Signals are a communications mechanism between processes and the kernel. They notify a process that a certain event has occurred, and they can be sent to a process or a group of processes. Based on the type of signal received, a process might take some necessary action. Included is a discussion on the types of signals, signal handlers, how signals are sent, and the signal stack feature.
Job control provides a means of managing processes during a login session. The discussion here includes an overview of job control, and STREAMS-based job control.
Also included are discussions of pipes, STREAMS-based pipes and FIFOs. Pipes are a mechanism which provide a means of passing information from one running process to another. As of UNIX System V Release 4, pipes and FIFOs have become STREAMS-based for network applications. For completeness, a discussion of this subject has also been included.