1000+ Operating System MCQ For Competitive Exams with FREE PDF

These Operating System MCQ For Competitive Exams are most important for your preparation. These Operating System Questions for Competitive Exams are very important for your interview. In this article, we provide you with the Operating System Objective Questions and answers for competitive exams. It includes a set of basic operating system questions and answers, which are mostly asked in job interviews.

Operating System MCQ For Competitive Exams

1. The hardware mechanism that allows a device to notify the CPU is called _______

a) polling

b) interrupt

c) driver

d) controlling

Answer: b


2. The CPU hardware has a wire called __________ that the CPU senses after executing every instruction.

a) interrupt request line

b) interrupt bus

c) interrupt receive line

d) interrupt sense line

Answer: a


3. In general the two interrupt request lines are ____________

a) maskable & non maskable interrupts

b) blocked & non maskable interrupts

c) maskable & blocked interrupts

d) none of the mentioned

Answer: a


4. The _________ are reserved for events such as unrecoverable memory errors.

a) non-maskable interrupts

b) blocked interrupts

c) maskable interrupts

d) none of the mentioned

Answer: a


5. The ________ can be turned off by the CPU before the execution of critical instruction sequences that must not be interrupted.

a) nonmaskable interrupt

b) blocked interrupt

c) maskable interrupt

d) none of the mentioned

Answer: c


6. The __________ is used by device controllers to request service.

a) nonmaskable interrupt

b) blocked interrupt

c) maskable interrupt

d) none of the mentioned

Answer: c


7. The interrupt vector contains ____________

a) the interrupts

b) the memory addresses of specialized interrupt handlers

c) the identifiers of interrupts

d) the device addresses

Answer: b


8. For large data transfers, _________ is used.

a) dma

b) programmed I/O

c) controller register

d) none of the mentioned

Answer: a


9. A character stream device transfers ____________

a) bytes one by one

b) block of bytes as a unit

c) with unpredictable response times

d) none of the mentioned

Answer: a


10. A block device transfers ____________

a) bytes one by one

b) block of bytes as a unit

c) with unpredictable response times

d) none of the mentioned

Answer: b


11. What is a dedicated device?

a) opposite to a sharable device

b) same as a sharable device

c) can be used concurrently by several processes

d) none of the mentioned

Answer: a


12. A keyboard is an example of a device that is accessed through a __________ interface.

a) block stream

b) set of blocks

c) character stream

d) none of the mentioned

Answer: c


13. In polling ____________

a) busy – wait cycles wait for I/O from device

b) interrupt handler receives interrupts

c) interrupt-request line is triggered by I/O device

d) all of the mentioned

Answer: a


14. A non blocking system call _________________

a) halts the execution of the application for an extended time

b) does not halt the execution of the application

c) does not block the interrupts

d) none of the mentioned

Answer: b


15. An asynchronous call ____________

a) returns immediately, without waiting for the I/O to complete

b) does not return immediately and waits for the I/O to complete

c) consumes a lot of time

d) is too slow

Answer: a


16. If one or more devices use a common set of wires to communicate with the computer system, the connection is called ______

a) CPU

b) Monitor

c) Wirefull

d) Bus

Answer: d


17. A ____ a set of wires and a rigidly defined protocol that specifies a set of messages that can be sent on the wires.

a) port

b) node

c) bus

d) none of the mentioned

Answer: c


18. When device A has a cable that plugs into device B, and device B has a cable that plugs into device C and device C plugs into a port on the computer, this arrangement is called a _________

a) port

b) daisy chain

c) bus

d) cable

Answer: b


19. The _________ present a uniform device-access interface to the I/O subsystem, much as system calls provide a standard interface between the application and the operating system.

a) Devices

b) Buses

c) Device drivers

d) I/O systems

Answer: c


20. Spooling ____________

a) holds a copy of the data

b) is fast memory

c) holds the only copy of the data

d) holds output for a device

Answer: c


21. The ________ keeps state information about the use of I/O components.

a) CPU

b) OS

c) kernel

d) shell

Answer: c


22. The kernel data structures include ____________

a) process table

b) open file table

c) close file table

d) all of the mentioned

Answer: b


23. Windows NT uses a __________ implementation for I/O.

a) message – passing

b) draft – passing

c) secondary memory

d) cache

Answer: a


24. A ________ is a full duplex connection between a device driver and a user level process.

a) Bus

b) I/O operation

c) Stream

d) Flow

Answer: c


25. I/O is a _________ in system performance.

a) major factor

b) minor factor

c) does not matter

d) none of the mentioned

Answer: a


26. If the number of cycles spent busy – waiting is not excessive, then ____________

a) interrupt driven I/O is more efficient than programmed I/O

b) programmed I/O is more efficient than interrupt driven I/O

c) both programmed and interrupt driven I/O are equally efficient

d) none of the mentioned

Answer: b


27. Buffering is done to ____________

a) cope with device speed mismatch

b) cope with device transfer size mismatch

c) maintain copy semantics

d) all of the mentioned

Answer: d


28. Caching is ________ spooling.

a) same as

b) not the same as

c) all of the mentioned

d) none of the mentioned

Answer: b


29. Caching ____________

a) holds a copy of the data

b) is fast memory

c) holds the only copy of the data

d) holds output for a device

Answer: a


30. In rate monotonic scheduling ____________

a) shorter duration job has higher priority

b) longer duration job has higher priority

c) priority does not depend on the duration of the job

d) none of the mentioned

Answer: a


31. In which scheduling certain amount of CPU time is allocated to each process?

a) earliest deadline first scheduling

b) proportional share scheduling

c) equal share scheduling

d) none of the mentioned

Answer: b


32. The problem of priority inversion can be solved by ____________

a) priority inheritance protocol

b) priority inversion protocol

c) both priority inheritance and inversion protocol

d) none of the mentioned

Answer: a


33. Time duration required for scheduling dispatcher to stop one process and start another is known as ____________

a) process latency

b) dispatch latency

c) execution latency

d) interrupt latency

Answer: b


34. Time required to synchronous switch from the context of one thread to the context of another thread is called?

a) threads fly-back time

b) jitter

c) context switch time

d) none of the mentioned

Answer: c


35. Which one of the following is a real time operating system?

a) RTLinux

b) VxWorks

c) Windows CE

d) All of the mentioned

Answer: d


36. VxWorks is centered around ____________

a) wind microkernel

b) linux kernel

c) unix kernel

d) none of the mentioned

Answer: a


37. In real time operating system ____________

a) all processes have the same priority

b) a task must be serviced by its deadline period

c) process scheduling can be done only once

d) kernel is not required

Answer: b


38. Hard real-time operating system has ______________ jitter than a soft real-time operating system.

a) less

b) more

c) equal

d) none of the mentioned

Answer: a


39. For real-time operating systems, interrupt latency should be ____________

a) minimal

b) maximum

c) zero

d) dependent on the scheduling

Answer: a


40. What is Event latency?

a) the amount of time an event takes to occur from when the system started

b) the amount of time from the event occurrence till the system stops

c) the amount of time from event occurrence till the event crashes

d) the amount of time that elapses from when an event occurs to when it is serviced.

Answer: d


Operating System MCQ and Answers – ThrashingOperating System MCQ and Answers – Linux
Operating System MCQ and Answers – MonitorsOperating System MCQ and Answers – File System
Operating System MCQ and Answers – Basics ProcessesOperating System MCQ and Answers – Security
Operating System MCQ and Answers – ThreadsOperating System MCQ and Answers – Structures

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