Low latency lateral decoding of data for retrieval from magnetic tape

A method includes reading a plurality of narrow-spread (NS) codewords 812 from M tracks of a magnetic tape medium 802 using a plurality of read elements, the plurality of NS codewords collectively comprising data logically organized as a predetermined number of two-dimensional arrays. Each two-dimensional array includes a predetermined number of NS codewords positioned orthogonally to a predetermined number of wide-spread (WS) codewords 810, with a first NS codeword from a first two-dimensional array 804 being read in its entirety from the magnetic tape medium prior to reading a second NS codeword from the first two-dimensional array. The method also includes laterally decoding each NS codeword from the first two-dimensional array read from the M tracks of the magnetic tape medium in succession prior to decoding any WS codewords from the first two-dimensional array. The NS codewords are protected with a stronger encoding than the WS codewords within each two-dimensional array. The lower latency from decoding the NS codewords can be used to drive decision-directed digital front-end functions of read channels such as asymmetry cancellation, adaptive equalization, interpolation and gain adjustment.