Dynamically allocated parallel equalization and detection of a PRML read channel in a multi-channel drive

1. A tape drive for use with magnetic tapes, the tape drive comprising:

a housing for receiving a magnetic tape having multiple parallel tracks;

a tape head for reading and writing the parallel tracks of the magnetic tape, wherein reading the parallel tracks produces a data signal for each track;

a plurality of partial response maximum likelihood (PRML) equalization/detection channels for processing the data signals to determine the data stream for each data signal;

wherein the plurality of PRML equalization/detection channels includes at least one PRML equalization/detection channel pre-assigned to each track; and

wherein the plurality of PRML equalization/detection channels further includes at least one floating PRML equalization/detection channel dynamically assignable on an as-needed basis.

2. The tape drive of claim 1 wherein there are at least two PRML equalization/detection channels assigned to each track.

3. The tape drive of claim 1 wherein there are sixteen parallel tracks processed at a time.

4. The tape drive of claim 1 wherein there are thirty-two parallel tracks processed at a time.

5. The tape drive of claim 1 wherein a floating PRML equalization/detection channel is dynamically assigned based on current per-track performance.

6. The tape drive of claim 5 wherein current per-track performance for a particular track is determined based on error rate.

7. The tape drive of claim 1 wherein a floating PRML equalization/detection channel is pre-assigned to a default track based on an expectation of per-track performance.

8. The tape drive of claim 7 wherein a track at the tape edge is pre-assigned a floating PRML equalization/detection channel.

9. The tape drive of claim 1 wherein the PRML equalization/detection channels are contained in a single application specific integrated circuit (ASIC).

10. An application specific circuit (ASIC) for use in a tape drive, the tape drive including a housing for receiving a magnetic tape having multiple parallel tracks and a tape head for reading and writing the parallel tracks of the magnetic tape, wherein reading the parallel tracks produces a data signal for each track, the ASIC comprising:

plurality of partial response maximum likelihood (PRML) equalization/detection channels for processing the data signals to determine the data stream for each data signal;

wherein the plurality of PRML equalization/detection channels includes at least one PRML equalization/detection channel pre-assigned to each track; and

wherein the plurality of PRML equalization/detection channels further includes at least one floating PRML equalization/detection channel dynamically assignable on an as-needed basis.

11. The ASIC of claim 10 wherein there are at least two PRML equalization/detection channels assigned to each track.

12. The ASIC of claim 10 wherein there are sixteen parallel tracks processed at a time.

13. The ASIC of claim 10 wherein there are thirty-two parallel tracks processed at a time.

14. The ASIC of claim 10 wherein a floating PRML equalization/detection channel is dynamically assigned based on current per-track performance.

15. The ASIC of claim 14 wherein current per-track performance for a particular track is determined based on error rate.

16. The ASIC of claim 10 wherein a floating PRML equalization/detection channel is pre-assigned to a default track based on an expectation of per-track performance.

17. The ASIC of claim 16 wherein a track at the tape edge is pre-assigned a floating PRML equalization/detection channel.

18. A drive for use with media, the drive comprising:

a housing for receiving a medium having multiple parallel tracks;

a head for reading and writing the parallel tracks of the medium, wherein reading the parallel tracks produces a data signal for each track;

a plurality of partial response maximum likelihood (PRML) equalization/detection channels for processing the data signals to determine the data stream for each data signal;

wherein the plurality of PRML equalization/detection channels includes at least one PRML equalization/detection channel pre-assigned to each track; and

wherein the plurality of PRML equalization/detection channels further includes at least one floating PRML equalization/detection channel dynamically assignable on an as-needed basis.

19. The drive of claim 18 wherein the PRML equalization/detection channels are contained in a single application specific integrated circuit (ASIC).

20. A partial response maximum likelihood (PRML) method for handling parallel tracks wherein reading the tracks produces a plurality of data signals, and wherein a plurality of partial response maximum likelihood (PRML) equalization/detection channels are provided for processing the data signals to determine the data stream for each data signal, the method comprising:

pre-assigning at least one PRML equalization/detection channel to each track; and

dynamically assigning at least one floating PRML equalization/detection channel on an as-needed basis.

21. The method of claim 20 wherein a floating PRML equalization/detection channel is dynamically assigned based on current per-track performance.

22. The method of claim 21 wherein current per-track performance for a particular track is determined based on error rate.

23. The method of claim 20 wherein a floating PRML equalization/detection channel is pre-assigned to a default track based on an expectation of per-track performance.

24. The method of claim 23 wherein a track at the tape edge is pre-assigned a floating PRML equalization/detection channel.