02OS

Processes p1 and p2 execute on a system with a single CPU and 2 identical I/O devices. Each process executes a compute-bound phase followed by an I/O-bound phase. The system uses multiprogramming without time-sharing. The following table shows the lengths of each phase.

	Compute	I/O
p1	10	70
p2	40	80

p1 starts first at time 0.

Without multiprogramming, the computation terminates at time ??????

With multiprogramming, the computation terminates at time ?????

Expected: 200, 130

p1 needs 10 + 70 = 80 time units and p2 needs 40 + 80 = 120 time units. Without multiprogramming, the processes execute in sequence for a total of 80 + 120 = 200 time units.

With multiprogramming, p1 runs from 0 to 10, followed by the I/O phase from 10 to 80. p2 starts as soon as p1's compute phase terminates and runs from 10 to 50, followed by the I/O phase from 50 to 130.

With multiprogramming, the compute phases are sequential because only 1 CPU is available, but the I/O phases can overlap since 2 I/O devices are available.

Processes p1 and p2 execute on a system with a single CPU and 2 identical I/O devices. Each process executes a compute-bound phase followed by an I/O-bound phase. The system uses multiprogramming without time-sharing. The following table shows the lengths of each phase. Compute I/O p1 10 70 p2 40 80 p1 starts first at time 0. Without multiprogramming, the computation terminates at time ???? With multiprogramming, the computation terminates at time ????? Expected: 200, 130 p1 needs 10 + 70 = 80 time units and p2 needs 40 + 80 = 120 time units. Without multiprogramming, the processes execute in sequence for a total of 80 + 120 = 200 time units. With multiprogramming, p1 runs from 0 to 10, followed by the I/O phase from 10 to 80. p2 starts as soon as p1's compute phase terminates and runs from 10 to 50, followed by the I/O phase from 50 to 130. With multiprogramming, the compute phases are sequential because only 1 CPU is available, but the I/O phases can overlap since 2 I/O devices are available.