Frasi di Edsger Dijkstra pagina 2

“L'informatica non riguarda i computer più di quanto l'astronomia riguardi i telescopi. ”

“Il test di un programma può essere usato per mostrare la presenza di bug, ma mai per mostrare la loro assenza.”

“La semplicità è un prerequisito per l'affidabilità.”

da Notes On Structured Programming, 1970

“Testing shows the presence, not the absence of bugs”

da How do we tell truths that might hurt? http://www.cs.utexas.edu/users/EWD/transcriptions/EWD04xx/EWD498.html, 1975

Edsger Dijkstra: Frasi in inglese

“In the good old days physicists repeated each other's experiments, just to be sure. Today they stick to FORTRAN, so that they can share each other's programs, bugs included.”

Dijkstra (1969) J.N. Buxton and B. Randell, eds, Software Engineering Techniques, April 1970, p. 16. Report on a conference sponsored by the NATO Science Committee, Rome, Italy, 27–31 October 1969. http://homepages.cs.ncl.ac.uk/brian.randell/NATO/nato1969.PDF Possibly the earliest documented use of the famous quote. 1960s

“The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offense.”

1970s, How do we tell truths that might hurt? (1975)

“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. (…) Software engineering has accepted as its charter "How to program if you cannot.”

1970s, How do we tell truths that might hurt? (1975)

“About the use of language: it is impossible to sharpen a pencil with a blunt axe. It is equally vain to try to do it with ten blunt axes instead.”

Dijkstra (1988) " On the cruelty of really teaching computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html (EWD1036). 1980s

“As a result of a long sequence of coincidences I entered the programming profession officially on the first spring morning of 1952, and as far as I have been able to trace, I was the first Dutchman to do so in my country.”

1970s, How do we tell truths that might hurt? (1975)

“Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians.”

1970s, The Humble Programmer (1972)

“What is the shortest way to travel from Rotterdam to Groningen, in general: from given city to given city. It is the algorithm for the shortest path, which I designed in about twenty minutes. One morning I was shopping in Amsterdam with my young fiancée, and tired, we sat down on the café terrace to drink a cup of coffee and I was just thinking about whether I could do this, and I then designed the algorithm for the shortest path. As I said, it was a twenty-minute invention. In fact, it was published in ’59, three years late. The publication is still readable, it is, in fact, quite nice. One of the reasons that it is so nice was that I designed it without pencil and paper. I learned later that one of the advantages of designing without pencil and paper is that you are almost forced to avoid all avoidable complexities. Eventually that algorithm became, to my great amazement, one of the cornerstones of my fame.”

1970s, How do we tell truths that might hurt? (1975)

“Our intellectual powers are rather geared to master static relations and … our powers to visualize processes evolving in time are relatively poorly developed. For that reason we should do (as wise programmers aware of our limitations) our utmost to shorten the conceptual gap between the static program and the dynamic process, to make the correspondence between the program (spread out in text space) and the process (spread out in time) as trivial as possible.”

Dijkstra (2001), in an interview with Philip L. Frana. (OH 330; Communications of the ACM 53(8):41–47)
2000s

“When I came back from Munich, it was September, and I was Professor of Mathematics at the Eindhoven University of Technology. Later I learned that I had been the Department's third choice, after two numerical analysts had turned the invitation down; the decision to invite me had not been an easy one, on the one hand because I had not really studied mathematics, and on the other hand because of my sandals, my beard and my "arrogance"”

Dijkstra (1968) " A Case against the GO TO Statement http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD215.PDF" cited in: Bill Curtis (1981) Tutorial, human factors in software development. p. 109. 1960s

“My point today is that, if we wish to count lines of code, we should not regard them as "lines produced" but as "lines spent": the current conventional wisdom is so foolish as to book that count on the wrong side of the ledger.”

whatever that may be Dijkstra (1993) "From my Life" http://www.cs.utexas.edu/users/EWD/transcriptions/EWD11xx/EWD1166.html (EWD 1166). 1990s

“In the wake of the Cultural Revolution and now of the recession I observe a mounting pressure to co-operate and to promote "teamwork". For its anti-individualistic streak, such a drive is of course highly suspect; some people may not be so sensitive to it, but having seen the Hitlerjugend in action suffices for the rest of your life to be very wary of "team spirit."”

Dijkstra (1988) " On the cruelty of really teaching computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html (EWD1036). 1980s

“The competent programmer is fully aware of the strictly limited size of his own skull; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague.”

