CPU调度E
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1.First come first served
2.Shortest job/process first
3.Shortest remaining time next
4.Round robin (quantum=2)
5.Round robin (quantum=1)
6.Priority (1-high priority, preemptive)
7.Priority (1-high priority, non-preemptive)
Answer:
1.A:6B:11C:12D:13Mean turnaround time=(6+11+12+13)/4=42/4=10.5
2.A:6B:15C:5D:6Mean turnaround time=(6+15+5+6)/4=8
3.A:10B:15C:2D:3Mean turnaround time=(10+15+2+3)/4=7.5
4.A:10B:15C:5D:8Mean turnaround time=(10+15+5+8)/4=9.5
5.A:13B:15C:7D:8Mean turnaround time=(13+15+7+8)/4=8.25
6.A:13,B:7,C:12,D:13Mean turnaround time=(13+7+12+13)/4=11.25
7.A:6,B:11,C:12,D:13Mean turnaround time=(6+11+12+13)/4=10.5 For the processes listed in the following table, please write out the turnaround time of each process and the average turnaround time for the following algorithms. You must write out the computing course.
1.Shortest remaining time next
2.Round robin (quantum=3s, run in order A,B,C,D)
A turnaround time is 7s
B turnaround time is 20s
C turnaround time is 12s
D turnaround time is 3s
Average turnaround time = (7+20+12+3)/4=42/4=10.5s
A turnaround time is 13s
B turnaround time is 20s
C turnaround time is 18s
D turnaround time is 12s
Average turnaround time = (13+20+18+12)/4=63/4=15.75s
A turnaround time is 12s
B turnaround time is 8s
C turnaround time is 20s
D turnaround time is 15s
Average turnaround time = (12+8+20+15)/4=55/4=13.75s
For the processes listed in the following table, please write out the turnaround time of each process and the average turnaround time for the following algorithms. You must write out the computing course.
1.FCFS
2.Shortest remaining time next
3.Round robin (quantum=6s, run in order A,B,C,D)
A turnaround time is 5s
B turnaround time is 14s
C turnaround time is 22s
D turnaround time is 28s
Average turnaround time = (5+14+22+28)/4=69/4=17.25s
A turnaround time is 5s
B turnaround time is 28s
C turnaround time is 19s
D turnaround time is 11s
Average turnaround time = (5+28+19+11)/4=63/4=15.75s
A turnaround time is 5s
B turnaround time is 26s
C turnaround time is 28s
D turnaround time is 23s
Average turnaround time = (5+26+28+23)/4=82/4=20.5s
A turnaround time is 14s
B turnaround time is 9s
C turnaround time is 22s
D turnaround time is 28s
Average turnaround time = (14+9+22+28)/4=73/4=18.25s