HP-UX Reference (11i v2 04/09) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

s
glossary(9) glossary(9)
shmid
See shared memory identifier.
signal
A software interrupt sent to a process, informing it of special situations or events. Also, the event itself.
See signal (2).
single-user state
A condition of the HP-UX operating system in which the system console provides the only communication
mechanism between the system and its user. By convention, single-user state is usually specified by
init (1M) as run-level
S or s. Do not confuse single-user state, in which the software is limiting a mul-
tiuser system to a single-user communication, with a single-user system, which can never communicate
with more than one fixed terminal. See also multiuser state.
slash
The literal character
/.Apath name consisting of a single slash resolves to the root directory of the
process. See also path name resolution.
solidus
See slash.
source code
The fundamental high-level information (program) written in the syntax of a specified computer
language. Object (machine-language) code is derived from source code. When dealing with an HP-UX
shell command language, source code is input to the command language interpreter. The term shell
script is synonymous with this meaning. When dealing with the C Language, source code is input to
the cc(1) command. Source code can also refer to a collection of sources meeting any of the above condi-
tions.
special file
A file associated with an I/O device. Often called a device file. Special files are read and written the
same as ordinary files, but requests to read or write result in activation of the associated device. Due to
convention and consistency, these files should always reside in the
/dev directory. See also file.
special processes
Processes with certain (small) process IDs are special. On a typical system, the IDs of 0, 1, and 2 are
assigned as follows: Process 0 is the scheduler. Process 1 is the initialization process
init, and is the
ancestor of every other process in the system. It is used to control the process structure. On paging sys-
tems with virtual memory, process 2 is the paging daemon.
SS/80
See CS/80.
standard error
The destination of error and special messages from a program, intended to be used for diagnostic mes-
sages. The standard error output is often called stderr, and is automatically opened for writing on file
descriptor 2 for every command invoked. By default, the user’s terminal is the destination of all data
written to stderr, but it can be redirected elsewhere. Unlike standard input and standard output, which
are never used for data transfer in the "wrong" direction, standard error is occasionally read. This is not
recommended practice, since I/O redirection is likely to break a program doing this.
standard input
The source of input data for a program. The standard input file is often called stdin, and is automati-
cally opened for reading on file descriptor 0 for every command invoked. By default, the user’s terminal
is the source of all data read from stdin, but it can be redirected from another source.
standard output
The destination of output data from a program. The standard output file is often called stdout, and is
automatically opened for writing on file descriptor 1 for every command invoked. By default, the user’s
terminal is the destination of all data written to stdout, but it can be redirected elsewhere.
HP-UX 11i Version 2: September 2004 − 22 − Hewlett-Packard Company Section 9−−23