Outline:

1. Recap: Lesson 2
   • process memory
   • process state
2. The OS kernel
   • dual-mode operation
   • memory protection
   • physical vs. virtual memory
3. Communication between kernel and user-level applications
   • signals
   • timer interrupts
   • system calls
4. Lab Assignment #1 and its design document

Reading assignment (to be completed by the next class):

• OSTEP Ch. 6
• Assignment 1: System Calls

Optional: OSTEP Ch. 39 on Files and Directories