Data storage device with real time fly height predictor for different servo seek sequences and other drive operations

1 . A data storage device, comprising:

one or more disks;

an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface of a corresponding disk among the one or more disks, the selected head including a heater associated with adjusting a fly height of the selected head; and

one or more processing devices, individually or in combination, configured to:

store heater power history data defining historic levels of heater power applied to the heater in the selected head;

based on the heater power history data, select one or more calibrations from plural calibrations that define relationships between the fly height of the selected head and different levels of heater power change; and

determine a predicted fly height of the selected head over a target sector of the one or more disks using the selected one or more calibrations and the heater power history data,

wherein the selecting and the determining are performed during a seek operation in which an ending point of the seek operation is changed after the seek operation has commenced.

2 . The data storage device of claim 1 , wherein the one or more processing devices, individually or in combination, are further configured to store the heater power history data associated with a predefined number of sectors.

3 . The data storage device of claim 2 , wherein the predefined number is a configurable parameter of the data storage device.

4 . The data storage device of claim 1 , wherein the one or more processing devices, individually or in combination, are further configured to:

compare the predicted fly height to an expected fly height; and

based on determining the predicted fly height is within a predefined tolerance of the expected fly height, perform a read operation or a write operation at the target sector.

5 . The data storage device of claim 1 , wherein the one or more processing devices, individually or in combination, are further configured to:

compare the predicted fly height to an expected fly height; and

based on determining the predicted fly height is not within a predefined tolerance of the expected fly height, perform an alternative action.

6 . The data storage device of claim 5 , wherein the alternative action comprises one of:

abort a read operation or a write operation at the target sector;

adjust a level of heater power being applied to the heater; or

adjust a duration of heater power being applied to the heater.

7 . The data storage device of claim 1 , wherein the one or more processing devices, individually or in combination, are further configured to:

determine the plural calibrations; and

store data defining the plural calibrations in persistent memory associated with the data storage device.

8 . The data storage device of claim 7 , wherein the plural calibrations are determined during manufacturing of the data storage device.

9 . The data storage device of claim 7 , wherein the determining the plural calibrations comprises determining a respective calibration for a respective level of heater power change for plural different levels of heater power change.

10 . The data storage device of claim 9 , wherein the determining the respective calibration for the respective level of heater power change comprises:

obtaining a heating timing profile that comprises first measured values of the fly height of the selected head that occur over time as a result of the respective level of heater power change from a first low value to a second high value; and

obtaining a cooling timing profile that comprises second measured values of the fly height of the selected head that occur over time as a result of the respective level of heater power change from the second high value to the first low value.

11 . The data storage device of claim 10 , wherein the determining the respective calibration for the respective level of heater power change further comprises:

determining a first mathematical expression that fits the heating timing profile; and

determining a second mathematical expression that fits the cooling timing profile.

12 . The data storage device of claim 11 , wherein the determining the respective calibration for the respective level of heater power change further comprises:

determining a first relationship between heater digital-to-analog converter value and magnitude of head protrusion based on the first mathematical expression; and

determining a second relationship between heater digital-to-analog converter value and magnitude of head protrusion based on the second mathematical expression.

13 . The data storage device of claim 1 , wherein the selecting and the determining are performed during a seek operation.

14 . A method comprising:

determining plural calibrations that define relationships between a fly height of a selected head and different levels of heater power change in a data storage device, wherein the plural calibrations are determined using measured values of the fly height of the selected head that occur over time as a result of applying respective ones of the levels of heater power change from a respective first value to a respective second value;

storing heater power history data defining historic levels of heater power applied to a heater in the selected head;

based on the heater power history data, selecting one or more calibrations from the plural calibrations;

determining a predicted fly height of the selected head over a target sector of one or more disks using the selected one or more calibrations and the heater power history data,

wherein the determining the plural calibrations, the storing, the selecting, and the determining the predicted fly height are performed by one or more processing devices individually or in combination.

15 . The method of claim 14 , further comprising the one or more processing devices, individually or in combination, performing:

comparing the predicted fly height to an expected fly height; and

based on the comparing, performing one of:

in response to determining the predicted fly height is within a predefined tolerance of the expected fly height, performing a read operation or a write operation at the target sector; or

in response to determining the predicted fly height is not within a predefined tolerance of the expected fly height, performing an alternative action.

16 . The method of claim 14 , wherein the determining the plural calibrations comprises determining a respective calibration for a respective level of heater power change for plural different levels of heater power change.

17 . The method of claim 14 , wherein the selecting and the determining the predicted fly height are performed during a seek operation in which an ending point of the seek operation is changed after the seek operation has commenced.

18 . One or more processing devices comprising, individually or in combination:

means for storing heater power history data defining historic levels of heater power applied to a heater in a selected head in a data storage device;

means for selecting, based on one or more changes in levels of heater power in the heater power history data, one or more calibrations from plural calibrations that define relationships between the fly height of the selected head and different levels of heater power change; and

means for determining a predicted fly height of the selected head over a target sector of one or more disks using the selected one or more calibrations and the heater power history data.

19 . The one or more processing devices of claim 18 , further comprising, individually or in combination:

means for comparing the predicted fly height to an expected fly height;

means for performing a read operation or a write operation at the target sector responsive to determining the predicted fly height being within a predefined tolerance of the expected fly height; and

means for performing an alternative action responsive to determining the predicted fly height being not within a predefined tolerance of the expected fly height.

20 . The one or more processing devices of claim 18 , further comprising, individually or in combination:

means for determining the plural calibrations; and

means for storing data defining the plural calibrations in persistent memory associated with the data storage device.

21 . The one or more processing devices of claim 20 , wherein the means for determining the plural calibrations comprises means for determining a respective calibration for a respective level of heater power change for plural different levels of heater power change.

22 . The one or more processing devices of claim 18 , wherein the selecting and the determining are performed during a seek operation in which an ending point of the seek operation is changed after the seek operation has commenced.