Chap 11 Flashcards
Examples of human-readable external I/O devices are printers, terminals, and keyboards.
TRUE
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.
FALSE
Direct memory access is the dominant form of transfer that must be supported by the operating system.
TRUE
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.
TRUE
The actual queuing and scheduling of I/O operations occurs at the logical I/O module.
FALSE
Access rights are managed at the physical organization layer.
FALSE
Double buffering is when a process transfers data to (or from) one buffer while the operating system empties (or fills) the other.
TRUE
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.
FALSE
The SCAN policy favors jobs whose requests are for tracks nearest to both innermost and outermost tracks, and favors the latest arriving jobs.
TRUE
RAID is a set of physical disk drives viewed by the operating system as a single logical drive.
TRUE
Windows has no way to support the encryption of entire volumes.
FALSE
Cache memory reduces average memory access time by exploiting the principle of locality.
TRUE
A key aspect of I/O is the use of buffers that are controlled by I/O utilities rather than by application processes.
TRUE
Two of the most widely used approaches to improve disk I/O performance are disk scheduling and disk cache.
TRUE
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.
FALSE
The __________ category of external devices is suitable for communicating with the computer user.
human-readable
The __________ unit is capable of mimicking the processor and of taking over control of the system bus just like a processor.
direct memory access
__________ external devices are suitable for communicating with electronic equipment.
Machine-readable
The requested operations and data are converted into appropriate sequences of I/O instructions, channel commands, and controller orders at the __________ layer.
device I/O
__________ external devices are suitable for communicating with modems.
Communication
__________ is a technique that smoothes out peaks in I/O demand.
Buffering
The advantage of _________ is that it provides extremely high data availability.
RAID 6
The _________ technique is used on a Windows server to optimize the use of threads.
I/O completion ports
On a moveable-head system, the time it takes to position the head at the track is known as ________.
seek time
The advantage of __________ is that it provides extremely high data availability.
RAID 6
The __________ technique allows multiple simultaneous I/O requests against a single device or file.
signaling an event object
__________ are an efficient way of making consistent snapshots of volumes so that they
can be backed up.
Shadow copies
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.
RAID 4
The disk scheduling algorithm that implements two sub-queues in a measure to avoid the problem of “arm stickiness” is the __________.
FSCAN policy
The simplest type of support that the operating system can provide is _________.
single buffering
External devices that engage in I/O with computer systems are grouped into three categories: human readable, machine-readable, and __________.
Communication
Disk drives, USB keys, sensors, and controllers are examples of __________ external I/O devices.
Machine Readable
A __________ module controls the exchange of data between main memory and an I/O module.
Direct Memory Access
Two objectives are paramount in designing the I/O facility: generality and __________.
Efficiency
The __________ module deals with the device as a logical resource and is not concerned with the details of actually controlling the device.
Logical I/O
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.
File System
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.
Directory Management
The __________ policy is to select the disk I/O request that requires the least movement of
the disk arm from its current position.
Shortest service time first
A __________ transfers data in and out as a stream of bytes, with no block structure.
stream-orientated device
When more than two buffers are used, the collection of buffers is itself referred to as a __________, with each individual buffer being one unit.
circular buffer
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.
access time
The simplest form of scheduling is ___________ scheduling, which processes items from the queue in sequential order.
FIFO
A set of logically consecutive strips that maps exactly one strip to each array member is referred to as a __________.
stripe
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.
cache memory
Windows supports two sorts of RAID configurations: Software RAID and ________.
hardware raid
