Module 3 - CPU Scheduling

Question 1

Which module gives control of the CPU to the process selected by the short-term scheduler?

Accepted Answer

dispatcher

Answer

interrupt

Answer

scheduler

Answer

None of the Above

Question 2

The processes that are residing in main memory and are ready and waiting to execute are kept on a list called

Accepted Answer

ready queue

Answer

job queue

Answer

execution queue

Answer

process queue

Question 3

The interval from the time of submission of a process to the time of completion is termed as

Accepted Answer

turnaround time

Answer

waiting time

Answer

response time

Answer

throughput

Question 4

Which scheduling algorithm allocates the CPU first to the process that requests the CPU first?

Accepted Answer

first-come, first-served scheduling

Answer

shortest job scheduling

Answer

priority scheduling

Answer

None of the Above

Question 5

In priority scheduling algorithm

Accepted Answer

CPU is allocated to the process with highest priority

Answer

CPU is allocated to the process with lowest priority

Answer

Equal priority processes can not be scheduled

Answer

None of the Above

Question 6

In priority scheduling algorithm, when a process arrives at the ready queue, its priority is compared with the priority of

Accepted Answer

currently running process

Answer

all process

Answer

parent process

Answer

init process

Question 7

Time quantum is defined in

Accepted Answer

round robin scheduling algorithm

Answer

shortest job scheduling algorithm

Answer

priority scheduling algorithm

Answer

multilevel queue scheduling algorithm

Question 8

Process are classified into different groups in

Accepted Answer

multilevel queue scheduling algorithm

Answer

shortest job scheduling algorithm

Answer

round robin scheduling algorithm

Answer

priority scheduling algorithm

Question 9

In multilevel feedback scheduling algorithm

Accepted Answer

a process can move to a different classified ready queue

Answer

classification of ready queue is permanent

Answer

processes are not classified into groups

Answer

None of the Above

Question 10

Which one of the following can not be scheduled by the kernel?

Accepted Answer

user level thread

Answer

kernel level thread

Answer

process

Answer

None of the Above

Question 11

CPU scheduling is the basis of ___________

Accepted Answer

multiprogramming operating systems

Answer

multiprocessor systems

Answer

larger memory sized systems

Answer

None of the Above

Question 12

With multiprogramming, ______ is used productively.

Accepted Answer

time

Answer

space

Answer

money

Answer

All of the Above

Question 13

The two steps of a process execution are :

Accepted Answer

CPU & I/O Burst

Answer

I/O & OS Burst

Answer

Memory & I/O Burst

Answer

OS & Memory Burst

Question 14

An I/O bound program will typically have :

Accepted Answer

many very short CPU bursts

Answer

a few very short CPU bursts

Answer

many very short I/O bursts

Answer

a few very short I/O bursts

Question 15

A process is selected from the ______ queue by the ________ scheduler, to be executed.

Accepted Answer

ready, short term

Answer

blocked, short term

Answer

wait, long term

Answer

ready, long term

Question 16

In the following cases non – preemptive scheduling occurs :

Accepted Answer

When a process goes from the running state to the waiting state

Answer

When a process switches from the running state to the ready state

Answer

When a process switches from the waiting state to the ready state

Answer

All of the Above

Question 17

The switching of the CPU from one process or thread to another is called :

Accepted Answer

All of the Above

Answer

process switch

Answer

task switch

Answer

context switch

Question 18

Dispatch latency is :

Accepted Answer

the time to stop one process and start running another one

Answer

the speed of dispatching a process from running to the ready state

Answer

the time of dispatching a process from running to ready state and keeping the CPU idle

Answer

None of the Above

Question 19

Scheduling is done so as to :

Accepted Answer

increase CPU utilization

Answer

decrease CPU utilization

Answer

keep the CPU more idle

Answer

None of the Above

Question 20

Scheduling is done so as to :

Accepted Answer

increase the throughput

Answer

decrease the throughput

Answer

increase the duration of a specific amount of work

Answer

None of the Above

Question 21

Turnaround time is :

Accepted Answer

the total time from the completion till the submission of a process

Answer

the total waiting time for a process to finish execution

Answer

the total time spent in the ready queue

Answer

the total time spent in the running queue

Question 22

Scheduling is done so as to :

Accepted Answer

decrease the turnaround time

Answer

increase the turnaround time

Answer

keep the turnaround time same

Answer

there is no relation between scheduling and turnaround time

Question 23

Waiting time is :

Accepted Answer

the total time spent in the ready queue

Answer

the total time in the blocked and waiting queues

Answer

the total time spent in the running queue

Answer

the total time from the completion till the submission of a process

Question 24

Scheduling is done so as to :

Accepted Answer

decrease the waiting time

Answer

increase the waiting time

Answer

keep the waiting time the same

Answer

none of the mentioned

Question 25

Response time is :

Accepted Answer

the total time taken from the submission time till the first response is produced

