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HSG80 Array Controller V8.7 Command Line Interface Reference Guide
Glossary–7
Glossary
DMA
Direct Memory Access.
DOC
DWZZA-on-a-chip. An SYM53C120 SCSI bus extender chip used to connect a SCSI bus in
one enclosure to the corresponding SCSI bus in another enclosure.
driver
A hardware device or a program that controls or regulates another device. For example, a
device driver is a driver developed for a specific device that allows a computer to operate with
the device, such as a printer or a disk drive.
dual data link
See DDL
dual-redundant configuration
A controller configuration consisting of two active controllers operating as a single controller.
If one controller fails, the other controller assumes control of the failing controller devices.
dual-simplex
A communications protocol that allows simultaneous transmission in both directions in a link,
usually with no flow control.
DUART
Dual Universal Asynchronous Receiver and Transmitter. An integrated circuit containing two
serial, asynchronous transceiver circuits.
DWZZA
A StorageWorks SCSI-bus-signal converter used to connect 8-bit single-ended devices to hosts
with 16-bit differential SCSI adapters. This converter extends the range of a single-ended
SCSI cable to the limit of a differential SCSI cable. See also SCSI bus signal converter.
DWZZB
A StorageWorks SCSI bus signal converter used to connect a variety of 16-bit single-ended
devices to hosts with 16-bit differential SCSI adapters. See also SCSI bus signal converter.
DWZZC
The 16-bit SCSI table-top SCSI bus signal converter used to extend a differential SCSI bus, or
to connect a differential SCSI bus to a single-ended SCSI bus. See also SCSI bus signal
converter.