Some codes for correcting and detecting unidirectional byte errors

Codes for correcting and detecting unidirectional byte errors are investigated. The relations between distances and the error-correcting and -detecting capabilities of such codes are derived. It is shown that a two-fold unidirectional b-bit-byte error-correcting (2-Ub EC) code requires at least three check bytes and that a one-fold unidirectional b-bit-byte error-correcting/2-fold unidirectional b-bit-byte error-detecting (1-UbEC/2-U bED) code requires at least two check bytes. Construction methods for 2-UbEC codes with three check bytes and 1-Ub EC/2-UbEd codes with two check bytes are proposed