1.
An operating system is running three concurrent P1,P2,P3 for three different users. each process
require 6 units of computing time . P1 consist of a single thread, P2 consists of two threads , each
requiring three of P2,6 TOTAL UNIT COMPUTING TIME....................
a) Suppose that the threads are kernel-supported and the kernel implements peemptive, round-
robin scheduling of threads with a quantum on one time unit. of the first six units of time how
many will devoted to each of the three process?
b) suppose threads are implemented entirely at the user level?
Solution
(a)
If  the threads are kernel-supported and the kernel implements peemptive, round-robin
scheduling of threads with a quantum on one time unit. of the first six units of time, then
Process 1 receives 1 time unit , Process 2 receives 2 time unit and Proces 3 receives 3 time
unit
(b)
If threads are implemented entirely at the user level then Process 1 receives 2 time unit , Process
2 receives 2 time unit and Proces 3 receives 2 time unit i.e all processes receives equal time of
2 units