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38 votes
38 votes

Consider the following statements about user level threads and kernel level threads. Which one of the following statements is FALSE?

  1. Context switch time is longer for kernel level threads than for user level threads.

  2. User level threads do not need any hardware support.

  3. Related kernel level threads can be scheduled on different processors in a multi-processor system.

  4. Blocking one kernel level thread blocks all related threads.

4 Answers

Best answer
62 votes
62 votes

Answer: (D)

  1. Context switch time is longer for kernel level threads than for user level threads. $-$ This is True, as Kernel level threads are managed by OS and Kernel maintains lot of data structures. There are many overheads involved in Kernel level thread management, which are not present in User level thread management !

  2. User level threads do not need any hardware support.$-$ This is true, as User level threads are implemented by Libraries programmably, Kernel does not sees them.

  3. Related kernel level threads can be scheduled on different processors in a multi-processor system.$-$ This is true.

  4. Blocking one kernel level thread blocks all related threads. $-$ This is false. If it had been user Level threads this would have been true, (In One to one, or many to one model !) Kernel level threads are independent.

edited by
10 votes
10 votes

D is False.

Kernel Level Threads are independent of each other.

Ref: http://www.personal.kent.edu/~rmuhamma/OpSystems/Myos/threads.htm

Answer:

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