Descriptor printing works well. Discovered that there are very few ACPI implementations that implement checksums, so I can't use this very obvious heuristic as such. However, checking all the lengths of the descriptors and checking as many values as possible is sufficient, it turns out.
Because I've been working from sunup to sundown all week, decided to take the afternoon off and went to Köln. We invited one of Kim's fellow-students to come with us.
On the way out of Utrecht, finished the break-in period for the car. We idled through the Netherlands at the limit. In Germany, though, we found roads with no speed limit and discovered just how fast a truck going 100 kph (~60 mph) approaches when you are going 125 mph (~200 kph). It is amazing how much my perspective has changed since picking up this car; 100 mph seemed plenty fast the first day; now it seems a very comfortable cruising speed. It will be difficult to slow down in the US; I think I'll have to find winding roads and enjoy the car's good handling instead.
In Köln, discovered that it was high season, and also realized that it was only a short drive from Utrecht, so decided not to stay the night. We parked at Köln Hbf (cheaper parking than even outlying neighborhoods in Utrecht) and touristed a bit. In particular, spent a good bit of time in the cathedral, next door to the Hbf. Tried to take pictures of stained glass windows again. Did not really grasp the cathedral's immensity until we went outside and crossed to the other side of the square and tried to take a picture. That was not exactly a success; with the camera at its widest angle lens setting I could not even capture the short face of the cathedral from side to side. I went down a street as far as I could and then could get it from side to side, but it still took three pictures vertically.
Ate supper at Cafe Piano, in part because our Korean friend wanted to try german food and they had it there, but in large part because their windows were open and we sat in a booth that was open both to the inside of the restaurant and the outside; they had simply moved the restaurant windows out of the way. Sometimes the waitress helped us from inside the restaurant, and sometimes, when she was waiting on the sidewalk tables, would walk over and help us from the outside. Piquant and new to us.
After supper, I was attacked by a street performer who wanted to take my camera. I was nonplussed and noncooperative.
Then we walked around the old market and across the Rhine and back on the railway bridge. On the Rhine, we saw two identical boats, one heavily-laden going upriver, and one unladen going down. Kim wished she had a video camera so that she could show it to her algebra students when they are doing word problems involving boats going upstream and down, as she is tired of having them assure her that boats travel much faster going upstream than down...
I decided that our Korean friend was not excessively frightened by my driving fast when she started taking pictures including the speedometer from the back seat in order (I think) to prove to her friends and relatives back home how fast we had been driving.