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100+ MCQS for operating system with Answers | NTS | PTS |CTS CSS

1:virtual memory is

  • An extremely large main memory
  • An extremely large secondary memory
  • An illusion of an extremely large memory
  • A type of memory use in super computers

2: spatial locality  refers to the problem that once a location is referenced

  • It will not be referenced agaig
  • It will be reference again
  • A nearby  location will be reference soon
  • None of the above

3: which of the  following is an example of a spooled device ?

  • The terminal used to enter the input date for a programming being executed.
  • The secondary memory devices in a virtual memory system
  • A line printer use to print output of a number of jobs
  • None of the above

4: pege fault occurs when                

  • The page is corrupted by application software
  • The page is in main memory
  • The page is in not main memory
  • One tries to divide a number by 0

5:  overlay  is 

  • Part of an operating system
  • A specific memory location
  • A  single contiguous  memory that was use in the  olden days for running                large programs by swaping.
  • Overloading the system with many user files

6: concurrent process are process that

  • Do not overlap in time
  • Overlap in time
  • Are executed hy a processor at the same time
  • None of these

7: the page replacement policy that sometime leads to more page fault when the size of the memory is increased is

  • FIFO (b) LRU       (c) no such policy exist    (d) none of these

8:the only state transition that is initiated by the user process Itself is

  • Block (b)dispatch (c)   wakeup   (d)  none of these

9: which of the following are real-time system  ?

  • an on-line railway reservation system (b)  a process control system

(c)Aircraft control system    (d) payroll process system

10: dijkstra is banking algorithm in an operating system solve the problems of (a)deadlock recovery   (b)deadlock avoidance

(c)mutual exclusion     (d) context switching

11: in page memory system , if the page size increase , then the internal fragmentation generally

(a)becomes less     (b) becomes more

(c) remains constant    (d) none of these

12: an operating system contain 3 user process each required  2 unites of resource R .the minimum number of unites of R such that no deadlock will ever occur is

  • 3 (b) 4 (c) 5           (d) 6

13:  kernel is

  • Considered as the critical part of the operating system

(b)the software which monitors the opeerating system

(c) the set of primitive function upon which the rest of operating system function are built up

(d) none of these

19: Necessary condition for deadlock are

(a)non-preemption and circular wait   (b) Mutual exclusion and partial   allocation       (c) both (a) and (b)

20:in a time sharing operating system when the time slot given to a process is complete , the process goes from the RUNNING state to the

(a)BLOCKED state     (b)READY state

(c) SUSPENDED state (d)TERMINATED  state

21:At a particular time , the value of counting  semaphore is 10. It will become 7 after (a)3 V  operations (b) 3 p operation

(c)5 V operation and 2 p operation  (d) 13 p operation and 10 V operation

22:Supevisor call

(a)is call made by the supervisor of the system (b) is call with control functions

(c)are privileged calls that are use to perform resource management function, which are controlled by the operating system

(d)is a call made by someone working in root directory

23: semaphores are use to solve the problems of

(a)race condition       (b)process synchronization

(c) mutual exclusion    (d) none of the above

24: if the property of locality of reference is will pronounced in a program

(a)the number of page fault will be more

(b) the number of page fault will be less

(c) the number of page faults will remain the same

(d)execution will be faster

25: At a particular time of computation, the value of a counting semaphore is 7. Then  20 p operations  and x  v operation were completed on this semaphore. If final value of the semaphore is 5. X will be

(a)15      (b) 22     (c) 18         (d) none of these

27:mutual exclusion problem occurs

(a)between two disjoint processes that do not interact

(b)among the process that share resources

(c) among the process that do not share the same resources

(d) none of the above

28: sector interleaving in disks is done by

  • The disk manufacture (b) the disk controller cord

(c)the operating system   (d) none of the above

29:memory protection is of no use in a

(a)single user system      (b)non-multiprogramming system

(c)non-multitasking  system   (d)none of these

30:some computer system support dual mode operating  the user mode and the supervisor  monitor mode . these refer to the modes

(a)by which user programs handle their data

(b)by which the operating system executes user programs

(c) in which the processor and the associated hardware operate

(d) of memory access

31:Disk scheduling involves deciding

(a)which disk should be accessed next

(b)the order in which disk access requests must be serviced

(c) the physical location where files should be accessed in disk

(d)none of the above

32:a computer system has 6 tape drives . with “n” processes competing for them .each process may  need 3 tape drives . the maximum value of “n” for which  the system is guaranteed to deadlock free is

(a)2         (b) 3            (c) 4                   (d)1

33: Dirty bit is used to show the

(a)page with corrupted date   (b)wrong page in the memory

(c)page that is modified after being loaded into cache memory

(d) page that is less frequently accessed

34: Fence Register is used for (a)  CPU protection (b)  memory protection (c) file  protection (d)  all of the above

35:Which of the following is a service not supported by the operating system?

