18. A system in accordance with claim 17 which includes means for establishing a trigger linkage to at least one job definition is established by linking the identifier for that job definition to locations in said memory that are in turn linked to the event definition and status data for the designated triggering signals, and wherein means for initiating execution include means for transferring the identifiers linked to the event definition and status data for a signal to means for scheduling the execution of job definitions.
18. A system in accordance with claim 17 which includes means for establishing a trigger linkage to at least one job definition is established by linking the identifier for that job definition to locations in said memory that are in turn linked to the event definition and status data for the designated triggering signals, and wherein means for initiating execution include means for transferring the identifiers linked to the event definition and status data for a signal to means for scheduling the execution of job definitions. 19. A system in accordance with claim 18 wherein means for chain-linking job-definition identifiers to the definitions of triggering event.