HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Command Line Interface Reference Guide (EK-G80CL-RA. C01, March 2005)

Glossary
317HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software
Command Line Interface Reference Guide
DAEMON
Pronounced “demon.” A program usually associated with a UNIX system that performs a
utility (housekeeping or maintenance) function without being requested or even known of
by the user. A daemon is a diagnostic and execution monitor.
data center cabinet (rack)
A generic reference to large subsystem racks, such as those in which HP StorageWorks
products can be mounted.
data striping
The process of segmenting logically sequential data, such as a single file, so that segments
can be written to multiple physical devices (usually disk drives) in a round-robin fashion.
This technique is useful if the processor is capable of reading or writing data faster than a
single disk can supply or accept the data. While data is being transferred from the first disk,
the second disk can locate the next segment.
DDL
Dual data link. The ability to operate on the CI bus using both paths simultaneously to the
same remote node.
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, after the devices are made known to the controller.
The targets, initiators, hubs, converters, adapters, and similar items interconnected to form a
SCSI bus. Connectors, expanders, and hubs do not use a SCSI bus ID. See also node;
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. DILX is a diagnostic used to test the data transfer capabilities of disk
drives in a way that simulates a high level of user activity.
DIMM
Dual Inline Memory Module.