View source for Edsger W. Dijkstra

{{short description|Dutch computer scientist (1930–2002)}}
{{Use dmy dates|date=August 2024}}
{{Infobox scientist
| name              = Edsger W. Dijkstra
| native_name_lang  = nl
| image             = Edsger Wybe Dijkstra.jpg
| caption           = Dijkstra in 2002
| birth_date        = {{Birth date|1930|05|11|df=yes}}
| birth_place       = [[Rotterdam]], Netherlands
| death_date        = {{death date and age|2002|08|06|1930|05|11|df=yes}}
| death_place       = [[Nuenen]], Netherlands
| spouse            = Ria C. Debets
| field             = {{Unbulleted list |[[Computer science]] |[[Theoretical computer science]]}}
| workplaces        = {{Unbulleted list |[[Centrum Wiskunde & Informatica|Mathematisch Centrum]] |[[Eindhoven University of Technology]] |[[Burroughs Corporation]] |[[University of Texas at Austin]]}}
| education         = [[Leiden University]] ([[Bachelor of Science|BS]], [[Master of Science|MS]])<br/>[[University of Amsterdam]] ([[Doctor of Philosophy|PhD]])
| doctoral_advisor  = [[Adriaan van Wijngaarden]]
| doctoral_students = {{Unbulleted list |[[Nico Habermann]] |[[Jan L. A. van de Snepscheut|Jan van de Snepscheut]] }}
| thesis_title      = Communication with an Automatic Computer
| thesis_year       = 1959
| prizes            = {{Unbulleted list |[[Turing Award]] (1972) |[[Harry H. Goode Memorial Award]] (1974) |[[Outstanding Contribution to Computer Science Education|SIGCSE Outstanding Contribution]] (1989) |[[ACM Fellow]] (1994) |[[Dijkstra Prize]] (2002)}}
| footnotes         = 
}}

'''Edsger Wybe Dijkstra''' ({{IPAc-en|ˈ|d|aɪ|k|s|t|r|ə}} {{respell|DYKE|strə}}; {{IPA|nl|ˈɛtsxər ˈʋibə ˈdɛikstraː|lang|Dijkstra.ogg|lang}}; 11 May 1930 – 6 August 2002) was a Dutch [[computer scientist]], [[programmer]], [[software engineer]], [[mathematician]], and science [[essay]]ist.<ref>{{Cite web|url=https://www.britannica.com/biography/Edsger-Dijkstra|title = Edsger Dijkstra &#124; Dutch computer scientist| date=2 August 2023 }}</ref>{{sfnp|Istrail|2008}}

Born in [[Rotterdam]] in the [[Netherlands]], Dijkstra studied mathematics and physics and then [[theoretical physics]] at the [[University of Leiden]]. [[Adriaan van Wijngaarden]] offered him a job as the first [[computer programmer]] in the Netherlands at the [[Centrum Wiskunde & Informatica|Mathematical Centre in Amsterdam]], where he worked from 1952 until 1962. He formulated and solved the [[shortest path problem]] in 1956, and in 1960 developed the first [[compiler]] for the programming language [[ALGOL 60]] in conjunction with colleague [[Jaap A. Zonneveld]]. In 1962 he moved to [[Eindhoven]], and later to [[Nuenen]], where he became a professor in the Mathematics Department at the [[Technische Hogeschool Eindhoven]]. In the late 1960s he built the [[THE multiprogramming system]], which influenced the designs of subsequent systems through its use of software-based paged virtual memory. Dijkstra joined [[Burroughs Corporation]] as its sole [[research fellow]] in August 1973. The Burroughs years saw him at his most prolific in output of research articles. He wrote nearly 500 documents in the "EWD" series, most of them technical reports, for private circulation within a select group.

Dijkstra accepted the Schlumberger Centennial Chair in the Computer Science Department at the [[University of Texas at Austin]] in 1984, working in [[Austin, Texas|Austin, USA]], until his retirement in November 1999. He and his wife returned from Austin to his original house in Nuenen, where he died on 6 August 2002 after a long struggle with cancer.<ref name="Goodwins">{{cite news |url=http://news.cnet.com/2100-1001-949023.html |title=Computer science pioneer Dijkstra dies |access-date=22 December 2010 |last=Goodwins |first=Rupert |date=8 August 2002}}</ref>
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He received the 1972 [[Turing Award]] for fundamental contributions to developing [[structured programming]] languages. Shortly before his death, he received the [[Association for Computing Machinery|ACM]] [[PODC]] Influential Paper Award in distributed computing for his work on [[self-stabilization]] of program computation. This annual award was renamed the [[Dijkstra Prize]] the following year, in his honor.

== Life and works ==

===Early years===
Edsger W. Dijkstra was born in [[Rotterdam]].  His father was a chemist who was president of the [[Dutch Chemical Society]]; he taught chemistry at a secondary school and was later its superintendent. His mother was a mathematician, but never had a formal job.<ref>{{cite web |title=Edsger Wybe Dijkstra |website=Stichting Digidome|date=3 September 2003 |url=http://www.digidome.nl/edsger_wybe_dijkstra.htm |archive-url=https://web.archive.org/web/20041206193322/http://www.digidome.nl/edsger_wybe_dijkstra.htm |archive-date=6 December 2004}}</ref><ref name=MacTutor.bio>{{cite web| title=Dijkstra biography |last1=O'Connor |first1=J. J. |last2=Robertson |first2=E. F. |website=MacTutor |publisher=School of Mathematics and Statistics, University of St Andrews, Scotland |date=July 2008 |url=http://www-history.mcs.st-and.ac.uk/Biographies/Dijkstra.html |access-date=18 January 2014 |archive-url=https://web.archive.org/web/20131011055811/http://www-history.mcs.st-and.ac.uk/Biographies/Dijkstra.html |archive-date=11 October 2013 |url-status=live}}</ref>

