Systems using extended servo patterns with multi-pass servowriting and self-servowriting
View Patent ↗The amount of position error written into a servo burst pattern can be reduced by using additional media revolutions to write the pattern. Where the edges of two servo bursts are used to define a position on the media, trimming the first burst and writing the second burst on separate revolutions will result in a different amount of position error being written into each burst. The end result will be a reduction in the overall error in position information. In order to further reduce the position error given by a burst pair, each burst also can be trimmed and/or written in multiple passes. 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.
1. A system for writing position information to a rotatable medium, comprising:
a rotatable medium capable of storing information written to the rotatable medium;
a write element capable of writing information to the rotatable medium; and
a control mechanism adapted to rotate the rotatable medium and position the write element relative to the rotatable medium, such that the write element can:
write a first servo burst during a first pass of a write element over a rotatable medium;
trim the fist servo bust during a second pass of the write element;
write a second servo burst during a third pass of the write element, wherein the write element undergoes the third pass can occur before the second pass; and
write a third servo burst during a fourth pass of the write element, wherein the first servo burst, second servo burst, and third servo burst each have an edge that can be used to determine position during a subsequent pass over those burst patterns.
2. A system according to claim 1 , wherein:
the rotatable medium is selected from the group consisting of magnetic disks, optical disks, and laser-recordable disks.
3. A system according to clam 1 , wherein:
the first servo burst, second servo burst, and third servo burst each have an edge that is positioned approximately along a track line, the track line extending circumferentially about the disk.
4. A system according to claim 1 , further comprising:
a read element adapted to read the first servo burst, second servo burst, and third servo burst on a subsequent pass over the rotatable medium.
5. A system according to claim 4 , further comprising:
a read/write head containing the read element and the write element.
6. A system according to claim 5 , further comprising:
read circuitry adapted to accept information from the read element and determine the position of the read/write head.
7. A system according to claim 1 , wherein:
the write element trims the first servo burst to have a trimmed edge defining a first portion of a burst boundary, and the write element writes each of the second and third servo bursts to have a written edge, the written edges defining a second portion of the burst boundary.
8. A system according to claim 1 , wherein:
the write element is further adapted to trim the first servo burst such that the width of the first servo burst after trimming is approximately equal to the width of a track of servo data.
9. A system according to claim 1 , wherein:
the write element only writes the third servo burst if the boundary defined by the first and second servo bursts determines the position of a data track centerline.
10. A system according to claim 1 , wherein:
the write element is further adapted to write the first, second, and third servo bursts in a servo wedge on the rotatable medium.
11. A system for writing position information to a rotatable medium, comprising:
a rotatable medium capable of storing information written to the rotatable medium;
a write element capable of writing information to the rotatable medium; and
a control mechanism adapted to rotate the rotatable medium and position the write element relative to the rotatable medium, such that the write element can:
write a first servo burst during a first pass of the write element over the rotatable medium;
trim the first servo burst during a second pass of the write element, wherein the write element can trim less than all of the first servo burst during the second pass;
write a second servo burst during a third pass of the write element wherein the first servo burst and second servo burst each have an edge forming a burst boundary that can be used to determine the position of the write element during a subsequent pass over those burst patterns; and
write a third servo burst during a fourth pass of the write element if the burst boundary defines the position of a data track centerline.
12. A system for writing position information to a rotatable medium, comprising:
a rotatable medium capable of storing information written to the rotatable medium;
a write element capable of writing information to the rotatable medium; and
a control mechanism adapted to rotate the rotatable medium and position the write element relative to the rotatable medium, such that the write element can:
write a first servo burst during a first pass of the write element over the rotatable medium;
trim the first servo burst during a second pass of the write element;
write a second servo burst during a third pass of the write element wherein the first servo burst and second servo burst each have an edge forming a burst boundary that can be used to determine the position of the write element during a subsequent pass over those burst patterns;
write a third servo burst during a fourth pass of the write element if the burst boundary defines the position of a data track centerline; and
use a fifth pass to trim that portion of the first servo burst that was not trimmed during the second pass.
13. A system for writing position information to a rotatable medium, comprising:
a rotatable medium capable of storing information written to the rotatable medium;
a write element capable of writing information to the rotatable medium; and
a control mechanism adapted to rotate the rotatable medium and position the write element relative to the rotatable medium, such that the write element can:
write at least a portion of a first burst pattern during a first pass of a write element over a rotating medium;
trim at least a portion but less than all of a first burst pattern during a second pass of the write element;
write at least a portion of a second burst pattern during a third pass of the write element,
wherein the first burst pattern and second burst pattern each have an edge defining a burst boundary that can be used to determine the position of the write element during a subsequent pass over those patterns; and
write at least a portion of a third burst pattern during a fourth pass of the write element if the boundary defines the position of a track centerline, wherein the third burst pattern is also used to define the burst boundary.
14. A system for writing position information to a rotatable medium, comprising:
means for writing a first servo burst during a first pass of a write element over a rotatable medium;
means for trimming the first servo burst during a second pass of the write element;
means for writing a second servo burst during a third pass of the write element; and
means for writing a third servo burst during a fourth pass of the write element, wherein the first servo burst, second servo burst, and third servo burst each have an edge that can be used to determine position during a subsequent pass over those burst patterns.