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

p
glossary(9) glossary(9)
permission bits
The nine least-significant bits of a file’s mode are referred to as file permission bits. These bits deter-
mine read, write, and execute permissions for the file’s owner, the file’s group, and all others. The bits
are divided into three parts: owner, group and other. Each part is used with the corresponding file class of
processes. The bits are contained in the file mode, as described in stat(5). The detailed usage of the file
permission bits in access decisions is described in file access permissions.
PIC
See position-independent code.
pipe
An interprocess I/O channel used to pass data between two processes. It is commonly used by the shell to
transfer data from the standard output of one process to the standard input of another. On a command
line, a pipe is signaled by a vertical bar (
|). Output from the command to the left of the vertical bar is
channeled directly into the standard input of the command on the right.
portable file name character set
The following set of graphical characters are portable across conforming implementations of IEEE Standard
P1003.1:
ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
01234567890._-
The last three characters are the dot, underscore and hyphen characters, respectively. The hyphen should
not be used as the first character of a portable file name.
position-independent code (PIC)
Object code that can run unmodified at any virtual address. Position-independent code can use PC-relative
addressing modes and/or linkage tables. It is most often used in shared libraries, in which case the linkage
tables are initialized by the dynamic loader. Position-independent code is generated when the
+z or +Z
compiler option is specified.
privileged groups
A privileged group is a group that has had a setprivgrp (see getprivgrp(2)) operation performed on
it, giving it access to some system calls otherwise reserved for the superuser. See appropriate
privileges.
process
An invocation of a program, or the execution of an image (see image). Although all commands and utilities
are executed within processes, not all commands or utilities have a one-to-one correspondence with
processes. Some commands (such as cd) execute within a process, but do not create any new processes.
Others (such as in the case of
ls | wc -l) create multiple processes. Several processes can be running
the same program, but each can be different data and be in different stages of execution. A process can also
be thought of as an address space and single thread of control that executes within that address space
and its required system resources. A process is created by another process issuing the fork(2) function.
The process that issues fork(2) is known as the parent process and the new process created by the fork(2)
as the child process.
process 1
See
init.
process group
Each process in the system is a member of a process group. This grouping permits the signaling of
related processes. A newly created process joins the process group of its creator.
process group ID
Each process group in the system is uniquely identified during its lifetime by a process group ID, a posi-
tive integer less than or equal to PIC_MAX.Aprocess group ID cannot be reused by the system until
the process group lifetime ends.
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