Dijkstra had considered a career in law and had hoped to represent the Netherlands in the [[United Nations]]. However, after graduating from school in 1948, at his parents' suggestion he studied mathematics and physics and then [[theoretical physics]] at the [[University of Leiden]].<ref name="Dijkstra_bio">{{cite web |last1=Faulkner |first1=Larry R. |last2=Durbin |first2=John R. |date=19 August 2013 |title=In Memoriam: Edsger Wybe Dijkstra |url=https://www.cs.utexas.edu/users/EWD/MemRes(USLtr).pdf |access-date=20 August 2015 |publisher=University of Texas at Austin}}</ref>

In the early 1950s, [[electronic computers]] were a novelty. Dijkstra stumbled on his career by accident, and through his supervisor, Professor {{Interlanguage link|Johannes Haantjes|nl}}, he met [[Adriaan van Wijngaarden]], the director of the Computation Department at the [[Centrum Wiskunde & Informatica|Mathematical Centre in Amsterdam]], who offered Dijkstra a job; he officially became the Netherlands' first "programmer" in March 1952.<ref name="Dijkstra_bio"/>

Dijkstra remained committed to physics for some time, working on it in [[Leiden]] three days out of each week. With increasing exposure to computing, however, his focus began to shift. As he recalled:<ref name="ewd340">{{cite web |last=Dijkstra |first=Edsger W. |year=1972 |title=The Humble Programmer |work=ACM Turing Lecture 1972 |id=EWD340 |url=http://www.cs.utexas.edu/users/EWD/transcriptions/EWD03xx/EWD340.html}}</ref>

{{ blockquote
| text = After having programmed for some three years, I had a discussion with A. van Wijngaarden, who was then my boss at the Mathematical Center in Amsterdam, a discussion for which I shall remain grateful to him as long as I live. The point was that I was supposed to study theoretical physics at the University of Leiden simultaneously, and as I found the two activities harder and harder to combine, I had to make up my mind, either to stop programming and become a real, respectable theoretical physicist, or to carry my study of physics to a formal completion only, with a minimum of effort, and to become....., yes what? A programmer? But was that a respectable profession? For after all, what was programming? Where was the sound body of knowledge that could support it as an intellectually respectable discipline? I remember quite vividly how I envied my hardware colleagues, who, when asked about their professional competence, could at least point out that they knew everything about vacuum tubes, amplifiers and the rest, whereas I felt that, when faced with that question, I would stand empty-handed. Full of misgivings I knocked on Van Wijngaarden's office door, asking him whether I could "speak to him for a moment"; when I left his office a number of hours later, I was another person. For after having listened to my problems patiently, he agreed that up till that moment there was not much of a programming discipline, but then he went on to explain quietly that automatic computers were here to stay, that we were just at the beginning and could not I be one of the persons called to make programming a respectable discipline in the years to come? This was a turning point in my life and I completed my study of physics formally as quickly as I could.
| author=Edsger Dijkstra|title=The Humble Programmer (EWD340)|source=[[Communications of the ACM]]
}}

When Dijkstra married Maria "Ria" C. Debets in 1957, he was required as a part of the marriage rites to state his profession. He stated that he was a programmer, which was unacceptable to the authorities, there being no such profession then in The Netherlands.<ref name="ewd340"/><ref>{{cite web|url=http://www.i-programmer.info/history/people/144-dijkstra.html |author=James, Mike |title=Edsger Dijkstra — The Poetry of Programming |publisher=i-programmer.info |date=1 May 2013 |access-date=12 August 2015}}</ref>
 
In 1959, he received his PhD from the [[University of Amsterdam]] for a thesis entitled 'Communication with an Automatic Computer',<ref>{{cite web|url=https://ir.cwi.nl/pub/23612 |author=Dijkstra, Edsger Wiebe |title=Communication with an automatic computer |publisher=Uitgeverij Excelsior/CWI |date=28 October 1959 |access-date=4 November 2022}}</ref> devoted to a description of the [[assembly language]] designed for the first commercial computer developed in the Netherlands, the [[Electrologica X1]]. His thesis supervisor was Van Wijngaarden.<ref name="Apt, Krzysztof R. 2002">
{{cite journal |last=Apt |first=Krzysztof R. |year=2002 |title=Edsger Wybe Dijkstra (1930 - 2002): A portrait of a genius |journal=Formal Aspects of Computing |volume=14 |issue=2 |pages=92–98 |arxiv=cs/0210001 |doi=10.1007/s001650200029 |s2cid=12482128 |doi-access=free}}</ref>

===Mathematisch Centrum, Amsterdam===
From 1952 until 1962, Dijkstra worked at the [[Mathematisch Centrum]] in Amsterdam,<ref name="Apt, Krzysztof R. 2002"/> where he worked closely with [[Bram Jan Loopstra]] and [[Carel S. Scholten]], who had been hired to build a computer. Their mode of interaction was disciplined: They would first decide upon the interface between the hardware and the software, by writing a programming manual. Then the hardware designers would have to be faithful to their part of the contract, while Dijkstra, the programmer, would write software for the nonexistent machine. Two of the lessons he learned from this experience were the importance of clear documentation, and that program debugging can be largely avoided through careful design.<ref name="Dijkstra_bio"/>
Dijkstra formulated and solved the [[shortest path problem]] for a demonstration at the official inauguration of the ARMAC computer in 1956. Because of the absence of journals dedicated to automatic computing, he did not publish the result until 1959.

At the Mathematical Centre, Dijkstra and his colleague {{Interlanguage link|Jaap Zonneveld|nl}} developed the first [[compiler]] for the programming language [[ALGOL 60]] by August 1960, more than a year before a compiler was produced by another group.<ref name="Dijkstra_bio"/> ALGOL 60 is known as a key advance in the rise of structured programming.

