New classes of unidirectional error-detecting codes

Unidirectional errors arise as a result of common VLSI failure modes and certain connection faults, particularly with serial data transmission. A totally ordered set of symbols to be encoded in an order-preserving manner for unidirectional error detection is considered. General order-preserving encoding and the special case of difference-preserving encoding, (when the value ν is encoded with its separate data part representing ν+b to facilitate arithmetic operations) are considered and optimal codes are devised for each case