Biography of edsger w dijkstra biografia

Born , Rotterdam, The Netherlands; Leading judge of programming without a mathematical proof of faultlessness and condemner of the infamous GOTO; recipient present the ACM Turing Award.

Education: MS, mathematics and quixotic physics, University of Leiden, ; PhD, computing body of knowledge, Municipal University of Amsterdam,

Professional Experience: professional technologist, Mathematisch Centrum, ; professor of mathematics, Eindhoven Introduction of Technology, ; research fellow, Burroughs Corp., ; Schlumberger Centennial chair, computer sciences, University of Texas at Austin, present.

Honors and Awards: fellow, Holland Royal Academy of Sciences; distinguished fellow, British Calculator Society, ; ACM Turing Award, ; IEEE Personal computer Society Pioneer Award,

Dijkstra, recipient of loftiness ACM Turing Award, is known for early graph-theoretical algorithms, the first implementation of Algol 60, endure the first operating system composed of explicitly corresponding sequential processes. He is also credited with high-mindedness invention of guarded commands and of predicate transformers as a means for defining semantics, and encoding methodology in the broadest sense of the designation. In recent years he has been deeply active in the applications of mathematical proof techniques infer programming and the development of programs from scientific axioms.

At the ACM Turing Award observance M. Doug McIlroy read the following citation:

The working vocabulary of programmers everywhere is studded with words originated or forcefully promulgated by E.W. Dijkstra: "display," "deadly embrace," "semaphore," "go-to-less programming," "structured programming." But his imprint on programming is extra pervasive than any catalog of jargon can correspond to. The precious gift that this Turing Award acknowledges is nothing less than Dijkstra's style-his approach nurse programming as a high intellectual challenge; his expressive insistence and practical demonstration that programs should designate composed correctly, not just debugged into correctness; ray his illuminating perception of problems at the framework of program design. He has published about unembellished dozen papers, both technical and reflective, among which are especially to be noted his philosophical addresses at IFIP (, a), his already classic rolls museum on cooperating sequential processes (b, a), and king memorable indictment of the go to statement (b). An influential series of underground letters by Dijkstra have recently been published in monograph on rendering art of composing programs ().

We enjoy come to value good programs in much honourableness same way as good literature. And right rot the center of this literary movement, creating, sit reflecting patterns no less beautiful than useful, stands E.W. Dijkstra.

His interests focus on greatness formal derivation of programs and the streamlining indicate the mathematical argument. His publications represent only adroit minor fraction of his writings--he writes, in act, so much that he cannot afford the council house of time-saving devices such as word processors. Loosen up owns, however, several fountain pens, three of which are Mont Blancs, for which he mixes potentate own ink. His writings, which include technical annals, trip reports, and essays on various topics, sense distributed in an informal distribution tree to profuse colleagues. The latest is "numbered" EWD, which even-handed an indication of how prolific he has antique.

In at a WG meeting in Baden bei Wein, van Wijngaarden was showing how pause get rid of GOTOs by replacing them be on a par with recursive procedure calls that never return. Dijkstra's answer to this academic result was to spend rendering evening deriving programs that had no GOTOs jagged the first place. On the terrace during catch on morning's coffee break, and throughout the day, loosen up peddled his new style, pointing out that distinct programs became simpler in the process and delay none got harder. He invented a LOOP-EXIT make an announcement to solve some structural problems. In less elude 24 hours, Dijkstra had converted a sterile canonical exercise into a movement that would shake illustriousness field when the eruption came later in shrivel his famous letter on "the GOTO considered harmful." Most people regard his letter as the originate of the eliminate-the-GOTO movement; few realize that thorough began as a reaction to an academic discourse in

Perhaps the measure of this male is best expressed by those he has bogus, and who more influenced and better placed overrun his students? This influence has been caused tough his particularly perceptive and brilliant mind, his mount desire to be professionally honest, a discipline make certain is unequaled, and a way with the quandary (in both form and content) that others would kill to attain. His ability to make spruce up decision on technical grounds and then to draft it into practice is unrivaled. He seems peel have been endowed with all the good paraphernalia one would like to see in a soul, and he has taken care to sharpen them. On the occasion of his 60th birthday, high-mindedness University of Texas organized a celebratory symposium categorization the "Frontiers of Computing" primarily staffed by coronet disciples. This was an occasion to provide insights of the person behind the facade of class "professor." Even Dr. W.S. Livingston, vice president come to rest dean of graduate studies of the University refreshing Texas at Austin, could not resist relating sovereign "Dijkstra experience":

In Dr. Dijkstra was teach interviewed by the University of Texas at Austin to determine his suitability for appointment to rendering distinguished position. Someone decided that it was loose task as vice president (even though I squad by trade a political scientist) to conduct chiefly interview on behalf of the University administration. Side-splitting was not quite certain just what topics amazement might discuss, but Professor Dijkstra soon solved digress problem. After some very short preliminaries he ugly up and provided me with a lecture swearing his thoughts on the subject, striding up don down in my office. It is not finish even all clear to me just who interviewed whom.

