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US 7,023,633 B2Granted
Adaptive track count determination for a self-servowritten disk drive
AssigneeHitachi Global Storage Technologies Netherland B.V.
InventorDaniel James Malone, Sr.
Life of this patent
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Abstract
A system and process for constructing a magnetic storage drive capable of single pass self-servowriting. A plurality of heads are sorted, or “binned,” into classifications based on at least an approximate magnetic width of each head. Only heads from a single classification are installed in a particular disk drive system. A track overlap value is calculated, preferably empirically, for the approximate magnetic widths of typical heads in the single classification. The overlap value is used to determine a track spacing utilized during a self-servowriting process.
Claims17
A method for constructing a magnetic storage drive capable of single pass self-servowriting, comprising:
- sorting a plurality of heads into classifications based on at least an approximate magnetic width of each head;
- installing only heads from a single classification in a particular disk drive system;
- writing two servobursts on a disk in the disk drive system using one of the heads;
- calculating a tack overlap value for the approximate magnetic widths of the one of the heads in the single classification based on magnitudes of the two servobursts by dividing a sum of the servoburst magnitudes by an amplitude obtained by centering the read head over one of the servobursts and taking a reading;
- and
- using the overlap value to determine a track spacing utilized during a self-servowriting process.
3 more elements
A method for constructing a magnetic storage drive, comprising:
- sorting a plurality of heads into classifications based on at least an approximate magnetic width of each head;
- installing only heads from a single classification in a particular disk drive system;
- calculating a track overlap value for the approximate magnetic widths of the heads in the single classification;
- and
- using the overlap value to determine a track spacing utilized during a self-servowriting process;
- wherein the overlap value is determined from an equation:
- OL=((Tr/TP+Tw/TP)−1)/(Tr/TP)
- where:
- OL=overlap value;
- Tr=amplitude obtained by a read head;
- Tw=amplitude of one of a bursts;
- and
- TP=total amplitude of a cylinder.
10 more elements
A method for constructing a magnetic storage drive, comprising:
- sorting a plurality of heads into classifications based on at least an approximate magnetic width of each head;
- installing only heads from a single classification in a particular disk drive system;
- calculating a track overlap value for the approximate magnetic widths of the heads in the single classification;
- and
- using the overlap value to determine a track spacing utilized during a self-servowriting process;
- wherein the overlap value is determined by;
- writing a servoburst on a given track of a disk;
- writing a second servoburst on a second track of the disk;
- centering a read head over a gap between the two servobursts;
- reading magnitudes of the two servobursts using the read head;
- adding the magnitudes of the two servobursts;
- and
- dividing a sum of the servoburst magnitudes by an amplitude obtained by centering the read head over one of the servo bursts and taking a reading.
10 more elements
A method for selecting desired average estimated overlaps for different sizes of heads, comprising:
- determining at least an approximate magnetic width of at least some of a plurality of heads;
- sorting the heads into classifications based on the magnetic widths;
- and
- selecting a track overlap value for each classification based on the approximate magnetic widths of the heads in each classification and the resultant track counts obtained after the self-servowrite process is completed, the track overlap value corresponding to a calculation for representative heads in the classification based on magnitudes of two servobursts created by the representative heads, wherein the overlap value is calculated by dividing a sum of the servoburst magnitudes by an amplitude obtained by centering the read head over one of the servobursts and taking a reading.
1 more element
A method for selecting desired average estimated overlaps for different sizes of heads, comprising:
- determining at least an approximate magnetic width of at least some of a plurality of heads;
- sorting the heads into classifications based on the magnetic widths;
- and
- selecting a track overlap value for each classification based on the approximate magnetic widths of the heads in each classification and the resultant track counts obtained after the self-servowrite process is completed;
- wherein the overlap value has been determined empirically from an equation:
- OL=((Tr/TP+Tw/TP)−1)/(Tr/TP)
- where:
- OL=overlap value;
- Tr=amplitude obtained by a read head;
- Tw=amplitude of one of a bursts;
- and
- TP=total amplitude of a cylinder.
9 more elements
A method for selecting desired average estimated overlaps for different sizes of heads, comprising:
- determining at least an approximate magnetic width of at least some of a plurality of heads;
- sorting the heads into classifications based on the magnetic widths;
- and
- selecting a track overlap value for each classification based on the approximate magnetic widths of the heads in each classification and the resultant track counts obtained after the self-servowrite process is completed;
- wherein the overlap value has been determined empirically by:
- writing a servoburst on a given track of a disk;
- writing a second servoburst on a second track of the disk;
- centering a read head over a gap between the two servobursts;
- reading magnitudes of the two servobursts using the read head;
- adding the magnitudes of the two servobursts;
- dividing a sum of the servoburst magnitudes by an amplitude obtained by centering the read head over one of the servobursts and taking a reading.
8 more elements
A magnetic storage system capable of single pass self-servowriting, comprising:
- magnetic media;
- at least one head for reading from and writing to the magnetic media, wherein each head has been sorted into a classification based on at least an approximate magnetic width of each head, wherein a track overlap value for the classification has been selected based on the approximate magnetic width of each head in the classification, the overlap value having been determined empirically based on a magnitude of at least two servobursts created by a representative head in the classification, wherein the overlap value is used to determine a track spacing during a self-servowriting process, wherein the overlap value is calculated by dividing a sum of the servoburst magnitudes by an amplitude obtained by centering the read head over one of the servobursts and taking a reading;
- a slider for supporting each head;
- and
- a control unit coupled to each head for controlling operation of each head.
2 more elements
A system capable of single pass self-servowriting, comprising:
- magnetic media;
- at least one head for reading from and writing to the magnetic media, wherein each head has been sorted into a classification based on at least an approximate magnetic width of each head, wherein a track overlap value for the classification has been selected based on the approximate magnetic width of each head in the classification, wherein the overlap value is used to determine a track spacing during a self-servowriting process;
- a slider for supporting each head;
- and
- a control unit coupled to each bead for controlling operation of each head;
- wherein the overlap value is determined by:
- writing a servoburst on a given track of a disk;
- writing a second servoburst on a second track of the disk;
- centering a read head over a gap between the two servobursts;
- reading magnitudes of the two servobursts using the read head;
- adding the magnitudes of the two servobursts;
- dividing a sum of the servoburst magnitudes by an amplitude obtained by centering the read head over one of the servobursts and taking a reading.
9 more elements
Dependencies are inferred from the claim text.