Glossary-4 Sixth Edition 95741
Glossary
host The primary computer on a network,
with which other computers interact.
host bus adapter (HBA) A circuit installed
in a multi-platform host or device that
interfaces between the device and the bus.
host interface Interface between a network
and host computer. (T)
hub A piece of hardware, separate from the
actual FC interface accessible on the
backplane of a device, which houses the port
bypass circuitry for configurations of 8 to 16
ports per hub. Hubs may be cascaded to
support larger configurations, and can usually
support a mix of both electrical and optical
media ports in the same hub.

I

indicator A device that gives a visual or
other indication of the existence of a defined
state. (T)
initialization The operations required for
setting a device to a starting state, before the
use of a data medium, or before
implementation of a process. (T)
Initial Program Load (IPL) The
initialization procedure that causes an
operating system to commence operation.
input/output (I/O) Pertaining to a device,
process, or channel involved in data input,
data output, or both. (IBM)
interface Hardware, software, or both, that
links systems, programs, or devices. (IBM)
I/O See input /output.
IPL See Initial Program Load.

L

laser A term meaning Light Amplification by
Stimulated Emission of Radiation. Laser
devices generate coherent radiation in the
visible, ultraviolet, and infrared portions of
the electromagnetic spectrum. Regarding FC,
lasers can be transmitting either short waves
or long waves, depending on the
composition of the arbitrated loop or fabric.
library installation The process of
installing the 9840 Tape Drive in a library
environment.
link A two-fiber connection made between
two FC ports in which one fiber is
transmitting, the other receiving, information.
logical device address A number used to
represent a terminal or terminal component
within a workstation. (IBM)

M

magnetic tape A tape with a magnetizable
layer on which data can be stored. (T)
manual operation Processing of data in a
system by direct manual techniques. (IBM)
MB Megabytes, or 1,048,576 bytes.
media defects Physical impurities or other
problems that cause the medium to function
improperly.
medium A physical material in or on which
data may be represented. (IBM)
menu A list of options displayed to the user
by a data processing system, from which the
user can select an action to be initiated. (T)
microcode A code, representing the
instructions of an instruction set, that is
implemented in a part of storage that is not
program-addressable. (IBM)

N

N_Port A Port within the Node that attaches
to a link.
network An arrangement of nodes and
branches, connecting data processing devices