Abstract: A method and means for enhancing the error detection and correction capability obtained when a plurality of data byte strings are encoded in a two-level, block-formatted linear code using codeword and block-level redundancy by logically summing the data byte strings and mapping the logical sum and the data byte strings into counterpart codewords including codeword check bytes in accordance with the same linear error correction code. Next, the codewords are logically summed. The codewords and their logical sum are interleaved in a predetermined pattern prior to being recorded on a storage device or the like. On read back, the codewords of a block and their logical sum are syndrome processed to resolve any identified errors within the correction capability of any single word and any errors within the correction capability of any single word and block-level redundancy, and to provide signal indication when the correction capacity has been exceeded.

Abstract: A computationally and storage efficient method and means for correcting errors and erasures in linear cyclic coded data, especially Reed-Solomon codes, in which erasure values are ascertained exclusively as a function of syndromes and derived error location polynomials without recourse to computation of intermediate error or erasure values.