CHAPTER 9: Input / Output

Question 1

Which of the following is not a requirement for a computer system to handle I/O in a sufficient and effective manner?

a) Peripheral devices must be individually addressable.
b) Peripheral devices must operate only in block mode.
c) Peripheral devices can initiate communication with the CPU.
d) Programmed I/O is suitable only for slow devices and individual word transfers.

Answer 1

b) Peripheral devices must operate only in block mode.

Question 2

An important difference between the I/O requirements of keyboards and disk drives is that

a) keyboard input is fast while disk drives are slow.
b) keyboards require constant monitoring, while disk drives do not.
c) disk drives have I/O controllers and keyboards do not have I/O controllers.
d) disk data is always transferred in blocks, never as individual bytes as with the keyboard.

Answer 2

d) disk data is always transferred in blocks, never as individual bytes as with the keyboard.

Question 3

From the perspective of a computer, the network

a) is just another I/O device.
b) requires an Ethernet connection.
c) is complex set of interconnected hosts.
d) is addressable only in blocks of 32 bit addresses.

Answer 3

a) is just another I/O device.

Question 4

The method used to communicate events that need special attention to the CPU are known as

a) interrupts.
b) I/O controllers.
c) programmed I/O.
d) device controllers.

Answer 4

a) interrupts.

Question 5

The method of transferring data one word at a time from the CPU to a device is called

a) polling.
b) programmed I/O.
c) vectored interrupt.
d) direct memory access.

Answer 5

b) programmed I/O.

Question 6

Computers provide interrupt capability by providing one or more special control lines to the central processor known as

a) fault lines.
b) address lines.
c) interrupt lines.
d) instruction lines.

Answer 6

c) interrupt lines.

Question 7

The program that determines the appropriate course of action in the event an interrupt occurs is called the

a) fault handler.
b) device handler.
c) interrupt handler.
d) instruction handler.

Answer 7

c) interrupt handler.

Question 8

When an interrupt causes temporary suspension of the program in progress, all the pertinent information about the program being suspended, including the location of the last instruction executed, and the values of data in various registers are stored in an area of memory known as the

a) register dump block.
b) memory dump block.
c) program method block.
d) process control block.

Answer 8

d) process control block.

Question 9

After interrupting a program in execution, and saving the program’s context, the computer then branches to a special program known as the

a) driver routine.
b) servicing program.
c) program service program.
d) interrupt handler program.

Answer 9

d) interrupt handler program.

Question 10

Since many interrupts exist to support I/O devices, most of the interrupt handling programs are also known as

a) device drivers.
b) device handlers.
c) peripheral handlers.
d) peripheral controllers.

Answer 10

a) device drivers.

Question 11

The method of continuously checking the various input devices to determine if input data is waiting is called

a) polling.
b) observing.
c) monitoring.
d) supervising.

Answer 11

a) polling.

Question 12

Which of the following is not a function of how interrupts are used?

a) A completion signal
b) An abnormal event indicator
c) A means of allocating CPU time
d) A way of buffering large amounts of data

Answer 12

d) A way of buffering large amounts of data

Question 13

Which of the following is an example of an interrupt being used as an external event notifier?

a) A keyboard input
b) A program inadvertently attempts to divide by zero
c) A time quantum has passed and the CPU is interrupted to start another task
d) An application program requests service from the operating system using a software interrupt

Answer 13

a) A keyboard input

Question 14

External events like keyboard input, mouse clicks, printer “out of paper” messages, and power failures are handled by

a) interrupts.
b) device handlers.
c) peripheral controllers.
d) suspension subprograms.

Answer 14

a) interrupts.

Question 15

The computer system provides an internal clock that sends an interrupt periodically to the CPU signaling that it’s time to start processing another program or thread. The time between interrupt pulses is known as a(n) a) delta.

b) quantum.
c) unit quantity.
d) atomic quantity.

Answer 15

b) quantum.

Question 16

Events related to problems or special conditions within the computer system itself, like divide by zero, or attempting to execute a nonexistent op code, are called

a) irregular events.
b) unusual events.
c) abnormal events.
d) anomalous events.

Answer 16

c) abnormal events.

Question 17

Internal interrupts caused by events related to problems or special conditions within the computer itself are
sometimes called

a) exclusions.
b) exemptions.
c) special errors.
d) traps or exceptions.

Answer 17

d) traps or exceptions.

