Operating System Design with XINU
Written in the 80's this book takes the reader through a full implementation of an operating system written in C. At the time this was a format which few authors ever attempted. Covers context switching, scheduling, process coordination, message passing, memory management, device drivers, file systems. (Prentice-Hall, 486 pages)
Internetworking with XINU
The sister book to the first. Delves into intermachine communications on top of the XINU OS. Again all source code supplied. Covers ethernet basics, UDP, TCP, Remote Boot up, client/server models, file servers, XINU has been around before Linux was even a concept and is still seen today a viable OS for embedded systems. In fact Zilog has produced an entire product line utlizing this OS. (Prentice-Hall, 567 pages)