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# OPERATING SYSTEM MCQ BASED QUESTION (Multi Choice Question)

This Blog cover all possible Multi Choice Question from topic operating system, type of operating system, process, synchronization , dead lock, memory management

Total amount of question covers in  This MCQ series is 100. They cover all the important aspect related to that topic provided below.

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# MCQ from Topic Process Scheduling

Q101. 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
Sol. d) I, II and III
In SRTF, It may cause starvation as shorter processes may keep coming and a long CPU burst process never gets CPU.
In Preemption, we force fully take the control from process, it leads starvation
In round robin it will execute up to time quantum. So Round Robin Scheduling improves response time as all processes get CPU after a specified time.

Q102 A scheduling algorithm assigns priority proportional to the waiting time of a process. Every process starts with priority zero (the lowest priority). The scheduler re-evaluates the process priorities every T time units and decides the next process to schedule. Which one of the following is TRUE if the processes have no I/O operations and all arrive at time zero?
a) This algorithm is equivalent to the first-come-first-serve algorithm
b) This algorithm is equivalent to the round-robin algorithm.
c) This algorithm is equivalent to the shortest-job-first algorithm..
d) This algorithm is equivalent to the shortest-remaining-time-first algorithm
Sol. This algorithm is equivalent to the round-robin algorithm.

Q103 Consider three CPU-intensive processes, which require 10, 20 and 30 time units and arrive at times 0, 2 and 6, respectively. How many context switches are needed if the operating system implements a shortest remaining time first scheduling algorithm? Do not count the context switches at time zero and at the end.
a) 1
b) 2
c) 3
d) 4

Sol. b) 2
Let three process be P0, P1 and P2 with arrival times 0, 2 and 6 respectively and CPU burst times 10, 20 and 30 respectively. At time 0, P0 is the only available process so it runs. At time 2, P1 arrives, but P0 has the shortest remaining time, so it continues. At time 6, P2 arrives, but P0 has the shortest remaining time, so it continues. At time 10, P1 is scheduled as it is the shortest remaining time process. At time 30, P2 is scheduled. Only two context switches are needed. P0 to P1 and P1 to P2.

Q104 The Program that is responsible for selecting next job to be executed is called
a) Scheduler
b) Compiler
c) Throughput
d) None of the above

Sol. Scheduler

Short term scheduler is responsible for selecting next job to be executed
Dispatcher is responsible for context switching

Q105 If the Dispatch Latency increase then degree of multiprogramming
a) Increase
b) Decrease
c) Remain Constant
d) None of the above

Sol. Decrease

As Dispatch Latency increase mean process execution time increase so degree of multiprogramming automatically get reduce

Q 106 Which of the following statement is false regarding FCFS?
a)  Performance of FCFS is always high
b) Average wait time is high .
c) Its implementation is based on FIFO queue.
d) FCFS is easy to understand and implement.

Sol. a) FCFS performance is high
In FCFS, some time it suffers from convey effect so it gives Poor in performance.

Q 107 The average amount of work done in per unit of time is called as
a) CPU utilization
b) Throughput
c) Turn around time
d) Bandwidth

Sol. b) Throughput

Q 108 The preemption of process take place after a fix interval of time
a) Time slice
b) Time Quantum
c) Response time
d) None of the above

Sol. b) Time Quantum

Q109 The indefinite blocking of low priority processes by a high priority processes that wait in the system for a long time is called as
b) Starvation
c) Blocking
d) None of the above

Sol. b) Starvation

Q110 Shortest Job Next is also known as?
a) Batch job
c) shortest job first
d) shortest job last
Sol. c) shortest job first
Explanation: Shortest Job Next (SJN) is also known as shortest job first (SJF)
Q111 Which scheduling algorithm allocates CPU to the process that requests first?
a) FCFS
b) SJF
c) Priority Based Algorithm
d) none of the mentioned

Sol. a) FCFS

Q112 In priority Based scheduling algorithm____________
a) Process with highest priority is allocated with CPU
b) Process with Lowest priority is allocated with CPU
c) Processes with equal priority  can not be scheduled
d) None of the mentioned
Sol. a) Process with highest priority is allocated with CPU
Q113 In priority based scheduling algorithm, when a process enter in the ready state, its priority is compared with ____________
a) the priority of all process
b) the priority of currently running process
c) the priority of parent process
d) the priority of First process
Sol. b) the priority of currently running process
Q114 Which algorithm is make use of  Time quantum for achieve multi tasking?
a) SJF
b) Round Robin algorithm
c) priority Based scheduling (PBS) algorithm
d) FCFS

