1. Five jobs arrive nearly simultaneously (i.e. all have arrived before the job scheduler establishes the queue) for processing and their estimated CPU cycles are, respectively: Job A a 16, Job B= 3, Job C - 12. Job D 9. and Job E - 3 ms.
a_ Using ECFS, and assuming the difference in arrival time is negligible, in what order would they he processed? DUI? What is the total time required to process all five jobs? What is the average turnaround time for all five jobs?
b. Using SJNI, and assuming the difference in arrival time is negligible, in what order would they be processed? What is the total time required to process all five jobs? What is the average turnaround time for all five jobs?
2. Assume that a multi-level queue system with a variable time quantum per queue where each job advances to the next higher queue when interrupted and that an incoming job needs 120 ms to run to completion. If the Level 1 queue has a time quantum of 5 ms and each queue thereafter has a time quantum that is twice as large as the previous one, how many times will the job be interrupted, how much processing time will it use in each queue and on which queue will it finish its execution?
3. Given the following information: Job Arrival CPU
Time Cycle
A 0 12
B 2 2
C 3 19
D G 7
E 9 1
Calculate which jobs will have arrived ready for processing by the time the first job is finished or first interrupted using each of the following scheduling algorithms.
a. First Comc First Served
b. Shortest Job Next
c. Shortest Remaining Time
d. Round robin (use a time quantum of 5. but ignore the time required for context switching and natural wait)
4. Given the following information for a real-time system using Earliest Deadline First:
|
Job:
|
A
|
B
|
C
|
D
|
E
|
F
|
|
Arrival time:
|
0
3
|
O
|
I
6
|
I
|
3
|
8
|
|
Execution Time:
|
2
|
7
|
|
|
Deadline:
|
7
|
2
|
40
|
4
|
16
|
IS
|
|
Time-before-deadline (at arrival time)
|
7
|
2
|
3Y
|
|
|
|
Compute the time-before-deadline for each incoming job and place it in the chart above. Give the order in which the six jobs will finish, and identify any jobs that fail to meet their deadline. It may help to draw a timeline.
Using the narrow staircase example from the beginning of chapter 5, list at least two actions or tasks that could be implemented by the building manager that would allow people to use the staircase without risking a deadlock or starvation