Mbyte

(Megabyte) An abbreviation for 1,000,000 (10 to the sixth power) bytes.

 

One Mbyte equals 1,000 Kbytes (kilobytes).

Multi-threaded

Having multiple concurrent or pseudo-concurrent execution sequences.

 

Used to describe processes in computer systems. Multi-threaded

 

processes allow throughput-intensive applications to efficiently use a disk

 

array to increase I/O performance.

Operating Environment

The operating environment includes the host computer where the array is attached, any I/O buses and adapters, the host operating system, and any additional software required to operate the array. For host-based arrays, the operating environment includes I/O driver software for the member disks, but does not include array management software, which is regarded as part of the array itself.

Parity

Parity is an extra bit added to a byte or word to reveal errors in storage

 

(in RAM or disk) or transmission. Parity is used to generate a set of

 

redundancy data from two or more parent data sets. The redundancy

 

data can be used to reconstruct one of the parent data sets, although it

 

does not fully duplicate the parent data sets. In RAID, this method is

 

applied to entire drives or stripes across all disk drives in an array. Parity

 

data is distributed among all the drives in the system. If a single disk

 

drive fails, the drive can be rebuilt from the parity of the respective data

 

on the remaining drives.

Partition

An array virtual disk made up of logical disks rather than physical ones.

 

Also known as logical volume.

Physical Disk

A hard disk drive that stores data. A hard disk drive consists of one or

 

more rigid magnetic discs rotating about a central axle with associated

 

read/write heads and electronics.

Physical Disk

The ability of some adapters to detect when disk drives have been

Roaming

moved to a different slot in the computer—for example, after a hot swap.

Protocol

A set of formal rules describing how to transmit data, especially across

 

a network. Low level protocols define the electrical and physical

 

standards to be observed, bit- and byte- ordering, and the transmission

 

and error detection and correction of the bit stream. High level protocols

 

deal with the data formatting, including the message syntax, the terminal-

 

to-computer dialogue, character sets, and sequencing of messages.

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