Sol. b) Round Robin algorithm

Q115  Process are Grouped in ____________
a) SJF
b) round robin scheduling algorithm
c) LJF
d) multilevel queue scheduling algorithm

Sol. d) multilevel queue scheduling algorithm

Q116 In multilevel feedback scheduling algorithm ____________
a) a process can move between different classified ready queue
b) classification of ready queue is Fixed
c) there is not classification into groups
d) none of the mentioned

Sol. a) a process can move between different classified ready queue

Q117 Which one of the following is not known to kernel?
a) Process
d) none of above

Q118 CPU scheduling Provide basis of which operating system ___________
a) Batch Operating System
b) multiprogramming operating systems
c) multiprocessor systems
d) none of above

Sol. b) multiprogramming operating systems

Q119 ______ is used productively using multiprogramming .
a) time
b) Storage
c) Cost
d) all of the mentioned
Sol. a) time

Q 120 the Goal of CPU Scheduling is
a) Increase CPU Utilization
b) Decrease CPU Utilization
c) Not effect CPU Utilization
d) None of the above

Sol. Increase CPU Utilization

Q 121 What are the two burst time included of a process execution?
a) I/O Burst time & OS Burst time
b) CPU Burst time & I/O Burst time
c) Memory Burst time & I/O Burst time
d) OS Burst time & Memory Burst time

Sol. b) CPU Burst time & I/O Burst time

Q 122 IO Bound Process
a) Increase CPU Utilization
b) Decrease CPU Utilization
c) Not effect CPU Utilization
d) None of the above

Sol. b) Decrease CPU Utilization

Q123 A process is selected by the ________ scheduler from ______queue , to be executed.
a) short term, blocked
b) long term, wait

Q124 In the following preemptive scheduling occurs?
a) When a process jump from the waiting state to the ready state
b) When a process goes from the running state to the waiting state
c) When a process goes from the running state to the ready state
d) All of the mentioned

Sol. a) When a process goes from the running state to the ready state

Q125 When CPU switching from one process to another is called____________
a) process switching
c) context switching
d) all of the mentioned

Sol. d) all of the mentioned

Q126  Dispatch latency is ?
a) the time taken to destroy process
b) the time of Swapping a process from running to ready state
c) the time to start another one and stop one process
d) none of the Above

Sol. c) the time to start another one and stop one process

Q127 Scheduling is done in order to
a) improve CPU utilization
c) increase CPU idleness
d) none of the above

Sol. a) improve CPU utilization

Q128 The Goal of CPU Scheduling is ____________
a) increase throughput
b) decrease throughput
c) has no impact on throughput
d) none of the mentioned

Sol. a) increase throughput

Q129 Turnaround time is?
a) the total waiting time of any process
b) the total amount of time spent in the ready state
c) the total amount of time spent in the running state
d) the total amount of time from the completion to starting of a process

Sol. d) the total amount of time from the completion to starting of a process

Q130 the Goal of Scheduling is ____________
a) to increase TAT (turnaround time)
b) to decrease TAT (turnaround time)
c) to keep the TAT (turnaround time) as it is
d) has no relation with TAT (turnaround time)

Sol. b) to decrease TAT (turnaround time)

Q131 Waiting time is ?
a) total  time spent in the blocked and waiting state
b) total  time spent in the ready state
c) total  time spent in the running state
d) the total amount of time from the completion to starting of a process

Sol. b) total time spent in the ready state

Q132 Purpose of CPU Scheduling is to ____________
a) increase WT (waiting time)
b) to maintain WT (waiting time)
c) decrease WT (waiting time)
d) none of the Above

Sol. c) decrease WT (waiting time)

Q133 What is Response time?
a) the total amount of time taken from the arrival time to the completion time
b) the total amount of time taken from the arrival time to the first response is produced
c) the total amount of time taken from arrival time to the response is output
d) none of the mentioned

Sol. b) the total amount of time taken from the arrival time to the first response is produced

Q134 Round robin scheduling algorithm is ____________ in nature
a) Non-preemptive
b) Preemptive
c) both
d) None of the above

Sol. b) Preemptive

Q135 Round Robin is most suitable for
a) Time Sharing Operating System
b) Distributed Operating System
c) Real time Operating System
d) None of the above
Sol. a) Time Sharing Operating System
Q136 Context Switching is the part of
a) Spooling
b) Polling
c) Interrupts handling
d) None of the above
Sol. c) Interrupts handling

