Consider a single$-$core machine on which an OS uses a single$-$queue round$-$robin scheduler with a time quantum of $4$ ms$.$ We assume that the context$-$switching overhead is zero.

At time $0,$ two jobs arrive in the system:

Job A: CPU burst time: $4$ ms$,$ I$/$O burst time $1$ ms

Job B: CPU burst time: $3$ ms$,$ I$/$O burst time $2$ ms

Each job begins with a CPU burst, and at the very beginning, Job A is ahead of Job B in the ready queue $($i$.$e$.,$ Job A runs first$).$ Assume that I$/$O can be done independently for Job A and Job B$.$ Answer the following questions.

Q$1$: Using letter A to denote $1$ ms of CPU utilization by job A$,$ and letter B to denote $1$ ms of CPU utilization by job B$,$ write the string of A$$s and B$$s that represents the first $21$ ms of utilization of the CPU $($e$.$g$.,$ your answer would be something like $$AABBABBA$...).$ You can insert spaces at each letter change for better readability.

Q$2$: Let$$s now assume that job A has an I$/$O burst time of $7$ ms$.$ Using letter A to denote $1$ ms of CPU utilization by job A$,$ letter B to denote $1$ ms of CPU utilization by job B$,$ and letter I to denote $1$ ms in which the CPU is idle, write the string of A$$s$,$ B$$s$,$ and I$$s that represents the first $24$ ms of utilization of the CPU $($e$.$g$.,$ your answer would be something like $$AABIIAAB$...).$ You can insert spaces at each letter change for better readability.