1690 + Mcqs in Operating System McqOptions

1.	______ is a unique tag, usually a number, identifies the file within the file system.
A.	File identifier
B.	File name
C.	File type
D.	None of the mentioned
Answer» B. File name

Discussion

2.	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.	14
C.	15
D.	11
Answer» E.

Discussion

3.	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» D. 11

Discussion

4.	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» B. 15

Discussion

5.	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» D. 11

Discussion

6.	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» B. 14

Discussion

7.	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» E.

Discussion

8.	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» C. it will cause memory problems

Discussion

9.	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» B. it may overlap several localities

Discussion

10.	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» C. memory size

Discussion

11.	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» D. {1, 2, 3, 4, 5}

Discussion

12.	A program is generally composed of several different localities, which _____ overlap.
A.	may
B.	must
C.	do not
D.	must not
Answer» B. must

Discussion

13.	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» B. it is in the same locality from where it was called

Discussion

14.	A locality is :
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» B. a space in memory

Discussion

15.	Thrashing _______ the CPU utilization.
A.	increases
B.	keeps constant
C.	decreases
D.	none of the mentioned
Answer» D. none of the mentioned

Discussion

16.	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» C. it has no memory allocated to it

Discussion

17.	________ replacement generally results in greater system throughput.
A.	Local
B.	Global
C.	Universal
D.	Public
Answer» C. Universal

Discussion

18.	One problem with the global replacement algorithm is that :
A.	it is very expensive
B.	many frames can be allocated to a process
C.	only a few frames can be allocated to a process
D.	a process cannot control its own page – fault rate
Answer» E.

Discussion

19.	_________ replacement allows each process to only select from its own set of allocated frames.
A.	Local
B.	Universal
C.	Global
D.	Public
Answer» B. Universal

Discussion

20.	_________ replacement allows a process to select a replacement frame from the set of all frames, even if the frame is currently allocated to some other process.
A.	Local
B.	Universal
C.	Global
D.	Public
Answer» D. Public

Discussion

21.	With either equal or proportional algorithm, a high priority process is treated ___________ a low priority process.
A.	greater than
B.	same as
C.	lesser than
D.	none of the mentioned
Answer» C. lesser than

Discussion

22.	The algorithm in which we allocate memory to each process according to its size is known as :
A.	proportional allocation algorithm
B.	equal allocation algorithm
C.	split allocation algorithm
D.	none of the mentioned
Answer» B. equal allocation algorithm

Discussion

23.	The algorithm in which we split m frames among n processes, to give everyone an equal share, m/n frames is known as :
A.	proportional allocation algorithm
B.	equal allocation algorithm
C.	split allocation algorithm
D.	none of the mentioned
Answer» C. split allocation algorithm

Discussion

24.	The maximum number of frames per process is defined by :
A.	the amount of available physical memory
B.	operating System
C.	instruction set architecture
D.	none of the mentioned
Answer» B. operating System

Discussion

25.	Consider a machine in which all memory reference instructions have only one memory address, for them we need at least _____ frame(s).
A.	one
B.	two
C.	three
D.	none of the mentioned
Answer» C. three

Discussion

26.	When a page fault occurs before an executing instruction is complete :
A.	the instruction must be restarted
B.	the instruction must be ignored
C.	the instruction must be completed ignoring the page fault
D.	none of the mentioned
Answer» B. the instruction must be ignored

Discussion

27.	The minimum number of frames to be allocated to a process is decided by the :
A.	the amount of available physical memory
B.	operating System
C.	instruction set architecture
D.	none of the mentioned
Answer» D. none of the mentioned

Discussion

28.	The implementation of the LFU and the MFU algorithm is very uncommon because :
A.	they are too complicated
B.	they are optimal
C.	they are expensive
D.	all of the mentioned
Answer» D. all of the mentioned

Discussion

29.	The reason for using the MFU page replacement algorithm is :
A.	an actively used page should have a large reference count
B.	a less used page has more chances to be used again
C.	it is extremely efficient and optimal
D.	all of the mentioned
Answer» C. it is extremely efficient and optimal

