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Operating System MCQ (Multiple Choice Questions) - SchoolingAxis

Operating System MCQ (Multiple Choice Questions) - SchoolingAxis

Operating System MCQ (Multiple Choice Questions)

 Que- How does the Hardware trigger an interrupt ? 

a. Sending signals to CPU through system bus 

b. Executing a special program called interrupt program 

c. Executing a special program called system program 

d. Executing a special operation called system call 


Answer- Sending signals to CPU through system bus        


Que- Which operation is performed by an interrupt handler ? 

a. Saving the current state of the system 

b. Loading the interrupt handling code and executing it 

c. Once done handling, bringing back the system to the original state it was before the interrupt occurred 

d. All of the mentioned 


Answer- All of the mentioned        


Que- 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        


Que- 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        


Que- 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        


Que- 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        


Que- 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        


Que- 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        


Que- Time quantum is defined in 

a. shortest job scheduling algorithm 

b. round robin scheduling algorithm 

c. priority scheduling algorithm 

d. multilevel queue scheduling algorithm  


Answer- round robin scheduling algorithm        


Que- 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         


Que- 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        


Que- 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        


Que- 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        


Que- With multiprogramming, ______ is used productively. 

a. time 

b. space 

c. money 

d. all of the mentioned 


Answer- time        


Que- The two steps of a process execution are : 

a. I/O & OS Burst 

b. CPU & I/O Burst 

c. Memory & I/O Burst 

d. OS & Memory Burst 


Answer- CPU & I/O Burst        


Que- 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        


Que- 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        


Que- 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        


Que- 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        


Que- Dispatch latency is : 

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        


Que- 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        


Que- 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        


Que- Turnaround time is : 

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        


Que- 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        


Que- Waiting time is : 

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        


Que- 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        


Que- Response time is : 

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        


Que- 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        


Que- 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        


Que- 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        


Que- 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        


Que- The 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        


Que- 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        


Que- Scheduling is : 

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        


Que- 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        


Que- 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        


Que- 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        


Que- 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        


Que- Which of the following statements are true ? (GATE 2010) I. Shortest remaining time first scheduling may cause starvation II. Preemptive scheduling may cause starvatio nIII. 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        


Que- The most optimal scheduling algorithm is : 

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        


Que- 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        


Que- The FCFS algorithm is particularly troublesome for ____________ 

a. time sharing systems 

b. multiprogramming systems 

c. multiprocessor systems 

d. operating systems 


Answer- multiprogramming systems        


Que- 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        


Que- 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        


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

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        


Que- "Aging" is : 

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        


Que- 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        


Que- 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- i, ii and iii        


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

a. FCFS 

b. SJF 

c. Round - robin 

d. Priority 


Answer- SJF        


Que- Concurrent access to shared data may result in : 

a. data consistency 

b. data insecurity 

c. data inconsistency 

d. none of the mentioned 


Answer- data inconsistency        


Que- A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called : 

a. data consistency 

b. race condition 

c. aging 

d. starvation 


Answer- race condition        


Que- The segment of code in which the process may change common variables, update tables, write into files is known as : 

a. program 

b. critical section 

c. non - critical section 

d. synchronizing 


Answer- critical section        


Que- The following three conditions must be satisfied to solve the critical section problem : 

a. Mutual Exclusion 

b. Progress 

c. Bounded Waiting 

d. All of the mentioned 


Answer- All of the mentioned        


Que- Mutual exclusion implies that : 

a. if a process is executing in its critical section, then no other process must be executing in their critical sections 

b. if a process is executing in its critical section, then other processes must be executing in their critical sections 

c. if a process is executing in its critical section, then all the resources of the system must be blocked until it finishes execution 

d. none of the mentioned 


Answer- if a process is executing in its critical section, then no other process must be executing in their critical sections        


Que- Bounded waiting implies that there exists a bound on the number of times a process is allowed to enter its critical section : 

a. after a process has made a request to enter its critical section and before the request is granted 

b. when another process is in its critical section 

c. before a process has made a request to enter its critical section 

d. none of the mentioned 


Answer- after a process has made a request to enter its critical section and before the request is granted        


Que- A minimum of _____ variable(s) is/are required to be shared between processes to solve the critical section problem. 

a. one 

b. two 

c. three 

d. four 


Answer- two        


Que- In the bakery algorithm to solve the critical section problem : 

a. each process is put into a queue and picked up in an ordered manner 

b. each process receives a number (may or may not be unique) and the one with the lowest number is served next 

c. each process gets a unique number and the one with the highest number is served next 

d. each process gets a unique number and the one with the lowest number is served next 


Answer- each process receives a number (may or may not be unique) and the one with the lowest number is served next        


Que- An un-interruptible unit is known as : 

a. single 

b. atomic 

c. static 

d. none of the mentioned 


Answer- atomic        


Que- The TestAndSet instruction is executed : 

a. after a particular process 

b. periodically 

c. atomically 

d. none of the mentioned 


Answer- atomically