Codes for limited magnitude asymmetric errors in flash memories

Error correction is tailored for the use of an ECC for correcting asymmetric errors with low magnitude in a data device, with minimal modifications to the conventional data device architecture. The technique permits error correction and data recovery to be performed with reduced-size error correcting code alphabets. For particular cases, the technique can reduce the problem of constructing codes for correcting limited magnitude asymmetric errors to the problem of constructing codes for symmetric errors over small alphabets. Also described are speed up techniques for reaching target data levels more quickly, using more aggressive memory programming operations.