What Is the SAF?

The service access facility (SAF) generalizes the procedures for service access so that login access on the local system and network access to local services are managed in similar ways. Under the SAF, systems can access services using a variety of port monitors, including ttymon, the listener, and port monitors written expressly for a user's application.

The manner in which a port monitor observes and manages access ports is specific to the port monitor and not to any component of the SAF. Users can therefore extend their systems by developing and installing their own port monitors. This ability to extend the SAF is one of its important features.

Relative to the SAF, a service is a process that is started. No restrictions are on the functions a service can provide.

The SAF consists of a controlling process, the service access controller (SAC), and two administrative levels corresponding to two levels in the supporting directory structure. The top administrative level is concerned with port monitor administration, the lower level with service administration.

From an administrative point of view, the SAF consists of the following components:

• The SAC

• A per-system configuration script

• The SAC administrative file

• The SAC administrative command sacadm

• Port monitors

• Optional per-port monitor configuration scripts

• An administrative file for each port monitor

• The administrative command pmadm

• Optional per-service configuration scripts