glossary.9 (2010 09)

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glossary(9) glossary(9)
file system
A collection of files and supporting data structures residing on a mass storage volume. A file system pro-
vides a name space for file serial numbers referring to those files. Refer to the System Administrator
manuals supplied with your system for details concerning file system implementation and maintenance.
file times update
Each file has three associated time values that are updated when file data is accessed or modified, or
when the file status is changed. These values are returned in the file characteristics structure, as
described in
<sys/stat.h>. For each function in HP-UX that reads or writes file data or changes the
file status, the appropriate time-related files are noted as "marked-for-update". When an update point
occurs, any marked fields are set to the current time and the update marks are cleared. One such update
point occurs when the file is no longer open for any process. Updates are not performed for files on
read-only file systems.
filter
A command that reads data from the standard input, performs a transformation on the data, and writes
it to the standard output.
foreground process group
Each session that has established a connection with a controlling terminal has exactly one process group
of the session as a foreground process group of that controlling terminal. The foreground process group
has certain privileges when accessing its controlling terminal that are denied to background process
groups. See read (2) and write (2).
foreground process group ID
The process group ID of the foreground process group.
fork
An HP-UX system call (see fork (2)), which, when invoked by an existing process, causes a new process to
be created. The new process is called the child process; the existing process is called the parent pro-
cess. The child process is created by making an exact copy of the parent process. The parent and child
processes are able to identify themselves by the value returned by their corresponding fork call (see
fork(2) for details).
graphic character
A character other than a control character that has a visual representation when hand-written, printed,
or displayed.
group
See group ID.
group ID
Associates zero or more users who must all be permitted to access the same set of files. The members of a
group are defined in the files
/etc/passwd and /etc/logingroup (if it exists) via a numerical
group ID that must be between zero and UID_MAX, inclusive. Users with identical group IDs are
members of the same group. An ASCII group name is associated with each group ID in the file
/etc/group. A group ID is also associated with every file in the file hierarchy, and the mode of each
file contains a set of permission bits that apply only to this group. Thus, if you belong to a group that is
associated with a file, and if the appropriate permissions are granted to your group in the file’s mode, you
can access the file. When the identity of a group is associated with a process, a group ID value is referred
to as a real group ID,aneffective group ID,asupplementary group ID,orasaved group ID.
See also privileged group and set-group-ID bit.
group access list
A set of supplementary group IDs used in determining resource accessibility. Access checks are per-
formed as described in file access permissions.
hardware path
A numeric string associated to a system component (bus, card, attached I/O device, and so on) and provid-
ing information related to the component location.
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