A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

51. Match the following for Unix rue system:

List-I                  List-II
a. Boot block     i. Information about file system,
free block list, free inode list etc.
b. Super block ii. Contains operating system files
as well as program and data files
created by users.
c. Inode block   iii. Contains boot program and
partition table.
d. Data block    iv. Contains a table for every file in
the file system. Attributes of files
are stored here.

Codes:
     a   b  c   d
a. iii   i   ii   iv
b. iii   i   iv  ii
c. iv  iii  ii   i
d. iv  iii  i    ii
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Answer: (b).iii   i   iv  ii

52. Some of the criteria for calculation of priority of a process are:

a. Processor utilization by an individual process.
b. Weight assigned to a user or group of users.
c. Processor utilization by a user or group of processes.

In fair share scheduler, priority is calculated based on:
a. only (a) and (b)
b. only (a) and (c)
c. (a), (b) and (c)
d. only (b) and (c)
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Answer: (c).(a), (b) and (c)

53. One of the disadvantages of user level threads compared to Kernel level threads is
a. If a user level thread of a process executes a system call, all threads in that process are blocked.
b. Scheduling is application dependent.
c. Thread switching doesn’t require kernel mode privileges.
d. The library procedures invoked for thread management in user level threads are local procedures.
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Answer: (a).If a user level thread of a process executes a system call, all threads in that process are blocked.

54. Names of some of the Operating Systems are given below:

(a) MS-DOS
(b) XENIX
(c) OS/2

In the above list, following operating systems didn’t provide multiuser facility.
a. (a) only
b. (a) and (b) only
c. (b) and (C) only
d. None of the above is correct
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Answer: (d).None of the above is correct

55. Consider a system with seven processes A through G and six resources R through W.
Resource ownership is as follows:

process A holds R and wants T
process B holds nothing but wants T
process C holds nothing but wants S
process D holds U and wants S & T
process E holds T and wants V
process F holds W and wants S
process G holds V and wants U

Is the system deadlocked ? If yes, ............. processes are deadlocked.
a. No
b. Yes, A, B, C
c. Yes, D, E, G
d. Yes, A, B, F
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Answer: (c).Yes, D, E, G

56. Suppose that the virtual Address space has eight pages and physical memory with four page frames. If LRU page replacement algorithm is used, .............. number of page faults occur with the reference string.

0 2 1 3 5 4 6 3 7 4 7 3 3 5 5 3 1 1 1 7 2 3 4 1
a. 11
b. 12
c. 10
d. 9
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Answer: (a).11

57. Consider a system having ‘m’ resources of the same type. These resources are shared by three processes P1, P2 and P3 which have peak demands of 2, 5 and 7 resources respectively. For what value of ‘m’ deadlock will not occur?
a. 70
b. 14
c. 13
d. 7
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Answer: (b).14

58. Five jobs A, B, C, D and E are waiting in Ready Queue. Their expected runtimes are 9, 6, 3, 5 and x respectively. All jobs entered in Ready queue at time zero. They must run in ............. order to minimize average response time if 3 < x < 5.
a. B, A, D, E, C
b. C, E, D, B, A
c. E, D, C, B, A
d. C, B, A, E, D
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Answer: (b).C, E, D, B, A

59. Consider three CPU intensive processes P1, P2, P3 which require 20, 10 and 30 units of time, arrive at times 1, 3 and 7 respectively. Suppose operating system is implementing Shortest Remaining Time first (pre-emptive scheduling) algorithm, then .............. context switches are required (suppose context switch at the beginning of Ready queue and at the end of Ready queue are not counted).
a. 3
b. 2
c. 4
d. 5
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Answer: (a).3

60. Consider a system which have ‘n’ number of processes and ‘m’ number of resource types. The time complexity of the safety algorithm, which checks whether a system is in safe state or not, is of the order of:
a. O(mn)
b. O(m^2n^2)
c. O(m^2n)
d. O(mn^2)
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Answer: (d).O(mn^2)

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