Granted Patent B2

US 7,184,233 · App. 10/861,220 · Granted Feb 27, 2007

Abstract

Claims (43)

1. A magnetic storage drive head assembly and positioning servo system, comprising:

a head assembly including a data transducer;

a primary position detector for sensing a position of a previously written data track on a magnetic storage medium while writing a data track adjacent the previously written data track;

a secondary position detector for sensing a position of a fixed reference associated with the magnetic storage medium while writing the data track; and

a controller for adjusting the position of the head assembly while writing the data track in response to a weighted average of the sensed positions of the previously written data track and the fixed reference, wherein the position of the previously written data track is weighted to the position of the fixed reference at more than a 5:1 ratio.

2. The system of claim 1 , wherein the primary position detector includes at least one servo read element.

3. The system of claim 2 , wherein the at least one read element is in a spatially fixed relationship with respect to a write element such that alignment of the at least one servo read element with at least a portion of the previously written data track aligns the write element adjacent the previously written data track.

4. The system of claim 1 , wherein the primary position detector includes three servo read elements, the three servo read elements including a first servo read element positioned at track center of the previously written data track, and second and third servo read elements positioned laterally adjacent and on opposing sides of the first servo read element.

5. The system of claim 4 , wherein the controller correlates servo read signals separately between a first read signal from the first servo read element and second and third read signals from the second and third servo read elements to determine relative offset of the transducer head to the previously written data track.

6. The system of claim 1 , wherein the secondary position detector includes an optical detector adapted to detect an edge of the storage medium.

7. The system of claim 1 , wherein the secondary position detector includes an optical detector adapted to detect a servo track on the storage medium.

8. The system of claim 1 , wherein the secondary position detector includes a magnetic detector adapted to detect an edge of the storage medium.

9. The system of claim 1 , wherein the secondary position detector includes a magnetic detector adapted to detect a servo track on the storage medium.

10. The system of claim 1 , wherein the controller weighs the position of the previously written data track to the position of the fixed reference at a 10:1 ratio.

11. The system of claim 1 , further including a low pass filter, wherein a signal from the secondary position sensor is filtered by the low pass filter.

12. The system of claim 1 , wherein the sensed positions of the previously written data track and the fixed reference are sensed continuously while writing the data track.

13. A method for positioning a transducer head relative to a magnetic storage medium, comprising:

writing a data track to a storage medium with a transducer head;

sensing a position of a previously written data track relative to the transducer head while writing the data track;

sensing a position of a fixed reference associated with the storage medium relative to the transducer head while writing the data track; and

repositioning the transducer head relative to the storage medium while writing the data track according to a weighted average of the sensed position of the previously written data track and the sensed position of the fixed reference, wherein the position of the previously written data track is weighted to the position of the fixed reference at more than a 5:1 ratio.

14. The method of claim 13 , wherein the act of sensing the fixed reference includes optically detecting the fixed reference.

15. The method of claim 13 , wherein the act of sensing the fixed reference includes magnetically detecting the fixed reference.

16. The method of claim 13 , wherein the fixed reference includes an edge of the storage medium.

17. The method of claim 13 , wherein the fixed reference includes a servo track.

18. The method of claim 13 , wherein the fixed reference includes a magnetically detectable servo track.

19. The method of claim 13 , wherein the fixed reference includes an optically detectable servo track.

20. The method of claim 13 , wherein sensing the position of the previously written data track includes receiving a read signal from at least one servo read element associated with the transducer head, the read signal generated in response to the previously written data track.

21. The method of claim 13 , wherein sensing the position of the previously written data track includes receiving read signals from three servo read elements including a first servo read element positioned at track center of the previously written data track, and the second and third servo read elements positioned laterally adjacent and on opposing sides of the first servo read element.

22. The method of claim 21 , further including correlating the read signals separately between a first signal from the first servo read element and second and third signals from the second and third servo read elements to determine a relative offset of the transducer head to the previously written data track.

23. The method of claim 13 , wherein the position of the previously written data track is determined from a characteristic of a read signal generated in response to the previously written data track.

24. The method of claim 23 , wherein the characteristic of the read signal varies as a function of offset between the reference track and a read element.

25. The method of claim 23 , wherein the position of the previously written data track is weighted to the position of the fixed reference at a 10:1 ratio.

26. The method of claim 23 , wherein sensing the position of the fixed reference include filtering a position signal with a low pass filter.

27. The method of claim 13 , wherein the sensed positions of the previously written data track and the fixed reference are sensed continuously while writing the data track.

28. A method for sensing the position of a transducer head relative to a magnetic storage medium, comprising:

writing a data track to a magnetic storage medium sensing a first feature of the magnetic storage medium to provide a primary source of positional information to a magnetic drive servo system while writing the data track;

sensing a second feature of the magnetic storage medium to provide a secondary source of positional information to the magnetic drive servo system while writing the data track; and

determining a relative offset of a transducer head with respect to the magnetic storage medium from a combination of the primary source of positional information and the secondary source of positional information, wherein the primary source of positional information is weighted to the secondary source of positional information at more than a 5:1 ratio.

29. The method of claim 28 , wherein the first feature of the magnetic storage medium includes a previously written data track.

30. The method of claim 28 , wherein the second feature of the magnetic storage medium includes a fixed reference associated with the magnetic storage medium.

31. The method of claim 30 , wherein the fixed reference includes one or more of an edge of the storage medium, a longitudinal optical track, or a longitudinal magnetic track.

32. The method of claim 28 , wherein the sensed positions of the first feature and the second feature are sensed continuously while writing the data track.

Assignments (9)