Chap 11

Question 1

Examples of human-readable external I/O devices are printers, terminals, and keyboards.

Answer 1

TRUE

Question 2

The use to which a device is put does not have an influence on the software and policies in the operating system and supporting utilities.

Answer 2

FALSE

Question 3

Direct memory access is the dominant form of transfer that must be supported by the operating system.

Answer 3

TRUE

Question 4

The hierarchical philosophy is that the functions of the operating system should be separated according to their complexity, their characteristic time scale, and their level of abstraction.

Answer 4

TRUE

Question 5

The actual queuing and scheduling of I/O operations occurs at the logical I/O module.

Answer 5

FALSE

Question 6

Access rights are managed at the physical organization layer.

Answer 6

FALSE

Question 7

Double buffering is when a process transfers data to (or from) one buffer while the operating system empties (or fills) the other.

Answer 7

TRUE

Question 8

RAID 0 provides real-time backups of all data so that in the event of a disk failure, all of the critical data is still immediately available.

Answer 8

FALSE

Question 9

The SCAN policy favors jobs whose requests are for tracks nearest to both innermost and outermost tracks, and favors the latest arriving jobs.

Answer 9

TRUE

Question 10

RAID is a set of physical disk drives viewed by the operating system as a single logical drive.

Answer 10

TRUE

Question 11

Windows has no way to support the encryption of entire volumes.

Answer 11

FALSE

Question 12

Cache memory reduces average memory access time by exploiting the principle of locality.

Answer 12

TRUE

Question 13

A key aspect of I/O is the use of buffers that are controlled by I/O utilities rather than by application processes.

Answer 13

TRUE

Question 14

Two of the most widely used approaches to improve disk I/O performance are disk scheduling and disk cache.

Answer 14

TRUE

Question 15

In the C-SCAN disk scheduling algorithm, the disk arm is required to move in one direction only until it reaches the last track or there are no more requests to service in that direction, then it reverses direction, and the scan proceeds in the opposite direction in the same fashion.

Answer 15

FALSE

Question 16

The __________ category of external devices is suitable for communicating with the computer user.

Answer 16

human-readable

Question 17

The __________ unit is capable of mimicking the processor and of taking over control of the system bus just like a processor.

Answer 17

direct memory access

Question 18

__________ external devices are suitable for communicating with electronic equipment.

Answer 18

Machine-readable

Question 19

The requested operations and data are converted into appropriate sequences of I/O instructions, channel commands, and controller orders at the __________ layer.

Answer 19

device I/O

Question 20

__________ external devices are suitable for communicating with modems.

Answer 20

Communication

Question 21

__________ is a technique that smoothes out peaks in I/O demand.

Answer 21

Buffering

Question 22

The advantage of _________ is that it provides extremely high data availability.

Answer 22

RAID 6

Question 23

The _________ technique is used on a Windows server to optimize the use of threads.

Answer 23

I/O completion ports

Question 24

On a moveable-head system, the time it takes to position the head at the track is known as ________.

Answer 24

seek time

Question 25

The advantage of __________ is that it provides extremely high data availability.

Answer 25

RAID 6

Question 26

The __________ technique allows multiple simultaneous I/O requests against a single device or file.

Answer 26

signaling an event object

Question 27

__________ are an efficient way of making consistent snapshots of volumes so that they can be backed up.

Answer 27

Shadow copies

Question 28

RAID 5 is organized in a similar fashion to _________, but is different in the fact that RAID 5 distributes the parity strips across all disks.

Answer 28

RAID 4

Question 29

The disk scheduling algorithm that implements two sub-queues in a measure to avoid the problem of "arm stickiness" is the __________.

Answer 29

FSCAN policy

Question 30

The simplest type of support that the operating system can provide is _________.

Answer 30

single buffering

Question 31

External devices that engage in I/O with computer systems are grouped into three categories: human readable, machine-readable, and __________.

Answer 31

Communication

Question 32

Disk drives, USB keys, sensors, and controllers are examples of __________ external I/O devices.

Answer 32

Machine Readable

Question 33

A __________ module controls the exchange of data between main memory and an I/O module.

Answer 33

Direct Memory Access

Question 34

Two objectives are paramount in designing the I/O facility: generality and __________.

Answer 34

Efficiency

Question 35

The __________ module deals with the device as a logical resource and is not concerned with the details of actually controlling the device.

Answer 35

Logical I/O

Question 36

The _________ layer deals with the logical structure of files and with the operations that can be specified by users, such as open, close, read, and write.

Answer 36

File System

Question 37

At the _________ layer, symbolic file names are converted to identifiers that either reference the file directly or indirectly through a file descriptor or index table.

Answer 37

Directory Management

Question 38

The __________ policy is to select the disk I/O request that requires the least movement of the disk arm from its current position.

Answer 38

Shortest service time first

Question 39

A __________ transfers data in and out as a stream of bytes, with no block structure.

Answer 39

stream-orientated device

Question 40

When more than two buffers are used, the collection of buffers is itself referred to as a __________, with each individual buffer being one unit.

Answer 40

circular buffer

Question 41

The sum of the seek time and the rotational delay equals the __________, which is the time it takes to get into a position to read or write.

Answer 41

access time

Question 42

The simplest form of scheduling is ___________ scheduling, which processes items from the queue in sequential order.

Answer 42

FIFO

Question 43

A set of logically consecutive strips that maps exactly one strip to each array member is referred to as a __________.

Answer 43

stripe

Question 44

The term _________ is usually used to apply to a memory that is smaller and faster than main memory and that is interposed between the aid memory and the processor.

Answer 44

cache memory

Question 45

Windows supports two sorts of RAID configurations: Software RAID and ________.

Answer 45

hardware raid