250+ TOP MCQs on I/O Subsystem and Answers

Operating System Multiple Choice Questions on “I/O Subsystem”.

1. I/O hardware contains ____________
a) Bus
b) Controller
c) I/O port and its registers
d) All of the mentioned

Answer: d
Clarification: None.

2. The data-in register of I/O port is ____________
a) Read by host to get input
b) Read by controller to get input
c) Written by host to send output
d) Written by host to start a command

Answer: a
Clarification: None.

3. The host sets _____ bit when a command is available for the controller to execute.
a) write
b) status
c) command-ready
d) control

Answer: c
Clarification: None.

4. When hardware is accessed by reading and writing to the specific memory locations, then it is called ____________
a) port-mapped I/O
b) controller-mapped I/O
c) bus-mapped I/O
d) none of the mentioned

Answer: d
Clarification: It is called memory-mapped I/O.

5. Device drivers are implemented to interface ____________
a) character devices
b) block devices
c) network devices
d) all of the mentioned

Answer: d
Clarification: None.

6. Which hardware triggers some operation after certain programmed count?
a) programmable interval timer
b) interrupt timer
c) programmable timer
d) none of the mentioned

Answer: a
Clarification: None.

7. The device-status table contains ____________
a) each I/O device type
b) each I/O device address
c) each I/O device state
d) all of the mentioned

Answer: d
Clarification: None.

8. Which buffer holds the output for a device?
a) spool
b) output
c) status
d) magic

Answer: a
Clarification: None.

9. Which one of the following connects high-speed high-bandwidth device to memory subsystem and CPU.
a) Expansion bus
b) PCI bus
c) SCSI bus
d) None of the mentioned

Answer: a
Clarification: None.

10. A process is moved to wait queue when I/O request is made with ____________
a) non-blocking I/O
b) blocking I/O
c) asynchronous I/O
d) synchronous I/O

Answer: b

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