Job control terminology
The following defines terms associated with Job Control:
Background Process-group -- a process-group that is a member of a session
that established a connection with a controlling terminal and is not the
Controlling Process -- a session leader that established a connection to
a controlling terminal.
Controlling Terminal -- a terminal that is associated with a session.
Each session may have at most one controlling terminal associated with it
and a controlling terminal may be associated with at most one session.
Certain input sequences from the controlling terminal cause signals to be sent
to the process-groups in the session associated with the controlling
Foreground Process Group -- each session that establishes a connection with
a controlling terminal distinguishes one process-group of the session as a foreground
The foreground process-group has certain privileges that are denied to background
process-groups when accessing its controlling terminal.
Orphaned Process Group -- a process-group in which the parent of every
member in the group is either a member of the group, or is not a member
of the process-group's session.
Process Group -- each process in the system is a member of a process-group that
is identified by a process-group ID.
Any process that is not a process-group leader may create a new process-group and
become its leader.
Any process that is not a process-group leader may join an existing process-group
that shares the same session as the process.
A newly created process joins the process-group of its creator.
Process Group Leader -- a process whose process ID is the same as its process
Process Group Lifetime -- a time period that begins when a process-group is
created by its process-group leader and ends when the last process that is a member
in the group leaves the group.
Process ID -- a positive integer that uniquely identifies each process in the
A process ID may not be reused by the system until the process lifetime,
process-group lifetime, and session lifetime ends for any process ID,
process-group ID, and session ID sharing that value.
Process Lifetime -- a time period that begins when the process is forked and
ends after the process exits, when its termination has been acknowledged by its
Session -- each process-group is a member of a session that is identified by
a session ID.
Session ID -- a positive integer that uniquely identifies each session in
It is the same as the process ID of its session leader.
Session Leader -- a process whose session ID is the same as its process and
Session Lifetime -- a time period that begins when the session is created by
its session leader and ends when the lifetime of
the last process-group that is a member of the session ends.
Job control signals
Overview of job control
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 27 April 2004