First-Come, First-served (FCFS)Scheduling ° EXample Process Burst time 24 3 3 Suppose that the processes arrive in the order(假定进程到达顺一 序如下):P1,P2,P3 The Gantt Chart for the schedule is(该调度的 Gantt图为): 24 27 30 ° Waiting time(等待时间)forP1=0;P2=24;P3=27 · Average waiting time(平均等待时间):(0+24+27)/3=17 Applied Operating System Concepts 6.9 Silberschatz, Galvin, and Gagne @19996.9 Silberschatz, Galvin, and Gagne ©1999 Applied Operating System Concepts First-Come, First-Served (FCFS) Scheduling • Example: Process Burst Time P1 24 P2 3 P3 3 • Suppose that the processes arrive in the order（假定进程到达顺 序如下）: P1 , P2 , P3 The Gantt Chart for the schedule is（该调度的Gantt图为）: • Waiting time（等待时间） for P1 = 0; P2 = 24; P3 = 27 • Average waiting time（平均等待时间）: (0 + 24 + 27)/3 = 17 P1 P2 P3 0 24 27 30