Suppose that the following processes arrive for execution at the times indicated. Each process will run for the amount of time listed. In answering the questions, base all decisions on the information you have at the time the decision must be made.
|
Process
|
Arrival Time
|
Burst Time
|
|
P1
|
0.0
|
5
|
|
P2
|
1.4
|
3
|
|
P3
|
3.0
|
1
|
1. What is the average turnaround time for these processes with the FCFS scheduling algorithm?
2. What is the average turnaround time for these processes with the no preemptive SJF scheduling algorithm?
3. The SJF algorithm is supposed to improve performance, but notice that we chose to run process P1 at time 0 because we did not know that two shorter processes would arrive soon. Compute what the average turnaround time will be if the CPU is left idle for the first 2 units and then no preemptive SJF scheduling is used. Remember that processes P1 and P2 are waiting during this idle time, so their waiting time may increase.
4. What is the average turnaround time for these processes with the preemptive SJF scheduling algorithm? For question 4, assume the CPU is NOT left idle for the first 2 units - the first process starts running at time 0.
Show your work: Include the Gantt charts for all the questions above.