Multiprocessor shared-memory information exchange

In distributed microprocessor-based instrumentation and control systems, the inter- and intra-subsystem communication requirements ultimately form the basis for the overall system architecture. The authors describe a software protocol which addresses the intra-subsystem communications problem. Specifically, the protocol allows for multiple processors to exchange information via a shared-memory interface. Their primary goal is to provide a reliable means for information to be exchanged between central application processor boards (masters) and dedicated function processor boards (slaves) in a single computer chassis. The resultant Multiprocessor Shared-Memory Information Exchange (MSMIE) protocol, a standard master-slave shared-memory interface suitable for use in nuclear safety systems, is designed to pass unidirectional buffers of information between the processors while providing a minimum, deterministic cycle time for this data exchange