Looking for good, but quick references for underlying OS concepts related to SQLOS (Memory Access, Scheduling, etc...)?

Looking for good, but quick references for underlying OS concepts related to SQLOS (Memory Access, Scheduling, etc...)? I am researching SQLOS and how threads and scheduling are handled, but I would like to review some OS concepts and how SQLOS interacts with the environment. I am aware of the Operating Systems Concepts textbook, but I was wondering if there was a good resource available online that is a little more brief and to the point.