Q137 In round robin scheduling algorithm  ____________
a) very large time slices converts it into FCFS
b) small time slices converts it into FCFS
c) small time slices improve the performance
d) small time slices converts it into SJF

Sol. a) very large time slices converts it into FCFS

Q138. The portion of the process scheduler that dispatches processes is concerned with ____________
a) assigning ready processes to CPU
b) assigning ready processes to waiting state
c) assigning running processes to blocked state
d) all of the mentioned
Sol. a) assigning ready processes to CPU

Q139. Complex scheduling algorithms are very appropriate for____________
a)  Computer with very large Computation
b) Computer with minimal resources
c) Computer with many resources
d) all of the mentioned
Sol. a)  Computer with very large Computation

Q140.  FIFO stands for?
a) first executes job that enter last in the ready queue
b) first executes job that enter first in the ready queue
c) first executes job that has minimal burst time
d) first executes job that has minimal burst time
Sol. b) first executes job that enter first in the ready queue

Q141. In RR Scheduling a ready queue is treated as a
a) Circular queue
c) Stack
d) None of the above
Sol. a) Circular queue

Q142. The strategy of running processes in temporarily suspended manner is called ____________
a) Non preemptive scheduling
b) Preemptive scheduling
c) SJF
d) FCFS
Sol. b) Preemptive scheduling

Q143. A Scheduling wherein the jobs are allowedto move between the queues
a) Multilevel Queue scheduling
b) RR Scheduling
c) Stack
d) Multi level feedback scheduling
Sol. d) Multi level feedback scheduling

Q144.Scheduling is?
a) Related deciding the sequence to use the processor
b) Scheduling is the mean of achieving high CPU utilization
c) all of the above
d) none of these
Sol. c) all of the above

Q145 RR Scheduling is a pre-emptive version of
a) FIFO
b) SJF
c) MLQ
d) none of the above
Sol. a) FIFO

Q146. There are 10 different processes running on a System. Idle processes are waiting for an input event in the waiting state. Busy processes are scheduled using RR Scheduling algorithm. 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
Sol. a) tQ = 15ms
Explanation:
because as mentioned in the question the process has short running time less than 10ms so 15ms is sufficient to execute the process in Round Robin manner

Q147. Process are execute in the Orders they arrive if _______ rule is used to sequences the jobs.
a) earliest due time
b) Shortest remaining time
c) first come first served
d) critical section
Sol. c) first come first served

Q148. Which of the following algorithms minimize the process TAT?
a) FCFS
b) SJF
c) LJF
d) None of the above
Sol. SJF

Q149. Under multiprogramming operating system, TAT for short process is usually ________ and that for long process is slightly ___________
a) Lengthened; Shortened
b) Shortened; Lengthened
c) Shortened; Shortened
d) Shortened; Unchanged
Sol. b) Shortened; Lengthened

Q150. 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
Sol. d) I, II and III

Q151. Which of the following is optimal scheduling algorithm?
a) FCFS
b) SJF
c) RR
d) None of the mentioned
Sol. b) SJF

Q152. Which of the following difficulty is associated with SJF ____________
a) It is Simple and efficient algorithm
b) it is difficult to know the length of the next CPU request
c) it is very complex to understand
d) none of the above
Sol. b) it is difficult to know the length of the next CPU request
Q153. Preemptive SJF scheduling is sometimes called ____________
a) Fast SJF
c) HRRN( Highest Response Ratio Next)
d) SRTN (Shortest Remaining Time Next)
Sol. d) SRTN (Shortest Remaining Time Next)
Q154. An SJF algorithm is simply a priority algorithm where ____________
a) the priority is  the predicted next CPU burst
b) the priority is  the counter of the predicted next CPU burst
c) the priority is the current CPU burst
d) None of the above
Sol. a) the priority is  the predicted next CPU burst

Explanation: The lower the CPU burst, the
higher the priority.

