Operating System Questions & Answers – Virtual Memory – Thrashing

This set of Operating System Multiple Choice Questions & Answers (MCQs) focuses 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
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2. Thrashing _______ the CPU utilization.
a) increases
b) keeps constant
c) decreases
d) none of the mentioned
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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
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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
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5. A program is generally composed of several different localities, which _____ overlap.
a) may
b) must
c) do not
d) must not
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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}
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Sanfoundry Global Education & Learning Series – Operating System.