HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Troubleshooting Guide (EK-G80TS-SA. C01, March 2005)

Glossary
280 HSG60 and HSG80 Array Controller and Array Controller Software Troubleshooting Guide
device
In its physical form, a magnetic disk that can be attached to a SCSI bus. The term is also
used to indicate a physical device that is made part of a controller configuration; that is, a
physical device that is known to the controller. Units (virtual disks) can be created from
devices, once the devices have been made known to the controller.
The targets, initiators, hubs, converters, adapters, and similar items are interconnected to
form a SCSI bus. Connectors, expanders, and hubs do not use a SCSI bus ID.
See also node and peripheral device.
differential I/O module
A 16-bit I/O module with SCSI bus converter circuitry for extending a differential SCSI
bus.
See also I/O module.
differential SCSI bus
A bus in which a signal level is determined by the potential difference between two wires.
A differential bus is more robust and less subject to electrical noise than is a single-ended
bus.
DILX
Disk Inline Exerciser. The controller diagnostic utility used to test the data transfer
capabilities of units in a way that simulates a high level of user activity.
DIMM
Dual inline memory module.
dirty data
The writeback cached data that has not been written to storage media, even though the host
operation processing the data has completed.
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 devices, such as a printer or a disk drive.