A decoder and decoding method in which a syndrome generator (410) calculates a syndrome vector from an erroneous codeword, an error location polynominal generator (420) calculates an error location polynominal from the syndrome vector, an error location generator (430) determines an error location from the error location polynominal, an error magnitude generator (440) calculates an error magnitude from the error location polynominal and a corrected codeword generator (450) corrects the codeword responsive to the error location and magnitude. In an intra-decoder block messaging scheme, one or more components (410, 420, 430, 440, 450) generate inactivity messages (640, 650) to signal an ability to process data corresponding to a next codeword. In a dual Chien search block (930, 940) implementation, a Chien block (930) is used to determine the number of errors in a specified code word, separately from the error location and magnitude calculations performed by a Chien-Forney block (940).