DIAGNOSTIC TESTING APPARATUS AND METHOD

摘要

A microprogrammable peripheral controller in addition to being operative to controlling plurality of input/output devices in response to commands for processing information signals from a magnetic medium also includes apparatus for independently establishing a minimum operating capability within the controller. The apparatus includes a read-only control store arranged to store microinstructions and a limited number of basic bit patterns. The apparatus in response to an external control signal is operative to condition the data recovery apparatus included in the controller to receive the blocks of synchronization and data patterns arranged in a predetermined format and generated from basic bit patterns obtained from the control store. Simultaneously therewith, the apparatus inhibits normal transfer of information from the magnetic medium. Additionally, a plurality of record error indicator circuits included in the data recovery apparatus are operative to be switched during the processing of each of the blocks of bit patterns transferred through the recovery apparatus. The apparatus further includes comparison circuits which compare the state of the record error indicators with a predicted bit pattern for detecting whether the recovery apparatus is operating properly in processing the block of bit patterns transferred thereto. The states of other indicator storage circuits are modified to signals indicative of conditions occurring during the transfer of the generated bit patterns. The comparison circuits also compare the states of these circuits with a predicted bit pattern as further verification of recovery apparatus operation.