Hi, everybody, I've got the problem fixed. In my kernel config, I'd forgotten to include a driver for my VIA "low speed" IDE controller. I've put that in, and I can now read CDs/DVDs (and probably burn them too).
I've stuck with the traditional /dev/hd[a-z] drivers for all the reasons I've ranted about in other posts. Thanks indeed to everybody who helped me get sorted! -- Alan Mackenzie (Nuremberg, Germany).
