HP-UX Reference (11i v2 03/08) - 5 Miscellaneous Topics, 7 Device (Special) Files, 9 General Information, Index (vol 9)

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glossary(9) glossary(9)
Subset 1980 See CS/80.
superblock A block on each file system’s mass storage medium which describes the file system. The
contents of the superblock vary between implementations. Refer to the system adminis-
trator manuals supplied with your system for details.
superuser The HP-UX system administrator. This user has access to all files, and can perform
privileged operations. superuser has a real user ID and effective user ID of 0, and,
by convention, the user name of root.
superior directory
See parent directory.
supplementary group ID
A process has up to
NGROUPS_MAX supplementary group IDs used in determining file
access permissions, in addition to the effective group ID. The supplementary group IDs
of a process are set to the supplementary group IDs of the parent process when the pro-
cess is created.
symbolic link A type of file that indirectly refers to a path name. See symlink(4).
system The HP-UX operating system. See also kernel.
system asynchronous I/O
A method of performing I/O whereby a process informs a driver or subsystem that it
wants to know when data has arrived or when it is possible to perform a write request.
The driver or subsystem maintains a set of buffers through which the process performs
I/O. See ioctl(2), read(2), select (2), and write(2) for more information.
system call An HP-UX operating system kernel function available to the user through a high-level
language (such as FORTRAN, Pascal, or C). Also called an ‘‘intrinsic’’ or a ‘‘system
intrinsic.’’ The available system calls are documented in Section 2 of the HP-UX Refer-
ence.
system console
A keyboard and display (or terminal) given a unique status by HP-UX and associated
with the special file
/dev/console. All boot ROM error messages, HP-UX system
error messages, and certain system status messages are sent to the system console.
Under certain conditions (such as the single-user state), the system console provides the
only mechanism for communicating with HP-UX. See the System Administrator manuals
and user guides provided with your system for details on configuration and use of the sys-
tem console.
system process
A system process is a process that runs on behalf of the system. It may have special
implementation-defined characteristics.
terminal A character special file that obeys the specifications of termio(7).
terminal affiliation
The process by which a process group leader establishes an association between itself and
a particular terminal. A terminal becomes affiliated with a process group leader (and
subsequently all processes created by the process group leader, see terminal group)
whenever the process group leader executes (either directly or indirectly) an open(2) or
creat(2) system call to open a terminal. Then, if the process which is executing open(2)
or creat(2) is a process group leader, and if that process group leader is not yet affiliated
with a terminal, and if the terminal being opened is not yet affiliated with a process
group, the affiliation is established (however, see open(2) description of O_NOCTTY).
An affiliated terminal keeps track of its process group affiliation by storing the process
group’s process group ID in an internal structure.
Two benefits are realized by terminal affiliation. First, all signals sent from the terminal
are sent to all processes in the terminal group. Second, all processes in the terminal
group can perform I/O to/from the generic terminal driver
/dev/tty, which automati-
cally selects the affiliated terminal.
Terminal affiliation is broken with a terminal group when the process group leader ter-
minates, after which the hangup signal is sent to all processes remaining in the process
group. Also, if a process (which is not a process group leader) in the terminal group
HP-UX 11i Version 2: August 2003 − 22 − Hewlett-Packard Company Section 9−−23