CSE258
Final exam review questions

Jeffrey A. Meunier

December 9, 2001

Here are some sample questions you are likely to find on the final exam. The chapter from which each question was taken can be found in parentheses at the beginning of the question. I reserve the right to change the wording of questions, or to add new questions for the exam. The chapters covered are: 9 Memory Management, 10 Virtual Memory, 13 I/O Systems, 14 Mass Storage Systems, 15 Distributed System Structures, 19 Security, 21 Windows 2000. See the CSE258 web page for updates to this list of questions:
http://www.engr.uconn.edu/~jeffm/Classes/CSE258-Fall-2001

1. What is an operating system?
2. List some reasons why it may be important to upgrade to the latest version of an operating system.
3. List some reasons why it may be important to stay with an older version of an operating system.
4. (3) Define microkernel.
5. (3) What is a virtual machine and how is it useful?
6. What is the difference between a preemptive and a non-preemptive system?
7. (4) What is message passing?
8. (9) Compare and contrast first fit, best fit, and worst fit. Describe each and list benefits and drawbacks.
9. (9) Define external fragmentation.
10. (9) Define internal fragmentation.
11. (9) What is the purpose of paging?
12. (9) Describe the advantages and disadvantages of paging.
13. (9) Describe segmentation and what its benefits are.
14. (10) What is virtual memory and what is it used for?
15. (10) How is simple paging different from virtual memory?
16. (10) Describe what happens during a page fault. Summarize, do not list the steps on page 326.
17. (10) What is demand paging?
18. (10) Describe what copy on write means.
19. (10) Does increasing the number of frames when using a FIFO page replacement policy always result in fewer page faults? Explain.
20. (10) Is there an optimal page replacement algorithm? If so, what is it? If not, why not?
21. (10) Compare and contrast the LFU and MFU page replacement algorithms.
22. (10) What is thrashing? What causes it? How can it be avoided?
23. (10) Why is it necessary sometimes to lock pages into memory? Give two examples.
24. (10) Define locality of reference.
25. (13) Compare polling to interrupt handling.
26. (13) Define and compare PIO and DMA.
27. (13) What is the difference between a cache and a buffer?
28. (14) Compare SSTF disk scheduling to SCAN scheduling.
29. (14) Discuss the merits of making swap space a separate partition as opposed to using a normal file (or set of files).
30. (14) Would it be better to place a swap space disk partition in the middle of the disk, between other partitions, or at one of the ends?
31. (14) If the MTBF (mean time between failures) of a particular brand of 10-GB disk is 100,000 hours, and you have a disk array of 100 of such disks, how many hours would you expect to elapse before you had a failure in any disk? About how many days is that?
32. (14) What does RAID mean? Briefly describe RAID levels 0, 1, and 5.
33. (14) What is a hot spare disk?
34. (15) What is a distributed system? (Describe its most common characteristics.)
35. (15) Briefly describe a few advantages of using a distributed system.
36. (15) Why is process migration difficult?
37. (15) What does fault tolerant mean?
38. (15) Consider the following network topologies: fully connected, partially connected, tree, star, ring. Which would you expect to have the highest fault tolerance? Why?
39. (15) What does reliability mean?
40. (19) What does security mean?
41. (19) What does encryption mean?
42. (19) What does authentication mean?
43. (19) What is the problem with detecting an actual denial of service attack?
44. (21) Describe the function of the HAL in Windows 2000 (and what HAL stands for).
45. (21) Describe the function of the kernel in W2K.
46. (21) What is the advantage of using a virtual machine in which to run programs?
47. (21) What is the advantage of having an operating system be POSIX compliant?