Systems and methods for multipass servowriting with a null burst pattern
AssigneeMatsushita Electrical Industrial Co., Ltd.
InventorsRichard Ehrlich, David Rutherford
Life of this patent
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Abstract
Embodiments of the present invention enables the trimming and writing of servo bursts in a null burst servo pattern as multiple portions in multiple passes while still demodulating each of the servo bursts as a single burst to obtain PES. Alternatively, the servo bursts can be trimmed and written using different currents in different passes respectively so that a gap can be created in the radial direction between the servo bursts. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.
Claims20
A method for servowriting a null burst servo pattern, comprising:
- writing a first servo burst in the null burst pattern on a surface of a rotatable medium wherein the null burst pattern may include at least one of a preamble, a SAM, a track-number, and one or more servo bursts;
- trimming a first portion of the first servo burst and writing a first portion of a second servo burst in the null burst pattern;
- trimming a second portion of the first servo burst and writing a second portion of the second servo burst in the null burst pattern;
- and
- demodulating both portions of the first and second servo burst as a single burst to obtain a PES.
A method for servowriting a null burst servo pattern, comprising:
- writing a first servo burst in the null burst pattern on one of the plurality of tracks, wherein the null burst pattern may include at least one of a preamble, a SAM, a track-number, and one or more servo bursts;
- trimming the first servo burst using high erase (write) current;
- writing a second servo burst in the null burst pattern using lower write current;
- and
- demodulating the first and second servo burst to obtain a PES.
A system for servowriting a null burst servo pattern, comprising:
- a rotatable medium including a surface having a plurality of tracks operable to store the null burst servo pattern, which may include at least one of a preamble, a SAM, a track-number, and one or more servo bursts;
- a write head operable to servowrite the null burst servo pattern;
- and one or more controllers operable to:
- position the write head relative to a surface of the rotatable medium for servowriting;
- write a first servo burst in the null burst pattern on one of the plurality of tracks via the write head;
- trim a first portion of the first servo burst and write a first portion of a second servo burst in the null burst pattern via the write head;
- trim a second portion of the first servo burst and write a second portion of the second servo burst in the null burst pattern via the write head;
- and
- demodulate both portions of the first and second servo burst as a single burst to obtain a PES.
A system for servowriting a null burst servo pattern, comprising:
- a rotatable medium including a surface having a plurality of tracks operable to store the null burst servo pattern, which may include at least one of a preamble, a SAM, a track-number, and one or more servo bursts;
- a write head operable to write the null burst servo pattern;
- and
- one or more controllers operable to:
- position the write head relative to a surface of a rotatable medium for servowriting;
- write a first servo burst in the null burst pattern on one of the plurality of tracks via the write head;
- trim the first servo burst using high erase (write) current via the write head;
- write a second servo burst in the null burst pattern using lower write current via the write head;
- and
- demodulate the first and second servo burst to obtain a PES.
Dependencies are inferred from the claim text.