Notification of change in a data base

The Supervisory Control and Diagnostics System for the Mirror Fusion Test Facility is an event driven system; tasks that handle specific events are active only when those events occur. One method of monitoring and generating events is the data base notification facility; a task can request that it be loaded and started by the dbms if a data element is touched or goes outside of a specified range. The motivations for this facility (along with an example of its use and some specifics regarding how it is done) are presented.