HP-UX Reference (11i v2 07/12) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

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glossary(9) glossary(9)
process group leader
A process group leader is a process whose process ID is the same as its process group ID.
process group lifetime
A period of time that begins when a process group is created and ends when the last remaining process in
the group leaves the group, either due to process termination or by calling the setsid(2) or setpgid(2) func-
tions.
process ID
Each active process in the system is uniquely identified during its lifetime by a positive integer less than or
equal to
PID_MAX called a process ID. A process ID cannot be reused by the system until after the pro-
cess lifetime ends. In addition, if there exists a process group whose process group ID is equal to that pro-
cess ID, the process ID cannot be reused by the system until the process group lifetime ends. A process
that is not a system process shall not have a process ID of 1.
process lifetime
After a process is created with a fork(2) function, it is considered active. Its thread of control and address
space exist until it terminates. It then enters an inactive state where certain resources may be returned
to the system, although some resources, such as the process ID are still in use. When another process
executes a
wait(), wait3(),orwaitpid() function (see wait(2)) for an inactive process, the remain-
ing resources are returned to the system. The last resource to be returned to the system is the process ID.
At this time, the lifetime of the process ends.
program
A sequence of instructions to the computer in the form of binary code (resulting from the compilation and
assembly of program source).
prompt
The characters displayed by the shell on the terminal indicating that the system is ready for a command.
The prompt is usually a dollar sign ($) for ordinary users (% in the C shell) and a pound sign (
#) for the
superuser, but you can redefine it to be any string by setting the appropriate shell variable (see sh(1) and
related entries). See also secondary prompt.
quit signal
The
SIGQUIT signal (see signal(2). The quit signal is generated by typing the character defined by the
teletype handler as your quit signal. (See stty(1), ioctl(2), and termio(7).) The default is the ASCII FS
character (ASCII value 28) generated by typing Ctrl-\. This signal usually causes a running program to
terminate and generates a file containing the "core image" of the terminated process. The core image is
useful for debugging purposes. (Some systems do not support core images, and on those systems no such
file is generated.)
radix character
The character that separates the integer part of a number from the fractional part. For example, in Ameri-
can usage, the radix character is a decimal point, while in Europe, a comma is used.
raw disk
The name given to a disk for which there exists a character special file that allows direct transmission
between the disk and the user’s read or write buffer. A single read or write call results in exactly one I/O
call.
read-only file system
A characteristic of a file system that prevents file system modifications.
real group ID
A positive integer which is assigned to every user on the system. The association of a user and his or her
real group ID is done in the file /etc/passwd . The modifier "real" is used because a user can also have
an effective group ID. The real group ID can then be mapped to a group name in the file /etc/group ,
although it need not be. Thus, every user is a member of some group (which can be nameless), even if that
group has only one member.
Every time a process creates a child process (via fork(2)), that process has a real group ID equal to the
parent process’s real group ID. This is useful for determining file access privileges within the process.
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