Glossary
Glossary-4
Compaq Smart Array 5i Plus Controller and Battery Backed Write Cache Enabler User Guide
COMPAQ CONFIDENTIAL
Writer: Amy L. Laffitte File Name: q-glossary
Codename: Executor Part Number: 266328-001 Last Saved On: 2/4/02 4:28 PM
LVDS (low voltage differential signaling)
A type of SCSI signaling that allows a maximum transfer rate of either 80 MB/s or 160 MB/s,
conforming to either the Wide Ultra2 or Wide Ultra3 SCSI standards respectively.
online spare
Also known as a hot spare, this is a drive in a fault-tolerant system that normally contains no
data. When any other drive in the array fails, the controller automatically rebuilds the missing
data that was on the failed drive onto the online spare. The controller constructs the missing
data from the duplicate or parity data that is on the remaining drives in the array.
ORCA (Option ROM Configuration for Arrays) utility
A ROM-based configuration utility for users who have simple configuration requirements.
POST (Power-On Self-Test)
A series of diagnostic tests that run automatically each time the server is started or reset.
RAID (Redundant Array of Independent Disks)
A form of fault tolerance. RAID 0 (no fault tolerance) uses data striping to distribute data
evenly across all physical drives in the array, but has no redundant data. RAID 1+0
(drive
mirroring) duplicates data from one drive onto a second drive. RAID 5 (distributed data
guarding) distributes parity data across all drives in the array, and uses the parity data and
data on remaining drives to reconstruct data from a failed drive. RAID ADG (advanced data
guarding) is similar to RAID 5, but uses two independent sets of parity data. See Appendix D
for more details.
rebuild
See
Automatic Data Recovery.
ROMPaq utility
A utility for updating the system or option firmware, available on the SmartStart and Support
Software CD or from the Compaq website (www.compaq.com). Your system must support
flashing to be able to take advantage of the ROMPaq utility.
SCSI ID
A unique ID number assigned to each SCSI device connected to a SCSI bus. The ID number
determines the device priority on the SCSI bus; ID 7 is the highest priority and is always
assigned to the SCSI controller.