===Eindhoven University of Technology===
[[File:TU Eindhoven.jpg|thumb|The [[Eindhoven University of Technology]], located in [[Eindhoven]] in the south of the Netherlands, where Dijkstra was a professor of mathematics from 1962 to 1984.]]
In 1962, Dijkstra moved to [[Eindhoven]], and later to [[Nuenen]], in the south of the Netherlands, where he became a professor in the Mathematics Department at the [[Eindhoven University of Technology]].<ref name="Apt, Krzysztof R. 2002"/> The university did not have a separate computer science department and the culture of the mathematics department did not particularly suit him. Dijkstra tried to build a group of computer scientists who could collaborate on solving problems. This was an unusual model of research for the Mathematics Department.<ref name="Dijkstra_bio"/> In the late 1960s, he built the [[THE multiprogramming system|THE operating system]] (named for the university, then known as [[Technische Hogeschool Eindhoven]]), which has influenced the designs of subsequent [[operating system]]s through its use of software-based paged virtual memory.<ref>{{Cite book |title=Operating System Concepts |last1=Silberschatz |first1=Abraham |last2=Peterson |first2=James L. |year=1988 |pages=512}}</ref>

===Burroughs Corporation===
Dijkstra joined the [[Burroughs Corporation]]—a company known then for producing computers based on an innovative hardware architecture—as its [[research fellow]] in August 1973. His duties consisted of visiting some of the firm's research centers a few times a year and carrying on his own research, which he did in the smallest Burroughs research facility, namely, his study on the second floor of his house in Nuenen. In fact, Dijkstra was the only research fellow of Burroughs and worked for it from home, occasionally travelling to its branches in the United States. As a result, he reduced his appointment at the university to one day a week. That day, Tuesday, soon became known as the day of the famous 'Tuesday Afternoon Club', a seminar during which he discussed with his colleagues scientific articles, looking at all aspects: notation, organisation, presentation, language, content, etc. Shortly after,  he moved in 1984 to the [[University of Texas at Austin]] (USA), a new 'branch' of the Tuesday Afternoon Club emerged in [[Austin, Texas]].<ref name="Apt, Krzysztof R. 2002"/>

The Burroughs years saw him at his most prolific in output of research articles. He wrote nearly 500 documents in the EWD series (described below), most of them technical reports, for private circulation within a select group.<ref name="Dijkstra_bio"/>

===The University of Texas at Austin===
[[File:Main Building at The University of Texas at Austin.jpg|thumb|The University of Texas at Austin, where Dijkstra held the Schlumberger Centennial Chair in Computer Sciences from 1984 until 1999.]]
Dijkstra accepted the Schlumberger Centennial Chair in the Computer Science Department at the University of Texas at Austin in 1984.

===Last years===
Dijkstra worked in [[Austin, Texas|Austin]] until his retirement  in November 1999. To mark the occasion and to celebrate his forty-plus years of seminal contributions to [[computer science|computing science]], the Department of Computer Sciences organized a symposium, which took place on his 70th birthday in May 2000.<ref name="Dijkstra_bio"/>

Dijkstra and his wife returned from Austin to his original house in Nuenen, Netherlands, where he found that he had only months to live. He said that he wanted to retire in Austin, [[Texas]], but to die in the Netherlands. Dijkstra died on 6 August 2002 after a long struggle with cancer.<ref name="Goodwins"/><ref>{{Cite web|date=7 August 2002|title=World-renowned University of Texas at Austin computer scientist Edsger Dijkstra dies|url=https://news.utexas.edu/2002/08/07/world-renowned-university-of-texas-at-austin-computer-scientist-edsger-dijkstra-dies/|access-date=4 August 2020|website=UT News|language=en-US}}</ref><ref>{{Cite book|last1=Dale|first1=Nell|url=https://books.google.com/books?id=_ENGBgAAQBAJ&pg=PA316|title=Computer Science Illuminated|last2=Lewis|first2=John|date=31 December 2014|publisher=Jones & Bartlett Publishers|isbn=978-1-284-05592-4|pages=316|language=en}}</ref><ref>{{Cite journal|date=2002|title=Edsger Dijkstra Passes Away|url=https://books.google.com/books?id=EWdVAAAAMAAJ&q=%22passed+away+on+August+6,+2002%22|journal=Dr. Dobb's Journal|volume=27|pages=14}}</ref> He and his wife were survived by their three children: Marcus, Femke, and the computer scientist Rutger M. Dijkstra.<ref name="Markoff 2002 n206">{{cite web | last=Markoff | first=John | title=Edsger Dijkstra, 72, Physicist Who Shaped Computer Era | website=The New York Times | date=10 August 2002 | url=https://www.nytimes.com/2002/08/10/us/edsger-dijkstra-72-physicist-who-shaped-computer-era.html | access-date=11 February 2024}}</ref>

== Personality ==
[[File:Edsger Dijkstra 1994.jpg|thumb|left|Dijkstra at the blackboard during a conference at [[ETH Zurich]] in 1994. He once remarked, "[[A picture is worth a thousand words|A picture may be worth a thousand words]], a [[formula]] is worth a thousand pictures."<ref>Dijkstra, E.W. (July 1996), ''[https://www.cs.utexas.edu/users/EWD/transcriptions/EWD12xx/EWD1239.html A first exploration of effective reasoning]'' [EWD896]. (E.W. Dijkstra Archive, Center for American History, [[University of Texas at Austin]])</ref>]]

=== Character ===
{{blockquote|text=You can hardly blame [[Massachusetts Institute of Technology|M.I.T.]] for not taking notice of an obscure computer scientist in a small town in the Netherlands.|source=Dijkstra, said about himself in Nuenen in the mid-1960s.<ref>Shasha, Dennis; Lazere, Cathy: ''Out of Their Minds: The Lives and Discoveries of 15 Great Computer Scientists''. (New York, NY: Springer, 1998, {{ISBN|978-0-387-98269-4}}), p. 64</ref>}}

