:Dennis Ritchie (right) Receiving Japan Prize.jpeg|thumb|Dennis Ritchie (right) with [[Doug McIlroy]] (left) in May 2011]]
<!-- BEFORE CHANGING DEATH CIRCUMSTANCES OR DATE, FIRST DISCUSS ON TALK PAGE, AND PROVIDE RELIABLE SOURCE(S)! -->
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.<ref name=NYTimes/> First news of his death came from his former colleague, [[Rob Pike]].<ref name=BBC/><ref name=RobPike/><ref>{{Citation |agency=Associated Press |title=Summary Box: Dennis Ritchie, pioneer in computer programming at Bell Labs, dies at 70 |date=October 13, 2011 |url=https://www.washingtonpost.com/business/summary-box-dennis-ritchie-pioneer-in-computer-programming-at-bell-labs-dies-at-70/2011/10/13/gIQAFKC7hL_story.html |archive-url=https://web.archive.org/web/20181224065622/https://www.washingtonpost.com/business/summary-box-dennis-ritchie-pioneer-in-computer-programming-at-bell-labs-dies-at-70/2011/10/13/gIQAFKC7hL_story.html |url-status=dead |archive-date=December 24, 2018 |newspaper=The Washington Post |quote=Not known: Alcatel-Lucent confirmed his death to The Associated Press but would not disclose the cause of death or when Ritchie died. |access-date=October 14, 2011}}</ref> He had been in frail health for several years following treatment for [[prostate cancer]] and [[heart disease]].<ref name=NYTimes/><ref name="BBC"/><ref>{{Cite magazine |last1=Gallagher |first1=Sean |date=October 13, 2011 |title=Dennis Ritchie, Father of C and Co-Developer of Unix, Dies |url=https://www.wired.com/wiredenterprise/2011/10/dennis-ritchie/ |magazine=[[Wired (magazine)|Wired]] |access-date=October 13, 2011}}</ref><ref>{{Cite web |title=Dennis Ritchie, in Memoriam |url=http://drdobbs.com/cpp/231900742?cid=DDJ_nl_upd_2011-10-13_h |last1=Binstock |first1=Andrew |website=Dr. Dobb's Journal |access-date=October 14, 2011}}</ref> News of Ritchie's death was largely overshadowed by the media coverage of the death of [[Apple Inc.|Apple]] co-founder [[Steve Jobs]], which occurred the week before.<ref>{{Cite web |last1=Srinivasan |first1=Rajeev |date=October 25, 2011 |title=Dennis Ritchie, a tech genius as great as Steve Jobs |url=https://www.firstpost.com/tech/news-analysis/dennis-ritchie-a-tech-genius-as-great-as-steve-jobs-2-3590163.html |access-date=2024-09-21 |website=[[Firstpost]]}}</ref>

==Legacy==
Following Ritchie's death, computer historian [[Paul E. Ceruzzi]] stated:<ref>{{Cite news |last1=Langer |first1=Emily |date=October 14, 2011 |title=Dennis Ritchie, founder of Unix and C, dies at 70 |newspaper=Washington Post |url=https://www.washingtonpost.com/local/obituaries/dennis-ritchie-founder-of-unix-and-c-dies-at-70/2011/10/13/gIQAXsVXiL_story.html |access-date=November 3, 2011}}</ref>

