Reference: Hewett, M. & Hayes-Roth, B. Real-Time I/O in Knowledge-Based Systems. November, 1988.
Abstract: Modern knowledge-based systems require flexible means of maintaining continuous and spontaneous communication with multiple external entities. Some of them are real-time systems, which must respond to an input within a specified interval of time. Two common approaches to communication in blackboard systems, communication knowledge sources and a communication phase in the reasoning cycle, can not generally satisfy real-time constraints. A design based on a concurrent communication process can satisfy real-time constraints. An application communicates with external entities solely through device-independent logical streams in its knowledge base. The communication process is continuallly transferring data between external physical streams and the logical streams. We describe an architecture-independent Communication Interface (CI), and describe its use with the BB1 blackboard architecture. In a suboptimal test configuration, the CI currently can effectively transmit data to the knowledge base at rates up to 8 items per second. The transmission rate can be increased in proportion to increases in processor speed, network speed, and by program optimization, independent of changes in the reasoning architecture.
Notes: 13 pages.