CSI Task $3.(20$ marks$)$

a$)$ A small computer using paged memory has enough RAM to store four $1$K pages. A process is using $6$K of memory, and accesses the pages in the sequence:

$12345$

After this there are $10$ more page accesses of the pages, so $15$ in total. You decide how the pages are accessed but make sure that each page is accessed a further two times, and the same page is not accessed consecutively. Calculate how many page faults will be generated.

b$)$ There are $5$ processes A$-$E$.$ Each of these has a runtime. Process A has a runtime of $4$ seconds. For each of the remaining processes choose a runtime from between $4$ and $7$ seconds. No two processes should have the same runtime.

A small single$-$processor computer is executing the set of processes:

Process A starts at time $0$ seconds.

Process B starts at time $1$ second.

Process C starts at time $2$ seconds.

Process D starts at time $3$ seconds.

Process E starts at time $4$ seconds.

Show the sequence of events if these processes are scheduled using the non$-$preemptive HRRN $($Highest Response Ratio next$)$ algorithm.