Glossary-4
Adaptec Ultra320 SCSI Cards User’s Guide
I
initialized array
An array that is ready for data reads and writes.
L
logical device
A read/write resource, such as an array or spare, that does not
exist until configured by the Software Management tool.
Logical Unit Number
See
low-level format
A low-level format completely cleans any data off the hard disk.
LUN
Stands for Logical Unit Number. The number assigned to a
subdevice (logical unit) of a SCSI target. Each SCSI target can
contain up to eight subdevices numbered 0 through 7; however,
most SCSI devices contain only one subdevice (LUN 0).
M
mirroring; mirrored array
Synonym for RAID 1. Full redundancy is obtained by maintaining
identical copies of data on two or more hard disks. Mirroring
provides fault tolerance with a minor performance penalty.
monitoring
The process of receiving, displaying, and logging system events.
O
off-line array
An array that is not responding.
P
parity
In RAID, a form of redundancy used to recreate the data of a failed
hard disk in a disk array. Used in RAID levels 2, 3, 4, and 5.
U320 UG.book Page 4 Tuesday, September 23, 2003 1:47 PM
