Questions (10 points = 1pt X 10)
1. What are the three main purposes of an operating system?
2. How does the distinction between kernel mode and user mode function as a rudimentary
form of protection (security) system?
3. Which of the following instructions should be privileged?
(a) Set value of timer.
(b) Read the clock.
(c) Issue a trap instruction.
(d) Turn off interrupts.
(e) Modify entries in device-status table.
(f) Switch from user to kernel mode.
(g) Access I/O device.
4. Describe the differences between symmetric and asymmetric multiprocessing. What are three
advantages and one disadvantage of multiprocessor systems?
5. What is the purpose of interrupts? What are the differences between a trap/exception and an
interrupt? Can a user program generate traps intentionally? If so, for what purpose?
6. What is the purpose of system calls?
7. Describe three general methods for passing parameters to the operating system.
8. Why is the separation of mechanism and policy desirable?
9. What are the main advantages of the microkernel approach to system design? How do user
programs and system services interact in micro-kernel architecture? What are the
disadvantages of using the microkernel approach?
10. What are the two models of interprocess communication? What are the strengths and
weaknesses of the two approaches?