In the world of computing science, Dijkstra is well known as a "character". In the preface of his book ''A Discipline of Programming'' (1976) he stated the following: "For the absence of a bibliography I offer neither explanation nor apology." In fact, most of his articles and books have no references at all.<ref name="Apt, Krzysztof R. 2002"/> Dijkstra chose this way of working to preserve his self-reliance.<ref>{{Cite journal |last=Apt |first=Krzysztof |date=28 September 2020 |title=The Man Who Carried Computer Science on His Shoulders |url=https://inference-review.com/article/the-man-who-carried-computer-science-on-his-shoulders |journal=Inference |language=en |volume=5 |issue=3}}</ref>

As a university professor for much of his life, Dijkstra saw teaching not just as a required activity but as a serious research endeavour.<ref name="Dijkstra_bio"/> His approach to teaching was unconventional.<ref>Irfan Hyder, Syed: Mathematics, Excellence and the Great Dijkstra (2013){{full citation needed|date=September 2020}}</ref> His lecturing style has been described as idiosyncratic. When lecturing, the long pauses between sentences have often been attributed to the fact that English is not Dijkstra's first language. However the pauses also served as a way for him to think on his feet and he was regarded as a quick and deep thinker while engaged in the act of lecturing. His courses for students in Austin had little to do with computer science but they dealt with the presentation of mathematical proofs.<ref name="Apt, Krzysztof R. 2002"/> At the beginning of each semester, he would take a photo of each of his students in order to memorize their names. He never followed a [[textbook]], with the possible exception of his own while it was under preparation. When lecturing, he would write proofs in chalk on a blackboard rather than using overhead foils. He invited the students to suggest ideas, which he then explored, or refused to explore because they violated some of his tenets. He assigned challenging homework problems, and would study his students' solutions thoroughly. He conducted his final examinations orally, over a whole week. Each student was examined in Dijkstra's office or home, and an exam lasted several hours.<ref name="Dijkstra_bio"/>

Dijkstra was also highly original in his way of assessing people's capacity for a job. When [[Vladimir Lifschitz]] came to Austin in 1990 for a job interview, Dijkstra gave him a puzzle. Lifschitz solved it and has been working in Austin since then.<ref name="Apt, Krzysztof R. 2002"/>

=== Use of technology ===
He eschewed the use of computers in his own work for many decades. Even after he succumbed to his UT colleagues' encouragement and acquired a [[Mac (computer)|Macintosh]] computer, he used it only for e-mail and for browsing the World Wide Web.<ref name="Dijkstra_bio"/> Dijkstra never wrote his articles using a computer. He preferred to rely on his [[typewriter]] and later on his [[Montblanc (company)|Montblanc]] pen.<ref name="Apt, Krzysztof R. 2002"/> Dijkstra's favorite writing instrument was the Montblanc [[Meisterstück]] [[fountain pen]].

He had no use for [[word processor]]s, believing that one should be able to write a letter or article without rough drafts, rewriting, or any significant editing. He would work it all out in his head before putting pen to paper, and once mentioned that when he was a physics student he would solve his homework problems in his head while walking the streets of [[Leiden]].<ref name="Dijkstra_bio"/>
Most of Dijkstra's publications were written by him alone. He never had a secretary and took care of all his correspondence alone.<ref name="Apt, Krzysztof R. 2002"/> When colleagues prepared a [[Festschrift]] for his sixtieth birthday, published by [[Springer-Verlag]], he took the trouble to thank each of the 61 contributors separately, in a hand-written letter.<ref name="Apt, Krzysztof R. 2002"/>

In ''The Humble Programmer'' (1972), Dijkstra wrote: "We must not forget that it is not our [computing scientists'] business to make programs, it is our business to design classes of computations that will display a desired behaviour."

Dijkstra also opposed the inclusion of [[software engineering]] under the umbrella of academic computer science. He wrote that, "As economics is known as "The Miserable Science", software engineering should be known as "The Doomed Discipline", doomed because it cannot even approach its goal since its goal is self-contradictory." And "software engineering has accepted as its charter 'How to program if you cannot.'"<ref>{{Cite EWD|1036|On the cruelty of really teaching computer science}}</ref>

=== Personal life ===
Dijkstra led a modest lifestyle, to the point of being spartan.<ref name="Apt, Krzysztof R. 2002"/> His and his wife's house in Nuenen was simple, small and unassuming. He did not own a television, a video player, or a mobile telephone, and did not go to the movies.<ref name="Apt, Krzysztof R. 2002"/> He played the piano, and, while in Austin, liked to go to concerts. An enthusiastic listener of [[classical music]], Dijkstra's favorite composer was [[Wolfgang Amadeus Mozart|Mozart]].<ref name="Dijkstra_bio"/>

== Essays and other writing ==
Throughout Dijkstra's career, his work was characterized by elegance and economy.<ref name="Apt, Krzysztof R. 2002"/> A prolific writer (especially as an essayist), Dijkstra authored more than 1,300 papers, many written by hand in his precise script. They were essays and parables; fairy tales and warnings; comprehensive explanation and pedagogical pretext. Most were about mathematics and computer science; others were trip reports that are more revealing about their author than about the people and places visited. It was his habit to copy each paper and circulate it to a small group of colleagues who would copy and forward the papers to another limited group of scientists.{{sfnp|Istrail|2008}}

