OSG-7 EXAM QUESTIONS AND
ANSWERS
c - ANSWER Which of the following statements is incorrect?
a. The term data rate refers to the speed with which data moves to and from the
individual I/O device
b. In the interrupt-driven I/O technique, the processor issues an I/O request,
continues with other work and eventually receives notification that the request
was fulfilled
c. A hard drive is an example of a character-oriented I/O device
d. None of the above
d - ANSWER Which approach is used to CPU communicate with the control
registers of the I/O device?
a. Separating I/O and memory space
b. Memory-mapped I/O
c. Hybrid: separating I/O and memory space and memory-mapped I/O
d. All of the other choices
c - ANSWER Which is the right order between the 4 I/O software layers?
a. User-level I/O software, Device drivers, Interrupt handlers, Device-
independent OS software
b. User-level I/O software, Interrupt handlers, Device drivers, Device-
independent OS software
c. Device-independent OS software, user-level I/O software, Device drivers,
Interrupt handlers
d. User-level I/O software, Device-independent OS software, Device drivers,
Interrupt handlers
c - ANSWER In general, which is the best technique for I/O Data transfer?
a. Programmed I/O
b. Interrupt-Driven I/O
c. Direct Memory Access
d. None of the other choices
, a - ANSWER What is the table where its entry contains the memory address of
Interrupt service routine
a. Interrupt vector table
b. Interrupt table
c. Address table
d. Address lines table
d - ANSWER Which of the following statement is not true about separating
I/O and memory space?
a. Device drivers must be written using assembly language
b. Programs must use 2 instructions to test whether the device is ready
c. There is special protection mechanism to keep user processes from
performing I/O
d. Caching a device control register would be disastrous
- ANSWER In separating I/O and memory space system, the set of I/O ports
form the I/O port space. This mechanism allows:
Programs in user space can easily access to I/O devices
Only programs in kernel can access to I/O devices
Both programs in user space and kernel can access to I/O devices
None of the other choices
d - ANSWER In the memory-mapped I/O system, in order that CPU
communicates with the control registers in the devices, the control register is
assigned :
Index
I/O address
Unique memory address
None of the other choices
b - ANSWER Which of the following statements about interrupts and trap
instructions is incorrect?
[A]
An interrupt is a hardware-generated change of control flow within the system
[B]
None of the other choices
[C]
A trap instruction is a software-generated interrupt
ANSWERS
c - ANSWER Which of the following statements is incorrect?
a. The term data rate refers to the speed with which data moves to and from the
individual I/O device
b. In the interrupt-driven I/O technique, the processor issues an I/O request,
continues with other work and eventually receives notification that the request
was fulfilled
c. A hard drive is an example of a character-oriented I/O device
d. None of the above
d - ANSWER Which approach is used to CPU communicate with the control
registers of the I/O device?
a. Separating I/O and memory space
b. Memory-mapped I/O
c. Hybrid: separating I/O and memory space and memory-mapped I/O
d. All of the other choices
c - ANSWER Which is the right order between the 4 I/O software layers?
a. User-level I/O software, Device drivers, Interrupt handlers, Device-
independent OS software
b. User-level I/O software, Interrupt handlers, Device drivers, Device-
independent OS software
c. Device-independent OS software, user-level I/O software, Device drivers,
Interrupt handlers
d. User-level I/O software, Device-independent OS software, Device drivers,
Interrupt handlers
c - ANSWER In general, which is the best technique for I/O Data transfer?
a. Programmed I/O
b. Interrupt-Driven I/O
c. Direct Memory Access
d. None of the other choices
, a - ANSWER What is the table where its entry contains the memory address of
Interrupt service routine
a. Interrupt vector table
b. Interrupt table
c. Address table
d. Address lines table
d - ANSWER Which of the following statement is not true about separating
I/O and memory space?
a. Device drivers must be written using assembly language
b. Programs must use 2 instructions to test whether the device is ready
c. There is special protection mechanism to keep user processes from
performing I/O
d. Caching a device control register would be disastrous
- ANSWER In separating I/O and memory space system, the set of I/O ports
form the I/O port space. This mechanism allows:
Programs in user space can easily access to I/O devices
Only programs in kernel can access to I/O devices
Both programs in user space and kernel can access to I/O devices
None of the other choices
d - ANSWER In the memory-mapped I/O system, in order that CPU
communicates with the control registers in the devices, the control register is
assigned :
Index
I/O address
Unique memory address
None of the other choices
b - ANSWER Which of the following statements about interrupts and trap
instructions is incorrect?
[A]
An interrupt is a hardware-generated change of control flow within the system
[B]
None of the other choices
[C]
A trap instruction is a software-generated interrupt
