Disk drive reading servo sectors recorded at a relative offset on multiple disk surfaces to increase the servo sample rate
View Patent ↗A disk drive is disclosed comprising a first disk surface and a second disk surface, wherein a first head is actuated radially over the first disk surface and a second head is actuated radially over the second disk surface. Each disk surface comprises a plurality of tracks, wherein each track comprises a plurality of data sectors for storing user data and N embedded servo sectors for storing servo data. The N embedded servo sectors on the tracks on the first disk surface are recorded at a physical angular offset from the N embedded servo sectors on the tracks on the second disk surface. While accessing a track on the first disk surface through the first head, the servo data on the first disk surface is read through the first head and the servo data on the second disk surface is read through the second head, thereby increasing the servo sample rate.
1. A disk drive comprising:
(a) a first disk surface and a second disk surface;
(b) a first head coupled to a first actuator arm and a second head coupled to a second actuator arm and;
(c) a voice coil motor for rotating the first and second actuator arms about a pivot axis, wherein:
each disk surface comprises a plurality of tracks;
a first track on the first disk surface comprises a plurality of data sectors for storing user data and N embedded servo sectors for storing servo data;
a second track on the second disk surface comprises a plurality of data sectors for storing user data and N embedded servo sectors for storing servo data;
the N embedded servo sectors are recorded at a periodic interval around a circumference of the first and second tracks;
the N embedded servo sectors on the first track are recorded at a physical angular offset from the N embedded servo sectors on the second track; and
while accessing the first track through the first head, the servo data on the first track is read through the first head and the servo data on the second track is read through the second head, wherein the servo data read from the second track is high pass filtered to generate a high pass signal for controlling the voice coil motor to actuate the first head over the first disk surface.
2. The disk drive as recited in claim 1 , wherein the servo data read from the second track through the second head is used to generate a shock detect signal representing a physical shock to the disk drive.
3. The disk drive as recited in claim 2 , wherein the servo data read from the first track through the first head is used to generate the shock detect signal.
4. The disk drive as recited in claim 2 , wherein the shock detect signal is generated in response to the high pass signal.
5. The disk drive as recited in claim 3 , wherein the shock detect signal is generated in response to the high pass signal.
6. The disk drive as recited in claim 2 , wherein:
(a) accessing the first track comprises writing data to the first track during a write operation; and
(b) the write operation is aborted if the shock detect signal indicates a physical shock of sufficient magnitude has occurred.
7. The disk drive as recited in claim 6 , wherein the write operation is aborted if the shock detect signal exceeds a predetermined threshold.
8. The disk drive as recited in claim 6 , wherein the write operation is aborted if the high-pass signal exceeds a predetermined threshold.
9. The disk drive as recited in claim 3 , wherein:
(a) accessing the first track comprises writing data to the first track during a write operation; and
(b) the write operation is aborted if the shock detect signal indicates a physical shock of sufficient magnitude has occurred.
10. The disk drive as recited in claim 9 , wherein the write operation is aborted if the shock detect signal exceeds a predetermined threshold.
11. The disk drive as recited in claim 9 , wherein the write operation is aborted if the high-pass signal exceeds a predetermined threshold.
12. The disk drive as recited in claim 1 , wherein the servo data read from the first and second tracks is used to control the position of the first head with respect to the first track.
13. The disk drive as recited in claim 1 , the disk drive further comprising:
(a) a first microactuator for actuating the first head radially over the first disk surface in fine movements in response to the servo data read from the first track; and
(b) a second microactuator for actuating the second head radially over the second disk surface in fine movements independent of the first microactuator in response to the servo data read from the second track.
14. The disk drive as recited in claim 13 , wherein the servo data read from the first track is used to control the voice coil motor.
15. The disk drive as recited in claim 13 , wherein the servo data read from the first and second tracks is used to control the voice coil motor.
16. The disk drive as recited in claim 1 , the disk drive further comprising
a microactuator for actuating the first head radially over the first disk surface and the second head radially over the second disk surface in fine movements in response to the servo data read from the first and second tracks.
17. A method of operating a disk drive, the disk drive comprising a first disk surface and a second disk surface, a first head coupled to a first actuator arm, a second head coupled to a second actuator arm, and a voice coil motor for rotating the first and second actuator arms about a pivot axis, wherein each disk surface comprises a plurality of tracks, a first track on the first disk surface comprises a plurality of data sectors for storing user data and N embedded servo sectors for storing servo data, a second track on the second disk surface comprises a plurality of data sectors for storing user data and N embedded servo sectors for storing servo data, the N embedded servo sectors are recorded at a periodic interval around a circumference of the first and second tracks, wherein the N embedded servo sectors on the first track are recorded at a physical angular offset from the N embedded servo sectors on the second track, the method comprising the steps of:
(a) positioning the first head over the first track on the first disk surface;
(b) accessing the first track through the first head; and
(c) while accessing the first track through the first head;
reading the servo data on the first track through the first head and reading the servo data on the second track through the second head; and
filtering the servo data read from the second track to generate a high pass signal for controlling the voice coil motor to actuate the first head over the first disk surface.
18. The method as recited in claim 17 , further comprising the step of generating a shock detect signal representing a physical shock to the disk drive in response to the servo data read from the second track through the second head.
19. The method as recited in claim 18 , further comprising the step of generating the shock detect signal in response to the servo data read from the first track through the first head.
20. The method as recited in claim 18 , wherein the shock detect signal is generated in response to the high pass signal.
21. The method as recited in claim 19 , wherein the shock detect signal is generated in response to the high pass signal.
22. The method as recited in claim 18 , wherein:
(a) wherein the step of accessing the first track comprises the step of writing data to the first track during a write operation; and
(b) further comprising the step of aborting the write operation if the shock detect signal indicates a physical shock of sufficient magnitude has occurred.
23. The method as recited in claim 22 , further comprising the step of aborting the write operation if the shock detect signal exceeds a predetermined threshold.
24. The method as recited in claim 22 , wherein the write operation is aborted if the high-pass signal exceeds a predetermined threshold.
25. The method as recited in claim 19 , wherein:
(a) the step of accessing the first track comprises the step of writing data to the first track during a write operation; and
(b) further comprising the step of aborting the write operation if the shock detect signal indicates a physical shock of sufficient magnitude has occurred.
26. The method as recited in claim 25 , further comprising the step of aborting the write operation if the shock detect signal exceeds a predetermined threshold.
27. The method as recited in claim 25 , wherein the write operation is aborted if the high-pass signal exceeds a predetermined threshold.
28. The method as recited in claim 17 , further comprising the step of controlling the position of the first head with respect to the first track in response to the servo data read from the first and second tracks.
29. The method as recited in claim 17 , further comprising the steps of:
(a) using a first microactuator to actuate the first head radially over the first disk surface in fine movements in response to the servo data read from the first track; and
(b) using a second microactuator to actuate the second head radially over the second disk surface in fine movements independent of the first microactuator in response to the servo data read from the second track.
30. The method as recited in claim 29 , further comprising the step of controlling the voice coil motor in response to the servo data read from the first track.
31. The method as recited in claim 29 , further comprising the step of controlling the voice coil motor in response to the servo data read from the first and second tracks.
32. The method as recited in claim 17 , further comprising the steps of
using a microactuator to actuate the first head radially over the first disk surface and the second head radially over the second disk surface in fine movements in response to the servo data read from the first and second tracks.