APPENDIX E : Glossary
Array Management Software, Firmware
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.
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.
Disk Striping
Data distributed across all the disks in the array. There is no redundant information
generated or stored.
Disk Mirroring
Data is duplicated on different sets of disks in the array.
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 book, as long as they have disks
attached to them.
Hot Spare
The substitution of a replacement unit in a disk system for defective one, where the
substitution can be performed while the controller is running.
Hot Swap
The substitution of a replacement unit in a disk controller for a defective one, where the
substitution can be performed by the controller itself while it continues to perform its
normal function. Hot Swaps do not require human intervention (i.e., hot spare)
Member Disks
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Disk channels configured for a particular RAID Level. Member disks are identified by a
status of
” displayed on the front panel LCD.
