Assume four jobs with arrival time, CPU burst times and I/O wait times as shown
ID: 3871852 • Letter: A
Question
Assume four jobs with arrival time, CPU burst times and I/O wait times as shown below:
Assuming that the Shortest Remaining Time First (SRTF - preemptive version of Shortest Job First) scheduling policy is used to schedule job CPU bursts, choose the job that will be scheduled in each of the time slot starting at each of the times indicated in the table below. If no job is scheduled in a given time slot, choose "-". Convention: if two jobs have the same remaining time, choose job that arrived earlier first.
Assuming that the Round Robin (RR) scheduling policy with a quantum size of 2 units is used to schedule job CPU bursts, choose the job that will be scheduled in each of the time slot starting at each of the times indicated in the table below. If no job is scheduled in a given time slot, choose "-".
Conventions:
1. If a job finishes before the end of its quantum, finish that quantum and begin a new one immediately.
2. If a job finishes its quantum at the same time as a new job (i.e., a new CPU burst for a job) arrives, place the job that just finished its quantum ahead of the newly arriving job in the job queue.
Job Arrival time CPU burst time I/O wait time A 4 2 4 4 B 1 4 2 3 C 3 1 D 0 5Explanation / Answer
a)Shortest Remaining Time First Scheduling:
T
Job Scheduled at time t Total Jobs Available
0
[ "D" ] ["A", "B", "C", "D", "-"]
1
[ "D" ] ["A", "B", "C", "D", "-"]
2
[ "D" ] ["A", "B", "C", "D", "-"]
3
[ "C" ] ["A", "B", "C", "D", "-"]
4
[ "D" ] ["A", "B", "C", "D", "-"]
5
[ "D" ] ["A", "B", "C", "D", "-"]
6
[ "A" ] ["A", "B", "C", "D", "-"]
7
[ "A" ] ["A", "B", "C", "D", "-"]
8
[ "B" ] ["A", "B", "C", "D", "-"]
9
[ "B" ] ["A", "B", "C", "D", "-"]
10
[ "B" ] ["A", "B", "C", "D", "-"]
11
[ "B" ] ["A", "B", "C", "D", "-"]
12
[ "A" ] ["A", "B", "C", "D", "-"]
13
[ "A "] ["A", "B", "C", "D", "-"]
14
[ "A" ] ["A", "B", "C", "D", "-"]
15
[ "A" ] ["A", "B", "C", "D", "-"]
16
[ "B" ] ["A", "B", "C", "D", "-"]
17
[ "B" ] ["A", "B", "C", "D", "-"]
18
[ "B" ] ["A", "B", "C", "D", "-"]
19
[ "-" ] ["A", "B", "C", "D", "-"]
b) Round Robin Scheduling:
T
Job Scheduled at time t Total Jobs Available
0
[ "D" ] ["A", "B", "C", "D", "-"]
1
[ "D" ] ["A", "B", "C", "D", "-"]
2
[ "B" ] ["A", "B", "C", "D", "-"]
3
[ "B" ] ["A", "B", "C", "D", "-"]
4
[ "D" ] ["A", "B", "C", "D", "-"]
5
[ "D" ] ["A", "B", "C", "D", "-"]
6
[ "C" ] ["A", "B", "C", "D", "-"]
7
[ "B" ] ["A", "B", "C", "D", "-"]
8
[ "B" ] ["A", "B", "C", "D", "-"]
9
[ "A" ] ["A", "B", "C", "D", "-"]
10
[ "A" ] ["A", "B", "C", "D", "-"]
11
[ "D" ] ["A", "B", "C", "D", "-"]
12
[ "B" ] ["A", "B", "C", "D", "-"]
13
[ "B "] ["A", "B", "C", "D", "-"]
14
[ "B" ] ["A", "B", "C", "D", "-"]
15
[ "A" ] ["A", "B", "C", "D", "-"]
16
[ "A" ] ["A", "B", "C", "D", "-"]
17
[ "A" ] ["A", "B", "C", "D", "-"]
18
[ "A" ] ["A", "B", "C", "D", "-"]
19
[ "-" ] ["A", "B", "C", "D", "-"]
Note : In Round Robin Scheduling at time slot starting with 14th sec, job B will be executed because I/O waiting time of job A has not been completed.
T
Job Scheduled at time t Total Jobs Available
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