Q155. Which of the following is disadvantage of the priority based scheduling algorithm?
a) it schedules the process in a very complex manner
b) its can takes up a lot of time
c) it can lead low priority process to waiting indefinitely for the execution
d) none of the above
Sol. c) it can lead low priority process to waiting indefinitely for the execution
Q156. â€˜Agingâ€™ means?
a) its keep track of  contents in cache
b) its keeping track of pages that currently residing in memory
c) its keeping track of count that how many times a given page is referenced
d) its increasing the priority of process to ensure that process termination in a finite time

Sol. d) its increasing the priority of process to ensure that process termination in a finite time

Q157. The solution to indefinite blockage of low priority processes is ____________
a) Increase Starvation
b) Size of Wait queue
d) Aging
Sol. d) Aging

Q158. Which of the following process scheduling algorithms gives minimum average waiting time?
a) First Come First Serve
b) Shortest Job First
c) Round â€“ robin scheduling algorithm
d) Priority base scheduling algorithm
Sol. b) Shortest Job First

Q159. the interface to access the services of operating system, is ___________
a) System calls
b) API
c) Library
d) Assembly instructions
Sol. a) System calls

Q160. Which of the following dynamically adds probes to a running system?
a) DMap
b) DLocate
c) DTrace

Sol. c) DTrace
Explanation: dynamically adds probes to a running system, both in user process and in the kernel is called DTrace. it is useful in troubleshooting kernels during execution.

Q161  Which of the following is command-line tool that displays system information and events.
a) DTrace
b) DLocate
c) DMap

Sol. a) DTrace
Explanation: DTrace is command-line tool that displays system information and events.

Q162. Which one of the following is not an example of real time operating system?
a) Palm OS
b) QNX
c) RTLinux
d) VxWorks

Sol.a) Palm OS

Explanation: all VxWorks,  RTLinux & QNX are example of real-time operating systems. Palm OS is a mobile operating system which is developed for Personal Digital Assistants.

Q163. The OS X is consist of ____________
a) monolithic kernel
b) hybrid kernel
c) microkernel
d) None of the above

Sol. b) hybrid kernel
Explanation: OS X has a hybrid kernel. Hybrid kernel is a combine feature of both monolithic kernel and microkernel. it is developed by Apple and also known as Mac OSX.

Q164. Which of the following systems, allow only one process execution at a time, are called __________
a) uniprogramming systems
b) uniprocessing systems
d) none of the above

Sol. b) uniprocessing systems
Explanation: Those systems which allows more than one process execution at a time, are called multiprocessing systems vise versa uniprocessing systems

Q165. In OS, each process has its own __________
a) address space and global variables
b) open files
c) Resources
d) all of the above

Sol. d) all of the above

Explanation: In Operating Systems, each process has its own address space which consist of code, data, stack and heap segments or sections. Each process also has a list of files which is opened by the process as well as resources handle by it.
Q166. In Unix, Which of the following system call is used to creates the new process?
a) fork
b) create
c) new
d) none of the mentioned

Sol. a) fork

Explanation: In UNIX operating system, a new process is created by fork() system call. Note that process id of the newly created child process is return by fork() System call.

Q167. Ready state is the state?
a) When process has all necessary resources
b) when process is unable to run until I/O has been completed
c) when process occupies the CPU
d) none of the mentioned

Sol. a) When process has all necessary resources

Explanation: Ready state is the state when process has all necessary resources and  ready for execution but waiting for the CPU to be allocated.

Q168. What do you mean by inter process communication?
a) it is the communication that happen with in process
b) it is the communication between two process
c) it is communication between two threads that belongs to same process
d) none of the mentioned

Sol. b) it is the communication between two process

Explanation: Inter process Communication (IPC) is a mechanism that allows two processes to communicate with each other and synchronize their actions using shared memory and message passing.

Q169. Processes is said to in deadlock if __________
a) Each process is waiting for situation which is not going to be happen in future
b) Each process is in terminated state
c) all processes are trying to terminate each other
d) none of the mentioned

Sol. a) Each process is waiting for situation which is not going to be happen in future

Explanation: Deadlock is a situation in which each process is waiting for situation which is not going to be happen in future like suppose there are two process waiting for each other to release the required resources

Q170. Which of the following detail does not contain by process stack
a) Function parameters
b) Local variables
d) PID of child process

Sol. d) PID of child process
Explanation: A process stack is able to contains details like Function parameters, Local variables and Return address.

Q171. Using which system call the parent can obtain the exit status of a terminated child.?
a) wait()
b) exit()
c) fork()
d) get()

Sol. a) wait()

Explanation: wait() system call is used by the parent process to determine termination of child process. The parent process uses wait() system call and gets the exit status of the child process as well as the pid of the child process which is terminated.
Q172. When a process affected by other processes executing than the processes is called?
a) cooperating process
b) child process
c) parent process
d) simple process
Sol. a) cooperating process
Q173. The situation where two or more processes are reading or writing some share data and the result depends on the particular order in
which the access takes place, is called?
a) Synchronization
c) Race Condition
d) None of the above

