Instructions: Place your answers in the blanks at right. Written resources (i.e. the textbook and printed notes) may be used; electronic ones may not. One exception: the use of printed copies of the Instructor's Solutions manual to the textbook is expressly forbidden. 20 points total.
The following processes are being scheduled using a preemptive, round-robin scheduling algorithm. Each process is assigned a numerical priority, with a higher number indicating a higher relative priority.
In addition to the processes listed below, the system also has an idle task (which consumes no CPU resources and is identified as process zero). This task has priority 0 and is scheduled whenever the system has no other available processes to run. The length of a time quantum is 5 units. If a process is preempted by a higher-priority process, the preempted process is placed at the front of the ready queue.
Process Priority Burst Arrival
1 40 20 0
2 30 25 25
3 30 25 27
4 35 15 60
5 5 10 100
6 10 10 105
1. Show the scheduling order of the processes by completing this Gantt chart, filling in each blank with the number of the process executing during that time quantum. (12 points)
10 20 30 40 50 60 70 80 90 100 110 120
-- -- - - - - -- -- P1: 20 P4: 15
2. What is the turnaround time for each process? (6 points)
P2: 55
P5: 20
P3: 60
P6: 10
3. What is the CPU utilization rate? (2 points)
= 87.5
