Rotating media storage device having a calibration track with unique calibration servo synch marks

1. A rotating media storage device (RMSD) comprising:

a head;

a disk including:

a plurality of tracks including a calibration track having a plurality of normal servo wedges distributed around the calibration track, at least one of the normal servo wedges including a normal servo synch mark (SSM N ); and

at least one calibration servo wedge distributed between a pair of normal servo wedges, the calibration servo wedge including a calibration servo synch mark (SSM C ), wherein the calibration SSM C includes a pattern that is different than a pattern associated with the normal SSM N ; and

a synch mark detection circuit having a normal synch mark detection mode and a calibration servo synch mark detection mode, wherein, in the normal synch mark detection mode, the synch mark detection circuit validates a servo synchronization signal based on the head detecting a normal SSM N associated with a normal servo wedge, and in the calibration synch mark detection mode, the synch mark detection circuit validates a servo synchronization signal based on the head detecting a calibration SSM C associated with a calibration servo wedge.

2. The RMSD of claim 1 , wherein after the detection of a normal calibration SSM N , a servo controller declares a calibration servo synch mark detection mode and calculates a time to a next predicted calibration SSM C .

3. The RMSD of claim 2 , wherein after a calibration SSM C is detected, the servo controller declares a hard calibration servo synchronization mode based upon a forecasted pattern of calibration SSM C s.

4. The RMSD of claim 1 , wherein detection of a normal SSM N includes decoding an encoded pattern of a normal SSM N .

5. The RMSD of claim 1 , wherein detection of a calibration SSM C includes decoding an encoded pattern of a calibration SSM C .

6. The RMSD of claim 1 , wherein each of the calibration servo wedges further includes a track identifier (TKID) field, a wedge identifier field, and a series of servo bursts.

7. The RMSD of claim 1 , wherein the calibration track is located at the outer diameter of the disk.

8. The RMSD of claim 1 , wherein the calibration track is located at the inner diameter of the disk.

9. A method for switching a disk drive servo control system from a normal servo mode to a calibration servo mode, the method comprising:

setting the normal servo mode by setting the servo control system to operate on a normal servo synch mark (SSM N ), wherein the normal SSM N includes a first pattern;

tracking on a normal track using the normal SSM N to search for normal servo sectors;

seeking to a calibration track;

tracking on the calibration track in the normal servo mode until an on-track condition is declared; then

setting the calibration servo mode by setting the servo control system to operate on a calibration servo synch mark (SSM C ); and

tracking on the calibration track using the calibration servo synch mark SSM C to search for calibration servo sectors, wherein the calibration SSM C includes a second pattern that is different than the first pattern associated with the normal SSM N .

10. The method of claim 9 , further comprising:

detecting a normal SSM N to validate a servo synchronization signal as part of a normal synch mark detection mode; and

detecting a calibration SSM C to validate a servo synchronization signal as part of a calibration synch mark detection mode.

11. The method of claim 10 , wherein after the detection of a normal SSM N , further comprising declaring the calibration synch mark detection mode and calculating a time to a next predicted calibration SSM C .

12. The method of claim 11 , wherein after the calibration SSM C is detected, further comprising declaring a hard calibration servo synchronization mode based upon a forecasted pattern of calibration SSM C s.

13. The method of claim 10 , wherein detection of a normal SSM N includes decoding an encoded pattern of a normal SSM N .

14. The method of claim 10 , wherein detection of a calibration SSM C includes decoding an encoded pattern of a calibration SSM C .

15. The method of claim 9 , wherein the calibration track is located at the outer diameter of the disk.

16. The method of claim 9 , wherein the calibration track is located at the inner diameter of the disk.

17. A computer system comprising a host computer and a rotating media storage device (RMSD), the RMSD comprising:

a disk having a plurality of tracks including a calibration track having a plurality of normal servo wedges distributed around the calibration track, at least one of the normal servo wedges including a normal servo synch mark (SSM N ) for synchronizing track-following in a normal servo mode, wherein the normal SSM N includes a first pattern; and

at least one calibration servo wedge distributed between a pair of normal servo wedges, the calibration servo wedge including a calibration servo synch mark (SSM C ) for synchronizing track-following in a calibration servo mode, wherein the calibration SSM C includes a second pattern that is different than the first pattern associated with the normal SSM N .

18. The computer system of claim 17 , further comprising a head and a synch mark detection circuit having a normal synch mark detection mode and a calibration servo synch mark detection mode, wherein, in the normal synch mark detection mode, the synch mark detection circuit validates a servo synchronization signal based on the head detecting a normal SSM N associated with a normal servo wedge, and in the calibration synch mark detection mode, the synch mark detection circuit validates a servo synchronization signal based on the head detecting a calibration SSM C associated with a calibration servo wedge.

19. The computer system of claim 18 , wherein after the detection of a normal SSM N , a servo controller declares a calibration servo synch mark detection mode and calculates a time to a next predicted calibration SSM C .

20. The computer system of claim 19 , wherein after the calibration SSM C is detected, the servo controller declares a hard calibration servo synchronization mode based upon a forecasted pattern of calibration SSM C s.

21. The computer system of claim 18 , wherein detection of a normal SSM N includes decoding an encoded pattern of a normal SSM N .

22. The computer system of claim 18 , wherein detection of a calibration SSM C includes decoding an encoded pattern of a calibration SSM C .

23. The computer system of claim 17 , wherein each of the calibration servo wedges further includes a track identifier (TKID) field, a wedge identifier field, and a series of servo bursts.

24. The computer system of claim 17 , wherein the calibration track is located at the outer diameter of the disk.

25. The computer system of claim 17 , wherein the calibration track is located at the inner diameter of the disk.

26. A rotating media storage device (RMSD) including a disk, the disk comprising:

a plurality of tracks including a calibration track having a plurality of normal servo wedges distributed around the calibration track, at least one of the normal servo wedges including a normal servo synch mark (SSM N ) for synchronizing track-following in a normal servo mode, wherein the normal SSM N includes a first pattern; and

at least one calibration servo wedge distributed between a pair of normal servo wedges, the calibration servo wedge including a calibration servo synch mark (SSM C ) for synchronizing track-following in a calibration servo mode, wherein the calibration SSM C includes a second pattern that is different than the first pattern associated with the normal SSM N .