To recap:
Kernel v2.0.23, previously very stable, now freezes within a day,
as do 2.0.24 and 2.0.25. Only changes: adding a local network and
a dumb terminal. My gcc version is 2.7.2; my binutils are 2.6.0.14.
The source tree is 2.0.0 plus all patches up to 23. I have reinstalled
the sources from scratch, and monitored the application of each patch,
to ensure that patch wasn't failing obscurely and messing up the source
in some arcane way. I'm sure, then, that I have a clean source tree.
The only non-standard bit is Micheal Beck's PC Speaker sound driver;
but this didn't cause problems before, when I had a stable 2.0.23.