My recommendation would be to work through Computer Systems: A Programmer's Perspective [0] if you're comfortable with K&R. David Hanson's C Interfaces and Imp

My recommendation would be to work through Computer Systems: A Programmer's Perspective [0] if you're comfortable with K&R. David Hanson's C Interfaces and Implementations is also excellent. [0] http://csapp.cs.cmu.edu/ http://csapp.cs.cmu.edu/