(a) production (b) accounting (c) compilation (d) I/o operation

36:  the first-fit, best-fit and the worst-fit algorithm can be used for

(a) contiguous allocation of memory (b) linked allocation of memory (c) index allocation of memory (d) all of the above

37: Which of the following are the single user operating system

(a)MS- DOS  (b) UNIX (C) XENIX (d)  os/2

 

38: Round Robin CPU scheduling asset and Quantum is increase average turn around time

(a)Increase       (b)decrease      (c)remains constant   (d)varies irregularly

40:  which of the following are true

(a)a re-entrent  procedure can be called any number of times

(b) A re-entrent  procedure can be called even before the product has not returned it previous call

(c)more then one procedure cannot be called

(d)a re-entrant procedure can be called cause recursively

41: Inner page memory the page head ratio is 0.35 the time required to access a page is secondary memory is equal 200 NS time required to access a page in primary memory is 10 NS the average time is required to access a page isn (a)3.0  ns    (b) 68 nsAC 68.5 78.5

42:  safe if the system can allocate resources to each process in some order and still avoid deadlock

Which of the following are true

(a)deadlock state is unsafe

(b)unsafe state may lead to other love situation

(c)unsafe that lead to a deadlock situation at situation

(d)Deadlock states is a subset of unsafe state

43: The size of the virtual memory depend on the size of

(a)data bus    (b)main memory    (c) address bus  (d)none of the above

44:

45: In which of the following scheduling policies does contact switching never take place

(a)Round Robin    (b)shortest job first    (c) pre-emptive  (d) First Come First serve

46:  in which of the following directory system is the possible to have the multiple complete path for a file starting from the root directory

(a)single level directory   (b) two level directory tree  (c)Trichy level directory fee structure directory (d)acyclic graph  directory  directly

47: suppose that a process is in blocked state waiting waiting for some iOS service when the service is complete it go to

(a)the running state  (b) ready state    (c) suspended state  (d) terminated state

48:A system that does not support sleeping

(a)in the compiler normal bit symbolic address to read located to the located address BCom below normal symbolic address to Physical address relocated address to Physical address binding of the symbolic address to Physical address normally takes place during execute execution

49: Open the gallery utilise dynamic loading with dynamic loading protein is not loaded. In is called for implementation in dynamic loading special support from hardware is essential special support from operating system is an essential special support from both hardware and operating system are essential user program user program can implement dynamic loading with without any special support from the operating system or the hardware

50: Which of the following is true 

The  linkage editor is used to edit program which have no be better linked together the linkage editor length object more models during compile in or assembling the link editor link object models are resolve external reference between them before loading the link linkage editor resolved external difference between the object give the execution time

51: Which of the following is true our Le are used to increase the size of physical memory power relay are used to increase the logical the logical address space when are they are used the size of process is not limited to the size of physical memory they are you when the physical address space is smaller than the logical address space

52:CPU scheduling policy is fcfs the average waiting time will be 12.8 Ms Ms 16 MS all of the above

53:CPU scheduling policy is sjf average waiting time will be 12.8 m s 6.8 m s 17 MS none of the above

54: if the CPU scheduling policy is sjf with  preemption the average waiting time will be that Ms 14556 Ms none of the above

55:CPU scheduling policy is priority scheduling without preemption the average waiting time will be

12.am 11.8 MS 10.8 Ms none of the above

56:HP CPU scheduling policies priority scheduling victory reaction the average waiting time will be 19 MS 7.6 Ms Ms none of the above

57:

58: Cascading termination refer to termination of the all child process before termination terminate normally normal or abnormal in all of you know

59: for implementation of multi programming operating system special support from the processor is essential special support from processor is not essential cache memory must be available more than one process more than one processor must be available

60:Consider a system having  resource of the same time. these resources are shared by 3 processes A ,B .C, which have peak time  demands of 3 ,4 , 6,  respectively .the minimum value of ‘M’ that ensures  that deadlock will never occur is 

11          (b)    12          (c)  13         (d) 14

61:System has 3 processes sharing 4 resources if each process need a maximum of 2 unites then, deadlock

(a) can never (b) may occur (C) has to occur  (d) none of the above

 

62: “m” Process share “n”  resource of the source of the same type the maximum need of each process does not exceed  “n” and the  sume all their maximum need is always less than m+ n  in this setup deadlock .

