Combined soft detection/soft decoding in tape drive storage channels

A tape drive system, comprising:

• a soft decoder, comprising logic configured to:
• execute a decoding algorithm on a first block of signal samples during a second time interval using first soft information received from a soft detector to produce second soft information;
• execute the decoding algorithm on the first block of signal samples during a fourth time interval using third soft information received from the soft detector;
• and
• output a first decoded block of signal samples based on execution of the decoding algorithm on the first block of signal samples during the fourth time interval.

A computer program product, the computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to:

• execute, using a soft detector, a first forward loop of a detection algorithm on a first block of signal samples during a first time interval;
• execute, using the soft detector, a first reverse loop of the detection algorithm on the first block of signal samples during a second time interval;
• execute, using the soft detector, the decoding algorithm on the first block of signal samples during a third time interval using first soft information;
• execute, using the soft detector, a second forward loop of the detection algorithm on the first block of signal samples during a fourth time interval using second soft information;
• execute, using the soft detector, a second reverse loop of the detection algorithm on the first block of signal samples during a fifth time interval using the second soft information;
• execute, using a soft decoder, a decoding algorithm on the first block of signal samples during a third time interval using the first soft information;
• execute, using the soft decoder, the decoding algorithm on the first block of signal samples during a sixth time interval using the third soft information;
• and
• output, using the soft decoder, a first decoded block of signal samples based on execution of the decoding algorithm on the first block during the sixth time interval,
• wherein a sum of the second, third, fourth, fifth, and sixth time intervals are about equal in duration to twice the first time interval.