Consider a mixed interactivebatch system with 30 terminals, each with anaverage think

Chapter 9, Problem 2

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Consider a mixed interactivebatch system with 30 terminals, each with anaverage think time of 15 s. The mean disk service time is 20 ms, and the diskscheduling algorithm is FCFS. An interactive job makes an average of 30 diskrequests and a batch job an average of 10 disk requests. The average CPU require-ment (E[B0, batch]) of a batch job is 5 s while that of a terminal user is 0.4 s. Around robin (RR) CPU scheduling algorithm with a small enough time quantumis employed so that the use of PS approximation is considered adequate. Deter-mine the effect of the degree of multiprogramming of batch jobs on the averageresponse time and batch throughput varying batch multiprogramming level from0 to 10 (assuming that such a variation is permissible). The actual size of mainmemory will support a batch multiprogramming level of 1. In order to improvebatch throughput, three alternatives are being considered:(a) Adding main memory so that batch multiprogramming level can beincreased up to 5.(b) Purchasing a new CPU with a speed improvement factor of 1.4.(c) Adding another disk of the same type.For each alternative, calculate the resulting improvement in batch throughputand the positive or adverse effect on the terminal response time.