(a) can never (b) may occur (C) has to occur  (d) none of the above

63: A process refers to 5 page  a  b  c d  and e in the order minus a ; b;  c;  d;  a ; b;  e;  a ; b; c; d; e;  if the page replacement algorithm is FIFO. the number of page in which transfer with an Empty internal storage of 3 frames

(a)     8             (B)            10             (c)          9            (d)             7

64: Distributed system should 

(a)Meet prescribe time constraints (b) aim better resource sharing (c) aim better system utilization (d) a low system overhead

65: the main  function of shared memory is to 

Use  primary memory efficiently (d)  do intra process communication (c) do intra process communication (d) none of the above

66: which of  the following is most suitable  scheduling scheme in a real-time  operating system ? 

(a) Round Robin (b) First Come First served  (c)  pre-emptive scheduling (d) random scheduling

67:

68:

 69:  if there are 32  segments ,  each of size 1 Kbytes,  then the logical address should have 

(a) 13 bits (B) 14 bits (c) 15 bits (d) 16 bits

70: Disk requests come to a disk  driver for cylinder in the order 10 ,22, 20, 2, 40, 6, and 38,at a  time when the disk driver drive is reading from the cylinder 20.the seek time is 6 MS per cylinder. he  total seek time, if the disks arm   scheduling algorithm is First Come First served is

(a) 360 ms        (b)     876 ms         (c)       850 MS       (d)    900ms

71:

72:

73:Memory protection is normally done by the

(a)processor and the associate hardware     (b) operating system

(c) compiler                                        (d) user program

74: which of the following scheduling algorithm give minimum average waiting time ?

(a)FCFS                  (b)DJF                          (c)Round-robin     (d)Priority

77:Which of the following page replacement algorithm surfers from Belady anomaly ?

(a)optimal replacement     (b)LRU      (c)FIFO      (d)Both optimal replacement and FIFO

78:which of the following scheduling policy is well suited for a time shared operating system ?

(a)shortest job first  (b)round robin (c) FCFO    (d)Elevator

79:the address sequence generated by tracing a particular  program executing in a pure demand paging system with 100 record per page ,with 1 free main memory frame is recorded as follows .what is the number of page faults ?

0100, 0200, 0430, 0499,0510,0530, 0560,  0120,   0220,  0240,   0260,  0320,   0370,

(a)13             (b)       8                (c)   7        (d)  10

80:A computer system has 4  k word cache organized in a block-set associative manner, with 4 block peer, 64 word per block. The number of bits in the Set and WORD fields of the main memory address format is

(a)15,4       (b) 6,4              (c)   7,2      (d) 4,6

82: 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)FIFO      (c)LFU      (d) none of these

83:consider the following heap

JOB1-50                    Free-150              JOB2-300        FREE-350       JOBS3-600

The sequence of requests for block of size 300,25,125,50 can be satisfied if we use

(a)either first fit or best fit policy  (b) first fit but not best fit

(c)best fit but not first fit     (d) none of the above

85:which of the following is a safe sequence ?

(a)p0, p1,  p2,  p3   (b) p1,    p0,  p3,   p2   (c) p2,  p0, p1,   p3 (d) none of these

87:consider a computer with 8 Mbytes of main memory and a 128 K cache .

The cache block size is 4 K . It uses a direct mapping scheme for cache management. How many  different main memory blocks can map onto a given physical cache block ?

(a)2048      (b)256       (c)  64   (d) none of the above

88:which of the following application are well suited for batch processing ?

(a)process control               (b) video game control

(c) preparing pay bills of employees   (d) preparing mailing addresses

91:Thrashing

(a)reduces Page I/O    (b) decreases the degree of multiprogramming

(c)implies excessive system performance (d) improves the system performance

92:Dirty bit for a page in a page table

(a)help avoid unnecessary writes on paging device (b)help maintain LRU information (c) allows only read on a page  (d) none of the above

94:when an interrupt occurs, an operating

(a)ignores the interrupt (b) always changes the state of the interrupted process after processing the interrupt .(c) always resumes execution of the interrupted processed

After processing the interrupt (d) may change the state of the interrupted process to “block” and schedule another process

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