Tricky Operating System Questions and Answers on “I/O System – Application I/O Interface”.
1. 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
Clarification: None.
2. 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
Clarification: None.
3. 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
Clarification: None.
4. 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
Clarification: None.
5. For large data transfers, _________ is used.
a) dma
b) programmed I/O
c) controller register
d) none of the mentioned
Answer: a
Clarification: None.
6. 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
Clarification: None.
7. 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
Clarification: None.
8. 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
Clarification: None.
9. 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
Clarification: None.
10. 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
Clarification: None.
11. 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
Clarification: None.
12. 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