Operating System Multiple Choice Questions on “Virtual Memory – Thrashing”.
1. A process is thrashing if ____________
a) it spends a lot of time executing, rather than paging
b) it spends a lot of time paging than executing
c) it has no memory allocated to it
d) none of the mentioned
Answer: b
2. Thrashing _______ the CPU utilization.
a) increases
b) keeps constant
c) decreases
d) none of the mentioned
Answer: c
3. What is a locality?
a) a set of pages that are actively used together
b) a space in memory
c) an area near a set of processes
d) none of the mentioned
Answer: a
4. When a subroutine is called ____________
a) it defines a new locality
b) it is in the same locality from where it was called
c) it does not define a new locality
d) none of the mentioned
Answer: a
5. A program is generally composed of several different localities, which _____ overlap.
a) may
b) must
c) do not
d) must not
Answer: a
6. In the working set model, for:
2 6 1 5 7 7 7 7 5 1 6 2 3 4 1 2 3 4 4 4 3 4 3 4 4 4 1 3 2 3
if DELTA = 10, then the working set at time t1 (….7 5 1) is?
a) {1, 2, 4, 5, 6}
b) {2, 1, 6, 7, 3}
c) {1, 6, 5, 7, 2}
d) {1, 2, 3, 4, 5}
Answer: c
Clarification: None.
7. The accuracy of the working set depends on the selection of ____________
a) working set model
b) working set size
c) memory size
d) number of pages in memory
Answer: b
Clarification: None.
8. If working set window is too small ____________
a) it will not encompass entire locality
b) it may overlap several localities
c) it will cause memory problems
d) none of the mentioned
Answer: a
Clarification: None.
9. If working set window is too large ____________
a) it will not encompass entire locality
b) it may overlap several localities
c) it will cause memory problems
d) none of the mentioned
Answer: b
Clarification: None.
10. If the sum of the working – set sizes increases, exceeding the total number of available frames ____________
a) then the process crashes
b) the memory overflows
c) the system crashes
d) the operating system selects a process to suspend
Answer: d
Clarification: None.
11. Consider the following page reference string.
1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6
For LRU page replacement algorithm with 4 frames, the number of page faults is?
a) 10
b) 14
c) 8
d) 11
Answer: a
Clarification: None.
12. Consider the following page reference string.
1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6
For LRU page replacement algorithm with 5 frames, the number of page faults is?
a) 10
b) 14
c) 8
d) 11
Answer: c
Clarification: None.
13. Consider the following page reference string.
1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6
For FIFO page replacement algorithms with 3 frames, the number of page faults is?
a) 16
b) 15
c) 14
d) 11
Answer: a
Clarification: None.
14. Consider the following page reference string.
1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6
For FIFO page replacement algorithms with 4 frames, the number of page faults is?
a) 16
b) 15
c) 14
d) 11
Answer: c
Clarification: None.
15. Consider the following page reference string.
1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6
For Optimal page replacement algorithms with 3 frames, the number of page faults is?
a) 16
b) 15
c) 14
d) 11
Answer: d