A brilliant computer scientist who researched program correctness, mathematical methodologies, algorithms, and systems. In 1968 Dijkstra wrote a letter to an editor entitled "GO TO Statement Considered Harmful", (Comm. ACM, August 1968), and began the movement toward reliable software development. Or so they say. He is probably best known for his shortest path algorithm, used in such link-state algorithm .

"Dijkstra probably hates me."

-Linus Torvalds


In researching whether or not Dijkstra is still at UT I came across a link for a symposium to celebrate Dijkstra's retirement.

Dijkstra did shun the use of computers during most of his life. He did, apparently, carry a cellular phone, but I guess since he couldn't actually use it to help him in his research it didn't count as a real computer in his mind. Back in the day if you were to finger dijkstra@cs.utexas.edu you would be instructed to include your snail mail address with any email you sent. His secretary would print out any email sent to him and he would hand write a response.

However, towards the end of his time at UT I've heard that the department did actually put a Macintosh in his office, although I don't actually know if/in what capacity he used it. Apparently the only feature he requested when he was getting a computer was that the documents printed by the printer were of the same quality as those he penned himself. Dijkstra had quite a love of pens and wrote about it extensively. He even went so far as to create his own ink because he was not happy with the quality of the ink that was available. I seem to remember it having something to do with it not being water proof. I don't know if a printer that lived up to these standards was ever found.

Despite his dislike for computers it would seem that he had a fondness for video games. On some computers in the Linux labs Dijkstra showed up as having the high score for XBoing.

Of course it could just be the case that someone discovered that the high score file was world writable and edited it with xemacs.

Dijkstra has made many contributions to computer science, primarily in the 60s when he was at TU Eindhoven.

He developed a multitasking OS, worked on programming methodology and more specifically, structured programming. He is well known for the letter to CACM exemplifiying these ideas, for Dijkstra's algorithm to operate on problems that can be described as graph traversals, and for semaphores.

For the production of text, Dijkstra preferred the use of handwriting to computers. Get the Dijkstra font if you want to know what it looks like.

From: "Edsger W. Dijkstra" 
Subject: from the family
Cc: faculty@cs.utexas.edu
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version=2.20
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Status: R


Grateful for most that has befallen him, has peacefully passed away,
   Edsger Wybe Dijkstra,
our husband and father.

We hold him very dear.

The cremation will take place on

Saterday, August 10th, (2002,) 12:30 PM at
Somerenseweg 120
Heeze
the Netherlands

Maria C. Dijkstra Debets
Marcus J. Dijkstra
Femke E. Dijkstra
Rutger M. Dijktra

Please forward this message to whomever you feel missing in the recipient list.

I think Dijkstra's death a few days ago was the first "celebrity" death that I've actually felt genuine sadness over. Dijkstra was an inspiration to me, though I knew of him only through reading some of his work and reading odd little anecdotes about him, such as how he supposedly refused to use computers, his fascination with fountain pens, and so on.

In a world where computers and the internet are increasingly becoming more convoluted and misunderstood daily by the general public, by polticians and lawmakers, and by corporations, I held Dijkstra's example close to my heart. He understood computers. He did not accept mediocrity in their implementation, because he knew their potential and he was seemingly distraught at their improper use and role. He kept his sense of humor throughout.

At the same time, though, he clearly put computers in perspective and saw them how they should be seen. He strived for perfection in them, but he respected computers. He wouldn't want them doing something that they really had no place doing, such as writing letters, in his case.

To him, computers were not a means to an end, they were an end in themselves, in a way. He has left us with a solid foundation, and I just hope that his vision and his principles live on in hearts and minds of true geeks and programmers everywhere. So, I didn't know Dijkstra personally. I wish I had though, and I'll miss him none the less. May he rest in peace.

I attended the University of Texas and got my degree in Computer Science there. I graduated in 1999. I had the privelege of taking a class from Dijkstra. The name of it escapes me, but it hardly matters, because it should have been named "Listen To Dijkstra's Views On Everything".

One class he spent the entire time discussing the importance of publicly funded radio stations. Seems he loved classical music, and some local Austin station was publicly funded and having financial difficulties, so he spent that class period talking to us about it.

On another occasion he devoted most of the class period praising brevity. He hated it when people wrote or spoke more than was necessary. Get to the point, say what you need to say, but don't talk just to talk. (As you can see from my writing, I wasn't able to fully integrate that lesson into my life).

Another crusade of his was that counting should begin at 0. Let's say you see a collection of items you wish to count. When you see the first object, you say 0. When you see the second, you say 1. And so on. When you reach the last one, you just add one to the last number you spoke, and that would be the number of items in the collection. He argued this had the advantage that you could count empty collections. That is, if you wanted to count a group that had nothing in it, you would say nothing, then you'd be done. You'd know the next number you would have spoken would have been 0, so that's the number of things in the group.

The closest we got to discussing computers was working on proofs. An example from the class -- suppose you have an 8 by 8 grid. Clearly the area is 64 square units. If you were given 31 pieces of material that were 2 units long and 1 unit wide, could you cover all of the grid other than the upper left and lower right corners? We had to answer and prove our answer. A hint -- it helps if you think of it as a checkerboard, remember that the squares are colored, and remember that any 2x1 pieces will cover one red and one black square.

The goal in these proofs was not to know the right answer. Or even, necessarily, to prove it. The goal was elegance. He firmly believed that there always existed an elegant proof of any assertion. If your proof wasn't elegant, you should find one that was. He hated proofs where you just showed every possible case (as would be possible in the proof I listed, although it would be laborious). He accepted that they were valid, but who cares? They weren't elegant.

The class was not graded in a normal sense. He gave assignments which you had to turn in (such as formally written proofs), but they were not returned with a grade. Your grade in the class was determined by your grade on the final exam. The final exam was a two hour oral exam with him in his office. What did that consist of? Just him talking to you about various propositions, how you would approach proving them, and then maybe trying to prove them right then and there, on his blackboard. I don't think I really knew what it meant to be under pressure until I was standing at a blackboard, thinking about a proof, with Edsger Dijkstra's gaze burning into my back. I managed to get an A in the class, but I had the advantage of having taken a lot of mathematics courses, so I had a good background in proofs. By the way, I do NOT recall a computer being in his office. He did make a point when he was teaching the class that he didn't use computers.

I was truly saddened to hear of Dijkstra's passing. I won't say he taught me more than anyone else ever did, but he was a man who had definite convictions. And he appreciated the beauty and elegance of math, which I respect and relate to. Rest In Peace, Edsger. You are missed.

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