Method and system for writing and reading closely-spaced data tracks

1. A method for reading data that have been encoded into codewords and written onto shingled tracks of a magnetic medium, wherein codewords have been divided into respective codeword portions with each respective codeword portion having been written to a respective different one of at least two shingled tracks of the magnetic medium, the method comprising:

obtaining data from each of the at least two shingled tracks;

using the data obtained from the at least two shingled tracks to cancel interference in the data obtained from each of the at least two shingled tracks caused by data in each other of the at least two shingled tracks;

recombining the respective codeword portions in data from which interference has been cancelled; and

decoding the recombined respective codeword portions from the at least two shingled tracks into at least one decoded data stream.

2. The method of claim 1 wherein:

the at least two shingled tracks of the magnetic medium includes a first number count of shingled tracks;

the obtaining data comprises reading the data using a plurality of read heads including a second number count of read heads; and

the second number count is at least equal to the first number count.

3. The method of claim 2 wherein the second number count is equal to the first number count.

4. The method of claim 3 wherein the first number count and the second number count are both 2.

5. The method of claim 1 wherein the obtaining data from each of the at least two shingled tracks, and the using the data obtained from the at least two shingled tracks to cancel interference in the data obtained from each of the at least two shingled tracks caused by data in each other of the at least two shingled tracks, comprises:

positioning a plurality of read heads to read, the plurality of read heads being positioned relative to a first group of the multiple shingled tracks so that each read head in the plurality of read heads reads a different track group portion of the first group of the multiple shingled tracks, wherein each different track group portion of the first group of multiple tracks overlaps at least one other different track group portion of the first group of multiple shingled tracks;

obtaining data from the plurality of read heads; and

detecting, from the obtained data, a first signal from a first read head in the plurality of read heads representing a first codeword portion of a first codeword that had been written to a first shingled track in the first group of multiple shingled tracks and a second codeword portion of the first codeword that had been written to a second shingled track in the first group of multiple shingled tracks, and a second signal from a second read head in the plurality of read heads representing the first codeword portion of the first codeword that had been written to the first shingled track in the first group of multiple shingled tracks and the second codeword portion of the first codeword that had been written to the second shingled track in the first group of multiple shingled tracks.

6. A storage device comprising:

a magnetic storage medium having thereon more than one track of data that have been encoded into codewords, wherein the more than one track are written in a shingled manner, and the codewords have been divided into respective codeword portions with each respective codeword portion having been written to a respective different one of multiple shingled tracks of the magnetic medium; and

reading apparatus comprising:

a detector configured to obtain data from each of at least two shingled tracks of the multiple shingled tracks;

interference cancellation circuitry configured to use the data obtained from the at least two shingled tracks to cancel interference in the data obtained from each one of the at least two shingled tracks caused by data in each other of the at least two shingled tracks;

interleaver circuitry configured to recombine the respective codeword portions in data from which interference has been cancelled; and

decoder circuitry configured to decode the recombined respective codeword portions from the at least two shingled tracks into at least one decoded data stream.

7. The storage device of claim 6 wherein:

the at least two shingled tracks of the magnetic medium includes a first number count of shingled tracks;

the detector comprises a plurality of read heads including a second number count of read heads; and

the second number count is at least equal to the first number count.

8. The storage device of claim 7 wherein the second number count is equal to the first number count.

9. The storage device of claim 8 wherein the first number count and the second number count are both 2.

10. The storage device of claim 6 wherein the detector comprises:

a plurality of read heads for positioning relative to a first group of the multiple shingled tracks so that each read head in the plurality of read heads reads a different track group portion of the first group of the multiple shingled tracks, wherein each different track group portion of the first group of multiple shingled tracks overlaps at least one other different track group portion of the first group of multiple shingled tracks; and

detector circuitry configured to detect, from the plurality of read heads, a first signal from a first read head in the plurality of read heads representing a first codeword portion of a first codeword that had been written to a first shingled track in the first group of multiple shingled tracks and a second codeword portion of the first codeword that had been written to a second shingled track in the first group of multiple shingled tracks, and a second signal from a second read head in the plurality of read heads representing the first codeword portion of the first codeword that had been written to the first shingled track in the first group of multiple shingled tracks and the second codeword portion of the first codeword that had been written to the second shingled track in the first group of multiple shingled tracks.

