Service Access Controller (SAC Program)

The Service Access Controller program (SAC) oversees all port monitors. A system automatically starts the SAC upon entering multiuser mode.

When the SAC program is invoked, it first looks for, and interprets, each system's configuration script. You can use the configuration script to customize the SAC program environment. This script is empty by default. The modifications made to the SAC environment are inherited by all the “children” of the SAC. This inherited environment might be modified by the children.

After the SAC program has interpreted the per-system configuration script, the SAC program reads its administrative file and starts the specified port monitors. For each port monitor, the SAC program runs a copy of itself, forking a child process. Each child process then interprets its per-port monitor configuration script, if such a script exists.

Any modifications to the environment specified in the per-port monitor configuration script affect the port monitor and will be inherited by all its children. Finally, the child process runs the port monitor program by using the command found in the SAC program administrative file.