-操作系统精髓与设计原理(第五版)+课后题答案1
9.16 a. Sequence with which processes will get 1 min of processor time:
1 2 3 4 5 Elapsed time A B C D E 5 A B C D E 10 A B C D E 15 A B D E 19 A B D E 23 A B D E 27 A B E 30 A B E 33 A B E 36 A E 38 A E 40 A E 42 A 43 A 44 A 45
The turnaround time for each process:
A = 45 min, B = 35 min, C = 13 min, D = 26 min, E = 42 min
The average turnaround time is = (45+35+13+26+42) / 5 = 32.2 min b.
Priority Job Turnaround Time 3 B 9 4 E 9 + 12 = 21 6 A 21 + 15 = 36 7 C 36 + 3 = 39 9 D 39 + 6 = 45
The average turnaround time is: (9+21+36+39+45) / 5 = 30 min c.
Job Turnaround Time A 15 B 15 + 9 = 24 C 24 + 3 = 27 D 27 + 6 = 33 E 33 + 12 = 45
The average turnaround time is: (15+24+27+33+45) / 5 = 28.8 min d.