User's Manual

P
param That portion of the HSV controller termination code display that defines:
• The 2-character parameter identifier that is a decimal number in the 0 through 30 range.
• The 8-character parameter code that is a hexadecimal number.
See also IDX and TC.
password A security interlock where the purpose is to allow:
• A management agent to control only certain storage systems
• Only certain management agents to control a storage system
PDM Power Distribution Module. A thermal circuit breaker-equipped power strip that distributes power
from a PDU to Enterprise Storage System elements.
PDU Power Distribution Unit. The rack device that distributes conditioned AC or DC power within a
rack.
physical disk A disk drive mounted in a drive enclosure that communicates with a controller pair through the
device-side Fibre Channel loops. A physical disk is hardware with embedded software, as opposed
to a virtual disk, which is constructed by the controllers. Only the controllers can communicate
directly with the physical disks.
The physical disks, in aggregate, are called the array and constitute the storage pool from which
the controllers create virtual disks.
physical disk array See array.
port A Fibre Channel connector on a Fibre Channel device.
port-colored A convention of applying the color of port or red wine to a CRU tab, lever, or handle to identify
the unit as hot-pluggable.
port_name A 64-bit unique identifier assigned to each Fibre Channel port. The port_name is communicated
during the login and port discovery processes.
power distribution
module
See PDM.
power distribution
unit
See PDU.
power supply An element that develops DC voltages for operating the storage system elements from either an
AC or DC source.
preferred address An AL_PA which a node port attempts to acquire during loop initialization.
preferred path A preference for which controller of the controller pair manages the virtual disk. This preference
is set by the user when creating the virtual disk. A host can change the preferred path of a virtual
disk at any time. The primary purpose of preferring a path is load balancing.
protocol The conventions or rules for the format and timing of messages sent and received.
Q
quiesce The act of rendering bus activity inactive or dormant. For example, “quiesce the SCSI bus
operations during a device warm-swap.”
R
rack A floorstanding structure primarily designed for, and capable of, holding and supporting storage
system equipment. All racks provide for the mounting of panels per Electronic Industries Alliance
(EIA) Standard RS310C.
rack-mounting unit A measurement for rack heights based upon a repeating hole pattern. It is expressed as “U”
spacing or panel heights. Repeating hole patterns are spaced every 1.75 inches (44.45 mm)
and based on EIA’s Standard RS310C. For example, a 3U unit is 5.25inches (133.35 mm) high,
and a 4U unit is 7.0inches (177.79 mm) high.
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