Question

Consider the following statements with respect to user-level threads and kernel-supported threads
(i) Context switch is faster with kernal-supported threads
(ii) For user-level threads, a system call can block the entire process
(iii) Kernel-supported threads can be scheduled independently
(iv) User-level threads are transparent to the kernel

Which of the above statements are true?

• A. (i), and (iii) only
• B. (i) and (ii) only
• C. (ii), (iii) and (iv) only
• D. (ii) and (iii) only

Answer 1

The correct option is C (ii), (iii) and (iv) only

Consider the each statement:

(i) Consider the false because there is no connection between kernel-supported threads and context switch.
(ii) Statement is true because it is the drawback of user- level threads blocking system call can block the entire process.
(iii) Statement is true because kernel-supported threads having own memory area and scheduled independently by the operating system.
(iv) Statement is true because kernel is unware about user level threads and there is no kernel support to user-level threads. So user-level threads are transparent to the kernel.