HP StorageWorks HSG80 ACS Solution Software V8.8 for Tru64 UNIX Installation and Configuration Guide (AA-RV1VA-TE, March 2005)

Glossary
272 HSG80 ACS Solution Software V8.8 for Tru64 UNIX Installation and Configuration Guide
controller A hardware device that, with proprietary software, facilitates
communications between a host and one or more devices organized in
an array. The HSG80 family controllers are examples of array
controllers.
copying A state in which data to be copied to the mirrorset is inconsistent with
other members of the mirrorset. See also normalizing.
copying
member
Any member that joins the mirrorset after the mirrorset is created is
regarded as a copying member. Once all the data from the normal
member (or members) is copied to a normalizing or copying member,
the copying member then becomes a normal member. See also
normalizing member.
CSR An acronym for control and status register.
daemon Pronounced “demon.” A program usually associated with a UNIX
systems 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
A generic reference to large subsystem cabinets, such as the cabinets in
which StorageWorks components 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 See 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.
DIMM Dual inline Memory Module.
dirty data The write-back cached data that has not been written to storage media,
even though the host operation processing the data has completed.
DMA Direct Memory Access.