Consider a program that performs the following steps repeatedly:

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

$2.$ By issuing an I$/$O$,$ use the disk for $14$ milliseconds.

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

$4.$ By issuing an I$/$O$,$ use network for $18$ milliseconds.

Assume that each step depends on data obtained from the previous step $($e$.$g$.,$ step $3$

cannot start before step $2$ is completed. Also assume that each resource $($CPU or disk

or network$)$ can be used by one process at a time.

Answer the following questions:

$($a$)$ Draw $3$ time$-$line diagrams $($horizontal axis is the time line; one line for each

resource. That is$,3$ parallel rows in the resulted figure.$)$ that illustrate the utilizations

of the CPU, disk, and network over the execution of two iterations of the program

above by a single process. $[6$ pts$]$

$($b$)$ What are the average utilizations of the CPU, disk and network over these two

iterations? $($Please note that the $$total time$$ should be the same across all resources,

from the entire system starts until all work on any resource has been done.$)[6$ pts$]$

$($c & d$)$ Assume that there are two independent processes in a multiprogramming

system $($i$.$e$.,$ when a process blocks for I$/$O$,$ another process can get the CPU$)$ and each

process runs one iteration of the program above. Answer parts $($a$)$ and $($b$)$ for this case

showing which part belongs to which process. You can ignore the time spent in context

switching. $[12$ pts$]$