Discussion

30.	The reason for using the LFU page replacement algorithm is :
A.	an actively used page should have a large reference count
B.	a less used page has more chances to be used again
C.	it is extremely efficient and optimal
D.	all of the mentioned
Answer» B. a less used page has more chances to be used again

Discussion

31.	The minimum number of page frames that must be allocated to a running process in a virtual memory environment is determined by :
A.	the instruction set architecture
B.	page size
C.	physical memory size
D.	number of processes in memory
Answer» B. page size

Discussion

32.	The essential content(s) in each entry of a page table is / are :
A.	Virtual page number
B.	Page frame number
C.	Both virtual page number and page frame number
D.	Access right information
Answer» C. Both virtual page number and page frame number

Discussion

33.	Increasing the RAM of a computer typically improves performance because:
A.	Virtual memory increases
B.	Larger RAMs are faster
C.	Fewer page faults occur
D.	None of the mentioned
Answer» D. None of the mentioned

Discussion

34.	Applying the LRU page replacement to the following reference string : 1 2 4 5 2 1 2 4 The main memory can accommodate 3 pages and it already has pages 1 and 2. Page 1 came in before page 2. How many page faults will occur ?
A.	2
B.	3
C.	4
D.	5
Answer» D. 5

Discussion

35.	There is a set of page replacement algorithms that can never exhibit Belady’s Anomaly, called :
A.	queue algorithms
B.	stack algorithms
C.	string algorithms
D.	none of the mentioned
Answer» C. string algorithms

Discussion

36.	In the stack implementation of the LRU algorithm, a stack can be maintained in a manner :
A.	whenever a page is used, it is removed from the stack and put on bottom
B.	the bottom of the stack is the LRU page
C.	the top of the stack contains the LRU page and all new pages are added to the top
D.	none of the mentioned
Answer» C. the top of the stack contains the LRU page and all new pages are added to the top

Discussion

37.	When using counters to implement LRU, we replace the page with the :
A.	smallest time value
B.	largest time value
C.	greatest size
D.	none of the mentioned
Answer» B. largest time value

Discussion

38.	The two methods how LRU page replacement policy can be implemented in hardware are:
A.	Counters
B.	RAM & Registers
C.	Stack & Counters
D.	Registers
Answer» D. Registers

Discussion

39.	For 3 page frames, the following is the reference string : 7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 How many page faults does the LRU page replacement algorithm produce ?
A.	10
B.	15
C.	11
D.	12
Answer» E.

Discussion

40.	LRU page – replacement algorithm associates with each page the ______
A.	time it was brought into memory
B.	the time of that page’s last use
C.	page after and before it
D.	all of the mentioned
Answer» C. page after and before it

Discussion

41.	Optimal page – replacement algorithm is difficult to implement, because :
A.	it requires a lot of information
B.	it requires future knowledge of the reference string
C.	it is too complex
D.	it is extremely expensive
Answer» C. it is too complex

Discussion

42.	Optimal page – replacement algorithm is :
A.	Replace the page that has not been used for a long time
B.	Replace the page that has been used for a long time
C.	Replace the page that will not be used for a long time
D.	None of the mentioned
Answer» D. None of the mentioned

Discussion

43.	A FIFO replacement algorithm associates with each page the _______
A.	time it was brought into memory
B.	size of the page in memory
C.	page after and before it
D.	all of the mentioned
Answer» B. size of the page in memory

Discussion

44.	The aim of creating page replacement algorithms is to :
A.	replace pages faster
B.	increase the page fault rate
C.	decrease the page fault rate
D.	to allocate multiple pages to processes
Answer» D. to allocate multiple pages to processes

Discussion

45.	When a page is selected for replacement, and its modify bit is set :
A.	the page is clean
B.	the page has been modified since it was read in from the disk
C.	the page is dirty
D.	the page has been modified since it was read in from the disk & page is dirty
Answer» E.

