DataDirect Networks EF2800, User Manual

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G l o s s a r y
DataDirect Networks EF2800 FC RAID Storage System User Guide (V 1.0)
335
Loop Resil-
iency Cir-
cuit (LRC):
Circuits within the
SM modules
which provide loop resiliency in the
event of a drive failing or being unplugged.
Low Voltage
Differential
(LVD)
LVD is a method of powering SCSI cables that will be formalized in the
SCSI-3 specifications. LVD uses less power than the current differential
drive (HVD), is less expensive, and allows for higher speeds such as
those of Ultra2 SCSI. LVD requires 3.3 volts (versus 5 volts for HVD).
LRC I/O mod-
ule
A plug-in Input/Output module used to connect the internal FC-AL
channels from the EF2800 backplane to the rear of the enclosure.
Management
Informa-
tion Base
(MIB)
A MIB is a database of managed objects accessed by network
management protocols. An SNMP MIB is a set of parameters that an
SNMP management station can query or set in the SNMP agent of a
network device (such as a router).
mapping table A mapping table is a table indexed by sequential LUN values. The values
indicate select bus:target:LUN devices. Mapping tables are used by
some routers to perform FC-to-SCSI operations by default.
Module (drive
carrier,
power sup-
ply/cool-
ing, storage
manager)
A module is a power supply, disk drive or electronics unit held in a
carrier that plugs into a bay inside the enclosure. An EF2800 enclosure
can contain sixteen
drive carrier modules
, two
power supply/cooling
modules
and two
Storage Manager modules
.
Operating sys-
tem
The software running the host computer. For example, on PCs it is
often Windows 95/98, Windows NT or OS/2 and on Hewlett-Packard
machines it could be HP-UX.
other control-
ler or SM
The opposite controller or Storage Module (SM) from the one currently
being used (that is, not the local controller or SM that you are
connected to) is referred to as the other.