SurfRAID LC16 Series, User Manual

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SurfRAID LC16 Series User’s
Manual 44
APPENDIX D. 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 subsystems, combined with a
body of
Array Management Software . Array Management Software controls the disks and pre-
sents them to the array’s 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.
FC-AL
Fibre Channel Arbitrated Loop
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 comput-
ers 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 subsystem is running.
Hot Swap
The substitution of a replacement unit in a disk subsystem for a defective one, where the substi-
tution can be performed by the subsystem itself while it continues to perform its normal function.
Hot Swaps do not require human intervention (i.e., hot spare)
Member Disks
Disk channels configured for a particular RAID Level. Member disks are identified by a status of “
0
”
displayed on the front panel LCD.
Mirroring
A form of RAID in which Array Management Software maintains two or more identical copies
of data on separate disks.
MTBF
An abbreviation for Mean Time Between Failure , the average time from start of use to failure in
a large population of identical components or devices.