Question :

Suppose we have a multi-programmed computer where each job has identical characteristics.

In one computation period, T, for a job, 2/3 of the time is spent in I/O and the rest of the time (i.e., 1/3) in processor activity. Each job runs for a total of 10 periods.

Assume that a simple round-robin scheduling is used, and that I/O operations can overlap with processor operation. We define the following quantities:

Turnaround time: actual time to complete a job (from the time a job submitted to the system to the time it is completed)

Throughput: Average number of jobs completed per time period T

Process utilization: percentage of time that the processor is active (not in idle mode/waiting).

Compute these quantities for the case of one job and three simultaneous jobs with the order of work in a period T is distributed as follows: I/O in the first and third periods, processor in the second period (I/O - P - I/O).