Appendix B – Glossary
47
A
A
p
p
p
p
e
e
n
n
d
d
i
i
x
x
B
B
G
G
G
l
l
l
o
o
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s
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s
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a
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r
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y
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y
Array
See Disk Array.
Array Management Software
The body of software, that provides common control and management for a disk array. Array
Management Software most often executes in a disk controller or intelligent host bus adapter,
but may also execute in a host computer. When it executes in a disk controller or adapter, Array
Management Software is often referred to as Firmware.
Cache
Controller memory used to speed up data transfer to and from a disk.
Disk Array
A collection of disks from one or more commonly accessible disk controllers, combined with a
body of Array Management Software. Array Management Software controls the disks and
presents them to the array operating environment as one or more virtual disks.
Firmware
See Array Management Software.
Host Computer
Any computer system to which disks are directly attached and accessible for I/O. Mainframes,
and servers, as well as workstations and personal computers, can all be considered host
computers in the context of this manual, as long as they have disks attached to them.
Parity
Parity information is redundancy information calculated from actual data values. If any single
piece of data is lost, the data remaining and the parity information can be used together to
compute the lost data. Parity information can either be stored on a separate, dedicated drive, or
be mixed with the data across all the drives in the array.
