NonStop System Glossary

Fibre Channel switch (FC switch)
Networking hardware that can connect an Enterprise Storage System and a NonStop server. This
switch allows any-to-any connectivity.
field
In a structured programming language, an addressable entry within a data structure. The term field
is sometimes used to mean member.
field-programmable gate array (FPGA)
A programmable integrated circuit that can be customized to perform specific functions.
field-replaceable unit (FRU)
A unit that can be replaced in the field only by qualified personnel trained by HP and cannot be
replaced by customers. A unit is classified as a FRU because of safety hazards such as weight,
size, sharp edges, or electrical potential; contractual agreements with suppliers; or national or
international standards. See also customer-replaceable unit (CRU).
FIFO
A type of Open System Services (OSS) special file that is always read and written in a first-in,
first-out manner.
FIFO special file
See FIFO.
file
An object to which data can be written or from which data can be read. A file has attributes such
as access permissions and a file type. In the Open System Services (OSS) environment, file types
include regular file, character special file, block special file, FIFO, and directory. In the Guardian
environment, file types include disk files, processes, and subdevices.
file class
The property of an Open System Services (OSS) file indicating access permissions for a process
related to the owner, group, or other identification of the process. See also file group class, file
other class, and file owner class.
file description
See open file description.
file descriptor
In the Open System Services (OSS) file system, the nonnegative integer that uniquely identifies a
single open of a file to a running process. Each file descriptor is associated with an open file
description that contains data about the file.
file group class
The property of an Open System Services (OSS) file indicating access permissions for a process
related to the group ID of the process. A process is in the file group class of a file if both:
• The process is not a member of the file owner class for the file.
• The process has an effective group ID or supplementary group ID that is the same as the group
ID associated with the file.
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