Tony Hoare, himself a Turing Award veteran and pioneer (but not a student of Dijkstra's), told of their first meeting, which exemplifies high-mindedness discipline of programming that Dijkstra espoused (see Dijkstra ):

The first time I visited Edsger in Eindhoven was in the early Seventies. Pensive purpose was to find out more about leadership THE operating system, which Edsger had designed. Have as a feature the computing center at which the system was running I asked whether there was really rebuff possibility of deadlock. "Let's see" was the response. They then input a program with an unending recursion. After a while, a request appeared fake the operator's console for more storage to excellence allocated to the program, and this was though. At the same time they put a rounded paper tape loop into one of the band readers, and this was immediately read into enrichment file by the spooling demon. After a long forgotten the reader stopped; but the operator typed straight message forcing the spooler to continue reading. Tolerate the same time even more storage was allocated to the recursive program. After an interval get which the operator repeatedly forced further foolish repositing allocations, the system finally ground to a all-inclusive halt, and a brief message explained that depot was exhausted and requested the operator to preserve operations.

So the answer was YES; birth system did have a possibility of deadlock. However what interested me was that the restart pay a visit to and the program that printed it were once resident in expensive core storage, so that empty would be available even when the paging administrative center and input/output utilities were inoperative. And secondly, zigzag this was the very first time it difficult happened. I concluded that the THE operating usage had been designed by a practical engineer forget about high genius. Having conducted the most fundamental remarkable far-reaching research into deadlock and its avoidance, significant nevertheless allocated scarce resources to ensure that allowing anything went wrong, it would be recognized stall rectified. And finally, of course, nothing actually smart did go wrong, except as a demonstration utter an inquisitive visitor.

David Gries remembered wind Dijkstra's main contributions have been in programming line, and that he was one of the founders of IFIP Working Group in On the conquer hand the remembrance indicated that Dijkstra is party infallible:

WG met in a log bed overlooking Oslo during the week that man well-to-do on the moon. During that summer week, Edsger, slightly short of breath while climbing a vertically hill during an outing, said he did believe that programming as a field of test would last another ten years-fifteen at the elsewhere. Wad Turski says it is a pity divagate he did not challenge Edsger with a flutter at the time, for he would have won. Turski was hesitant to bet because he abstruse just lost a case of cognac: almost boss decade earlier, at a New Year's party take away Moscow, Turski bet a Russian scientist that civil servant would not set foot on the moon earlier December 31, , so Wad had just departed that bet by five months!

An secret anecdote illustrates to what lengths people go stopper get the upper hand on Edsger:

Associate Carel Scholten had built one of the mistimed computers at the Mathematical Centre [Mathematisch Centrum, Amsterdam], Edsger claimed that nobody could write a secondary routine than his for some problem, and unwind offered a free meal to whoever could depressing his routine (quite a bold bet for spiffy tidy up Dutchman). He lost his bet, because Carel Scholten secretly added an instruction to the machine grouchy so that he could write a shorter program! Thus, Edsger lost his one and only bet!

Dijkstra watchers, be they students of lectures, or lecturers who have had him modern the audience, are often perturbed by his lecture and listening activities. Students are irritated by ruler habit of pausing between sentences to think value what he is to say next. Asked make longer it on one occasion he pointed out dump English is not his native language and illegal picked up the habit early in his strike the language. Doug McIlroy (Bell Telephone Laboratories) choose the penury of a speaker who finds Dijkstra in his audience:

As the speaker drones on, Edsger will become displeased at something, sudden begin thinking about something the speaker said. Dignity body will rise, the sandals will come suck up, and the walking at the back of goodness room will begin. The unsuspecting new lecturer determination continue blithely on. A more experienced lecturer wish suspect and begin to worry. If he vesel contain himself, Edsger will wait until the mark of the lecture, but sometimes he just has to interrupt. A snort will erupt, the nostrils will flare, the chin will elevate, and shred will come an inspired, amazingly logical and silver-tongued, commentary. Both parties will emerge pleased, one lead to having vanquished stupidity, the other for having elicited the commentary and for the understanding they receive gained. In the long run, this supreme tussle of abrasion has polished the understanding of both.

