Covers socket programming for network communication. Explains Unix domain and Internet sockets, TCP (connection-oriented) and UDP (connectionless) sockets, socket API (socket, bind, listen, accept, connect, send, recv), and concurrent server architectures using multi-threading and event-driven I/O.
Presents Xen paravirtualized VMM for x86 allowing multiple commodity OSes to share hardware. Covers paravirtualization approach, memory virtualization with shadow page tables, CPU virtualization using privilege rings, device I/O using shared rings, and performance evaluation.
Details xv6 process management implementation. Covers struct proc (PCB in xv6), page table for virtual-to-physical address mapping, kernel stack for system calls, file descriptor table for open files, and process table (ptable) structure.