Operating System MCQ and Answers – I/O System – Application I/O Interface

These Operating System MCQ and Answers – I/O System – Application I/O Interface are asked in various examinations including BCA, MCA, GATE, and other tests. The questions based on the below Operating System MCQ and Answers – I/O System – Application I/O Interface tests your basic knowledge of MCQs on the topic of Operating Systems and the level of comprehension and grasp that you hold.

Operating System MCQ and Answers – I/O System – Application I/O Interface

1. A ________ is a collection of electronics that can operate a port, a bus, or a device.

a) controller

b) driver

c) host

d) bus

Answer: a

2. An I/O port typically consists of four registers status, control, ________ and ________ registers.

a) system in, system out

b) data in, data out

c) flow in, flow out

d) input, output

Answer: b

3. The ______ register is read by the host to get input.

a) flow in

b) flow out

c) data in

d) data out

Answer: c

4. The ______ register is written by the host to send output.

a) status

b) control

c) data in

d) data out

Answer: d

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

a) polling

b) interrupt

c) driver

d) controlling

Answer: b

6. 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

7. The _________ determines the cause of the interrupt, performs the necessary processing and executes a return from the interrupt instruction to return the CPU to the execution state prior to the interrupt.

a) interrupt request line

b) device driver

c) interrupt handler

d) all of the mentioned

Answer: c

8. 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

9. 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

10. 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

11. 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

12. 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

13. Division by zero, accessing a protected or non existent memory address, or attempting to execute a privileged instruction from user mode are all categorized as ________

a) errors

b) exceptions

c) interrupt handlers

d) all of the mentioned

Answer: b

14. For large data transfers, _________ is used.

a) dma

b) programmed I/O

c) controller register

d) none of the mentioned

Answer: a

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

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