IBM Enterprise Storage Server 2105 E10, Introduction And Planning Manual

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FRU. See field replaceable unit.
full duplex. See duplex.
G
GB. See gigabyte.
gigabyte (GB). A gigabyte of storage is 10
9
bytes. A
gigabyte of memory is 2
30
bytes.
group. See DDM group.
H
HA. See host adapter.
hard disk drive (HDD). (1) A storage medium within a
storage server used to maintain information that the
storage server requires. (2) A mass storage medium for
computers that is typically available as a fixed disk
(such as the disks used in system units of personal
computers or in drives that are external to a personal
computer) or a removable cartridge.
HDA. See
head and disk assembly.
HDD. See
hard disk drive.
hdisk. An AIX term for storage space.
head and disk assembly (HDA). The portion of an
HDD associated with the medium and the read/write
head.
home address. A nine-byte field at the beginning of a
track that contains information that identifies the
physical track and its association with a cylinder.
host adapter (HA). A physical subunit of a storage
controller that provides the ability to attach to one or
more host I/O interfaces.
host processor. A processor that controls all or part of
a user application network. In a network, the processing
unit in which the data communication access method
resides. See
host system.
host system. (1) A data processing system used to
prepare programs and operating environments for use
on another computer or controller. (2) The data
processing system to which a network is connected and
with which the system can communicate. (3) The
controlling or highest level system in a data
communication configuration.
hot plug. Pertaining to the ability to add or remove a
hardware facility or resource to a unit while power is on.
I
IBM product engineering (PE). The third-level of IBM
service support. Product engineering is composed of
IBM engineers who have experience in supporting a
product or who are knowledgeable about the product.
ID. See identifier.
identifier (ID). A unique name or address that
identifies things such as programs, devices, or systems.
implicit allegiance. In the ESA/390 architecture, a
relationship that a controller creates between a device
and a channel path when the device accepts a read or
write operation. The controller guarantees access to the
channel program over the set of channel paths that it
associates with the allegiance.
initial program load (IPL). The initialization procedure
that causes an operating system to commence
operation.
initiator. A SCSI term for the part of a host computer
that communicates with its attached targets.
i-node. The internal structure in an AIX operating
system that describes the individual files in the
operating system. It contains the code, type, location,
and owner of a file.
input/output (I/O). Pertaining to (a) input, output, or
both or (b) a device, process, or channel involved in
data input, data output, or both.
Internet Protocol (IP). In the Internet suite of
protocols, a protocol without connections that routes
data through a network or interconnecting networks and
acts as an intermediary between the higher protocol
layers and the physical network.
invalidate. The action of removing a logical data unit
from cache memory because it cannot support
continued access to the logical data unit on the device.
This removal may be the result of a failure within the
storage controller or a storage device that is associated
with the device.
I/O. See input/output.
I/O device. An addressable read and write unit, such
as a disk drive device, magnetic tape device, or printer.
I/O interface. An interface that you define to allow a
host to perform read and write operations with its
associated peripheral devices.
IP. See Internet Protocol.
IPL. See initial program load.
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