Inventors:
Anthony P. Herff - Los Angeles CA
Assignee:
Bell & Howell Company - Chicago IL
International Classification:
G06F 1110
Abstract:
Data are modified prior to processing and are restored to their original format after processing in order to enable the detection and correction of errors that would otherwise escape detection by conventional parity checking techniques. In particular, processed data are subjected to a first parity check and to a correction of errors detected in that first parity check and modified to render further errors detectible by a parity check on the basis of which the further errors are then corrected.