From ULSA "Chapter 3 -- Booting and Shutting Down"

   You should know the historical sequence of BIOS reads the first
   block from some device (the order of device preferences can
   (usually) be specified by configuring the BIOS); first block has
   executable code which is executed.  In Linux, this gets you as far
   as GRUB; GRUB then figures out where the kernel and initial
   filesystem (a memory image) is located, lays them out in memory,
   and starts the kernel. The kernel runs for a bit, then pivots over
   into its actual file system. It then runs either traditional init,
   or maybe one of its successors, such as upstart or systemd.

From ULSA "Chapter 4 -- Access Control and Rootly Powers"

   The original Unix model of access control via chown and chmod, and the
   "root exception". Understand that "root execution" means that a process
   is executing as UID 0. Understand "setuid/setgid" and its relationship
   to file ownership.

   From modern access control, despite the book's dismissive tone,
   SELinux is important and you should know at least the basics (look at p.
   923 though the details aren't that critical right now.)

   POSIX capabilities are a developing subject, and there is some
   confusion in the community about where they are going. 

   PAM is an important and successful subject, and you should be familiar
   with its fundamental concepts.

   The program sudo is worth knowing about.

From ULSA "Chapter 5 -- Controlling Processes"

   Processes, their state, and lifecycles; UIDs, GIDs, and controlling terminals.
   
   Signals: HUP, KILL, TERM, STOP/CONT. Using kill(1) to do kill(2).

   Using tools such as ps and top, and how these get their information
   from /proc. Using strace and truss.

From MWS2008R2 "Chapter 3 -- The New Server: Introduction to Server Core"

   Motivation for Server Core. General concepts with installing and configuring
   Server Core, and its remote administration capabilities. Firewall issues.
   Major roles and features.