INTER-SYSTEM DATA BASE SHARING SYSTEM

摘要

PURPOSE:To attain an exclusive control system that needs no special hardware and has the reduced communication overhead by dividing logically shared data resources to send them to a lock manager for execution of exclusive control and setting an alternate data processor. CONSTITUTION:The exclusive control of the shared data resources is carried out by a lock manager set on a data processor serving as a master of the data resources. Thus said exclusive control is performed within a lock manager. This avoids such malfunction where a double locking action is permitted. The consistency can be kept for the data resources with a trouble of a data processor or a subsystem since the shared data resources under application are set under an access inhibiting state. Furthermore an alternate data processor can be set and therefore an exclusive master is shifted to the alternate data processor under operation despite the multiple fault of the data processor. In such a way, the reliability of this system is improved.