IBM TotalStorage NAS 300, User Reference

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logical drive. A unit of virtual storage that is made available to the network through virtual logical unit numbers
(VLUNs) and iSCSI client logical-unit number (iLUNs). It consists of one or more physical disks that are combined
using RAID 0, 1, 1E, 5, or 5E technology.
logical unit. A type of network-accessible unit that enables users to gain access to network resources and
communicate with each other.
logical unit number (LUN). An identifier used on a SCSI bus to distinguish among up to eight devices (logical units)
with the same SCSI ID.
loop. A closed unidirectional signal path connecting input/output devices to a system.
LUN. See logical unit number .
M
megahertz (MHz). A unit of measure of frequency. One megahertz equals 1 000 000 hertz.
MHz. See megahertz .
multicast address. A type of IP address, which identifies a group of interfaces and permits all of the systems that
are in that group to receive the same packet of information.
N
N. See newton .
NAS. See network-attached storage .
NetBIOS. A standard interface to networks, IBM personal computers (PCs), and other compatible PCs. It is used on
LANs to provide message, print-server, and file-server functions. Application programs that use NetBIOS need not
manage the details of LAN data-link-control protocols.
network-attached storage (NAS). A task-optimized storage device directly attached to a network that operates
independently of the general-purpose file servers.
Network File System (NFS). A protocol, developed by Sun Microsystems, Incorporated, that allows any host in a
network to mount another host’s file directories. After a file directory is mounted, it appears to reside on the local host.
network information services (NIS). A set of UNIX network services (for example, a distributed service for retrieving
information about the users, groups, network addresses, and gateways in a network) that resolve naming and
addressing differences among computers in a network.
newton (N). The unit of force required to impart an acceleration of one meter per second per second to a mass of
one kilogram (1 m/s
2
).
NFS. See Network File System .
NIS. See network information services .
O
optical cable. A fiber, multiple fibers, or a fiber bundle in a structure built to meet optical, mechanical, and
environmental specifications (E).
P
path. In a network, a route between two nodes.
path group. A collection of equivalent paths. Storage devices may have one - n path groups.
PCI. See Peripheral Component Interconnect .
Glossary of terms and abbreviations
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