{{blockquote|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.<ref name="ForbesKernighanInterview2011-11-04">{{Cite magazine |last1=Prasad |first1=Shishir |date=November 4, 2011 |title=No one thought 'C' would become so big: Brian Kernighan |url=http://forbesindia.com/interview/special/brian-kernighan-no-one-thought-c-would-become-so-big/29982/1 |magazine=[[Forbes India]] |access-date=November 28, 2011 |quote=Q Did Dennis Ritchie or you ever think C would become so popular? [Kernighan] I don't think that at the time Dennis worked on Unix and C anyone thought these would become as big as they did. Unix, at that time, was a research project inside Bell Labs.}}</ref>
Kernighan told ''[[The New York Times]]'' "The tools that Dennis built—and their direct descendants—run pretty much everything today."<ref>{{Cite news |last1=Lohroct |first1=Steve |date=October 13, 2011 |title=Dennis Ritchie, 70, Dies, Programming Trailblazer |work=[[The New York Times]] |url=https://www.nytimes.com/2011/10/14/technology/dennis-ritchie-programming-trailblazer-dies-at-70.html |access-date=November 14, 2016}}</ref> 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]].<ref>{{Cite news |date=November 28, 2011 |title=Myths of Steve Jobs |work=[[Deccan Herald]] |url=http://www.deccanherald.com/blog/?p=220 |url-status=dead |access-date=November 28, 2011 |archive-url=https://web.archive.org/web/20130727010843/http://www.deccanherald.com/blog/?p=220 |archive-date=July 27, 2013 |quote=Dennis Ritchie, the inventor of the C language and co-inventor of the Unix operating system, died a few days after Steve Jobs. He was far more influential than Jobs.}}</ref><ref>{{Cite news |last1=Datta |first1=Subhajit |date=November 14, 2011 |title=The tale of three deeply different technologists |work=[[The Hindu]] |url=http://www.thehindu.com/news/states/karnataka/article2622056.ece |url-status=dead |access-date=November 28, 2011 |archive-url=https://web.archive.org/web/20111116000934/http://www.thehindu.com/news/states/karnataka/article2622056.ece |archive-date=November 16, 2011}}</ref> Other testimonials to his influence followed.<ref>{{Cite news |last1=Cardinal |first1=David |date=November 2, 2011 |title=Dennis Ritchie, creator of C, bids "goodbye, world" |publisher=[[Extreme Tech]] |url=http://www.extremetech.com/computing/102835-dennis-ritchie-creator-of-c-bids-goodbye-world |access-date=November 28, 2011 |quote=The book came off the shelf in service of teaching another generation a simple, elegant way to program that allows the developer to be directly in touch with the innards of the computer. The lowly integer variable—int—has grown in size over the years as computers have grown, but the C language and its sparse, clean, coding style live on. For that we all owe a lot to Dennis Ritchie.}}</ref><ref name="TheEconomist">{{Cite news |date=November 5, 2011 |title=Dennis Ritchie and John McCarthy: Dennis Ritchie and John McCarthy, machine whisperers, died on October 8th and 24th respectively, aged 70 and 84 |newspaper=The Economist |url=http://www.economist.com/node/21536536 |access-date=November 28, 2011 |quote=Now that digital devices are fashion items, it is easy to forget what really accounts for their near-magical properties. Without the operating systems which tell their different physical bits what to do, and without the languages in which these commands are couched, the latest iSomething would be a pretty but empty receptacle. The gizmos of the digital age owe a part of their numeric souls to Dennis Ritchie and John McCarthy.}}</ref><ref>{{Cite news |date=November 23, 2011 |title=The Strange Birth and Long Life of Unix |publisher=Newswise |url=http://www.newswise.com/articles/the-strange-birth-and-long-life-of-unix |access-date=November 28, 2011 |quote=Four decades ago, Ken Thompson, the late Dennis Ritchie, and others at AT&T's Bell Laboratories developed Unix, which turned out to be one of the most influential pieces of software ever written. Their work on this operating system had to be done on the sly, though, because their employer had recently backed away from operating-systems research.}}</ref><ref>{{Cite news |last1=Das |first1=Shyamanuja |date=November 1, 2011 |title=The forgotten tech luminaries: The new generation of the digital age owe a part of their numeric souls to Dennis Ritchie and John McCarthy |work=Ciol.com |url=http://www.ciol.com/News/News/News-Reports/The-forgotten-tech-luminaries/156641/0/ |url-status=dead |access-date=November 28, 2011 |archive-url=https://web.archive.org/web/20160703005812/http://www.ciol.com/News/News/News-Reports/The-forgotten-tech-luminaries/156641/0/ |archive-date=July 3, 2016 |quote=UNIX, to the development of which Ritchie greatly contributed, and whose C made it possible it to be ported to other machines, is, even today, in its different avatars, the de facto OS for anything that is mission critical. [[Oracle Solaris|Solaris]], [[IBM AIX|AIX]], [[HP-UX]], Linux—all these are derived from UNIX.}}</ref>

