Other sources specifically about writing device drivers.
Randy Bentson recently wrote an interesting book called Inside Linux. It has some information on basic operating system theory, some that is specifically related to Linux, and occasional parts that aren't really related to Linux at all (such as a discussion of the Georgia Tech shell). ISBN 0-916151-89-1, published by Specialized System Consultants
Inline Assembly with DJGPP really applies to any version of GCC on a 386, and some of it is generic GCC inline assembly. Definitely required reading for anyone who wants to do inline assembly with Linux and GCC.
The Annotated Bibliography mentions plenty of books out that don't have ``Linux'' in the title which may be useful to Linux programmers. Especially if you are new to kernel programming, you may do well to pick up one of the textbooks recommended in the bibliography.
Copyright (C) 1996 Michael K. Johnson,