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Test Questions – Chapter 2
Modern Operating Systems, 2nd ed.
Multiple choice – in the blank at the left place the letter of the word or phrase which best
answers the question or completes the statement.
1. _____ What concept allows multiple executions to take place in the same process
environment, more or less independently?
A) interrupts, B) PCBs, C) threads, D) kernel, E) none of these
2 – 4
consider the conditions required to maintain mutual exclusion.
2. _____ No process running outside its critical region may
A) block other processes, B) do I/O, C) change from ready to running, D) terminate,
E) none of these
3. _____ No assumptions are made about speeds or
A) the size of memory, B) the number of CPUs, C) the number of printers, D) the number of
secondary memory devices, E) none of these
4. _____ No two processes may be simultaneously inside
A) the print spooler, B) memory, C) their critical region, D) the interrupt vector,
E) none of these
5. _____ Which of these operating systems has no concept of a process hierarchy?
A) UNIX, B) Windows, C) Excel, D) all of these have process hierarchy, E) none of these
have process hierarchy,
6. _____ Which of the following are items private to each thread?
A) stack, B) open files, C) accounting information, D) all of these are private, E) none
of these are private
7. _____ What is the first thing done when an interrupt starts?
A) registers of current running program saved, B) information pushed onto the stack by
interrupt is removed, C) program jumps to interrupt, D) scheduler chooses next process to
execute, E) none of these
8. _____ A situation in which all processes continue to run indefinitely but fail to make
any progress is called
A) non rendezvous, B) starvation, C) mutual exclusion, D) mutex, E) none of these
9. _____ What causes a process to terminate?
A) normal exit, B) the program discovers a fatal error, C) the program causes a fatal
error, D) all of these, E) none of these
10. _____ What was the higher-level synchronization primitive proposed by Hoare and Hansen?
A) thread, B) mutex, C) semaphore, D) monitor, E) none of these
11. _____ What data structure contains information about a process' state, its program
counter, stack pointer, and other information?
A) the scheduler, B) the interrupt vector, C) the process control block, D) the thread,
E) none of these
12. _____ A preemptive version of shortest job first is
A) shortest remaining time next, B) three-level scheduling, C) first-come first served,
D) round-robin scheduling, E) none of these.
Modern Operating Systems, 2nd ed.
Test Questions – Chapter 2
13. _____ The goal of a scheduling algorithm for batch systems is
A) keep the CPU free from jobs in case of emergency, B) maximize the time between
submission of a job and its termination, C) maximize the number of jobs per unit time,
D) all of these, E) none of these
14. _____ A place to buffer a certain number of messages is called a
A) mailbox, B) semaphore, C) barrier, D) rendezvous, E) none of these
15. _____ A thread that is created to handle an incoming message and requires no registers
or stack to be restored is called a
A) sub-thread, B) pop-up thread, C) base thread, D) multi-thread, E) none of these
Short Answer Questions:
16. Name the principal events that cause processes to be created
17. What events occur to cause a process to change states?
18. Why should processes not be programmed with built-in assumptions about timing?
19. In what two places may threads be implemented?
20. Name the three states a process can be in
A)
B)
C)
21. Describe why threads are useful.
22. What does it mean to separate the scheduling mechanism from the scheduling policy?
23. Name four scheduling algorithms presented by the text, suitable for interactive systems.
A)
B)
C)
D)
24. Describe the two operations possible on a semaphore variable
25. Name three situations when scheduling of a process is needed
26. Describe the differences between a preemptive and a nonpreemptive scheduling algorithm.
27. Describe the meaning of the term "pseudoparallelism".
What is "pseudo" about it?
28. How did personal computers change the need for efficient scheduling algorithms?
29. Describe why there is no protection between threads.
30. Name four proposals for achieving mutual exclusion.
Modern Operating Systems, 2nd ed.
Test Questions – Chapter 2
Problem Solving:
31. You are computerizing a call waiting system for a technological help desk. There is one
person at the help desk advising over the phone. The maximum number of calls the system ill
keep on hold is 10. If there are no incoming calls, the help person sits and reads PC Week.
When a call arrives while she is idle the help person answers the call and begins
conversing. If a call arrives while she is busy talking, they must queue up. If the
maximum number on hold is reached, the next caller gets a busy signal. What semaphores
would be used to program this and prevent a race condition? What does each do?
32. Given Jobs and corresponding remaining times required, determine the wait times and
turnaround times for FCFS scheduling. Also, determine the average wait and turnaround times
Job
Time remaining
A
B
C
D
E
Wait time
Turnaround time
5
12
7
8
2
Averages
33. Given jobs and corresponding remaining times required, determine the order, the wait
time, and turnaround time for SJF scheduling. Also, determine the average wait and
turnaround time
Job
Time remaining
A
B
C
D
E
F
Order
7
14
3
12
9
Averages
Wait time
Turnaround time
Modern Operating Systems, 2nd ed.
Test Questions – Chapter 2
34. Given jobs and corresponding remaining times required, determine
finish for round robin scheduling with a quantum of 3.
Job
Time remaining
A
B
C
D
7
5
2
8
Turnaround time
time required to