Glossary
GL–7
single-ended bus
A bus in which the voltage of a single wire in relation to ground determines
each signal’s logic level.
small computer
system interface
See SCSI.
StorageWorks
The set of enclosure products that allows customers to design and configure
their storage subsystem. Components include power, packaging, and
interconnections in a StorageWorks enclosure. SBBs and array controllers are
integrated therein to form storage subsystems. System-level enclosures to
house the enclosures and standard mounting devices for SBBs are also
included.
target
A SCSI device that performs an operation requested by an initiator.
terminator
The interconnect component that form the ends of the transmission lines in
bus segments. A SCSI domain must have at least one segment and therefore at
least two terminators. The terminators ensure that inactive SCSI bus signals
are in a known state.
There are two basic types of terminators—active and passive:
•
Single-ended bus segments use active, linear terminators.
•
Differential bus segments use a passive (linear totem pole) terminators
except for special cases where the electrical transmission lines are very
short and only one termination or pull-up is required.
UL
Underwriters Laboratories. An organization that tests and certifies electrical
devices.
Ultra SCSI
An improvement in SCSI technology invented in 1993 by the Digital
Equipment Corporation StorageWorks Engineering Group. Subsequently the
ANSI SCSI standards committee issued standard X3T10 for Ultra SCSI.
The Ultra SCSI improvements over FAST SCSI include the following:
•
Maximum transfer rate increases from 10 Mb/s to 20 Mb/s
•
Maximum wide bus bandwidth increases from 20 MB/s to 40 MB/s
•
VHDCI cables and connectors are significantly thinner and smaller
Also known as FAST 20.
Underwriters
Laboratories
See UL.
