Critical state, Cylinder, Dac960 series – Avago Technologies AcceleRAID 170LP User Manual
Page 63: Db-9, Dedicated hot spare, Degraded mode

Glossary
Manual No. DB11-000024-00
G-5
CPU
Central Processing Unit, the circuitry that performs the basic instructions
that drive the computer.
Critical State
A Logical Drive is in a “critical” state if it has been configured at RAID level
1, 3, 5, or 0+1, and one (and only one) of its SCSI drives is not “online.” A
logical drive is considered “critical” because any failure of another of its
SCSI drives may result in a loss of data.
Note: I/O operation can only be performed with system drives that are online
or critical.
Cylinder
The tracks of a disk storage device that can be accessed without
repositioning the access mechanism.
DAC960 Series
Disk Array Controller 960 Series, a family of RAID controllers from Mylex
Corporation. The DAC960 series includes both internal PCI-based RAID
controllers and external RAID controllers. The DAC960 series controllers
use Intel’s® i960 microprocessor.
DB-9
A type of connector used for serial interfaces.
Dedicated Hot Spare
A disk drive configured to replace a failed drive in a single or spanned disk
array. Compare with Global Hot Spare and Hot Spare.
Degraded Mode
A RAID mode used when a component drive has failed.