Determining head non-linearity in a disk drive
AssigneeWestern Digital Technologies, Inc.
InventorsJames P. R. McFadyen, Noureddine Kermiche
Life of this patent
Estimating the term…
Abstract
Disclosed is a disk drive that determines dynamic fly height (DFH) head non-linearity. A processor of the disk drive controls operations in the disk drive including: estimating a first and second set of head media spacing (HMS) actuation data for a DFH head at a first and second data frequency by commanding the application of power to the DFH head across a pre-defined power range; determining a first and second HMS value based upon the first and second sets of HMS actuation data; calculating a difference value between the first and second HMS values; determining whether the difference value exceeds a threshold.
Claims25
A method to determine head non-linearity in response to a dynamic fly height (DFH) control signal for a disk drive, the method comprising:
- estimating a first and second set of head media spacing (HMS) actuation data for the head for a first and second data frequency by applying power to the head across a pre-defined power range;
- determining a first and second HMS value based upon the first and second sets of HMS actuation data;
- calculating a difference value between the first and second HMS values;
- and
- determining that the difference value exceeds a threshold.
A disk drive to determine head non-linearity comprising:
- a disk;
- a dynamic fly height (DFH) head to write and read data to and from the disk, wherein a fly height of the DFH head is controlled responsive to a DFH control signal;
- a processor for controlling operations to determine DFH head non-linearity, the processor under the control of a program to:
- estimate a first and second set of head media spacing (HMS) actuation data for the head for a first and second data frequency by applying power to the DFH head across a pre-defined power range;
- determine a first and second HMS value based upon the first and second sets of HMS actuation data;
- calculate a difference value between the first and second HMS values;
- and
- determine that the difference value exceeds a threshold.
A disk drive to determine head non-linearity comprising:
- means for controlling a fly height of a head responsive to a dynamic fly height (DFH) control signal;
- means for estimating a first and second set of head media spacing (HMS) actuation data for the head for a first and second data frequency including means for applying power to the head across a pre-defined power range;
- means for determining a first and second HMS value based upon the first and second sets of HMS actuation data;
- means for calculating a difference value between the first and second HMS values;
- and
- means for determining that the difference value exceeds a threshold.
Dependencies are inferred from the claim text.