1. A method of processing channel values received from a two-dimensional (2-D) inter-symbol interference (ISI) channel to which was provided a plurality of input values, the channel values being associated with a plurality of rows that together form a matrix, the method comprising: (a) computing, by way of a processing device, a plurality of sets of combination values respectively based upon a plurality of overlapping subsets of the rows of the channel values; (b) applying an a-postiori probability (app) algorithm to the plurality of sets of combination values; and (c) producing result values that are indicative of the input values that gave rise to the channel values, wherein the result values are produced based upon results from the application of the app algorithm, and wherein the computing of the plurality of sets of combination values includes determining a plurality of symbol probability values, and wherein at least one of the symbol probability values is based upon at least two probability values that are respectively functionally related to at least two of the channel values that are associated with different rows of the matrix.