Apparatus of fault-handling in a multiprocessing system

In a data processing system in which a switching matrix provides electrical interconnections between horizonal MACD buses and vertical ACD buses connected in said matrix by means of nodes, and in which a fault-handling mechanism provides an error-reporting matrix including horizontal Bus Error Report Lines (BERLs) and vertical Module Error Report Lines (MERLs), said BERLs being associated with said MACD buses such that all nodes sharing an MACD bus are connected with a BERL so that errors occurring in error confinement areas may be rebroadcast over one of said BERLs, said MERLs being associated with said ACD buses such that all nodes sharing an ACD bus are conneted with a MERL so that errors occurring in error-confinement areas may be reported over a corresponding one of said MERLs;

• error-report log means connected at the intersection of one of said MERLs and one of said BERLs comprising:
• holding means connected to said MERLS and said BERLS for holding information from a most recent error-report message;
• logging means connected to said holding means for logging error reports, said logging means including means for uniquely identifying said error reports so that said error reports are distinguishable as between the single occurrence of an error, and repeated occurrences of the same error;
• and,
• logic means connected to said holding means and said logging means for immediately updating said logging means upon te condition that an error-report message is received, said logic means including an error-count means, and means connected to said error-count means for incrementing said error count means upon the condition that the single occurrence of an error is reported.

In a data processing system in which a switching matrix provides electrical interconnections between horizontal MACD buses and vertical ACD buses connected in said matrix by means of nodes, and in which a fault-handling mechanism provides an error-reporting matrix including horizontal Bus Error Report Lines (BERLs) and vertical Module Error Report Lines (MERLs), said BERLs being associatd with said MACD buses such that all nodes sharing an MACD bus are connected with a BERL so that errors occurring in error-confinement areas may be reported over one of said BERLs, said MERLs being associated with said ACD buses such that all nodes sharing an ACD bus are connected with a MERL so that errors occurring in error-confinement areas may be rebroadcast over one of said MERLs;

• error-reporting logic testing means at one node connected at the intersection of one of said MERLs and one of said BERLs comprising:
• test command receiving means connected to said MACD bus for receiving a test command;
• said test command including means which identifies said one node as a node (tested node) to be tested,
• said test command being comprised of a read access request for read data from said one node, said read access request being directed to said one node (tested node) from another node (testing node) over said MACD bus;
• and,
• test logic means connected to said test command receiving means and to said MACD bus, responsive to said test command receiving means, for returning said read data to said testing node;
• said test logic means including means for causing a known error condition to occur in said read data, thereby forcing an error at one of said confinement areas.