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."<ref>{{Cite news |last1=Duncan |first1=Geoff |date=October 13, 2011 |title=Was Dennis Ritchie more important than Steve Jobs? |url=http://www.digitaltrends.com/apple/was-dennis-ritchie-more-important-than-steve-jobs/ |publisher=Digital Trends |access-date=November 14, 2016}}</ref> 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."<ref>{{Cite news |title=Without Dennis Ritchie, there would be no Steve Jobs |url=https://www.zdnet.com/article/without-dennis-ritchie-there-would-be-no-jobs/ |last1=Perlow |first1=Jason |date=October 9, 2015 |website=ZDNet.com |access-date=November 14, 2016}}</ref> 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,..."<ref>{{Cite news |last1=Biggs |first1=John |date=October 15, 2011 |title=What Can We Learn From Dennis Ritchie? |url=https://techcrunch.com/2011/10/15/what-can-we-learn-from-dennis-ritchie/ |website=TechCrunch |access-date=November 14, 2016}}</ref>

The [[Fedora 16]] [[Linux distribution]], which was released about a month after he died, was dedicated to his memory.<ref name="F16Phoronix">{{Cite news |last1=Larabel |first1=Michael |date=8 November 2011 |title=Red Hat Releases Fedora 16 "Verne" |url=https://www.phoronix.com/scan.php?page=news_item&px=MTAxMjg |work=[[Phoronix]] |access-date=November 8, 2011}}</ref> [[FreeBSD]] 9.0, released January 12, 2012, was also dedicated in his memory.<ref name="FreeBSD">{{Cite news |last1=Jude |first1=Allan |date=January 12, 2012 |title=FreeBSD-9.0 Announcement |url=http://www.freebsd.org/releases/9.0R/announce.html |website=FreeBSD.org |access-date=January 12, 2012}}</ref>

Asteroid [[294727 Dennisritchie]], discovered by astronomers [[Tom Glinos]] and [[David H. Levy]] in 2008, was named in his memory.<ref name="MPC-object"/> The official {{MoMP|294727|naming citation}} was published by the [[Minor Planet Center]] on 7 February 2012 ([[Minor Planet Circulars]] (M.P.C.) 78272).<ref name="MPC-Circulars-Archive"/>

== Notable works ==
* [[B (programming language)|B language]]
* [[C (programming 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.
* ''[[Man page|Unix Programmer's Manual]]'' (1971)
* ''[[The C Programming Language]]'' (sometimes referred to as ''K&R''; 1978 with [[Brian Kernighan]])<ref>{{Cite book |last1=Kernighan |first1=Brian W. |url=https://archive.org/details/cprogramminglang00kern |title=The C Programming Language |last2=Ritchie |first2=Dennis M. |date=1978 |publisher=Prentice-Hall |isbn=978-0131101630 |location=Englewood Cliffs, N.J. |oclc=3608698 |url-access=registration}}</ref>

== Publications and academic papers ==
Ritchie has been the author or contributor to about 50 academic papers, books and textbooks and which have had over 15,000 citations.<ref>{{Cite web|title=Dennis Ritchie|url=https://scholar.google.com/citations?user=w1WB5d0AAAAJ&oi=ao|access-date=2021-02-02|website=scholar.google.com}}</ref>

Here are some of his most cited works:

