Composite data recovery procedure

1. A method comprising:

designating one or more data sectors as failed data sectors when a first or a second read attempt on the one or more data sectors does not result in recovery of data from the one or more data sectors, wherein the data to be recovered is different from any position information;

recovering the data from the one or more failed data sectors by:

estimating a reader offset position from the first or the second read attempt of the one or more failed data sectors at a current set of channel parameters and basing the estimated reader offset position on, at least in part, a position error signal generated during the first or second read attempt;

performing at least one read on the one or more failed data sectors at the estimated reader offset position to obtain one or more samples from a read waveform resulting from an attempt to read the data from the one or more failed data sectors during the performance of the at least one read on the one or more failed data sectors at the estimated reader offset position;

processing the one or more samples to obtain a processed sample; and

performing iterative outer code recovery on the processed sample.

2. The method of claim 1 , further comprising replacing the current set of channel parameters with a new set of channel parameters selected from adaptive channel parameters or predetermined channel parameters.

3. The method of claim 2 , wherein replacing the current set of channel parameters with the new set of channel parameters is carried out after estimating the reader offset position and before performing multiple reads at the estimated reader offset position.

4. The method of claim 1 , wherein processing the one or more samples to obtain the processed sample comprises averaging the one or more samples to obtain the processed sample.

5. The method of claim 1 , wherein processing the one or more samples to obtain the processed sample comprises averaging the one or more samples, comparing each sample to each other and to the averaged sample and selecting one of the samples or the averaged sample to be the processed sample.

6. The method of claim 1 , further comprising storing the processed sample in a buffer.

7. The method of claim 6 , further comprising removing interference from the processed sample to obtain an updated processed sample before performing the iterative outer code recovery, wherein interference is derived from one or more data sectors that are adjacent to the one or more failed data sectors.

8. The method of claim 7 , wherein performing the iterative outer code recovery comprises performing the iterative outer code recovery on the updated processed sample.

9. The method of claim 1 , further comprising removing interference from each of the at least one read before processing the one or more samples, wherein the interference is derived from an adjacent track having one or more data sectors that are adjacent to the one or more failed data sectors.

10. A method comprising:

designating one or more data sectors as failed data sectors when a first or a second read attempt on the one or more data sectors does not result in recovery of data from the one or more data sectors, wherein the data to be recovered is different from any position information;

recovering the data from the one or more failed data sectors by:

estimating a reader offset position from the first or the second read attempt of the one or more failed data sectors at a current set of channel parameters and basing the estimated reader offset position on, at least in part, a position error signal generated during the first or second read attempt;

replacing the current set of channel parameters with a new set of channel parameters selected from adaptive channel parameters or predetermined channel parameters;

performing at least one read on the one or more failed data sectors at the estimated reader offset position and using the new set of channel parameters to obtain one or more samples from a read waveform resulting from an attempt to read the data from the one or more failed data sectors during the performance of the at least one read on the one or more failed data sectors at the estimated reader offset position;

processing the one or more samples to obtain a processed sample; and

performing iterative outer code recovery on the processed sample.

11. The method of claim 10 , wherein processing the one or more samples to obtain the processed sample comprises averaging the one or more samples to obtain the processed sample.

12. The method of claim 10 , wherein processing the one or more samples to obtain the processed sample comprises averaging the one or more samples, comparing each sample to each other and to the averaged sample and selecting one of the samples or the averaged sample to become the processed sample.

13. The method of claim 10 , further comprising removing interference from the processed sample to obtain an updated processed sample before performing iterative outer code recovery, wherein interference is derived from one or more data sectors that are adjacent to the one or more failed data sectors.

14. The method of claim 13 , wherein performing iterative outer code recovery comprises performing iterative outer code recovery on the updated processed sample.

15. The method of claim 10 , further comprising removing interference from each of the at least one read before processing the one or more samples, wherein the interference is derived from an adjacent track having one or more data sectors that are adjacent to the one or more failed data sectors.

16. A method comprising:

designating one or more data sectors as failed data sectors when a first or a second read attempt on the one or more data sectors does not result in recovery of data from the one or more data sectors, wherein the data to be recovered is different from any position information;

recovering the data from the one or more failed data sectors by:

estimating a reader offset position from the first or the second read attempt of the one or more failed data sectors at a current set of channel parameters and basing the estimated reader offset position on, at least in part, a position error signal generated during the first or second read attempt;

replacing the current set of channel parameters with a new set of channel parameters selected from adaptive channel parameters or predetermined channel parameters;

performing multiple reads on the one or more failed data sectors at the estimated reader offset position and using the new set of channel parameters to obtain a plurality of samples from read waveforms resulting from attempts to read the data from the one or more failed data sectors during the performance of the multiple reads on the one or more failed data sectors at the estimated reader offset position;

processing the plurality of samples to obtain a processed sample; and

removing interference from the processed sample to obtain an updated processed sample, wherein the interference is derived from an adjacent track having one or more data sectors that are adjacent to the one or more failed data sectors.

17. The method of claim 16 , wherein processing the plurality of samples to obtain the processed sample comprises averaging the plurality of samples to obtain the processed sample.

18. The method of claim 16 , wherein processing the plurality of samples to obtain the processed sample comprises averaging the plurality of samples, comparing each sample to each other and to the averaged sample and selecting one of the samples or the averaged sample to be the processed sample.

19. The method of claim 16 , further comprising storing the processed sample in a buffer before removing interference from the processed sample.

20. The method of claim 16 , further comprising performing iterative outer code recovery on the updated processed sample.