$1$ Process Scheduling

The following table shows processes and their arrival time, burst time needed, and priority. Note that independent

of the algorithm used, each switch of a process does incur a $1$ ms penalty. For algorithms that support it$,$ process

priority $$aging$$ begins after $3$ ms of waiting and a priority of $0$ is the highest priority possible. For algorithms that

support it$,$ assume a time quantum of $4$ ms$.$ Apply an $$idle$$ process whenever the CPU has nothing to work on$.$

Table $1$: Physical Memory

Process Arrival time Burst Time Priority

P$1153$

P$2262$

P$3371$

P$4480$

What are the average turnaround times for the following schedulers?

a$)$ Preemptive Shortest Job First

b$)$ Preemptive Priority

c$)$ Round$-$Robin

Question $1(1\mathrm{.}5$ Points$)$

What are the average response times for the following schedulers?

a$)$ Preemptive Shortest Job First

b$)$ Preemptive Priority

c$)$ Round$-$Robin

Question $2(1\mathrm{.}5$ Points$)$

Which scheduler would you select for the following workloads and why:

a$)$ Foreground processes

b$)$ Background processes

$2$ Memory Replacement Strategies

Physical memory consists of $4$ page frames, initially all empty.

Using the reference string $\{5,5,5,3,2,2,6,5,5,5,7,3,3,4\}($Homer Simpson$$s home and work phone numbers$)$ determine the number of page faults for each of the following strategies:

a$)$ First In$,$ First Out $($FIFO$)$

b$)$ Optimal

c$)$ Least Recently Used $($LRU$)$

Question $4(1\mathrm{.}5$ Points$)$

Using the reference string $\{2,1,2,5,5,5,2,6,6,8,1,8,0,0,3,6,2,8,6,7,2\}($The Simpson$$s NY City$$s parking

department phone number $212-555-$BOOT and Dr Nick$$s $"$B$"$argain Medical Services phone number $1-800-$

DOCTORB$)$ determine the number of page faults for each of the following strategies:

a$)$ First In$,$ First Out $($FIFO$)$

b$)$ Least Frequently Used $($LFU$)$