CSC 453 - Operating Systems

Dr. R. M. Siegfried

Study Questions for the Midterm Exam

Definitions:

  1. Multiprogramming
  2. Batch
  3. Real-time
  4. DMA
  5. Supervisor mode
  6. Asymmetric multiprocessing
  7. Thread
  8. FCFS
  9. SJF
  10. Deadlock
  11. Real time operating system
  12. Process
  13. Symmetric multiprocessing
  14. Buffering
  15. DMA
  16. LAN
  17. Lottery Scheduling
  18. Kernel
  19. Thread
  20. SPOOLing
  21. Interrupt
  22. Trap
  23. Semaphores
  24. Monitors

Questions:

  1. Under what circumstances would a user be better off working on a time-sharing system, rather than on a stand-alone PC or workstation?
  2. What is the main advantage of multiprogramming? Would it be possible to design a multitasking operating system without multiprogramming?
  3. What is the difference between an interrupt and a trap? What is the use of each of these functions?
  4. What is the main advantage to the layered approach to operating system design?
  5. As enumerated in the text, enumerate three of the five major activities in regard to process management.
  6. Describe the differences between long-term and short-term scheduling of processes.
  7. What are the three most common states in which processes may be found? Enumerate and describe these states.
  8. What are the five states of a process? Show the various transitions through which a process can go from one state to another.
  9. What advantages do threads offer over heavyweight processes? What are the two different methods of supporting threads?
  10. Given the following sets of processes, with the CPU-burst lengths shown, assume that they arrive in the order P0, P1, P2, P3, and P4 at time t0.
    1. What is the order in which they will arrive given the following scheduling algorithms: FCFS, SJF, Round-Robin (quantum = 1) and a non-preemptive priority algorithm where smaller numbers imply higher priorities
    2. What is the average turnaround time for these four algorithms?
    Process Burst Time Priority
    P0 4 1
    P1 12 1
    P2 2 3
    P3 1 2
    P4 3 3
  11. Why is memory caches useful?
  12. How does the distinction between monitor mode and user mode provide a basic form of protection to an operating system?
  13. What are semaphores and monitors? How are they different? How are they similar?

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