Edsger Dijkstra

I was most honoured, but also somewhat confused, by the invitation to give a banquet speech about the late great Edsger Dijkstra at WORDS 2003. This is because the term "banquet speech" is American, and translating it into the English term "after-dinner speech" is rather misleading. In Britain an "after-dinner speech" is meant to be, above all, humorous, so as to be capable of entertaining, and retaining at least the attention, if not the enthusiasm, of an audience that have just eaten and drunk, to excess in all probability. But the privilege of talking to you about Edsger Dijkstra is not an occasion for humour — or at least only occasional humour, in the very personal portrait I’m going to try and give you of one of computer science’s intellectual giants, one I am honoured to have called a friend. I have another cause for misgivings. What I can say about Dijkstra is bound to seem inadequate to any of you who knew him — and will feel to me to be inadequate for any who didn’t. But with these caveats, let me begin. You have, I believe, all been given a copy of a leaflet [Campbell-Kelly 2002] about Dijkstra — I hope you’ve had a chance to read it. My aim is not to relate all the factual statements it contains, which between them amply testify to the extent and importance of his contributions to computer science, but rather to augment these statements with some mainly personal recollections — and also to encourage all of you to explore for yourself some of his work through his many writings. I should explain the background to this leaflet. It was produced for a British Computer Society meeting last year honouring the memory of Edsger Dijkstra, a meeting at which Tony Hoare and I were the main speakers. I used the invitation to speak at the meeting as an opportunity to tell Ria Dijkstra (Edsger’s widow) and a lot of people who knew Dijkstra well, or at least knew lots about Dijkstra, what a debt I owed to him. I will use here some of the remarks I made on that occasion, but I will include rather more information about Dijkstra’s work and its significance than I did in my brief talk at the BCS meeting.