=== EWDs ===
Dijkstra was well known for his habit of carefully composing manuscripts with his [[fountain pen]]. The manuscripts are called EWDs, since Dijkstra numbered them with ''EWD'', his initials, as a prefix. According to Dijkstra himself, the EWDs started when he moved from the Mathematical Centre in [[Amsterdam]] to the Eindhoven University of Technology (then Technische Hogeschool Eindhoven). After going to [[Eindhoven]], Dijkstra experienced a [[writer's block]] for more than a year. He distributed photocopies of a new EWD among his colleagues. Many recipients photocopied and forwarded their copies, so the EWDs spread throughout the international computer science community. The topics were computer science and mathematics, and included trip reports, letters, and speeches. These short articles span a period of 40 years. Almost all EWDs appearing after 1972 were hand-written. They are rarely longer than 15 pages and are consecutively numbered. The last one, No. 1318, is from 14 April 2002. Within computer science they are known as the EWD reports, or, simply the EWDs. More than 1300 EWDs have been scanned, with a growing number transcribed to facilitate search, and are available online at the Dijkstra archive of the University of Texas.<ref>{{cite web |website=E. W. Dijkstra Archive |publisher=University of Texas |url=http://www.cs.utexas.edu/users/EWD/ |title=The manuscripts of Edsger W. Dijkstra}}</ref>

=== Writing style ===
His interest with [[simplicity]] came at an early age and under his mother's guidance. He once said he had asked his mother whether trigonometry was a difficult topic. She replied that he must learn all the formulas and that further, if he required more than five lines to prove something, he was on the wrong track.<ref name="Denken_als_Discpline">{{cite web |last=Dijkstra |first=Edsger |title=Denken als Discipline |url=http://www.vpro.nl/speel.POMS_VPRO_212868.html |website=VPRO |date=10 April 2001 |publisher=Noorderlicht |access-date=21 June 2016}}</ref>

Dijkstra was famous for his wit, eloquence, rudeness, abruptness and often cruelty to fellow professionals, and way with words, such as in his remark, "The question of whether Machines Can Think (…) is about as relevant as the question of whether Submarines Can Swim."<ref>{{Cite EWD|898|The threats to computing science|quote=Alan M. Turing thought about criteria to settle the question of whether Machines Can Think, a question of which we now know that it is about as relevant as the question of whether Submarines Can Swim.}}, 1984</ref> His advice to a promising researcher, who asked how to select a topic for research, was the phrase: "Do only what only you can do".<ref name="Dijkstra_bio"/> Dijkstra was also known for his vocal criticism and absence of social skills when interacting with colleagues. As an outspoken and critical visionary, he strongly opposed the teaching of [[BASIC]].<ref name="EWD498">{{Cite EWD|498|How do we tell truths that might hurt?}}</ref>

=== Recurring themes ===
In many of his more witty essays, Dijkstra described a fictional company of which he served as chairman. The company was called Mathematics, Inc., a company that he imagined having [[commercialized]] the production of mathematical [[theorem]]s in the same way that software companies had commercialized the production of computer programs.  He invented a number of activities and challenges of Mathematics Inc. and documented them in several papers in the EWD series. The imaginary company had produced a proof of the [[Riemann Hypothesis]] but then had great difficulties collecting [[royalties]] from mathematicians who had proved results assuming the Riemann Hypothesis. The proof itself was a [[trade secret]].<ref name="Cite EWD|475">{{Cite EWD|475}}</ref> Many of the company's proofs were rushed out the door and then much of the company's effort had to be spent on [[Software maintenance|maintenance]].<ref>{{Cite EWD|539}}</ref> A more successful effort was the Standard Proof for [[Pythagoras' Theorem]], that replaced the more than 100 incompatible existing proofs.<ref>{{Cite EWD |427}}</ref> Dijkstra described Mathematics Inc. as "the most exciting and most miserable business ever conceived".<ref name="Cite EWD|475"/> EWD 443 (1974) describes his fictional company as having over 75% of the world's market share.<ref>{{Cite EWD|443}}</ref><ref>{{cite book |last=Dijkstra |first=Edsger W |title=Selected Writings on Computing: A Personal Perspective |url=https://archive.org/details/selectedwritings0000dijk |url-access=registration |publisher=Springer-Verlag |location=Berlin |year=1982 |isbn=978-0-387-90652-2}}</ref>

== Legacy ==
Dijkstra won the Turing award in 1972 for his advocacy of structured programming, a programming paradigm that makes use of structured control flow as opposed to unstructured jumps to different sections in a program using [[Goto]] statements. His 1968 letter to the editor of ''Communications of ACM, "''Go To statement considered harmful''"'', caused a major debate. Modern programmers generally adhere to the paradigm of structured programming.<ref>{{Cite web |title=Edsger W. Dijkstra - A.M. Turing Award Laureate |url=https://amturing.acm.org/award_winners/dijkstra_1053701.cfm |access-date=12 January 2023 |website=amturing.acm.org}}</ref>

Among his most famous contributions to computer science is ''[[Dijkstra's algorithm]],'' for finding the shortest path through a network, which is widely taught in modern computer science undergraduate courses, and is used in the computer network routing protocols [[Open Shortest Path First|OSPF]] and [[IS-IS]].<ref>{{cite news |last1=Moy |first1=John |title=OSPF Version 2 |newspaper=Ietf Datatracker |date=April 1998 |url=https://datatracker.ietf.org/doc/html/rfc2328 |publisher=IETF |access-date=24 July 2022}}</ref><ref>{{cite web |title=ISO/IEC 10589:2002 |url=https://www.iso.org/standard/30932.html |publisher=International Organization for Standardization |access-date=24 July 2022}}</ref>

Other important work included the ''[[Shunting yard algorithm]]'' for parsing; the [[THE multiprogramming system|"THE" operating system]], an early example of structuring an operating system as a set of layers; the ''[[Banker's algorithm]]'' for resource allocation; and the [[Semaphore (programming)|semaphore]] construct for coordinating multiple processes. Another concept formulated by Dijkstra in the field of distributed computing is that of [[self-stabilization]], a method of ensuring fault-tolerance.

