Dell Adaptec U320 SCSI Raid 0 or 1 Controller Card - Manual (Page 47)

C
cache
Fast-access memory on the controller that serves as intermediate storage for data that is read from, or written to,
drives.
capacity
Total usable space available in megabytes or gigabytes.
channel
Any path, or bus, used for the transfer of data and the control of information between storage devices and a RAID
controller.
D
degraded
A redundant (for example, a RAID 1) array in which one or more members have failed. The data is intact but
redundancy has been compromised. Any further failure would cause the array to fail and result in data loss.
discovery
The process by which information about a system or subsystem is obtained.
disk
See hard disk .
disk ID
Consists of the bus number, SCSI ID, and LUN, for example, 1:04:0. See also bus; LUN; SCSI ID.
drive light
An indicator light on a disk that illuminates during read or write operations.