Installation guide

G-4 AcceleRAID 150 Installation Guide
Logical Drives
See “System Drives.”
LVD – Low Voltage Differential
Low Voltage Differential is a form of SCSI signalling that was introduced
with Ultra2 SCSI. Low Voltage Differential allows cable lengths of up to 12
meters (approximately 39 feet) with up to 15 devices. The devices need to be
Ultra2 SCSI LVD devices in order to take advantage of the LVD signalling.
LVD uses data high and data low signal lines to increase transmission
distances over those of single-ended (conventional SCSI signalling). LVD
differs from conventional differential signalling. LVDs advantages are that it
consumes less power and it can sense single-ended devices on the bus and
revert to single-ended signalling.
Mirroring
Refers to the 100 percent duplication of data on one disk drive to another
disk drive. Each disk will be the mirror image of the other.
Pack
See “Drive Groups (or Drive Packs).”
Parity
See “Rotated XOR Redundancy.”
PCI
Peripheral Component Interconnect – This is a high-performance, backplane
interface, expansion slot architecture that is found on PCs, Macintoshes, and
UNIX workstations. PCI is a standardized architecture that provides a high-
speed data path between peripherals and the CPU. PCI cards are portable
across hardware platforms with the help of various software drivers.