==Awards and honors==
Among Dijkstra's awards and honors are:<ref name="Dijkstra_bio"/>
* Member of the [[Royal Netherlands Academy of Arts and Sciences]] (1971)<ref>{{cite web|url=http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00004832 |title=Edsger Wybe Dijkstra (1930–2002) |publisher=Royal Netherlands Academy of Arts and Sciences |access-date=17 July 2015}}</ref>
* Distinguished Fellow of the [[British Computer Society]] (1971)
* The [[Association for Computing Machinery]]'s [[A.M. Turing Award]] (1972)<ref>{{cite web |url=http://awards.acm.org/homepage.cfm?srt=all&awd=140 |title=A. M. Turing Award |publisher=[[Association for Computing Machinery]] |access-date=5 February 2011 |archive-date=12 December 2009 |archive-url=https://web.archive.org/web/20091212132624/http://awards.acm.org/homepage.cfm?srt=all&awd=140 |url-status=dead }}</ref>
* [[Harry H. Goode Memorial Award]] from the [[IEEE Computer Society]] (1974).<ref>{{cite web|url=http://www.computer.org/portal/web/awards/dijkstra|title=Edsger W. Dijkstra 1974 Harry H. Goode Memorial Award Recipient|publisher=[[IEEE Computer Society]]|access-date=17 January 2014}}</ref>
* Foreign Honorary Member of the [[American Academy of Arts and Sciences]] (1975)
* Doctor of Science [[Honoris Causa]] from the [[Queen's University Belfast]] (1976)
* Computer Pioneer Charter Recipient from the [[IEEE Computer Society]] (1982)
* ACM/[[SIGCSE]] Award for Outstanding Contributions to Computer Science Education (1989)
* [[ACM Fellow|Fellow]] of the [[Association for Computing Machinery]] (1994)<ref>{{cite web |url=http://fellows.acm.org/homepage.cfm?alpha=D&srt=alpha |title=ACM Fellows – D |publisher=[[Association for Computing Machinery]] |access-date=15 February 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110124181256/http://fellows.acm.org/homepage.cfm?alpha=D&srt=alpha |archive-date=24 January 2011}}</ref>
* Honorary doctorate from the [[Athens University of Economics & Business]], Greece (2001).

In 1969, the [[British Computer Society]] (BCS) received approval for an award and fellowship, [[Distinguished Fellow of the British Computer Society]] (DFBCS), to be awarded under [[bylaw]] 7 of their [[royal charter]]. In 1971, the first election was made, to Dijkstra.<ref>{{cite web |title=Roll of Distinguished Fellows |url=http://www.bcs.org/content/conWebDoc/1650 |publisher=[[British Computer Society]] |access-date=10 September 2014 |url-status=dead |archive-url=https://web.archive.org/web/20160304025814/http://www.bcs.org/content/conWebDoc/1650 |archive-date=4 March 2016}}</ref>

In 1990, on occasion of Dijkstra's 60th birthday, the Department of Computer Science (UTCS) at the University of Texas at Austin organized a two-day seminar in his honor. Speakers came from all over the United States and Europe, and a group of computer scientists contributed research articles which were edited into a book.<ref>{{Cite book 
|editor1-last=Feijen 
|editor1-first=W.H.J. 
|editor2-last=van Gasteren 
|editor2-first=A.J.M.
|editor3-last=Gries
|editor3-first=D. 
|editor-link3=David Gries 
|editor4-last=Misra 
|editor4-first=J.
|editor-link4=Jayadev Misra 
|date=1990
|title=Beauty is our Business
|series=Monographs in Computer Science
|publisher=Springer Verlag
|url=https://link.springer.com/book/10.1007/978-1-4612-4476-9
|location=New York|doi=10.1007/978-1-4612-4476-9 
|isbn=978-1-4612-8792-6 
|s2cid=24379938 
}}</ref>

In 2002, the C&C Foundation of Japan recognized Dijkstra "for his pioneering contributions to the establishment of the scientific basis for computer software through creative research in basic software theory, algorithm theory, structured programming, and semaphores." Dijkstra was alive to receive notice of the award, but it was accepted by his family in an award ceremony after his death.

Shortly before his death in 2002, Dijkstra received the ACM [[PODC Influential-Paper Award]] in [[distributed computing]] for his work on self-stabilization of program computation. This annual award was renamed the [[Dijkstra Prize]] ([[Edsger W. Dijkstra Prize in Distributed Computing]]) the following year, in his honor.

The Dijkstra Award for Outstanding Academic Achievement in Computer Science ([[Loyola University Chicago]], Department of Computer Science) is named for Edsger W. Dijkstra. Beginning in 2005, this award recognizes the top academic performance by a graduating computer science major. Selection is based on GPA in all major courses and election by department faculty.<ref>{{cite web |url=https://www.luc.edu/cs/resources/undergraduateawards/ |title=Undergraduate Awards |publisher=Loyola University Chicago |access-date=2025-04-29}}</ref>

The Department of Computer Science (UTCS) at the University of Texas at Austin hosted the inaugural Edsger W. Dijkstra Memorial Lecture on 12 October 2010. [[Tony Hoare]], Emeritus Professor at Oxford and Principal Researcher at Microsoft Research, was the speaker for the event. This lecture series was made possible by a generous grant from Schlumberger to honor the memory of Dijkstra.