Very. Dijkstra (1994) "The strengths of the academic enterprise" http://www.cs.utexas.edu/users/EWD/transcriptions/EWD11xx/EWD1175.html (EWD 1175). 1990s

“In short, I suggest that the programmer should continue to understand what he is doing, that his growing product remains firmly within his intellectual grip. It is my sad experience that this suggestion is repulsive to the average experienced programmer, who clearly derives a major part of his professional excitement from not quite understanding what he is doing. In this streamlined age, one of our most undernourished psychological needs is the craving for Black Magic and apparently the automatic computer can satisfy this need for the professional software engineer, who is secretly enthralled by the gigantic risks he takes in his daring irresponsibility. For his frustrations I have no remedy……”

Dijkstra (1972) The Humble Programmer http://www.cs.utexas.edu/users/EWD/transcriptions/EWD03xx/EWD340.html (EWD340). 1970s

“Write a paper promising salvation, make it a 'structured' something or a 'virtual' something, or 'abstract', 'distributed' or 'higher-order' or 'applicative' and you can almost be certain of having started a new cult.”

Unknown date

“FORTRAN's tragic fate has been its wide acceptance, mentally chaining thousands and thousands of programmers to our past mistakes.”

Dijkstra (1979) My hopes of computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD07xx/EWD709.html (EWD 709). 1970s

“Several people have told me that my inability to suffer fools gladly is one of my main weaknesses.”

1970s, The Humble Programmer (1972)

“LISP has been jokingly described as "the most intelligent way to misuse a computer". I think that description a great compliment because it transmits the full flavor of liberation: it has assisted a number of our most gifted fellow humans in thinking previously impossible thoughts.”

Dijkstra (1978) The pragmatic engineer versus the scientific designer http://www.cs.utexas.edu/users/EWD/transcriptions/EWD06xx/EWD690.html (EWD 690). 1970s

“Don't blame me for the fact that competent programming, as I view it as an intellectual possibility, will be too difficult for "the average programmer" — you must not fall into the trap of rejecting a surgical technique because it is beyond the capabilities of the barber in his shop around the corner.”

1970s, The Humble Programmer (1972)

“May, in spite of all distractions generated by technology, all of you succeed in turning information into knowledge, knowledge into understanding, and understanding into wisdom.”

Dijkstra (1975) Comments at a Symposium http://www.cs.utexas.edu/users/EWD/transcriptions/EWD05xx/EWD512.html (EWD 512). 1970s

“When FORTRAN has been called an infantile disorder, full PL/1, with its growth characteristics of a dangerous tumor, could turn out to be a fatal disease.”

Dijkstra (1998) https://www.cs.utexas.edu/users/vl/notes/dijkstra.html 1990s

“We can found no scientific discipline, nor a hearty profession, on the technical mistakes of the Department of Defense and, mainly, one computer manufacturer.”

1970s, The Humble Programmer (1972)

“The art of programming is the art of organizing complexity, of mastering multitude and avoiding its bastard chaos as effectively as possible.”

1970s, How do we tell truths that might hurt? (1975)

“The problems of the real world are primarily those you are left with when you refuse to apply their effective solutions.”

Dijkstra (1970) " Notes On Structured Programming http://www.cs.utexas.edu/users/EWD/ewd02xx/EWD249.PDF" (EWD249), Section 3 ("On The Reliability of Mechanisms"), p. 7. 1970s

“FORTRAN, 'the infantile disorder', by now nearly 20 years old, is hopelessly inadequate for whatever computer application you have in mind today: it is now too clumsy, too risky, and too expensive to use.”

Dijkstra (1988) " On the cruelty of really teaching computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html (EWD1036). 1980s

“APL is a mistake, carried through to perfection. It is the language of the future for the programming techniques of the past: it creates a new generation of coding bums.”

1970s, How do we tell truths that might hurt? (1975)

“On Our Inability To Do Much.”

1970s, How do we tell truths that might hurt? (1975)

“[Though computer science is a fairly new discipline, it is predominantly based on the Cartesian world view. As Edsgar W. Dijkstra has pointed out] A scientific discipline emerges with the - usually rather slow! - discovery of which aspects can be meaningfully 'studied in isolation for the sake of their own consistency.”

Dijkstra (1972) "Structured Programming", Chapter title in O.J. Dahl, E.W. Dijkstra, and C.A.R. Hoare. Academic Press, 1972 ISBN 0122005503.
1970s

“When we had no computers, we had no programming problem either. When we had a few computers, we had a mild programming problem. Confronted with machines a million times as powerful, we are faced with a gigantic programming problem.”

Dijkstra (1982) as cited in: Douglas Schuler, Douglas Schuler Jonathan Jacky (1989) Directions and Implications of Advanced Computing, 1987. Vol 1, p. 84.
1980s

“The major cause [of the software crisis] is that the machines have become several orders of magnitude more powerful! To put it quite bluntly: as long as there were no machines, programming was no problem at all; when we had a few weak computers, programming became a mild problem, and now we have gigantic computers, programming has become an equally gigantic problem. In this sense the electronic industry has not solved a single problem, it has only created them, it has created the problem of using its products.”

Dijkstra (1986) Visuals for BP's Venture Research Conference http://www.cs.utexas.edu/users/EWD/transcriptions/EWD09xx/EWD963.html (EWD 963). 1980s