Deck 11: Io Management and Disk Scheduling

Question 1

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

Answer 1

True

Question 2

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

Answer 2

False

Question 3

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

Answer 3

True

Question 4

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

A) interrupt-driven I/O
B) I/O channel
C) direct memory access
D) programmed I/O

Question 5

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.

Question 6

__________ external devices are suitable for communicating with electronic equipment.

A) Communication
B) Application
C) Machine readable
D) Human readable

Question 7

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

Question 8

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

Question 9

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

A) application
B) machine readable
C) communication
D) human readable

Question 10

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

A) device I/O
B) scheduling and control
C) logical I/O
D) physical organization

Question 11

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

Question 12

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

Question 13

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.

Question 14

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

Question 15

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

Question 16

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

Question 17

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

Question 18

__________ external devices are suitable for communicating with modems.

A) Human readable
B) Application
C) Machine readable
D) Communication

Question 19

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.

Question 20

Access rights are managed at the physical organization layer.

Question 21

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

Question 22

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.

Question 23

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

Question 24

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

A) C-SCAN policy
B) FSCAN policy
C) DMA
D) N-step-SCAN policy

Question 25

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

Question 26

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

A) asynchronous procedure call
B) signaling an event object
C) polling
D) signaling the file object

Question 27

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

A) Photo copies
B) Process copies
C) Transfer copies
D) Shadow copies

Question 28

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

A) overflow buffering
B) dual buffering
C) single buffering
D) circular buffering

Question 29

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

A) Buffering
B) Blocking
C) Smoothing
D) Tracking

Question 30

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.

A) RAID 3
B) RAID 2
C) RAID 1
D) RAID 4

Question 31

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

A) access time
B) seek time
C) transfer time
D) rotational delay

Question 32

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

Question 33

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.

Question 34

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

A) RAID 3
B) RAID 6
C) RAID 5
D) RAID 4

Question 35

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

Question 36

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

Question 37

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

A) polling
B) asynchronous procedure call
C) signaling an event object
D) I/O completion ports

Question 38

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

Question 39

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

A) RAID 2
B) RAID 4
C) RAID 0
D) RAID 6

Question 40

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

Question 41

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

Question 42

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

Question 43

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

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 main memory and the processor.

Question 45

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