11. The storage device of claim 6 wherein:

the decoder circuitry is an iterative decoder;

the storage device further comprising:

de-interleaver circuitry configured to de-interleave output of the decoder circuitry for re-input to the detector.

12. A method for reading data that have been encoded into codewords and written onto shingled tracks of a magnetic medium, the method comprising:

positioning a plurality of read heads to read codewords that have been divided into respective codeword portions with each respective codeword portion having been written to a respective different one of multiple shingled tracks of the magnetic medium, the plurality of read heads being positioned relative to a first group of the multiple shingled tracks so that each read head in the plurality of read heads reads a different track group portion of the first group of the multiple shingled tracks, wherein each different track group portion of the first group of multiple tracks overlaps at least one other different track group portion of the first group of multiple shingled tracks;

obtaining data from the plurality of read heads;

detecting, from the obtained data, a first signal from a first read head in the plurality of read heads representing a first codeword portion of a first codeword that had been written to a first shingled track in the first group of multiple shingled tracks and a second codeword portion of the first codeword that had been written to a second shingled track in the first group of multiple shingled tracks, and a second signal from a second read head in the plurality of read heads representing the first codeword portion of the first codeword that had been written to the first shingled track in the first group of multiple shingled tracks and the second codeword portion of the first codeword that had been written to the second shingled track in the first group of multiple shingled tracks; and

decoding the detected first and second signals to read multiple tracks simultaneously in the first group of multiple shingled tracks.

13. The method of claim 12 wherein the first group of multiple shingled tracks includes a first number of tracks, the plurality of read heads includes a second number of read heads, and the second number is at least equal to the first number.

14. The method of claim 13 wherein the second number is equal to the first number.

15. The method of claim 14 wherein the first number and the second number are both 2.

16. A storage device comprising:

a magnetic storage medium having thereon more than one track of data that have been encoded into codewords, wherein the more than one track are written in a shingled manner; and

reading apparatus comprising:

a plurality of read heads for positioning to read codewords that have been divided into respective codeword portions with each respective codeword portion having been written to a respective different one of multiple shingled tracks of the magnetic medium, the plurality of read heads being for positioning relative to a first group of the multiple shingled tracks so that each read head in the plurality of read heads reads a different track group portion of the first group of the multiple shingled tracks, wherein each different track group portion of the first group of multiple shingled tracks overlaps at least one other different track group portion of the first group of multiple shingled tracks;

detector circuitry that detects, from the plurality of read heads, a first signal from a first read head in the plurality of read heads representing a first codeword portion of a first codeword that had been written to a first shingled track in the first group of multiple shingled tracks and a second codeword portion of the first codeword that had been written to a second shingled track in the first group of multiple shingled tracks, and a second signal from a second read head in the plurality of read heads representing the first codeword portion of the first codeword that had been written to the first shingled track in the first group of multiple shingled tracks and the second codeword portion of the first codeword that had been written to the second shingled track in the first group of multiple shingled tracks;

interleaver circuitry that combines the detected first and second signals; and

decoder circuitry that decodes the combined detected first and second signals to read multiple tracks simultaneously in the first group of multiple shingled tracks.

17. The storage device of claim 16 wherein the first group of multiple shingled tracks includes a first number of tracks, the plurality of read heads includes a second number of read heads, and the second number is at least equal to the first number.

18. The storage device of claim 17 wherein the second number is equal to the first number.

19. The storage device of claim 18 wherein the first number and the second number are both 2.

20. The storage device of claim 16 wherein:

the decoder circuitry is an iterative decoder;

the storage device further comprising:

de-interleaver circuitry that de-interleaves output of the decoder circuitry for re-input to the detector circuitry.