Operating System Multiple choice Questions and Answers-IO Systems

1.	The initial program that is run when the computer is powered up is called :
a.	boot program
b.	bootloader
c.	initializer
d.	bootstrap program

Discuss

Answer: (d).bootstrap program

2.	How does the software trigger an interrupt ?
a.	Sending signals to CPU through bus
b.	Executing a special operation called system call
c.	Executing a special program called system program
d.	Executing a special program calle interrupt trigger program

Discuss

Answer: (b).Executing a special operation called system call

3.	What is a trap/exception ?
a.	hardware generated interrupt caused by an error
b.	software generated interrupt caused by an error
c.	user generated interrupt caused by an error
d.	None of these

Discuss

Answer: (b).software generated interrupt caused by an error

4.	What is an ISR ?
a.	Information Service Request
b.	Interrupt Service Request
c.	Interrupt Service Routine
d.	Information Service Routine

Discuss

Answer: (c).Interrupt Service Routine

5.	An interrupt vector
a.	is an address that is indexed to an interrupt handler
b.	is a unique device number that is indexed by an address
c.	is a unique identity given to an interrupt
d.	None of these

Discuss

Answer: (a).is an address that is indexed to an interrupt handler

6.	DMA is used for :
a.	High speed devices(disks and communications network)
b.	Low speed devices
c.	Saving CPU cycles
d.	Both a and c

Discuss

Answer: (d).Both a and c

7.	In a memory mapped input/output :
a.	the CPU uses polling to watch the control bit constantly, looping to see if device is ready
b.	the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available
c.	the CPU receives an interrupt when the device is ready for the next byte
d.	the CPU runs a user written code and does accordingly

Discuss

Answer: (b).the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available

8.	In a programmed input/output(PIO) :
a.	the CPU uses polling to watch the control bit constantly, looping to see if device is ready
b.	the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available
c.	the CPU receives an interrupt when the device is ready for the next byte
d.	the CPU runs a user written code and does accordingly

Discuss

Answer: (a).the CPU uses polling to watch the control bit constantly, looping to see if device is ready

9.	In an interrupt driven input/output :
a.	the CPU uses polling to watch the control bit constantly, looping to see if device is ready
b.	the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available
c.	the CPU receives an interrupt when the device is ready for the next byte
d.	the CPU runs a user written code and does accordingly

Discuss

Answer: (c).the CPU receives an interrupt when the device is ready for the next byte

10.	In the layered approach of Operating Systems :
a.	Bottom Layer(0) is the User interface
b.	Highest Layer(N) is the User interface
c.	Bottom Layer(0) is the hardware
d.	Both b and c

Discuss

Answer: (d).Both b and c