Diagnostic subsystem.

摘要

A device adapter with an on-board diagnostic capability for a SCSI controller is provided by a gate array driven by a microprocessor on board the adapter. The gate array has data and control inputs driven from the micro-processor and data and control outputs which are dot OR'ed with corresponding in/out terminals of the SCSI controller. A reset signal from a SCSI bus forms a further input to the gate array. For testing purposes the micro-processor detects the gate array inputs to simulate a fault-free or faulty device. The micro-processor detects the response of the SCSI controller to the device simulation and thereby can determine the state of health of the SCSI controller.