Technique for controlling the execution of an action in a low layer system by a high layer system

摘要

In a network system in which a request of executing a process is sent from the higher level system to the lower level system, a time period of not executing a requested job is assured in the lower level system while assuring an asynchronism between the both systems and a certainty of the requested job. The higher level system transmits a pair of signals (a preparatory signal and an execution signal) to the lower level system in a predetermined interval after it holds a processing request to be sent to the lower system. The higher level system then resumes transmission of the processing request a predetermined time after transmitting the pair of signals. The lower level system calculates an estimated time which will be required to process the processing request currently requested to process using the pair of signals and determines whether or not the sum of the estimated time and the time of a predetermined operation which is executed while the processing request is not accepted is less than the time during which the higher level system holds the processing request. The predetermined operation is executed only when the sum of the times is less than the time during which the higher level system holds the processing request.