Question 62Asked in UGC NET Computer Science, November 2017 (Paper II & III, Selected Questions)

User level threads are threads that are visible to the programmer and are unknown to the kernel. The operating system kernel supports and manages kernel…

User level threads are threads that are visible to the programmer and are unknown to the kernel. The operating system kernel supports and manages kernel level threads. Three different types of models relate user and kernel level threads. Which of the following statements is/are true? (A) (i) The many to one model maps many user threads to one kernel thread (ii) The one - to - one model maps one user threads to one kernel thread (iii) The many model maps many user threads to smaller or equal kernel threads (B) (i) Many - to- one model maps many kernel threads to one user thread (ii) One - to - one model maps one kernel thread to one user thread (iii) Many - to - many model maps many kernel threads to smaller or equal user threads Code :
  1. A(A) is true; (B) is false
  2. B(A) is false; (B) is true
  3. CBoth (A) and (B) are true
  4. DBoth (A) and (B) are false
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Correct answer: (A) (A) is true; (B) is false

Explanation

In statement set (A), the many-to-one model maps many user threads to one kernel thread, the one-to-one model maps one user thread to one kernel thread, and the many-to-many model maps many user threads to a smaller or equal number of kernel threads; all are true. Set (B) reverses the roles of user and kernel threads, so it is false.

From UGC NET Computer Science PYQ, November 2017 (Paper II & III, Selected Questions)

This is question 62 of UGC NET Computer Science PYQ, November 2017 (Paper II & III, Selected Questions). See all questions of this paper with answers, or attempt the paper as a timed online test to get your score and all-India rank.