* [[The C Programming Language]], BW Kernighan, DM Ritchie, Prentice Hall, Englewood Cliffs, New Jersey (1978)<ref>{{Cite book |last1=Kernighan |first1=Brian W. |url=https://books.google.com/books?id=Yi5FI5QcdmYC&q=The+C+programming+language+BW+Kemighan,+DM+Ritchie+- |title=C Programming Language: C PROGRAMMING LANG _p2 |last2=Ritchie |first2=Dennis |date=1988-03-22 |publisher=Prentice Hall |isbn=978-0-13-308621-8 |language=en}}</ref>
* Programming languages, D Ritchie (1978) <ref>{{Cite web |title=Dennis Ritchie |url=https://scholar.google.com/citations?user=w1WB5d0AAAAJ&oi=ao#d=gs_md_cita-d&u=/citations?view_op=view_citation&user=w1WB5d0AAAAJ&citation_for_view=w1WB5d0AAAAJ:9vf0nzSNQJEC&tzom=480 |access-date=2021-02-02 |website=scholar.google.com}}</ref>
*The UNIX time-sharing system, DM Ritchie, K Thompson, Classic operating systems, 195-220 (2001)<ref>{{Cite book |last1=Ritchie |first1=Dennis M. |last2=Thompson |first2=Ken |date=2001 |chapter=The Unix Time-Sharing System |chapter-url=https://doi.org/10.1007/978-1-4757-3510-9_11 |title=Classic Operating Systems: From Batch Processing to Distributed Systems |pages=195–220 |editor1-last=Hansen |editor1-first=Per Brinch |place=New York, NY |publisher=Springer |language=en |doi=10.1007/978-1-4757-3510-9_11 |isbn=978-1-4757-3510-9 |access-date=2021-02-02}}</ref>
*[[Advanced Programming in the Unix Environment]], WR Stevens, SA Rago, DM Ritchie, Addison-Wesley (1992, 2008)<ref>{{Cite book |last1=Stevens |first1=W. Richard |last2=Rago |first2=Stephen A.|date=2008 |url=https://books.google.com/books?id=wHI8PgAACAAJ |title=Advanced Programming in the UNIX Environment |publisher=Addison-Wesley |isbn=978-0-321-52594-9 |language=en}}</ref>

==See also==
* [[List of pioneers in computer science]]

== References ==
{{Reflist|refs=

<ref name="Computerhistory">{{Cite web |title=Dennis Ritchie |url=http://www.computerhistory.org/fellowawards/hall/bios/Dennis,Ritchie/ |publisher=Computer History Museum|url-status=dead |archive-url=https://web.archive.org/web/20150103005313/http://www.computerhistory.org/fellowawards/hall/bios/Dennis,Ritchie/ |archive-date=January 3, 2015 |access-date=January 5, 2015}}</ref>

<ref name="NYTimes">{{Cite news |last1=Lohr |first1=Steve |date=October 12, 2011 |title=Dennis Ritchie, Programming Trailblazer, Dies at 70 |url=https://www.nytimes.com/2011/10/14/technology/dennis-ritchie-programming-trailblazer-dies-at-70.html |work=The New York Times |archive-url=https://web.archive.org/web/20210725032530/https://www.nytimes.com/2011/10/14/technology/dennis-ritchie-programming-trailblazer-dies-at-70.html |quote=Dennis M. Ritchie, who helped shape the modern digital era by creating software tools that power things as diverse as search engines like Google and smartphones, was found dead on Wednesday at his home in Berkeley Heights, N.J. He was 70. Mr. Ritchie, who lived alone, was in frail health in recent years after treatment for prostate cancer and heart disease, said his brother Bill. |access-date=October 13, 2011|archive-date=July 25, 2021}}</ref>

<ref name="BBC">{{Cite news |date=October 13, 2011 |title=Unix creator Dennis Ritchie dies aged 70 |work=BBC News |url=https://www.bbc.co.uk/news/technology-15287391 |access-date=October 14, 2011 |quote=Pioneering computer scientist Dennis Ritchie has died after a long illness. ... The first news of Dr Ritchie's death came via Rob Pike, a former colleague who worked with him at Bell Labs. Mr Ritchie's passing was then confirmed in a statement from Alcatel-Lucent which now owns Bell Labs.}}</ref>

