Operating Systems for Programmers - Module 4 - Post-Quiz

Question 1

The surface of a magnetic disk platter is divided into ____.

Accepted Answer

tracks

Answer

sectors

Answer

arms

Answer

cylinders

Question 2

A(n) ____ file is a sequence of functions.

Accepted Answer

source

Answer

text

Answer

object

Answer

executable

Question 3

Transfers between memory and disk are performed a ____.

Accepted Answer

block at a time

Answer

byte at a time

Answer

file at a time

Answer

sector at a time

Question 4

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.

Accepted Answer

control

Answer

status

Answer

data-in

Answer

transfer

Question 5

On media that uses constant linear velocity, the ____.

Accepted Answer

density of bits per track is uniform

Answer

disk's rotation speed increases as the head moves towards the middle of the disk from either side

Answer

disk's rotation speed remains constant

Answer

density of bits decreases from the inner tracks to the outer tracks

Question 6

An interrupt priority scheme can be used to ____.

Accepted Answer

all of the above

Answer

allow the most urgent work to be finished first

Answer

make it possible for high-priority interrupts to preempt the execution of a low priority interrupt

Answer

defer the handling of a low-priority interrupt without masking off all interrupts

Question 7

DMA controllers ____.

Accepted Answer

can steal memory access cycles from the main CPU

Answer

do not utilize an additional, special purpose, processor

Answer

are a nonstandard component in PCs of today

Answer

can access main memory at the same time as the main CPU

Question 8

A character-stream device ____.

Accepted Answer

transfers data a byte at a time

Answer

transfers data in blocks of bytes

Answer

is a device such as a disk drive

Answer

is similar to a random access device

Question 9

____ I/O accesses a block device as a simple array of blocks.

Accepted Answer

Raw

Answer

Stream

Answer

Indirect

Answer

Cooked

Question 10

Which of the following allocation methods ensures that only one access is needed to get a disk block using direct access?

Accepted Answer

contiguous allocation

Answer

linked allocation

Answer

indexed allocation

Answer

hashed allocation

Question 11

Which of the following is true of a blocking system call?

Accepted Answer

The execution of the application is suspended when the call is issued.

Answer

The application continues to execute its code when the call is issued.

Answer

The call returns immediately without waiting for the I/O to complete.

Answer

Blocking application code is harder to understand than non-blocking application code.

Question 12

Consider a disk queue holding requests to the following cylinders in the listed order: 116, 22, 3, 11, 75, 185, 100, 87. Using the SSTF scheduling algorithm, what is the order in which the requests are serviced, assuming the disk head is at cylinder 88 and moving upward through the cylinders?

Accepted Answer

87 - 75 - 100 - 116 - 185 - 22 - 11 - 3

Answer

116 - 22 - 3 - 11 - 75 - 185 - 100 - 87

Answer

100 - 116 - 185 - 87 - 75 - 22 - 11 - 3

Answer

100 - 116 - 185 - 3 - 11 - 22 - 75 - 87

Question 13

A(n) ____ is a buffer that holds output for a device that cannot accept interleaved data streams.

Accepted Answer

spool

Answer

escape

Answer

block device

Answer

cache

Question 14

The simplest file access method is ____.

Accepted Answer

sequential access

Answer

logical access

Answer

relative access

Answer

direct access

Question 15

A sense key reports on the failure of a SCSI device by ____.

Accepted Answer

stating the general nature of the failure

Answer

stating the general category of failure

Answer

giving detailed information about the exact cause of failure

Answer

maintaining internal pages of error-log information

Question 16

A(n) ____ is a front-end processor that multiplexes the traffic from hundreds of remote terminals into one port on a large computer.

Accepted Answer

terminal concentrator

Answer

network daemon

Answer

I/O channel

Answer

context switch coordinator

Question 17

Host-attached storage is ____.

Accepted Answer

accessed via local I/O ports

Answer

a special purpose storage system that is accessed remotely over a data network

Answer

not suitable for hard disks

Answer

not suitable for use in raid arrays

Question 18

Which of the following is true of the direct access method?

Accepted Answer

It allows programs to read and write records in no particular order.

Answer

It is the most common mode of access.

Answer

Files are made up of records of variable lengths.

Answer

It is not a good method for accessing large amounts of data quickly.

Question 19

Which of the following is a principle that can improve the efficiency of I/O?

Accepted Answer

Move processing primitives into hardware.

Answer

Increase the number of context switches.

Answer

Use small data transfers.

Answer

Decrease concurrency using DMA controllers.

Question 20

Swap space management ____.

Accepted Answer

tries to provide the best throughput for the virtual memory system

Answer

is a high-level operating system task

Answer

is primarily used to increase the reliability of data in a system

Answer

none of the above

Question 21

RAID level ____ is the most common parity RAID system.

Accepted Answer

5

Answer

0

Answer

0+1

Answer

4

Question 22

Which of the following disk head scheduling algorithms does not take into account the current position of the disk head?

Accepted Answer

FCFS

Answer

SSTF

Answer

SCAN

Answer

LOOK

Question 23

The file-allocation table (FAT) used in MS-DOS is an example of _____.

Accepted Answer

linked allocation

Answer

contiguous allocation

Answer

indexed allocation

Answer

multilevel index

Question 24

Which of the following is a key property of an immutable file?

Accepted Answer

The file name may not be reused.

Answer

The contents of the file may be altered.

Answer

It is difficult to implement in a distributed system.

Answer

The file name may be reused.

Question 25

Which of the following statements is false?

Accepted Answer

Typically, entire processes are swapped into memory.

Answer

Swapping works in conjunction with virtual memory techniques.

Answer

Some systems allow for multiple swap spaces (disks).

Answer

Solaris only swaps pages of anonymous memory.

Question 26

A mount point is _____.

Accepted Answer

the location within the file structure where the file system is to be attached

Answer

a root of the file system

Answer

a location of a shared file system

Answer

only appropriate for shared file systems

Question 27

Which of the following statements regarding the WAFL file system is incorrect?

Accepted Answer

It provides little replication.

Answer

Clones are similar to snapshots.

Answer

WAFL is used exclusively on networked file servers.

Answer

Part of caching uses non-volatile RAM (NVRAM).

Question 28

A _____ is a private network connecting servers and storage units.

Accepted Answer

storage area network

Answer

host-attached storage

Answer

network-attached storage

Answer

private area network

Question 29

Which of the following statements regarding solid state disks (SSDs) is false?

Accepted Answer

They generally consume more power than traditional hard disks.

Answer

They have the same characteristics as magnetic hard disks, but can be more reliable.

Answer

They are generally more expensive per megabyte than traditional hard disks.

Answer

They have no seek time or latency.

Question 30

A __________ contains the same pages for memory-mapped IO as well as ordinary IO.

Accepted Answer

unified buffer cache

Answer

double cache

Answer

unified virtual memory

Answer

page cache

Operating Systems for Programmers - Module 4 - Post-Quiz

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