An Operating Systems Vade Mecum

54 Time Management Chapter 25 EXERCISES1. What does the scheduler do under RR when there is only one process that can run?2. What does the scheduler do under RR when there are no processes that can run?3. Of all the policies discussed in the chapter, which requires the least amount ofoverhead time, that is, time needed to compute the policy?4. Which of the policies would you prefer if ρ=2?5. The expected amount of time needed by a process is always 1/β under theexponential distribution. Is a process therefore expected never to terminate?6. Consider the following process arrival list:Name Arrival time Service timeA 0 3 B 2 6 C 3 10 D 7 1 E 8 5 F 15 2 G 25 7 Figure 2.15 depicts this situation graphically.8E133C132B80 3 7 815 17 2532ADFG0 5 10 15 2025 30Figure 2.15 Process arrival listComplete the figure, showing which process is executing over time, and calculateT , M , and P for each process, under the following policies: FCFS, SPN, PSPN,HPRN, RR with q = 1, RR with q = 5, and SRR with b/a= 0.5 and q = 1.Assume that if events are scheduled to happen at exactly the same time, newarrivals precede terminations, which precede quantum expirations.