1. A method to analyze errors in a system, the system having a plurality of resources with replaceable units, a display, a processor, and memory means for storing decision trees, data structures, and error analysis tasks, the resources including a diagnostics card having a processor and memory means for storing resource analysis tasks, and communication resources, the method comprising the steps of: (a) testing said resources intermittently by said error analysis tasks invoking a card analysis task on said diagnostics card to test for an error in said communication resources in said system; (b) detecting an error and invoking an appropriate error analysis task to further diagnose the cause of said error; (c) isolating said error to a replaceable unit by automatically traversing said decision trees in said error analysis task on said diagnostics card; (d) writing data to record said error in said data structure in said memory of said system; and (e) displaying a message indicative of said error on said display of said system.