Say we have a system that has:

$-$two processes A$,$ B

$-$one processor

$-$one I$/$O device that both A and B will use

Both processes will perform regular processing on the CPU for $100$ time units, then engage the I$/$O device for $50$ time units, and then exit.

In the following, assume that the overhead of anything other than CPU processing and I$/$O is negligible.

A$)$ If our system does not use multiprogramming, then the total time needed to complete both processes will be time units. $($enter a numeric value$)$

B$)$ If our system uses multiprogramming, then the total time needed to complete both processes will be time units.

C$)$ If our system uses time$-$sharing, then the total time needed to complete both processes will be time units. $($don$\text{'}$t forget, we have one I$/$O device!$)$

D$)$ If our system uses time$-$sharing and we have two I$/$O devices that can be used by the processes, then the total time needed to complete both processes will be time units.