You could try the (very pricey) Andrew Tanenbaum book, which helped linus torvalds on his way:
http://www.amazon.com/exec/obidos/tg...=UTF8&v=glance
HTH
Charlie
--
Don't Stand on your head - you'll get footprints in your hair
http://charlieharvey.org.uk
http://charlieharvey.com