Systems and methods for overlapping parity sectors

1. An apparatus for processing data, comprising:

a data detector configured to detect data values in data sectors to yield detected data;

a data decoder configured to decode the detected data, wherein the data detector and the data decoder are configured to process the data sectors in a series of global iterations;

a memory configured to store parity sector soft information of a failed sector that failed to converge; and

a scheduler configured to control overlapping reprocessing of the failed sector in the data detector and the data decoder based on the parity sector soft information with processing of another data sector in the data detector and the data decoder,

wherein the parity sector soft information is generated from first minimum log likelihood ratios, next minimum log likelihood ratios, index of minimum log likelihood ratios, and hard decisions for each symbol associated with a parity sector in a data track.

2. The apparatus of claim 1 , wherein the data decoder comprises a low density parity check decoder.

3. The apparatus of claim 1 , wherein the parity sector soft information to be stored in the memory is gathered from the data detector for the failed one of the data sectors when it is kicked out of the apparatus.

4. The apparatus of claim 1 , wherein the parity sector soft information to be stored in the memory is gathered from the data detector for the failed one of the data sectors during reprocessing of said failed one of the data sectors.

5. The apparatus of claim 1 , wherein the parity sector soft information to be stored in the memory is gathered from the data decoder for the failed one of the data sectors when it is kicked out of the apparatus.

6. The apparatus of claim 1 , wherein the parity sector soft information to be stored in the memory is gathered from the data decoder for the failed one of the data sectors during reprocessing of said failed one of the data sectors.

7. The apparatus of claim 1 , wherein the memory is further configured to store the hard decisions for retained sectors.

8. The apparatus of claim 7 , wherein the data decoder is operable to generate the parity sector soft information.

9. A method of processing data, comprising:

processing sectors of a first data track iteratively in a data detector circuit and a data decoding circuit during a processing period for the first data track;

identifying sectors of the first data track that failed to converge during processing of the first data track;

processing sectors of a second data track iteratively in the data detector circuit and the data decoding circuit during the processing period for the second data track, overlapped with reprocessing of the sectors of the first data track that failed to converge, the reprocessing being performed during the processing period for the second data track;

gathering soft information for retained ones of the sectors of the first data track that failed to converge, wherein the soft information for retained ones of the sectors of the first data track that failed to converge comprises minimum log likelihood ratios, next minimum log likelihood ratios, and index of minimum log likelihood ratios for each symbol in the retained ones of the sectors.

10. A method of processing data, comprising:

processing sectors of a first data track iteratively in a data detector circuit and a data decoding circuit during a processing period for the first data track;

identifying sectors of the first data track that failed to converge during processing of the first data track; and

processing sectors of a second data track iteratively in the data detector circuit and the data decoding circuit during the processing period for the second data track, overlapped with reprocessing of the sectors of the first data track that failed to converge, the reprocessing being performed during the processing period for the second data track, wherein the first data track and the second data track are different data tracks on a magnetic storage medium.

11. The method of claim 10 , wherein the reprocessing of the sectors of the first data track that failed to converge is performed based at least in part on parity sector soft information for the sectors of the first data track that failed to converge.

12. The method of claim 10 , further comprising gathering soft information for retained ones of the sectors of the first data track that failed to converge.

13. The method of claim 12 , wherein the soft information for retained ones of the sectors of the first data track that failed to converge is gathered from the data detector circuit.

14. The method of claim 12 , wherein the soft information for retained ones of the sectors of the first data track that failed to converge is gathered from the data decoding circuit.

15. The method of claim 12 , wherein the soft information for retained ones of the sectors of the first data track that failed to converge is gathered on the fly and stored during the processing period for the first data track.

16. The method of claim 12 , wherein the soft information for retained ones of the sectors of the first data track that failed to converge is gathered during the reprocessing during the processing period for the second data track.

17. The method of claim 10 , further comprising accumulating hard decisions in a syndrome buffer for each of the sectors of a first data track as they converge during the processing period for the first data track, and accumulating hard decisions in a second syndrome buffer for each of the sectors of the first data track that failed to converge during the processing period for the first data track and that are not retained in a memory circuit between the data detector circuit and the data decoding circuit.

18. The method of claim 17 , further comprising generating parity sector hard decisions based at least in part on the hard decisions in the syndrome buffer and the hard decisions in the second syndrome buffer.

19. A storage system comprising:

a storage medium;

a head assembly to retrieve data tracks from the storage medium;

a data detector to detect data values in sectors from the data tracks and to decode the sectors from the data tracks;

a memory to store parity sector soft information for retained failed ones of the sectors that failed to converge; and

a scheduler to schedule overlapping reprocessing of the retained failed ones of the sectors based at least in part on the parity sector soft information and processing of another of the sectors from another of the data tracks, wherein the parity sector soft information for the retained failed ones of the sectors that failed to converge is generated from minimum log likelihood ratios, next minimum log likelihood ratios, and index of minimum log likelihood ratios for each symbol in the retained failed ones of the sectors.

20. The storage system of claim 19 , wherein the parity sector soft information is further generated based from hard decisions.