== Selected publications ==
===Books===

{{refbegin}}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=A Primer of ALGOL 60 Programming: Together with Report on the Algorithmic Language ALGOL 60 |publisher=Academic Press |year=1962 |isbn=978-0122162503}}
* {{cite book|ref=none |author-mask=1 |last1=Dijkstra |first1=Edsger W. |last2=Dahl |first2=Ole-Johan |author2-link=Ole-Johan Dahl |last3=Hoare |first3=C.A.R. |author3-link=Tony Hoare |year=1972 |title=Structured Programming |publisher=[[Academic Press]] |isbn=978-0-12-200550-3}}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=A Discipline of Programming |url=https://archive.org/details/disciplineofprog0000dijk |url-access=registration |publisher=Prentice Hall |year=1976 |isbn=978-0132158718}}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=Selected Writings on Computing: A Personal Perspective |publisher=Springer |year=1982 |isbn=978-0387906522 |series=Monographs in Computer Science |url = https://books.google.com/books?id=Y54ACAAAQBAJ}}
*{{cite book|ref=none |author-mask=1 |first1=Edsger W. |last1=Dijkstra |last2=Feijen |first2=W.H.J. |last3=Sterringa |first3=Joke |title=A Method of Programming |publisher=Addison-Wesley |year=1988 |isbn=978-0201175363}}
*{{cite book|ref=none |author-mask=1 |first1=Edsger W. |last1=Dijkstra |author2-link=Carel S. Scholten |last2=Scholten |first2=Carel S. |title=Predicate Calculus and Program Semantics |publisher=Springer-Verlag |year=1990 |isbn=978-0387969572 |series=Texts and Monographs in Computer Science |url = https://books.google.com/books?id=cCbjBwAAQBAJ}}
{{refend}}

===Selected articles===
{{cleanup list|section|date=November 2023}} <!-- pare down too 3-5 most important ones selected according to a clear objective criterion -->
{{refbegin}}
* {{cite journal|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |title=A Note on Two Problems in Connexion with Graphs |journal=Numerische Mathematik |volume=23 |year=1959 |issue=3 |pages=269–271 |doi=10.1007/BF01386390 |url=http://www-m3.ma.tum.de/foswiki/pub/MN0506/WebHome/dijkstra.pdf |citeseerx=10.1.1.165.7577 |s2cid=123284777}}
* {{cite book|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1962 |chapter=Some Meditations on Advanced Programming |title=Proc. IFIP Congress |publisher=North-Holland |location=Amsterdam |pages=535–8}}
* {{cite tech report|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1965 |title=Cooperating Sequential Processes |publisher=Technische Hogeschool Eindhoven |id=EWD-123 |url=https://www.cs.utexas.edu/users/EWD/transcriptions/EWD01xx/EWD123.html |access-date=20 September 2020}} Reprinted in {{cite book|ref=none |editor-first=F. |editor-last=Genuys |title=Programming Languages: N.A.T.O. Advanced Summer School Held in Villard-de-Lans in 1966 |publisher=Academic Press |year=1968 |oclc=499952053 |pages=43–112}} Published as {{cite book|ref=none |last=Dijkstra |first=E.W. |date=1968 |chapter=Cooperating Sequential Processes |editor-last=Hansen |editor-first=P.B. |title=The Origin of Concurrent Programming |pages=65–138 |publisher=Springer |location=New York |isbn=978-1-4419-2986-0 |doi=10.1007/978-1-4757-3472-0_2|url=https://research.tue.nl/nl/publications/cooperating-sequential-processes(4b2c511e-dce0-4d2c-a1ee-51d4129c6fa4).html }}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=Solution of a Problem in Concurrent Programming Control |journal=Comm. ACM |volume=8 |issue=9 |pages=569 |year=1965 |doi=10.1145/365559.365617|s2cid=19357737|doi-access=free }}
*{{cite book|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1965 |chapter=Programming Considered as a Human Activity |title=Proc. IFIP Congress |pages=213–7}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |department=Letters to the editor |title=Go To Statement Considered Harmful |journal=Comm. ACM |volume=11 |issue=3 |pages=147–8 |year=1968 |doi=10.1145/362929.362947 |s2cid=17469809|doi-access=free }}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=A Constructive Approach to the Problem of Program Correctness |journal=BIT Numerical Mathematics |volume=8 |issue=3 |pages=174–186 |year=1968 |doi= 10.1007/bf01933419 |s2cid=62224342}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=The Structure of the 'THE'-Multiprogramming System |journal=Comm. ACM |volume=11 |issue=5 |pages=341–346 |date=May 1968 |doi=10.1145/363095.363143 |s2cid=2021311|doi-access=free }}
*{{cite report|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |date=April 1970 |title=Notes on Structured Programming |id=70-WSK-03 |via=E.W. Dijkstra Archive. Center for American History, University of Texas at Austin |url=http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD249.PDF}}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=A Short Introduction to the Art of Computer Programming |publisher=Technische Hogeschool |location=Eindhoven |year=1971 |oclc=3474242 |id=EWD316}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=Hierarchical Ordering of Sequential Processes |journal=Acta Inform. |volume=1 |issue= 2|pages=115–138 |year=1971 |doi= 10.1007/bf00289519 |s2cid=31573213}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=The Humble Programmer |journal=Comm. ACM |volume=15 |issue=10 |pages=859–866 |year=1972 |doi= 10.1145/355604.361591|doi-access=free}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=Programming as a Discipline of Mathematical Nature |journal=American Mathematical Monthly |volume=81 |issue= 6 |pages=608–612 |date=June–July 1974 |doi= 10.2307/2319209 |jstor=2319209}}
* {{cite news|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1974 |title=On the role of scientific thought |id=EWD447 |publisher=E.W. Dijkstra Archive, Center for American History, [[University of Texas at Austin]]}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=Self-stabilizing Systems in Spite of Distributed Control |journal=Comm. ACM |volume=17 |issue=11 |pages=643–4 |year=1974 |doi=10.1145/361179.361202 |s2cid=11101426|doi-access=free }}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |year=1975 |chapter=How do we tell truths that might hurt? |title=Selected Writings on Computing: A Personal Perspective |publisher=Springer |publication-date=1982 |isbn=978-0387906522 |series=Monographs in Computer Science |pages=129–131 |url=https://books.google.com/books?id=Y54ACAAAQBAJ}}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |year=1975 |chapter=Craftsman or Scientist |title=ACM Pacific 1975 |pages=217–223}}
* {{cite journal|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W |year=1975 |title=On the teaching of programming, i. e. on the teaching of thinking |journal=Language Hierarchies and Interfaces |volume=1975 |pages=1–10}}
* {{cite journal|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W |year=1977 |title=Programming: From Craft to Scientific Discipline |journal=International Computing Symposium |volume=1977 |pages=23–30}}
*{{cite book|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |year=1978 |chapter=On the Interplay between Mathematics and Programming |title=Program Construction |volume=69 |pages=35–46 |chapter-url= https://www.springer.com/gb/book/9783540092513 |doi=10.1007/BFb0014649 |isbn=978-3-540-09251-3 |series=Lecture Notes in Computer Science |s2cid=26233314}}
* {{cite book|ref=none |author-mask=1 |doi=10.1145/800027.808478 |doi-access=free |chapter=Correctness concerns and, among other things, why they are resented |title=Proceedings of the international conference on Reliable software |date=1975 |last1=Dijkstra |first1=Edsger W. |page=546 }}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=Guarded Commands, Nondeterminacy and Formal Derivation of Programs |journal=Comm. ACM |volume=18 |issue=8 |pages=453–7 |year=1975 |doi=10.1145/360933.360975 |s2cid=1679242|doi-access=free }}
* {{cite journal|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1978 |title=Finding the Correctness Proof of a Concurrent Program |journal=Program Construction |volume=1978 |pages=24–34}}
* {{cite news|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1984 |title=The threats to computing science |id=EWD898 |publisher=E.W. Dijkstra Archive, Center for American History, [[University of Texas at Austin]]}}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |year=1986 |title=On a Cultural Gap |journal=The Mathematical Intelligencer |volume=8 |issue=1 |pages=48–52 |doi=10.1007/BF03023921 |s2cid=120847834}}
* {{cite journal|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W |year=1987 |title=Mathematicians and Computing Scientists: The Cultural Gap |journal=Abacus |volume=4 |issue=4 |pages=26–31}}
* {{cite journal|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=1989 |title=On the Cruelty of Really Teaching Computer Science |journal=Comm. ACM |volume=32 |issue=12 |pages=1398–1404 |department=A debate on teaching computing science |doi=10.1145/76380.76381 |s2cid=16961489 |doi-access=free }}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title= Computing Science: Achievements and challenges|journal= ACM SIGAPP Applied Computing Review|volume=7 |issue=2 |pages=2–9 |year=1999 |doi=10.1145/335527.335528 |s2cid=34430415|doi-access=free }}
*{{cite journal|ref=none |author-mask=1 |first=Edsger W. |last=Dijkstra |title=The End of Computing Science? |journal=Comm. ACM |volume=44 |issue=3 |pages=92 |year=2001 |doi=10.1145/365181.365217 |s2cid=31142279}}
* {{cite news|ref=none |author-mask=1 |last=Dijkstra |first=Edsger W. |year=2001 |title=What led to ''Notes on Structured Programming'' |publisher=E.W. Dijkstra Archive, Center for American History, [[University of Texas at Austin]]}}
{{refend}}

