EWD 484

Trip report E.W.Dijkstra, London, 9–10 March 1975.

This will be a short report on a short trip. I flew from Amsterdam to London (Heathrow) on Sunday afternoon and returned —with a direct(!) flight from London (Gatwick) to Eindhoven— on Monday evening, to be back in time for my Tuesday lectures at the University. Both flights were absolutely punctual (KLM and NLM respectively) and no misery about that part of the trip is to be reported. A number of people —in particular the Conference chairman, my good friend Mike Woodger and Infotech's Ian Hugo— expressed their regret that I could (or did) not stay for the full three days of the Conference, but I did not regret my quick return: the arrangement of the emergency exits in the Regent Centre Hotel in London seemed to me to be such that I was quite happy to have survived the one night I had to stay in that place. (A minor complication was further that all personnel were from non-English speaking countries and that most of the service had been delegated to slot machines that were out of order. Horst Heunke —from GDM, Bonn— was furious!)

Upon arrival in the Hotel, I discovered —by looking over the girl's shoulder— that at the porter's desk there was a message for me; it had been dictated over the telephone and the written rendering of it was not quite clear, but I figured out that I would be met in the hall at the ground level at about seven o'clock by Hugo from Infotech. Just to be on the safe side I checked with the girl at the reception that the next morning I should not pay, but only sign the bill, as Infotech had promised to pay my expenses, but that part of the arrangement was unknown at the reception (as usual). Later in the evening, two people from Infotech have spent more than fifteen minutes clearing that up. I found Horst Heunke, who was also expected to speak at the conference and had dinner with him and a next speaker (Thompson from Bell Labs) and a few people from Infotech. At ten o'clock Horst and I left the table and went for a refreshing walk. From eleven to twelve o'clock Horst and I have had a glass of whisky in my room and when Horst had left me, I have written for an hour or so. To talk with Horst is always very instructive for me, because the worlds in which we live have a very nearly empty intersection: but it is correspondingly hard to communicate. Horst is absolutely full of how to live with the IBM360 (hard by itself), how to live with the German government (also hard by itself) and how to live with the combination of the two. It seems impossible, but he is still very much alive: I have a slight suspicion that he likes it. He told me that Carl Adam Petri has not gone to Dortmund, but had stayed at the GMD, and heard that some illuminating stories about the German end of the "Mariage a trois" that the world knows under the name UNIDATA.

On Monday morning we walked from our hotel to the Piccadilly Hotel, where the Infotech Conference was held. (The original estimation was 80 people, but the title "Structured Programming" —what else?— had attracted about 280 participants, and they had had to move locations.) A walk through London in the early morning is somewhat depressing; the Piccadilly Hotel's main distinction seems to be worn carpets and primitive toilets. Mike opened the Conference at 9.30 and then acted as the first speaker. His talk was well prepared and quite nice, although perhaps a little bit boring. After the coffee break, during which I prepared some visuals, I had to perform.

The Infotech protocol is a very tiring one. It has been designed on the assumption that the "delegates" —although the texts are handed out at the beginning of the Conference— cannot read and that therefore the speaker is expected to read his text —or what is written on his visuals— slowly and in a clear voice. (Speaker's instructions are of the nature "First announce what you are going to say, then say what you have to say, and finally summarize what you have said.") I find this protocol very irritating. So I have started to comment for at least twenty minutes on my two visuals, and only then started to read my text. But then I heard the pages being turned in the audience, so this time the delegates could read, and from then onwards I departed more and more from my text (which was not very good anyhow: it had been produced under great pressure during two nights). My second visual was a four line program that I had tested by "desk simulation". No one saw the bug, so, after they had been looking at it while I was reading, I pointed out "the" case that went wrong, and repaired the program. Another fifteen minutes later, when I really did not feel like going on with the reading of my text, I told the audience that the program was still not OK. Mike more or less suggested that I should tell what was wrong, but I refused to do so and asked the audience to spot the error: it took them another few minutes, and I think that that (although a little bit cruel) drove the message home.

I had a pleasant lunch with Martin Richards from Cambridge and was picked up at two o'clock by Mr.Bachelor from Burroughs, who had arranged a lecture for people from Burroughs. (The location was a conference room in one of the buildings of Barclay's Bank, near Victoria Station, apparently conveniently located.) I spoke there for quite an inspiring audience from half past two until half past four. I used the opportunity to try out a semi-prepared talk that I am expecting to give next month at Berkeley and at Stanford. And it is a good thing that I tried it out, because it became clear that it needs some further work on it. As I had been warned that during the rush hour a train ride to Gatwick could not be expected to be very comfortable, I gratefully accepted Mr.Bachelor's offer that the chauffeur should drive me to the Airport, where I had a ham sandwich and a glass of milk (courtesy NLM, because nothing was served during the flight).

When I arrived at a quarter to ten at Eindhoven's tiny airport Welschap, it was as if war had just broken out, say the Belgian army crossing the frontier at the Eykse Barriere: the airport was fully guarded by soldiers with arms and dogs, and there was floodlight all over the place. I have no explanation....

Shortly after ten o'clock I was home again, reading the mail that had arrived that day.

12th March 1975
Plataanstraat 5
NUENEN – 4565
prof.dr.Edsger W.Dijkstra
Burroughs Research Fellow

transcribed by Tristram Brelstaff
revised Wed, 24 Aug 2005