1.2 main reasons for operating systems to exist How do they make the system easier to use? What services they offered? 

2.How do they use system resources more efficiently? What services offered?

3.What is an interrupt, how and when generated, and how handled by OS? 

4.What is a trap, how and when generated, and how handled by OS?

5.Concept of multiprogramming. What is goal, how implemented?

6.When do processes give up control of CPU? 

7.Extension to multiprogramming = time-sharing. What is goal, how implemented? When do processes give up CPU now? What is a process? 

8.Dual-mode execution. What is purpose? How used? 9.What is a system call?