Question

Consider a demand-paged computer system where the degree of mul- tiprogramming is currently fixed at four. The system was recently measured to determine utilization of the CPU and the paging disk. Three alternative results are shown below. For each case, what is happening? Can the degree of multiprogramming be increased to increase the CPU utilization? Is the paging helping?

*CPU utilization 13 percent; disk utilization 97 percent

*CPU utilization 87 percent; disk utilization 3 percent

*CPU utilization 13 percent; disk utilization 3 percent

Answer 1

1)

Here the disk utilization=97 percent

where as CPU=13 percent is very Low

So this causes process execution takes more time

TO increase CPU utilization we have to suspend the process so the degree of multi programming CANNOT be increased.

This causes THRASHING

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2)Here is disk is underused because of high Cpu utilization and very less Disk utilization.

we increase degree of multi programming it will eventually end up TRASHING

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3)Both utilization is very low.

So if we increase the degree of multi programming then it would increase CPU utilization