IBM TotalStorage DS4100, Installation, User'S, And Maintenance Manual

Page: 167 / 180

Internet Protocol (IP). A protocol that routes data
through a network or interconnected networks. IP acts
as an intermediary between the higher protocol layers
and the physical network.
Internet Protocol (IP) address. The unique 32-bit
address that specifies the location of each device or
workstation on the Internet. For example, 9.67.97.103 is
an IP address.
interrupt request (IRQ). A type of input found on
many processors that causes the processor to suspend
normal processing temporarily and start running an
interrupt handler routine. Some processors have several
interrupt request inputs that allow different priority
interrupts.
IP. See Internet Protocol .
IPL. See initial program load .
IRQ. See interrupt request .
ISA. See Industry Standard Architecture .
isolated group. A collection of isolated devices not
connected to the storage area network (SAN) but
discovered by the SANavigator tool. The isolated group
displays with a gray background near the bottom of the
Physical and Data Path maps.
Java Runtime Environment (JRE). A subset of the
Java Development Kit (JDK) for end users and
developers who want to redistribute the Java Runtime
Environment (JRE). The JRE consists of the Java virtual
machine, the Java Core Classes, and supporting files.
JRE. See Java Runtime Environment .
label. A discovered or user entered property value that
is displayed underneath each device in the Physical and
Data Path maps.
LAN. See local area network .
LBA. See logical block address .
local area network (LAN). A computer network
located on a user’s premises within a limited geographic
area.
logical block address (LBA). The address of a logical
block. Logical block addresses are typically used in
hosts’ I/O commands. The SCSI disk command
protocol, for example, uses logical block addresses.
logical partition (LPAR). (1) A subset of a single
system that contains resources (processors, memory,
and input/output devices). A logical partition operates as
an independent system. If hardware requirements are
met, multiple logical partitions can exist within a system.
(2) A fixed-size portion of a logical volume. A logical
partition is the same size as the physical partitions in its
volume group. Unless the logical volume of which it is a
part is mirrored, each logical partition corresponds to,
and its contents are stored on, a single physical
partition. (3) One to three physical partitions (copies).
The number of logical partitions within a logical volume
is variable.
logical unit number (LUN). An identifier used on a
small computer system interface (SCSI) bus to
distinguish among up to eight devices (logical units) with
the same SCSI ID.
loop address. The unique ID of a node in
fibre-channel loop topology sometimes referred to as a
loop ID.
loop group. A collection of storage area network
(SAN) devices that are interconnected serially in a
single loop circuit. Loop groups are discovered by the
SANavigator tool and displayed with a gray background
on the Physical and Data Path maps.
loop port. A node port (N_port) or fabric port (F_port)
that supports arbitrated loop functions associated with
an arbitrated loop topology.
LPAR. See logical partition .
LUN. See logical unit number .
MAC. See medium access control .
management information base (MIB). The
information that is on an agent. It is an abstraction of
configuration and status information.
man pages. In UNIX-based operating systems, online
documentation for operating system commands,
subroutines, system calls, file formats, special files,
stand-alone utilities, and miscellaneous facilities.
Invoked by the man command.
MCA. See micro channel architecture .
media scan. A media scan is a background process
that runs on all logical drives in the storage subsystem
for which it has been enabled, providing error detection
on the drive media. The media scan process scans all
logical drive data to verify that it can be accessed, and
optionally scans the logical drive data also.
medium access control (MAC). In local area
networks (LANs), the sublayer of the data link control
layer that supports medium-dependent functions and
uses the services of the physical layer to provide
services to the logical link control sublayer. The MAC
sublayer includes the method of determining when a
device has access to the transmission medium.
Metro Mirroring. This term is used to refer to a
remote logical drive mirror pair which is set up with
synchronous write mode. See also remote mirroring ,
Global Mirroring .
MIB. See management information base .
Glossary
135