Anyone who's hacking on NetBSD on the i386 architecture would probably
be interested in the new second edition of Hans-Peter Messmer's "The
Indispensable PC Hardware Book" published by Addison-Wesley.  The
first edition was pretty good and was a valued part of my bookshelf
but had gotten a bit dated -- the new edition covers all that happened
since the first was published and more!

In one 1300 page volume, it summarizes everything from how to program
the 8253 timer chip to all the current PC buses (including PCI and
some facts on PCMCIA), to the instruction sets on all Intel x86
microprocessors, to the pinouts on RS-232 and how to program VGA
cards. Truly an encyclopedic work -- it even has an example on
programming FM synthesis on SoundBlaster cards!

There are a few errors and the thing neccessarily doesn't go into as
much depth as it could, but its the best thing I've found thus far (if
anyone knows of better please pipe up!).  -- I heartily recommend this
new version.

Perry