CSC 415 OPERATING SYSTEMS ALL UNITS | 632 QUESTIONS
AND ANSWERS | 2026 UPDATE | WITH COMPLETE SOLUTION
I/O subsystem is integrated into process manager, memory manager and file
system.
Select one:
True
False Answer - False
Device drivers
Select one:
a. manage only the basic I/O hardware elements
b. manage only the newly emerging I/O devices that are unlike previous
devices
c. All the other answers
d. present a uniform device- access interface to the I/O subsystem Answer - d.
present a uniform device- access interface to the I/O subsystem
An interrupt priority scheme can be used to ____.
Select one:
a. All the other answers
b.allow the most urgent work to be finished first
,c.defer the handling of low-priority interrupt without masking off all interrupts
d.make it possible for high-priority interrupts to preempt the execution of a
low priority interrupt Answer - a. All the other answers
DMA controllers ____.
Select one:
a.are a nonstandard component in PCs of today
b.can steal memory access cycles from the main CPU
c.do not utilize an additional, special purpose, processor
d.can access main memory at the same time as the main CPU Answer - b.can
steal memory access cycles from the main CPU
The ____ register of an I/O port can be written by the host to start a command
or to change the mode of a device.
Select one:
a. status
b. transfer
c. data-in
d. control Answer - d. control
____ I/O accesses a block device as a simple array of blocks.
Select one:
a. Raw
b. Cooked
,c. Stream
d. Indirect Answer - a. Raw
A character-stream device ____.
Select one:
a. is a device such as a disk drive
b.transfers data in blocks of bytes
c.transfers data a byte at a time
d. is similar to a random access device Answer - c.transfers data a byte at a
time
Which of the following is true of a blocking system call?
Select one:
a.The application continues to execute its code when the call is issued.
b.Blocking application code is harder to understand than nonblocking
application code
c.The call returns immediately without waiting for the I/O to complete.
d.The execution of the application is suspended when the call is issued.
Answer - d.The execution of the application is suspended when the call is
issued.
Although caching and buffering are distinct functions, sometimes a region of
memory can be used for both purposes.
Select one:
True
, False Answer - True
A sense key reports on the failure of a SCSI device by ____.
Select one:
a.giving detailed information about the exact cause of failure
b.stating the general category of failure
c.stating the general nature of the failure
d.maintaining internal pages of error-log information Answer - c.stating the
general nature of the failure
A(n) ____ is a buffer that holds output for a device that cannot accept
interleaved data streams.
Select one:
a. cache
b. spool
c. escape
d. block device Answer - b. spool
On a read operation, the device driver first checks if the data already available
in the buffer cache.
Select one:
True
False Answer - False
AND ANSWERS | 2026 UPDATE | WITH COMPLETE SOLUTION
I/O subsystem is integrated into process manager, memory manager and file
system.
Select one:
True
False Answer - False
Device drivers
Select one:
a. manage only the basic I/O hardware elements
b. manage only the newly emerging I/O devices that are unlike previous
devices
c. All the other answers
d. present a uniform device- access interface to the I/O subsystem Answer - d.
present a uniform device- access interface to the I/O subsystem
An interrupt priority scheme can be used to ____.
Select one:
a. All the other answers
b.allow the most urgent work to be finished first
,c.defer the handling of low-priority interrupt without masking off all interrupts
d.make it possible for high-priority interrupts to preempt the execution of a
low priority interrupt Answer - a. All the other answers
DMA controllers ____.
Select one:
a.are a nonstandard component in PCs of today
b.can steal memory access cycles from the main CPU
c.do not utilize an additional, special purpose, processor
d.can access main memory at the same time as the main CPU Answer - b.can
steal memory access cycles from the main CPU
The ____ register of an I/O port can be written by the host to start a command
or to change the mode of a device.
Select one:
a. status
b. transfer
c. data-in
d. control Answer - d. control
____ I/O accesses a block device as a simple array of blocks.
Select one:
a. Raw
b. Cooked
,c. Stream
d. Indirect Answer - a. Raw
A character-stream device ____.
Select one:
a. is a device such as a disk drive
b.transfers data in blocks of bytes
c.transfers data a byte at a time
d. is similar to a random access device Answer - c.transfers data a byte at a
time
Which of the following is true of a blocking system call?
Select one:
a.The application continues to execute its code when the call is issued.
b.Blocking application code is harder to understand than nonblocking
application code
c.The call returns immediately without waiting for the I/O to complete.
d.The execution of the application is suspended when the call is issued.
Answer - d.The execution of the application is suspended when the call is
issued.
Although caching and buffering are distinct functions, sometimes a region of
memory can be used for both purposes.
Select one:
True
, False Answer - True
A sense key reports on the failure of a SCSI device by ____.
Select one:
a.giving detailed information about the exact cause of failure
b.stating the general category of failure
c.stating the general nature of the failure
d.maintaining internal pages of error-log information Answer - c.stating the
general nature of the failure
A(n) ____ is a buffer that holds output for a device that cannot accept
interleaved data streams.
Select one:
a. cache
b. spool
c. escape
d. block device Answer - b. spool
On a read operation, the device driver first checks if the data already available
in the buffer cache.
Select one:
True
False Answer - False