Sol. c) Race Condition

Q174. If a process is executing in its critical section, then no other processes are allowed to enter critical section. This condition is called?
a) mutual exclusion
b) critical exclusion
c) synchronous exclusion
d) asynchronous exclusion

Sol. a) mutual exclusion

Q175 The portion of Code or section of code which is changing the share variable is called
a) Atomicity
b) Critical Section
c) Procedure
d) None of the above

Sol. b) Critical Section

Q176. Which one of the following can be used to achieve synchronization?
a) clock
b) pipe
c) semaphore
d) socket
Sol. c) semaphore

Q177 DI stands for
a) Demand Input
b) Disable Interrupt
c) Demand Interrupt
d) None of the above

Sol. b) Disable Interrupt

Q178 A semaphore can have
a) Boolean value
b) Integer value
c) both a) and b)
d) None of the above

Sol. c) both a) and b)

Q179. Mutual exclusion can be Achieved by
a) mutex
b) semaphores
c) both mutex and semaphores
d) none of the mentioned

Sol. c) both mutex and semaphores

Q180. Process synchronization have following type of solution _________
a) hardware type
b) software type
c) both hardware and software type
d) none of the mentioned
Sol. c) both hardware and software type

Q181. Bakery Algorithm will provide
a) Two Process Solution
b) Multi Process Solution
d) None of the above

Sol. b) Multi Process Solution

Q182 Which of the following is not Software type Solution
a) Lock Variable
b) Strict Alternative & Decker Algorithm
c) Peterson Solution
d) Binary Semaphore

Sol. d) Binary Semaphore

Q183 Which of the following are condition to achieve  Synchronization
a) Mutual Exclusion
b) Progression
c) Bounded Wait
d) All of the above

Sol. d) All of the above

Q184 Semaphores were given by
a) Albrecht
b) Dijkstra
c) Peterson
d) None of the Above

Sol. b) Dijkstra

Q185. Spinlocks refers to
a) Binary Semaphores
b) Counting Semaphores
c) Monitors
d) None of the above

Sol.  a) Binary Semaphores

Q186 Critical Region and Conditional critical regions were proposed by
a) Dijkstra
b) Peterson
c) Brinch Harson
d) none of the above

Sol. c) Brinch Harson

Q187. A monitor is a Package that consist of __________
a) data structures
b) collection of procedures
c) synchronization between concurrent process
d) all of the mentioned

Sol. d) all of the mentioned

Q189. In order to enable any process to wait within the monitor __________
a) a condition variable must be declared
b) a condition variable must be not declared
c) semaphore must be used
d) all of the mentioned

Sol. a) a condition variable must be declared

Q190. Cascading termination is a termination of all child processes before the parent terminates ______
a) Normally
b) Abnormally
c) Normally or abnormally
d) None of the mentioned

Sol. a) Normally

Q191 With _____________ only one process can execute at a time while other process are waiting for the processor. With ______________ more than one process can be running simultaneously each on a different processor.
a) Multiprocessing, Multiprogramming
b) Multiprogramming, Uniprocessing
c) Multiprogramming, Multiprocessing
d) Uniprogramming, Multiprocessing

Sol. d) Uniprogramming, Multiprocessing

Q192. In UNIX, each process is identified by its __________
a) Process Control Block
b) Device Queue
c) Process Id
d) None of the mentioned

Sol. c) Process Identifier

Q193. The Return value for the fork() is _____ for the child process and _____ for the parent.
a) A Negative integer, Zero
b) Zero, A Negative integer
c) Zero, A nonzero integer
d) A nonzero integer, Zero

Sol. c) Zero, A nonzero integer

Q194. The child process can __________
a) be a duplicate of the parent process
b) never be a duplicate of the parent process
c) cannot have another program loaded into it
d) never have another program loaded into it

Sol. a) be a duplicate of the parent process

Q195. The child process completes execution, but
the parent keeps executing, then the child
process is known as __________
a) Orphan
b) Zombie
c) Body

Sol. b) Zombie

Q196 Checkpoint are also named as
a) Syncpoint
b) Savepoint
c) Both a and b
d) None of the above

Sol. c) Both a and b

Q197 A semaphore count of negative means that queue contain
a) (n+1) waiting process
b) n waiting process
c) (n-1) waiting process
d) none of the above

Sol. b) n waiting process

Q198 to avoid race condition the number of processes that may be simultaneously inside the critical section is
a) 0
b) 1
c) 2
d) 4

Sol. b) 1

Q199. Solaris contain
b) Spinlocks
c) Dispatcher
d) None of the above