IBM 2145UPS-1U Hardware Installation Manual page 205

dense wavelength division multiplexing (DWDM)
A technology that places many optical signals onto one single-mode fiber
using slightly different optical frequencies. DWDM enables many data
streams to be transferred in parallel.
dependent write operations
A set of write operations that must be applied in the correct order to
maintain cross-volume consistency.
destage
A write command initiated by the cache to flush data to disk storage.
device In the CIM Agent, the storage server that processes and hosts client
application requests.
IBM definition: A piece of equipment that is used with the computer and
does not generally interact directly with the system, but is controlled by a
controller.
HP definition: 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 has
been 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 have been made known to the controller.
device provider
A device-specific handler that serves as a plug-in for the Common
Information Model (CIM); that is, the CIM object manager (CIMOM) uses
the handler to interface with the device.
directed maintenance procedures
The set of maintenance procedures that can be run for a cluster. These
procedures are run from within the SAN Volume Controller application
and are documented in the IBM System Storage SAN Volume Controller:
Service Guide.
disconnected
In a Metro or Global Mirror relationship, pertains to two clusters when
they cannot communicate.
discovery
The automatic detection of a network topology change, for example, new
and deleted nodes or links.
disk controller
A device that coordinates and controls the operation of one or more disk
drives and synchronizes the operation of the drives with the operation of
the system as a whole. Disk controllers provide the storage that the cluster
detects as managed disks (MDisks).
disk drive
A disk-based, nonvolatile, storage medium.
disk zone
A zone defined in the storage area network (SAN) fabric in which the SAN
Volume Controller can detect and address the logical units that the disk
controllers present.
Distributed Management Task Force (DMTF)
An organization that defines standards for the management of distributed
systems. See also Common Information Model.
DMP See directed maintenance procedures.
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Glossary