Low latency lateral decoding of data for retrieval from magnetic tape

A method, comprising:

• reading a plurality of narrow-spread (NS) codewords from M tracks of a magnetic tape medium 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 comprising a predetermined number of NS codewords positioned orthogonally to a predetermined number of wide-spread (WS) codewords, wherein a first NS codeword from a first two-dimensional array is read in its entirety from the magnetic tape medium prior to reading a second NS codeword from the first two-dimensional array;
• and
• 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,
• wherein the predetermined number of NS codewords within each two-dimensional array are protected with a stronger encoding than the predetermined number of WS codewords within each two-dimensional array.

A computer program product, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the embodied program instructions being executable by a processing circuit to cause the processing circuit to:

• cause, by the processing circuit, reading of a plurality of narrow-spread (NS) codewords from M tracks of a magnetic tape medium 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 comprising a predetermined number of NS codewords positioned orthogonally to a predetermined number of wide-spread (WS) codewords, wherein a first NS codeword from a first two-dimensional array is read in its entirety from the magnetic tape medium prior to reading a second NS codeword from the first two-dimensional array;
• and
• laterally decode, by the processing circuit, 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,
• wherein the predetermined number of NS codewords within each two-dimensional array are protected with a stronger encoding than the predetermined number of WS codewords within each two-dimensional array.