Chaparral Chaparral FS 1310 ユーザーズマニュアル

ページ / 96
 
Glossary
G-3
Loop address—Loop address is an FC term that indicates the unique ID of a node in FC 
loop topology. A loop address is sometimes referred to as a Loop ID. 
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). 
Management information 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 (for 
example, 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.
Other controller—In Active-Active mode, the opposite controller from the one 
currently being used (that is, not the local controller) is referred to as the other controller.
Ownership—In an active-active configuration, a single controller has ownership of the 
following resources: arrays and dedicated spares. When a controller fails, the other 
controller assumes temporary ownership of its resources.
Point to Point—A point-to-point connection is a communication link between two end 
systems. Chaparral uses this term to refer to a link between the controller or router (N-
port) and the F-port on a switch. The point-to-point topology is one of three FC topologies, 
in which two ports are directly connected by a link; there are no fabric, loop, or switching 
elements present. 
Router—A router is a device that enables connectivity between SCSI devices and FC 
networks. It routes each data command to the appropriate SCSI channel based on the 
address it is intended for.
SCSI adapter —A SCSI adapter is a 16-bit fast/wide or 8-bit narrow, single-ended or 
differential physical connection between a router and SCSI devices. Each SCSI adapter 
supports up to 16 (fast/wide) or 8 (narrow) SCSI devices, including itself.
SCSI addressing—Each device supported by a SCSI adapter has its own unique SCSI 
address, which dictates the device’s priority when arbitrating for access to the SCSI bus. A 
SCSI address of 7 has the highest priority. For a fast/wide SCSI adapter that supports up to 
16 devices, the next highest priority address is 6, then 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 
9, and 8. A narrow SCSI adapter supports up to eight devices, including itself. The SCSI 
address 7 has the highest priority, followed by 6, 5, 4, 3, 2, 1, and 0.
SCSI bus—A SCSI bus provides a means of transferring data between SCSI devices. A 
SCSI bus is either an 8- or 16-bit bus that supports up to 8 or 16 devices, including itself. 
The bus can consist of any mix of initiators and targets, with the requirement that at least 
one initiator and one target must be present. 
SCSI device—A SCSI device is a single unit on a SCSI bus that originates or services 
SCSI commands. A SCSI device is identified by a unique SCSI address. SCSI devices can 
act as initiators or targets.