DRV_AVAILABILITY is a derived field whose purpose is two fold. If the Registrant has already registered for the class, their Registration Status will display in this field. If the Registrant has NOT registered for the class, this field will display the availability of the class.
The Class Availability is determined using the preference CLASS_PERC_FULL. The preference provides a percentage to use to determine how close the class is to becoming full. If the number of registrants is less than X% of the Class' Maximum size the status will reflect as OPEN. If the number of registrants is greater than or equal with the Maximum size the status will reflect as FULL. If the number of registrants is between X% of the Maximum size and the Maximum size the status will reflect as ALMOST FULL.