Multiple Choice Questions & Answers on CPU Scheduling
Multiple Choice Questions & Answers on CPU Scheduling
CPU Scheduling MCQ
1. In priority scheduling algorithm ____________
a) CPU is allocated to the process with highest priority
b) CPU is allocated to the process with lowest priority
c) Equal priority processes can not be scheduled
d) None of the mentioned
Answer: CPU is allocated to the process with highest priority
2. Process are classified into different groups in ____________
a) shortest job scheduling algorithm
b) round robin scheduling algorithm
c) priority scheduling algorithm
d) multilevel queue scheduling algorithm
Answer: multilevel queue scheduling algorithm
Introduction to CPU Scheduling Algorithms3. The interval from the time of submission of a process to the time of completion is termed as ____________
a) waiting time
b) turnaround time
c) response time
d) throughput
Answer: turnaround time
4. In multilevel feedback scheduling algorithm ____________
a) a process can move to a different classified ready queue
b) classification of ready queue is permanent
c) processes are not classified into groups
d) none of the mentioned
Answer: a process can move to a different classified ready queue
5. The processes that are residing in main memory and are ready and waiting to execute are kept on a list called _____________
a) job queue
b) ready queue
c) execution queue
d) process queue
Answer: ready queue
6. In priority scheduling algorithm, when a process arrives at the ready queue, its priority is compared with the priority of ____________
a) all process
b) currently running process
c) parent process
d) init process
Answer: currently running process
7. Which module gives control of the CPU to the process selected by the short-term scheduler?
a) dispatcher
b) interrupt
c) scheduler
d) none of the mentioned
Answer: dispatcher
8. Which one of the following can not be scheduled by the kernel?
a) kernel level thread
b) user level thread
c) process
d) none of the mentioned
Answer: user level thread
9. Which algorithm is defined in Time quantum?
a) shortest job scheduling algorithm
b) round robin scheduling algorithm
c) priority scheduling algorithm
d) multilevel queue scheduling algorithm
Answer: round robin scheduling algorithm
10. Which scheduling algorithm allocates the CPU first to the process that requests the CPU first?
a) first-come, first-served scheduling
b) shortest job scheduling
c) priority scheduling
d) none of the mentioned
Answer: first-come, first-served scheduling
CPU Scheduling Benefits MCQ
1. The switching of the CPU from one process or thread to another is called ____________
a) process switch
b) task switch
c) context switch
d) all of the mentioned
Answer: all of the mentioned
2. An I/O bound program will typically have ____________
a) a few very short CPU bursts
b) many very short I/O bursts
c) many very short CPU bursts
d) a few very short I/O bursts
Answer: many very short CPU bursts
3. Scheduling is done so as to ____________
a) increase CPU utilization
b) decrease CPU utilization
c) keep the CPU more idle
d) none of the mentioned
Answer: increase CPU utilization
4. Scheduling is done so as to ____________
a) increase the turnaround time
b) decrease the turnaround time
c) keep the turnaround time same
d) there is no relation between scheduling and turnaround time
Answer: decrease the turnaround time
5. CPU scheduling is the basis of ___________
a) multiprocessor systems
b) multiprogramming operating systems
c) larger memory sized systems
d) none of the mentioned
Answer: multiprogramming operating systems
6. Scheduling is done so as to ____________
a) increase the throughput
b) decrease the throughput
c) increase the duration of a specific amount of work
d) none of the mentioned
Answer: increase the throughput
7. Scheduling is done so as to ____________
a) increase the waiting time
b) keep the waiting time the same
c) decrease the waiting time
d) none of the mentioned
Answer: decrease the waiting time
8. With multiprogramming ______ is used productively.
a) time
b) space
c) money
d) all of the mentioned
Answer: time
9. A process is selected from the ______ queue by the ________ scheduler, to be executed.
a) blocked, short term
b) wait, long term
c) ready, short term
d) ready, long term
Answer: ready, short term
10. What is Response time?
a) the total time taken from the submission time till the completion time
b) the total time taken from the submission time till the first response is produced
c) the total time taken from submission time till the response is output
d) none of the mentioned
Answer: the total time taken from the submission time till the first response is produced
11. What is Dispatch latency?
a) the speed of dispatching a process from running to the ready state
b) the time of dispatching a process from running to ready state and keeping the CPU idle