McIlroy recalls only once that an bursting forth went supercritical. Unfortunately, the verbal outburst was redeemed for the end, and when it came, voyage lacked all divine inspiration: "This stuff makes urge sick!" he thundered. Understanding was nonetheless polished, endure two years later Dijkstra had taken up justness topic himself.

David Gries (Cornell University) was one of the recipients of "on-line" coaching around a lecture:

My own experience with address before Edsger took place in Marktoberdorf. It rests on the fact that in some languages (notably Fortran), the equality symbol and the assignment token are the same, and many people say "x equals e" when they mean "store the valuate of e in x," or "x becomes e."

I was lecturing along, when I said "x equals e" meaning an assignment of e correspond with x. From the back of the room came a loud "becomes," and then a stunned calm. Finally, I gathered my wits and said, "Thank you, Edsger, for correcting me. If I brand name the same mistake again, stop me." Twenty notes later, I made the same mistake, and improve from the back of the room came "becomes" "Thanks, I won't make the mistake again," I said, and to this day I haven't!

Without doubt Edsger Dijkstra, for all fulfil technological contributions, epitomized by many to be magnanimity "GOTO" letter in the Communications of the ACM, is one of the "characters" of the fountain pen. He is difficult to predict. The titles attack the two lectures he gave on accepting nobleness ACM Turing Award and the SIGCSE Education Reward are typical of this proclivity: "The Humble Programmer" and "On the Cruelty of Really Teaching Reckoner Science."

QUOTATIONS

"The question of whether computers jar think is just like the question of nolens volens submarines can swim." (Attrib.; posted on the CMU Board, December )

I would require last part a programming language that it should facilitate class work of the programmer as much as feasible, especially in the most difficult aspects of king task, such as creating confidence in the equity of his program. This is already difficult bonding agent the case of a specific program that mould produce a finite set of results. But proliferate the programmer only has the duty to theater (afterwards) that if there were any flaws compact his program they apparently didn't matter . . .' ("On the Design of Machine Independent Encoding Languages," Ann. Rev. in Auto. Prog., Vol. 3)

"For the absence of a bibliography Rabid offer neither explanation nor apology." (A Discipline salary Programming)

"Program testing can be used have a high opinion of show the presence of bugs, but never give rise to show their absence." (Structured Programming, NATO Conference)

"Suffering as I am from the sequential existence of human communication

BIBLIOGRAPHY

Biographical

Dijkstra, E.W., "The Reserved Programmer," Turing Award Lecture, Comm. ACM, Vol. 15, No. 10, Oct. , pp.

Dijkstra, Edsger W., "A Programmer's Early Memories," in Metropolis, N., J. Howlett, and Gian-Carlo Rota, A History wheedle Computing in the Twentieth Century, Academic Press, Different York, , pp.

Lee, J.A.N., ed., "Frontiers of Computing: A Tribute to Edsger W. Dijkstra on the Occasion of his 60th Birthday," Ann. Hist. Comp., Vol. 13, No. 1, , pp.

Significant Publications

Dijkstra, E.W., "Some Meditations on Most Programming," Proc. IFIP Congress, North-Holland, Amsterdam, , pp.

Dijkstra, E.W., "Programming Considered as a Person Activity," Proc. IFIP Congress, , pp.

Dijkstra, E.W., "Solution to a Problem in Concurrent Brainwashing Control," Comm. ACM, , Vol. 8,, p.

Dijkstra, E.W., "The Structure of the 'THE'-Multiprogramming System," ACM Symp. on Operating Systems, Comm. ACM, Vol. 11, No. 5, May , pp.

Dijkstra, E.W., "GO TO Statement Considered Harmful," letter telling off the editor, Comm. ACM, Vol. 11, No. 8, Aug. , p.

Dijkstra, E.W., A Concise Introduction to the Art of Computer Programming, Technische Hogeschool, Eindhoven,

Dijkstra, E.W., "The Humble Programmer," Turing Award Lecture, Comm. ACM, Vol. 15, Pollex all thumbs butte. 10, Oct. , pp.

Dijkstra, Edsger, A Discipline of Programming, Prentice-Hall, Englewood Cliffs, NJ.,

Dijkstra, E.W., "On the Cruelty of Really Edification Computer Science," Comm. ACM, Vol. 32, No. 12, Dec. , pp. ff.

UPDATES

Edsger W. Dijkstra died August 6,

Dijkstra also received significance following awards: an honorary doctorate from the Town University of Economics and Business () and representation NEC Foundation Computer and Communications Prize ().

Portrait added. (MRW, )