System information

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Eclipse™ 2640 SAN Router Administration and Configuration Manual
Glossary
and can communicate with another attached device if both devices
are in the same zone, or if the default zone is enabled. Contrast with
offline state.
Open Systems
Architecture
OSI. A model that represents a network as a hierarchical structure of
functional layers. Each layer provides a set of functions that can be
accessed and used by the layer above. Layers are independent, in that
implementation of a layer can be changed without affecting other
layers (D).
operating system OS. Software that controls execution of applications and provides
services such as resource allocation, scheduling, I/O control, and
data management. Most operating systems are predominantly
software, but partial hardware implementations are possible (D, T).
Operating System/390 OS/390™. An integrated, open-enterprise server operating system
developed by IBM that incorporates a leading-edge and open
communications server, distributed data and file services, parallel
Sysplex™ support, object-oriented programming, distributed
computing environment, and open application interfaces (D).
optical cable Single fiber, multiple fibers, or a fiber bundle in a structure built to
meet optical, mechanical, and environmental specifications (D, E). See
also
jumper cable; trunk cable. Synonymous with fiber-optic cable.
optical drive backup A data backup system that uses rewriteable optical cartridges (ROCs)
as the storage medium (D).
optical fiber
connector
Synonymous with connector.
ordered set In Fibre Channel protocol, four 10-bit characters (a combination of
data and special characters) providing low-level link functions, such
as frame demarcation and signaling between two ends of a link. It
provides for initialization of the link after power-on and for some
basic recovery functions.
original equipment
manufacturer
OEM. A company that has a special relationship with computer
producers. OEMs buy components and customize them for a
particular application. They sell the customized computer under their
own name. OEMs may not actually be the original manufacturers.
They are usually the customizers and marketers.
OS See operating system.