a plurality of write channels, each configured to supply separate testing data comprising a unique pattern to each track of a multiple track parallel tape head for separately writing said separate and unique testing data to each track of a group of parallel data tracks of a multiple track magnetic tape, and for writing a Synch pattern with said testing data representing the beginning of a data record;

memory configured to store data representing said separate testing data comprising said unique patterns separately written to each said parallel track of said group of parallel data tracks;

a plurality of read channels, each configured to read data sensed by a tape head from a parallel track to which said separate test data was written, said read data corresponding to said separately written test data for said parallel track;

a control state machine configured to respond to a detection of said Synch pattern by at least one of said plurality of read channels, to pass said corresponding data read from each of said tracks to said error processing logic and to drive a record and address count to synchronize said memory with said corresponding read data of each parallel track of said group of parallel tracks;

wherein said error processing logic configured to separately compare and detect differences between said stored separate testing data comprising said unique patterns of said memory for each of said parallel tracks, and said corresponding data read from said track of said group of parallel data tracks.