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Data processing system wherein all subsystems check for message errors

  • US 4,583,161 A
  • Filed: 04/16/1981
  • Issued: 04/15/1986
  • Est. Priority Date: 04/16/1981
  • Status: Expired due to Term
First Claim
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1. In a data processing system of the type having a plurality of subsystems, each having a sending means for sending messages and receiving means for receiving meassages, said data processing system employing broadcast packet switching for broadcasting a message transmitted by one of said subsystems and to be received by another of said subsystems, the improvement comprising:

  • a system bus for linking all of said subsystems and carrying each broadcasted message, said system bus comprising a communication channel that includes;

    pairs of transmission lines, each of said pairs of transmission lines associated with at least one of said subsystems and including a first transmission line connected to the sending means of any subsystem associated therewith for carrying a message transmitted by its associated subsystem and a second transmission line connected to the receiving means of any subsystem associated therewith for carrying a message to be received by its associated subsystem; and

    a star coupler for coupling said pairs of transmission lines so that a message received from any of said first transmission lines is passed to each of said second transmission lines; and

    a plurality of system bus interface means, one associated with each of said subsystems for coupling each of said subsystems to its associated pair of transmission lines such that the receiving means of all of the subsystems receive all meassage sent by the sending means of all subsystems, including its own sending means, each of said system bus interface means including;

    means for detecting a swamp error in any message broadcasted over said system bus;

    means for sensing an idle condition of said system bus in order to detect an idle error in any message broadcasted over said system bus;

    means for performing a CRC error check for detecting a CRC error in any message broadcasted over said system bus;

    means for generating an ABORT signal if one of a swamp error, idle error, and CRC, error is detected;

    means for receiving the ABORT signal and responsive thereto, placing signals on said associated second transmission line thereby garbling the message being broadcasted over said system, bus; and

    means in each of said system bus interface means for rejecting a garbled message being broadcasted over said system bus whereby all of said subsystems connected to said system bus reject the garbled message.

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