HW1::CMSC421::Spring 2009::Due 10 March 2009::Total Pts 1000) (12 pts) When a process performs a blocking send, it must receive anacknowledgement message to unblock. What problem might result fromthis scheme, and how can it be avoided?1) (12 pts) Define the difference between preemptive and non-preemptivescheduling. State why strict non-preemptive scheduling is unlikely to beused in a computer center.2) (12 pts) Suppose that a scheduling algorithm (at the level of short-termcpu scheduling) favors those programs which have used little processor timein the recent past. Why will this algorithm favor I/O bound programs andyet not permanently starve cpu-bound programs?3) (12 pts) Can a system detect that some of its processes are starving? Ifthe answer is yes, explain how. If the answer is no, explain how the systemmay deal w ith the starvation problem.4)(12 pts) A producer P and a consumer C have a buffer of capacity 2 be-tween them. The following sequence of actions occurs:Step Actor Item1 P 12 P 23 P 34 C 15 C 26 P 47 P 57 C 39 C 410 C 511 P 612 C 6After which steps does P and/or C s leep? What is in the buffer after eachstep (draw a table with the first column having the heading “After Step”and the second column having “Buffer Contents”)?15) (20 pts) Consider a computing system with 13 tape drives. All jobs run-ning on this system require a maximum of 5 tape drives to complete, butthey each run for long periods of time with just 4 drives and request thefifth one only at the very end of the run. The job stream is endless.If your operating system supports a very conservative device allocation pol-icy no job will be started unless all tapes required have been allocated to itfor the duration of its run.i) What is the maximum number of jobs that can be active at once?ii) What are th e minimum and maximum number of tape drives that maybe idle as a result of this policy?6) (20 pts) Our textbook claims (page 190) that SJF is “provably optimal, inthat it gives the mimimum average waiting time for a given set of processes.”Prove this statement in its most general