Diagnostic system for run-time monitoring of computer operations

摘要

A monitoring system is coupled to an external computer system by an interface between a data bus internal to the monitoring system and a target bus within the external computer system. Data captured by the monitoring system from the external computer system is provided in parallel to a triggering circuit and to a buffer for temporary storage. The triggering circuit identifies the occurrence of a transaction on the bus of the external computer system and generates a signal to mark a captured data block within the buffer as being characteristic of the triggering transaction. The captured data block is compared with predetermined sets of known transaction data to determine if the captured data block is consistent with the normal operation of the external computer system. A second monitoring facility is provided to perform boundary scan testing on the external computer system.