UGC NET COMPUTER SCIENCE SOLVED PAPERS 2014-16 - UGC NET Computer Science Paper 3 December 2015

36. Which of the following is/are correct with reference to Abstract class and interface?
(a)A class can inherit only one Abstract class but may inherit several interfaces.
(b)An Abstract class can provide complete and default code but an interface has no code.
Codes:

  • Option : C
  • Explanation :
    A class can inherit only one Abstract class but may inherit several interfaces. An Abstract class can provide complete and default code but an interface has no code. For more information on Abstract class Refer:Pure Virtual Functions and Abstract Classes in C++ Option (C) is correct.
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37. Match the following with respect to various memory management algorithms :

List IList II
(a) Demand paging   (i) degree of multiprogramming
(b) Segmentation(ii) working set
(c) Dynamic partitions(iii) supports user view of memory
(d) Fixed partitions(iv) compaction

Codes:

 (a)(b)(c)(d)
(1)(iii)(iv)(ii)(i)
(2)(ii)(iii)(i)(iv)
(3)(iv)(iii)(ii)(i)
(4)(ii)(iii)(iv)(i)

  • Option : D
  • Explanation :
  • Working set is purest form of page replacement algorithm used in demand paging.
  • In segmentation memory is divided into various size chunks to support user view of memory, here memory chunks are allocated to the process.
  • Dynamic partition is used for compaction in which allocated objects moving together, and leaving empty space together.
  • Fixed partition is dividing memory into fixed size of block for degree of multiprogramming.
  • So, option (D) is correct.
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38. Function of memory management unit is:

  • Option : A
  • Explanation :
    The Function of the memory management unit is to address translation and manage the primary memory of the computer.
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39. Consider a system with twelve magnetic tape drives and three processes P1, P2 and P3. Process P1 requires maximum ten tape drives, process P2 may need as many as four tape drives and P3 may need upto nine tape drives. Suppose that at time t1, process P1 is holding five tape drives, process P2 is holding two tape drives and process P3 is holding three tape drives. At time t1, system is in:

  • Option : B
  • Explanation :
    P1 is holding 5 tape drive but it require 10 tape drive, 5 tapes are required for P1. P2 is holding 2 tape drive but it require 4 tape drive, 2 tapes are required for P2. P3 is holding 3 tape drive but it require 9 tape drive, 6 tapes are required for P3. We have total 12 tape out of which 10 are allocated, 2 tape are free. These 2 tape can be allocated to P2. After P2 complete its execution it will free 4 tape, but these 4 tape can not fulfill requirement for P1 or P3. That's why system is in unsafe state. So, option (B) is correct.
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40. In Unix operating system, special files are used to:

  • Option : B
  • Explanation :
    In Unix operating system, special files are used to provide a mechanism to map physical device to file names. For more information on Unix file system Refer:Operating System | Unix File System Option (B) is correct.
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