Discussion

46.	If no frames are free, _____ page transfer(s) is/are required.
A.	One
B.	Two
C.	Three
D.	Four
Answer» C. Three

Discussion

47.	Users _______ that their processes are running on a paged system.
A.	are aware
B.	are unaware
C.	may unaware
D.	none of the mentioned
Answer» C. may unaware

Discussion

48.	A virtual memory system uses First In First Out (FIFO) page replacement policy and allocates a fixed number of frames to a process. Consider the following statements : P : Increasing the number of page frames allocated to a process sometimes increases the page fault rate Q : Some programs do not exhibit locality of reference Which of the following is TRUE?
A.	Both P and Q are true, and Q is the reason for P
B.	Both P and Q are true, but Q is not the reason for P
C.	P is false but Q is true
D.	Both P and Q are false
Answer» D. Both P and Q are false

Discussion

49.	A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is :
A.	LRU
B.	LFU
C.	FIFO
D.	None of the mentioned
Answer» D. None of the mentioned

Discussion

50.	In question 2, if the number of page frames is increased to 4, then the number of page transfers :
A.	decreases
B.	increases
C.	remains the same
D.	none of the mentioned
Answer» C. remains the same

Discussion

Explore topic-wise MCQs in Testing Subject.

______ is a unique tag, usually a number, identifies the file within the file system.

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 :

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 :

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 :

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 :

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 :

If the sum of the working – set sizes increases, exceeding the total number of available frames :

If working set window is too large :

If working set window is too small :

The accuracy of the working set depends on the selection of :

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 program is generally composed of several different localities, which _____ overlap.

When a subroutine is called,

A locality is :

Thrashing _______ the CPU utilization.

A process is thrashing if :

________ replacement generally results in greater system throughput.

One problem with the global replacement algorithm is that :

_________ replacement allows each process to only select from its own set of allocated frames.

_________ replacement allows a process to select a replacement frame from the set of all frames, even if the frame is currently allocated to some other process.

With either equal or proportional algorithm, a high priority process is treated ___________ a low priority process.

The algorithm in which we allocate memory to each process according to its size is known as :

The algorithm in which we split m frames among n processes, to give everyone an equal share, m/n frames is known as :

The maximum number of frames per process is defined by :

Consider a machine in which all memory reference instructions have only one memory address, for them we need at least _____ frame(s).

When a page fault occurs before an executing instruction is complete :

The minimum number of frames to be allocated to a process is decided by the :

The implementation of the LFU and the MFU algorithm is very uncommon because :

The reason for using the MFU page replacement algorithm is :

The reason for using the LFU page replacement algorithm is :

The minimum number of page frames that must be allocated to a running process in a virtual memory environment is determined by :

The essential content(s) in each entry of a page table is / are :

Increasing the RAM of a computer typically improves performance because:

Applying the LRU page replacement to the following reference string : 1 2 4 5 2 1 2 4 The main memory can accommodate 3 pages and it already has pages 1 and 2. Page 1 came in before page 2. How many page faults will occur ?

There is a set of page replacement algorithms that can never exhibit Belady’s Anomaly, called :

In the stack implementation of the LRU algorithm, a stack can be maintained in a manner :

When using counters to implement LRU, we replace the page with the :

The two methods how LRU page replacement policy can be implemented in hardware are:

For 3 page frames, the following is the reference string : 7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1 How many page faults does the LRU page replacement algorithm produce ?

LRU page – replacement algorithm associates with each page the ______

Optimal page – replacement algorithm is difficult to implement, because :

Optimal page – replacement algorithm is :

A FIFO replacement algorithm associates with each page the _______

The aim of creating page replacement algorithms is to :

When a page is selected for replacement, and its modify bit is set :

If no frames are free, _____ page transfer(s) is/are required.

Users _______ that their processes are running on a paged system.

A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is :

In question 2, if the number of page frames is increased to 4, then the number of page transfers :