Operating System Design: Internet Working With Xinu by Douglas Comer (1987) is a nice explanation with lots of C code of how to add a networking stack to an operating system, in this case his educational unix-inspired XINU.
I actually can't find the book you are referencing. I do see:
"Operating System Design: The Xinu Approach" and also the books "Internetworking with TCP /IPvolumes1-3." Might you have a link to the title you are referencing here? I have read the Internetworking series which is excellent.
It looks the the second volume that goes with "Operating System Design".
I can't be 100% certain, as I didn't find a table of content for either of the 1st edition books, but the 2nd edition of "Operating System Design" includes a section in implementing ethernet, so perhaps the two volumes got combined into one for the second edition.
