Two user-level thread to kernel-level thread mapping schemes are shown in picture below (a) and (b).

(i). Describe the effect on the process when the user thread 2 in the picture(a) causes a system call.

(ii). Describe the impact on the process when the user thread 4 in the picture(b) causes a system call.

(iii). Describe the advantages of the thread mapping scheme in the picture(b).

(iv). Describe how the OS converts user threads into kernel threads.

 

(1) User threads (2) (3) k (4) (a) Kernel thread (1) k User threads (2) (3) (1) (3) k (4) k (b) Kernel threads