Electronic data processing system for real time data processing

Claim 1

An electronic data processing system for real time data processing comprising (a) a main computer station for supporting man-machine communication and application program development and system maintenance; (b) a plurality of microcomputer stations at spaced locations and coupled to said main computer station, each of said microcomputer stations comprising (1) an input power supply; (2) a resettable time-out circuit coupled to said power supply; (3) an internal working storage coupled to said power supply; (4) a microprocessor coupled to said internal working storage; (5) input/output devices coupled to said working storage; (6) a test control loop coupled to said input/output devices; (7) an interchange switch means including switching gates; and (8) a station controller for controlling the switching state of said switching gates; (c) a ring bus system for interconnecting said plurality of microcomputer stations through said interchange switch means for conveying messages between said computer stations in a bitserial mode, said ring bus system providing two independent paths; (d) fault detecting means in each of said microcomputer stations, said fault detecting means comprising a station controller for monitoring activities on internal paths including activities of said power supply, said working storage, and said resettable time-out circuit, and for monitoring outside activities including activities of said ring bus and outputs of programs stored in said working storage for producing defined signals in real time for controlling said test loop; said fault detection means including means for generating fault reports, including a status word stored in the station controller, and including means for transmitting status reporting messages to each other microcomputer station for triggering external control by another computer of said system through control of the switching state of said switching gates in said interchange switching unit, said station controller receiving said status reporting messages in accordance with the transmitting or receiving activity on the ring bus; whereby, failure of one of said microcomputers consisting of said microprocessor and said working storage causes said microcomputer to be disconnected by means of said gates and another microcomputer station of the system triggered in said manner supplies said input/output devices by means of messages conveyed by said ring bus and said gates; and whereby failure of one of said interchange units or said ring bus closes one of said gates and the exchange of messages with other computer stations is suspended and the associated microcomputer supplies the input/output devices in an isolated manner.