Question 18

Instructions that are intended for use by an operating system program, but not by an application program, are called

a) control instructions
b) limited instructions
c) prevalent instructions
d) privileged instructions

Answer 18

d) privileged instructions

Question 19

The software interrupt is very similar to which type of instruction?

a) STORE
b) LOAD
c) IF-THEN-ELSE
d) SUBROUTINE JUMP

Answer 19

d) SUBROUTINE JUMP

Question 20

The mnemonic for the x86 architecture instruction that simulates an interrupt is

a) SVC.
b) INT.
c) JMP.
d) GTO.

Answer 20

b) INT.

Question 21

One way to assure that multiple programs do not unintentionally alter another program’s files or intermingle printer output is to

a) only execute one interrupt at a time.
b) give programs in execution the highest priority.
c) not allow programs in execution to be interrupted.
d) require that all I/O to shared devices be handled by the operating system.

Answer 21

d) require that all I/O to shared devices be handled by the operating system.

Question 22

When the device generating the interrupt request identifies its address as part of the interrupt, it is called

a) polling interrupt.
b) discrete interrupt.
c) vectored interrupt.
d) monitoring interrupt.

Answer 22

c) vectored interrupt.

Question 23

Multiple interrupts can be handled by assigning _______ to each interrupt.

a) priorities
b) a time delay
c) queue levels
d) execution tickets

Answer 23

a) priorities

Question 24

Power failures, internal time-sensitive events, or external events that are time sensitive will trigger interrupts that are

a) low priority events.
b) high priority events.
c) dependent on the device generating the interrupt.
d) measured for time-to-complete and scheduled accordingly.

Answer 24

b) high priority events.

Question 25

Interrupts that can be temporarily disabled by program instructions are called

a) variable.
b) maskable.
c) changeable.
d) transferable.

Answer 25

b) maskable.

Question 26

Interrupts that can never be temporarily disabled by program instructions are called

a) invariable.
b) unchangeable.
c) nonmaskable.
d) non-transferable.

Answer 26

c) nonmaskable.

Question 27

Interrupts are normally checked

a) during the operation of the instruction cycle.
b) immediately, without regard to the instruction cycle.
c) simultaneously with the beginning of an execution cycle.
d) after one instruction is finished and before another begins.

Answer 27

d) after one instruction is finished and before another begins.

Question 28

An I/O technique that transfers block data directly between the I/O controller and computer memory, is called

a) direct block access.
b) direct RAM access.
c) direct block transfers.
d) direct memory access.

Answer 28

d) direct memory access.

Question 29

Data from disks, and tapes, and flash memory are transferred only in

a) bits.
b) chunks of data.
c) blocks of data.
d) characters or bytes of data.

Answer 29

c) blocks of data.

Question 30

Which of the following is not one of the three primary conditions for direct memory access to take place?

a) The I/O device must have an internal buffer.
b) There must be a method to connect together the I/O interface and memory.
c) There must be a means to avoid conflict between the CPU and the I/O controller.
d) The I/O controller associated with the particular device must be capable of reading and writing to memory.

Answer 30

a) The I/O device must have an internal buffer.

Question 31

Four pieces of data must be provided to the I/O controller for a particular I/O device to initiate the DMA transfer. Which of the following is not required?

a) The size of the block to be transferred.
b) The location of the data on the I/O device.
c) The length of time required to transfer the data.
d) The starting location of the block of data in memory.

Answer 31

c) The length of time required to transfer the data.

Question 32

The incompatibilities in speed between the various devices and the CPU make I/O synchronization difficult, especially if there are multiple devices attempting to do I/O at the same time. To handle these problems data is usually stored

a) in a buffer.
b) on the network.
c) on the disk drive.
d) in external storage.

Answer 32

a) in a buffer.

Question 33

I/O controllers that control a single type of device are often called

a) device controllers.
b) precision controllers.
c) peripheral controllers.
d) single-type controllers.

Answer 33

a) device controllers.

Question 34

An I/O controller that is designed to control hard disks is called a

a) disk handler.
b) disk controller.
c) disk coordinator.
d) disk interrupt handler.

Answer 34

b) disk controller.

Question 35

Which of the following is not a common function of an I/O disk controller?

a) The I/O disk controller manages main memory during the transfer.
b) The I/O disk controller recognizes messages addressed to it and accepts commands from the CPU.
c) The I/O disk controller has interrupt capability, which it uses to notify the CPU when the transfer is complete.
d) The I/O disk controller provides a buffer where the data from memory can be held until it can be transferred to the disk.

Answer 35

a) The I/O disk controller manages main memory during the transfer.