==See also==
* ''[[Go To Statement Considered Harmful]]''
* ''[[On the Cruelty of Really Teaching Computer Science]]''
* [[List of pioneers in computer science]]

== References ==
{{Reflist}}

== Citations ==
* {{cite magazine |first=Sorin |last=Istrail |title=Storytelling About Lighthouses: ''Criticizing Professor Dijkstra Considered Harmless'' |magazine=Conduit |publisher=Brown University Department of Computer Science |volume=17 |issue=2 |date=Fall–Winter 2008 |pages=10–17 |url=https://cs.brown.edu/about/conduit/conduit_v17n2.pdf}}

==External links==
{{Commons category|Edsger Wybe Dijkstra}}
{{wikiquote}}
* {{cite web |title=E.W. Dijkstra Archive |publisher=Center for American History, [[University of Texas at Austin]] |url=http://www.cs.utexas.edu/users/EWD/}}
* {{cite web |title=Dijkstra's Rallying Cry for Generalization |publisher=A site devoted to Dijkstra’s works and thoughts, created and maintained by the historian of computing Edgar Graham Daylight |url=http://www.dijkstrascry.com/}}

{{Edsger Dijkstra}}
{{Timelines of computing}}
{{Concurrent computing}}
{{Software engineering}}
{{Computer science}}
{{ALGOL programming}}
{{Turing Award laureates}}
{{Authority control}}

{{DEFAULTSORT:Dijkstra, Edsger}}
[[Category:Edsger W. Dijkstra| ]]
[[Category:1930 births]]
[[Category:2002 deaths]]
[[Category:Computer science educators]]
[[Category:Computer science writers]]
[[Category:Dutch computer scientists]]
[[Category:Dutch computer programmers]]
[[Category:Dutch software engineers]]
[[Category:20th-century Dutch inventors]]
[[Category:Dutch technology writers]]
[[Category:Formal methods people]]
[[Category:Programming language designers]]
[[Category:Programming language researchers]]
[[Category:Researchers in distributed computing]]
[[Category:Software engineering researchers]]
[[Category:Theoretical computer scientists]]
[[Category:Dijkstra Prize laureates]]
[[Category:Fellows of the British Computer Society]]
[[Category:Members of the Royal Netherlands Academy of Arts and Sciences]]
[[Category:Turing Award laureates]]
[[Category:Burroughs Corporation people]]
[[Category:Academic staff of the Eindhoven University of Technology]]
[[Category:University of Texas at Austin faculty]]
[[Category:Leiden University alumni]]
[[Category:University of Amsterdam alumni]]
[[Category:Dutch expatriates in the United States]]
[[Category:Deaths from colorectal cancer in the Netherlands]]
[[Category:Scientists from Rotterdam]]
[[Category:20th-century Dutch engineers]]
[[Category:20th-century Dutch mathematicians]]
[[Category:20th-century Dutch essayists]]
[[Category:1994 fellows of the Association for Computing Machinery]]