Operating System Multiple Choice Questions on “CPU Scheduling Algorithms”.
1. Round robin scheduling falls under the category of ____________
a) Non-preemptive scheduling
b) Preemptive scheduling
c) All of the mentioned
d) None of the mentioned
Answer: b
Clarification: None.
2. With round robin scheduling algorithm in a time shared system ____________
a) using very large time slices converts it into First come First served scheduling algorithm
b) using very small time slices converts it into First come First served scheduling algorithm
c) using extremely small time slices increases performance
d) using very small time slices converts it into Shortest Job First algorithm
Answer: a
Clarification: All the processes will be able to get completed.
3. The portion of the process scheduler in an operating system that dispatches processes is concerned with ____________
a) assigning ready processes to CPU
b) assigning ready processes to waiting queue
c) assigning running processes to blocked queue
d) all of the mentioned
Answer: a
Clarification: None.
4. Complex scheduling algorithms ____________
a) are very appropriate for very large computers
b) use minimal resources
c) use many resources
d) all of the mentioned
Answer: a
Clarification: Large computers are overloaded with a greater number of processes.
5. What is FIFO algorithm?
a) first executes the job that came in last in the queue
b) first executes the job that came in first in the queue
c) first executes the job that needs minimal processor
d) first executes the job that has maximum processor needs
Answer: b
Clarification: None.
6. The strategy of making processes that are logically runnable to be temporarily suspended is called ____________
a) Non preemptive scheduling
b) Preemptive scheduling
c) Shortest job first
d) First come First served
Answer: b
Clarification: None.
7. What is Scheduling?
a) allowing a job to use the processor
b) making proper use of processor
c) all of the mentioned
d) none of the mentioned
Answer: a
Clarification: None.
8. There are 10 different processes running on a workstation. Idle processes are waiting for an input event in the input queue. Busy processes are scheduled with the Round-Robin time sharing method. Which out of the following quantum times is the best value for small response times, if the processes have a short runtime, e.g. less than 10ms?
a) tQ = 15ms
b) tQ = 40ms
c) tQ = 45ms
d) tQ = 50ms
Answer: a
Clarification: None.
9. Orders are processed in the sequence they arrive if _______ rule sequences the jobs.
a) earliest due date
b) slack time remaining
c) first come, first served
d) critical ratio
Answer: c
Clarification: None.
10. Which of the following algorithms tends to minimize the process flow time?
a) First come First served
b) Shortest Job First
c) Earliest Deadline First
d) Longest Job First
Answer: b
Clarification: None.
11. Under multiprogramming, turnaround time for short jobs is usually ________ and that for long jobs is slightly ___________
a) Lengthened; Shortened
b) Shortened; Lengthened
c) Shortened; Shortened
d) Shortened; Unchanged
Answer: b
Clarification: None.
12. Which of the following statements are true? (GATE 2010)
I. Shortest remaining time first scheduling may cause starvation II. Preemptive scheduling may cause starvation III. Round robin is better than FCFS in terms of response time
a) I only
b) I and III only
c) II and III only
d) I, II and III
Answer: d
Clarification: I) Shortest remaining time first scheduling is a preemptive version of shortest job scheduling. It may cause starvation as shorter processes may keep coming and a long CPU burst process never gets CPU.
II) Preemption may cause starvation. If priority based scheduling with preemption is used, then a low priority process may never get CPU.
III) Round Robin Scheduling improves response time as all processes get CPU after a specified time.