Operating System MCQ’s With answers-Chapter 05

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81. In multi processor scheduling; A: Gang scheduling, B: Dynamic scheduling, C: Dedicated processor management.;
1- The number of threads in a process can be altered during the course of execution.
2-This provides implicit scheduling defined by the assignment of threads to processors,
3-It is applied to the simultaneous scheduling of threads that make up a single process.
(A) A – 1, B – 2, C – 3
(B) A – 2, B – 1, C – 3
(C) A – 1, B – 3, C – 2
(D) A – 3, B – 1, C – 1

82. In real time computing
(A) The result of computation does not depend on the time at which computation is done.
(B) The result of computation also depends on the time at which computation is done.
(C) The results are independent of the time considered.
(D) None of these.

83. In soft real time tasks
(A) The dead line is always mandatory.
(B) The dead line is desirable but not mandatory.
(C) The results are independent of the time, when it took place.
(D) None of these.

84. In real time scheduling: A: Static table driven approach, B: Static priority driven preemptive approach, C: Dynamic planning based approach;
1- A static analysis of feasible scheduler of dispatching is done and implemented.
2- A static analysis of feasible schedules of dispatching is done and assigns priorities to tasks.
3- Feasibility is determined at run time.
(A) A – 1, B – 2, C – 3
(B) A – 2, B – 3, C – 1
(C) A – 3, B – 1, C – 2
(D) None of these.

85. Match the following I/O devices : A- Keyboard,
1- Human readable, B- Disk and tape drives,
2- Communication, C- Modems,
3-Machine readable
(A) A – 1, B – 3, C – 2
(B) A – 1, B – 2, C – 3
(C) A – 3, B – 2, C – 1
(D) A – 2, B – 1, C – 3

86. Arrange the following I/O device in increasing data rate Hard disk, Floppy disk, Key board
(A) Key board, Floppy disk, Hard disk
(B) Floppy disk, Key board, Hard disk
(C) Key board, Hard disk, Floppy disk
(D) Hard disk, Floppy disk, Key board.

87. In I/O management when buffering is allowed then :
Statement A: Input transfer is performed before request is made.
Statement B: Output transfer is performed after request is made. Statement A and B are both true
(A) Statement A and B are both false
(B) Statement A is true but Statement B is false
(C) Statement B is true but statement A is false.
(D) Statement A and B Both are true

88. Resident set of process is
(A) Portion of a process that is actually in main memory at any time.
(B) Portion of a process that is actually in virtually memory at any time.
(C) A and b both true.
(D) None of these.

89. Main memory is referred as
(A) Virtual memory
(B) Real memory
(C) A and B both
(D) None of these.

90. Memory that is located on the disk either Hard or floppy is referred as
(A) Virtual memory
(B) Real memory
(C) Main memory
(D) None of these.

91. The principle of locality states
(A) The program and data references within a process tend to cluster.
(B) The program and data references within a process do not tend to cluster.
(C) A process actually referred in virtual memory.
(D) None of these.

92. In memory management : A- Fetch Policy BCleaning Policy C- Placement Policy:
1- It determines when a modified page should be written out to secondary memory.
2- It determines when a page should be bought into main memory.
3- It determines where in real memory a process piece is to be reside.
(A) A – 1, B – 2, C – 3
(B) A – 2, B – 1, C – 3
(C) A – 2, B – 1, C – 3
(D) A – 3, B – 1, C – 2

93. In memory management when demand cleaning policy is applied
(A) A modified page is written before their page frames are needed to so that pages can be written out in batches.
(B) A page is written out to secondary memory only when it has been selected for replacement.
(C) A and B both true.
(D) None of these.

94. In two level scheme for page table, if one assume byte-level addressing and 4-kbyte (212 pages) then the 4-Gbyte (232) virtual address space is composed of
(A) 210 pages
(B) 220 pages
(C) 230 pages
(D) 240 pages

95. When pre cleaning policy is applied in memory management
(A) A page is written out to secondary memory only when it has been selected for replacement.
(B) Modified pages are written before their page frames are needed so that can be written out in batches.
(C) A and B both true.
(D) None of these.

96. In virtual memory management, when local control policy is applied
(A) It determines the number of processes that are to be resident in main memory.
(B) It determines the number of processes that are to be resident in virtual memory.
(C) It determines when a modified page should be written out to secondary memory.
(D) None of these.

97. In two level scheme if each page is mapped by 4-byte (22) page table entry then to create a page table composed of 220 page table entry one requires
(A) 222 bytes
(B) 212 bytes
(C) 216 bytes
(D) None of these.

98. In defining page table structure in virtual memory, A page number portion of a virtual address is mapped into a hash table using simple hash function, where hash table contains a pointer to the inverted page table, which contains page table entries, this approach is referred as
(A) One page table per process structure.
(B) Two level page table structure.
(C) Inverted page table structure.
(D) None of these.

99. A fetch policy for virtual memory determines
(A) When a page should be bought into main memory.
(B) Where in real memory a process piece is to be reside.
(C) The selection of a page in memory that is to replaced.
(D) The page in memory that is not been referenced for long time.

100. The demand paging and pre paging of virtual memory management are
(A) Fetch policy for virtual memory management.
(B) Placement policy for virtual memory management.
(C) Replacement policy for virtual memory management.
(D) None of these.
(i) A- Fetch, B-Demand paging, C-Prepaging;
1-Determines when a page should be bought into main memory.
2-A page is bought into main memory only when a reference is made to a location on that page.
3-Pages other than the one demanded by a page fault are bought in.
(E) A – 1, B – 2, C – 3
(F) A – 3, B – 2, C – 1
(G) A – 2, B – 3, C – 1
(H) A – 3, B – 1, C – 2


81. (D) 82. (B) 83. (B) 84. (A) 85. (A)
86. (A) 87. (D) 88. (A) 89. (B) 90. (A)
91. (A) 92. (C) 93. (B) 94. (B) 95. (B)
96. (A) 97. (A) 98. (C) 99. (A) 100. (A)