Consider a program that performs the following steps repeatedly:

$1.$ Use the CPU for $4$ milliseconds.

$2.$ Issue in I$/$O to disk for $14$ milliseconds.

$3.$ Use the CPU for $10$ milliseconds.

$4.$ Issue an I$/$O to the network for $18$ milliseconds.

Assume that each step depends on data obtained from the previous step. Also, assume that it takes $2$

millisecond to execute the device driver code on the CPU for both the disk and the network at the beginning

of the I$/$O$.$ Answer the following questions:

$($a$)$ Draw $3$ time$-$line diagrams $($time on the x$-$axis and utilization on the y$-$axis$)$ that illustrate the utilizations

of the CPU, disk, and network over the execution of two iterations of the program above. $[3$ pts$]$

$($b$)$ What are the average utilizations of the CPU, disk and network over these two iterations? $[3$ pts$]$

$($c & d$)$ Assume that there are two processes of the program above running in a multiprogramming system

$($i$.$e$.,$ when a process blocks for I$/$O$,$ another process can get the CPU$),$ answer parts $($a$)$ and $($b$)$ for this

case showing which part belong to which process. You can ignore the time spent in context switching.