c) the time to stop one process and start running another one
d) none of the mentioned
Answer: the time to stop one process and start running another one
12. What is Waiting time?
a) the total time in the blocked and waiting queues
b) the total time spent in the ready queue
c) the total time spent in the running queue
d) the total time from the completion till the submission of a process
Answer: the total time spent in the ready queue
13. What are the two steps of a process execution?
a) I/O & OS Burst
b) CPU & I/O Burst
c) Memory & I/O Burst
d) OS & Memory Burst
Answer: CPU & I/O Burst
14. What is Turnaround time?
a) the total waiting time for a process to finish execution
b) the total time spent in the ready queue
c) the total time spent in the running queue
d) the total time from the completion till the submission of a process
Answer: the total time from the completion till the submission of a process
15. In the following cases non – preemptive scheduling occurs?
a) When a process switches from the running state to the ready state
b) When a process goes from the running state to the waiting state
c) When a process switches from the waiting state to the ready state
d) All of the mentioned
Answer: When a process goes from the running state to the waiting state
CPU Scheduling Algorithms MCQ
1. 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: Preemptive scheduling
2. A solution to the problem of indefinite blockage of low – priority processes is ____________
a) Starvation
b) Wait queue
c) Ready queue
d) Aging
Answer: Aging
3. Preemptive Shortest Job First scheduling is sometimes called ____________
a) Fast SJF scheduling
b) EDF scheduling – Earliest Deadline First
c) HRRN scheduling – Highest Response Ratio Next
d) SRTN scheduling – Shortest Remaining Time Next
Answer: SRTN scheduling – Shortest Remaining Time Next
4. 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: Preemptive scheduling
5. An SJF algorithm is simply a priority algorithm where the priority is ____________
a) the predicted next CPU burst
b) the inverse of the predicted next CPU burst
c) the current CPU burst
d) anything the user wants
Answer: the predicted next CPU burst
6. The real difficulty with SJF in short term scheduling is ____________
a) it is too good an algorithm
b) knowing the length of the next CPU request
c) it is too complex to understand
d) none of the mentioned
Answer: knowing the length of the next CPU request
7. 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: using very large time slices converts it into First come First served scheduling algorithm
8. The FCFS algorithm is particularly troublesome for ____________
a) time sharing systems
b) multiprogramming systems
c) multiprocessor systems
d) operating systems
Answer: multiprogramming systems
9. 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: assigning ready processes to CPU
10. 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: are very appropriate for very large computers
11. 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: first come, first served
12. 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: Shortened; Lengthened
13. 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: first executes the job that came in first in the queue
14. 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: allowing a job to use the processor
15. 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: tQ = 15ms
16. 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: Shortest Job First
17. Which of the following statements are true?
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: I, II and III
18. Which is the most optimal scheduling algorithm?
a) FCFS – First come First served
b) SJF – Shortest Job First
c) RR – Round Robin
d) None of the mentioned
Answer: SJF – Shortest Job First
19. Consider the following set of processes, the length of the CPU burst time given in milliseconds.
Process Burst time
P1 6
P2 8
P3 7
P4 3
Assuming the above process being scheduled with the SJF scheduling algorithm.
a) The waiting time for process P1 is 3ms
b) The waiting time for process P1 is 0ms
c) The waiting time for process P1 is 16ms
d) The waiting time for process P1 is 9ms
Answer: The waiting time for process P1 is 3ms
20. Choose one of the disadvantages of the priority scheduling algorithm?
a) it schedules in a very complex manner
b) its scheduling takes up a lot of time
c) it can lead to some low priority process waiting indefinitely for the CPU
d) none of the mentioned
Answer: it can lead to some low priority process waiting indefinitely for the CPU
21. What is ‘Aging’?
a) keeping track of cache contents
b) keeping track of what pages are currently residing in memory
c) keeping track of how many times a given page is referenced
d) increasing the priority of jobs to ensure termination in a finite time
Answer: increasing the priority of jobs to ensure termination in a finite time
22. Which of the following statements are true?
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: i, ii and iii
23. Which of the following scheduling algorithms gives minimum average waiting time?
a) FCFS
b) SJF
c) Round – robin
d) Priority
Answer: SJF
24. Using Priority Scheduling algorithm, find the average waiting time for the following set of processes given with their priorities in the order: Process : Burst Time : Priority respectively .
P1 : 10 : 3
P2 : 1 : 1
P3 : 2 : 4
P4 : 1 : 5
P5 : 5 : 2
a) 8 milliseconds
b) 8.2 milliseconds
c) 7.75 milliseconds
d) 3 milliseconds
Answer: 8.2 milliseconds
25. Which of the following is a criterion to evaluate a scheduling algorithm?
a) CPU Utilization: Keep CPU utilization as high as possible
b) Throughput: number of processes completed per unit time
c) Waiting Time: Amount of time spent ready to run but not running
d) All of the above
Answer: All of the above
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