In a batch operating system, four jobs JOB1, JOB2, JOB3, JOB4 are submitted for execution. Each job involves an I/O activity, followed by a CPU time, followed by another I/O activity of the same time span as the first. Each job is associated with a different I/O device. JOB1 requires a total of 15 ms, with 1 ms CPU time. JOB2 requires 8 ms total time with 2 ms CPU time. JOB3 requires 45 ms total time with 5 ms CPU time. JOB4 requires 21 ms total time with 3 ms CPU time.

Assume a uniprogramming system and answer the following:

1.  What will be the total time to the completion of all jobs?

2.  What will be the total CPU time? 

3.  What will be the CPU utilisation?

Assume a multiprogramming system and answer the following:

4.  What will be the total time the completion of all jobs?

5.  What will be the CPU utilisation? 

6.  What will be the turnaround time of JOB4? 

7. What will be the average turnaround time?