Answer

the total time taken from the submission time till the completion time

Answer

the total time taken from submission time till the response is output

Answer

None of the Above

Question 26

Round robin scheduling falls under the category of :

Accepted Answer

Preemptive scheduling

Answer

Non preemptive scheduling

Answer

All of the Above

Answer

None of the Above

Question 27

With round robin scheduling algorithm in a time shared system,

Accepted Answer

using very large time slices converts it into First come First served scheduling algorithm

Answer

using very small time slices converts it into First come First served scheduling algorithm

Answer

using extremely small time slices increases performance

Answer

using very small time slices converts it into Shortest Job First algorithm

Question 28

The portion of the process scheduler in an operating system that dispatches processes is concerned with :

Accepted Answer

assigning ready processes to CPU

Answer

assigning ready processes to waiting queue

Answer

assigning running processes to blocked queue

Answer

All of the Above

Question 29

Complex scheduling algorithms :

Accepted Answer

are very appropriate for very large computers

Answer

use minimal resources

Answer

use many resources

Answer

All of the Above

Question 30

The FIFO algorithm :

Accepted Answer

first executes the job that came in first in the queue

Answer

first executes the job that came in last in the queue

Answer

first executes the job that needs minimal processor

Answer

first executes the job that has maximum processor needs

Question 31

The strategy of making processes that are logically runnable to be temporarily suspended is called :

Accepted Answer

Preemptive scheduling

Answer

Non preemptive scheduling

Answer

Shortest job first

Answer

First come First served

Question 32

Scheduling is :

Accepted Answer

allowing a job to use the processor

Answer

making proper use of processor

Answer

All of the Above

Answer

None of the Above

Question 33

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 ?

Accepted Answer

tQ = 15ms

Answer

tQ = 40ms

Answer

tQ = 45ms

Answer

tQ = 50ms

Question 34

Orders are processed in the sequence they arrive if _______ rule sequences the jobs.

Accepted Answer

first come, first served

Answer

earliest due date

Answer

slack time remaining

Answer

critical ratio

Question 35

Which of the following algorithms tends to minimize the process flow time ?

Accepted Answer

Shortest Job First

Answer

First come First served

Answer

Earliest Deadline First

Answer

Longest Job First

Question 36

Under multiprogramming, turnaround time for short jobs is usually ________ and that for long jobs is slightly ___________

Accepted Answer

Shortened; Lengthened

Answer

Lengthened; Shortened

Answer

Shortened; Shortened

Answer

Shortened; Unchanged

Question 37

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

Accepted Answer

I, II and III

Answer

I only

Answer

I and III only

Answer

II and III only

Question 38

The most optimal scheduling algorithm is :

Accepted Answer

SJF – Shortest Job First

Answer

FCFS – First come First served

Answer

RR – Round Robin

Answer

None of the Above

Question 39

The real difficulty with SJF in short term scheduling is :

Accepted Answer

knowing the length of the next CPU request

Answer

it is too good an algorithm

Answer

it is too complex to understand

Answer

None of the Above

Question 40

The FCFS algorithm is particularly troublesome for ____________

Accepted Answer

multiprogramming systems

Answer

time sharing systems

Answer

multiprocessor systems

Answer

operating systems

Question 41

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 :

Accepted Answer

The waiting time for process P1 is 3ms

Answer

The waiting time for process P1 is 0ms

Answer

The waiting time for process P1 is 16ms

Answer

The waiting time for process P1 is 9ms

Question 42

Preemptive Shortest Job First scheduling is sometimes called :

Accepted Answer

SRTN scheduling – Shortest Remaining Time Next

Answer

Fast SJF scheduling

Answer

EDF scheduling – Earliest Deadline First

Answer

HRRN scheduling – Highest Response Ratio Next

Question 43

An SJF algorithm is simply a priority algorithm where the priority is :

Accepted Answer

the predicted next CPU burst

Answer

the inverse of the predicted next CPU burst

Answer

the current CPU burst

Answer

anything the user wants

Question 44

One of the disadvantages of the priority scheduling algorithm is that :

Accepted Answer

it can lead to some low priority process waiting indefinitely for the CPU

Answer

it schedules in a very complex manner

Answer

its scheduling takes up a lot of time

Answer

None of the Above

Question 45

‘Aging’ is :

Accepted Answer

increasing the priority of jobs to ensure termination in a finite time

Answer

keeping track of cache contents

Answer

keeping track of what pages are currently residing in memory

Answer

keeping track of how many times a given page is referenced

Question 46

A solution to the problem of indefinite blockage of low – priority processes is :

Accepted Answer

Aging

Answer

Starvation

Answer

Wait queue

Answer

Ready queue

Question 47

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

Accepted Answer

i, ii and iii

Answer

i only

Answer

i and iii only

Answer

ii and iii only

Question 48

Which of the following scheduling algorithms gives minimum average waiting time ?

Accepted Answer

SJF

Answer

FCFS

Answer

Round – robin

Answer

Priority

Module 3 - CPU Scheduling

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