Mad C Skillz OEMG

I want to jump to the next level in C. I'm a quite skilled programmer for what I do, know the whole K&R but I feel like I miss something, especially about those weird techniques proPROgrammers use in OS dev and related. Suggested readings?

>>53
distributed operating system
So, not Unix.

research successor to Unix
So, not Unix, else it would have been called Unix rather than its research successor.