Apparatus and method for altering track scan data based on head width relative to data track width and determining the position error signal from the altered track scan data to qualify the head in a data storage device
AssigneeSeagate Technology LLC
InventorsAlexei Hiram Sacks, Haoying Sun
Life of this patent
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Abstract
A method and apparatus to qualify heads to be used in disc drives. The method and apparatus collect a set of track scan data by moving the head across transitions in a track on a medium. The track scan data is changed based on a difference between a writer width of the head and a nominal track width to produce modified track scan data. Position error signal data is then determined from at least some of the data in the modified set of track scan data. The linearity of the position error signal data is used to qualify the head.
Claims20
A method of qualifying a head to be used in a disc drive, the method comprising steps of:
- (a) collecting a set of track scan data by moving the head across transitions in a track on a medium;
- (b) altering the number of data points used from the set of track scan data based on a difference between a writer width of the head and a nominal track width to produce a modified set of track scan data;
- (c) determining a position error signal data from at least some of the data in the modified set of track scan data;
- and
- (d) qualifying the head based on the linearity of the position error signal data.
An apparatus for qualifying heads for a disc drive, the apparatus comprising:
- a data collector for collecting track scan data;
- an expander/contractor for altering the number of data points used from the track scan data based on the difference between a head's writer width and a nominal track width to produce modified track scan data;
- a position error signal generator for generating a description of a position error signal based on the modified track scan data;
- a gain ratio calculator for calculating a gain ratio based on the description of the position error signal;
- and
- a rejection component that determines whether to reject the head based on the gain ratio.
An apparatus for qualifying heads for a disc drive, the apparatus comprising:
- a data collector for collecting track scan data produced by a head;
- rejection means for altering the number of data points from the track scan data based on the difference between a head's writer width and a nominal track width to produce modified track scan data and for rejecting a head based on the modified track scan data.
Dependencies are inferred from the claim text.