<ref name="RobPike">{{Citation |first1=Rob |last1=Pike |author-link1=Rob Pike |date=October 12, 2011 |title=(untitled post to Google+) |url=https://plus.google.com/101960720994009339267/posts/ENuEDDYfvKP |archive-url=https://web.archive.org/web/20180217120050/https://plus.google.com/101960720994009339267/posts/ENuEDDYfvKP?hl=en |quote=I just heard that, after a long illness, Dennis Ritchie (dmr) died at home this weekend. I have no more information. |access-date=October 14, 2011|archive-date=February 17, 2018}}</ref>

<!-- <ref name="Guardian">{{Cite news |last1=Campbell-Kelly |first1=Martin |date=October 13, 2011 |title=Dennis Ritchie obituary |url=https://www.theguardian.com/technology/2011/oct/13/dennis-ritchie |work=The Guardian |quote=Dennis MacAlistair Ritchie, computer scientist, born 9 September 1941; died 12 October 2011 |access-date=October 13, 2011}}</ref> -->

<ref name="WSJ-2018">{{Cite news |last1=Miller |first1=Stephen |date=2011-10-14 |title=Pioneer Programmer Shaped the Evolution of Computers |work=Wall Street Journal |url=https://www.wsj.com/articles/SB10001424052970204774604576629354123067080 |language=en-US |access-date=2018-03-03 |issn=0099-9660}}</ref>

<ref name="NJ-2011">{{Cite news |last1=Keill |first1=Liz |date=February 1, 2011 |title=Berkeley Heights man wins Japan Prize for inventing UNIX operating system |url=http://www.nj.com/independentpress/index.ssf/2011/02/japan_prize_for_unix_was_a_sur.html |publisher=Independent Press |access-date=October 17, 2011 |quote=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.}}</ref>

<ref name="MPC-object">{{Cite web |title=294727 Dennisritchie (2008 BV41) |url=https://www.minorplanetcenter.net/db_search/show_object?object_id=294727 |website=Minor Planet Center |access-date=12 September 2019}}</ref>

<ref name="MPC-Circulars-Archive">{{Cite web |title=MPC/MPO/MPS Archive |url=https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html |website=Minor Planet Center |access-date=12 September 2019}}</ref>

}}<!-- end of reflist -->

==External links==
{{Commons category}}
{{Wikiquote}}
{{Spoken Wikipedia|Dennis Ritchie.ogg|date=June 17, 2006}}
* {{Official website|www.bell-labs.com/usr/dmr/www}}, Bell Labs
* [http://www.gotw.ca/publications/c_family_interview.htm "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]
* {{usurped|1=[https://web.archive.org/web/20071011053711/http://www.linux-mag.com/id/801/ "The Guru" – article in Linux Magazine, June 2001]}}
* [https://abcnews.go.com/Technology/video/unix-starting-point-personal-computer-13869282?tab=9482931&section=1206840&playlist=11496627&page=1 Dennis Ritchie's video interview June 2011]

{{Multics}}
{{C programming language}}
{{Richard W. Hamming Medal recipients}}
{{Turing award}}
{{Japan Prize}}
{{Authority control}}

{{DEFAULTSORT:Ritchie, Dennis}}
[[Category:1941 births]]
[[Category:2011 deaths]]
[[Category:American computer scientists]]
[[Category:American technology writers]]
[[Category:Harvard John A. Paulson School of Engineering and Applied Sciences alumni]]
[[Category:Turing Award laureates]]
[[Category:Multics people]]
[[Category:Unix people]]
[[Category:Plan 9 people]]
[[Category:Inferno (operating system) people]]
[[Category:C (programming language)]]
[[Category:Scientists at Bell Labs]]
[[Category:National Medal of Technology recipients]]
[[Category:Programming language designers]]
[[Category:People from Bronxville, New York]]
[[Category:People from Berkeley Heights, New Jersey]]
[[Category:People from Summit, New Jersey]]
[[Category:Summit High School (New Jersey) alumni]]
[[Category:20th-century American inventors]]
[[Category:Scientists from New York (state)]]