Systems for self-servowriting with multiple passes per servowriting step
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 servo bursts are used to define a position on the media, trimming a first burst and writing a second burst on separate revolutions of the media 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 combination of bursts, each burst also can be trimmed and/or written in multiple passes. The overall error in position should decrease as the number of passes used to write a burst combination increases. 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 rotating 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 servowriting step of the write element over the rotatable medium;
trim the first servo burst during a first pass of a second servowriting step of the write element; and
write a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have a substantially common edge that can be used to determine the position of the write element during a subsequent pass over those servo bursts; wherein the second servo burst can be written before the first servo burst is trimmed.
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 claim 1 , wherein:
the first servo burst and second 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 and second 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 is further adapted to trim the first servo burst to have a width approximately equal to the width of a track of servo data.
8. A system according to claim 1 , wherein:
the write element is adapted to write the first and second servo bursts in a servo wedge on the rotatable medium.
9. A system according to claim 1 , wherein:
the write element executes the second pass of the second servowriting step before the first pass of the second servowriting step.
10. A system for writing position information to a magnetic disk, comprising:
a magnetic disk capable of storing information written to the magnetic disk;
a write element capable of writing information to the magnetic disk; and
a control mechanism adapted to rotate the magnetic disk and position the write element relative to the magnetic disk, such that the write element can:
write a first servo burst during a first servowriting step of the write element over a magnetic hard disk;
trim the first servo burst during a first pass of a second servowriting step of the write head, the first servo burst being trimmed so as to have a trimmed edge in about a predetermined position on the magnetic disk; and
write a servo burst during a second pass of the second servowriting step of the write head, wherein the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define a position that can be used to adjust the radial location over the disk of the write head during subsequent passes over those bursts; wherein the second servo burst can be written before the first servo burst is trimmed.
11. A system for writing position information to a magnetic disk, comprising:
means for writing a first servo burst during a first servowriting step of a write head over a magnetic hard disk;
means for trimming the first servo burst during a first pass of a second servowriting step of the write head, the first servo burst being trimmed so as to have a trimmed edge in about a predetermined position on the magnetic disk; and
means for writing a servo burst during a second pass of the second servowriting step of the write head, wherein the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define a position that can be used to adjust the radial location over the disk of the write head during subsequent passes over those bursts; wherein the second servo burst can be written before the first servo burst is trimmed.
12. A system for writing position information to a rotating medium in order to reduce repeatable runout, 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 servowriting step of the write element over the rotatable medium;
trim the first servo burst during a first pass of a second servowriting step of the write element; and
write a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have substantially common edge that can be used to determine the position of the write element in order to reduce repeatable runout; wherein the second servo burst can be written before the first servo burst is trimmed.
13. A method for writing position information to a rotating medium, comprising:
writing a first servo burst during a first servowriting step of a write element over a rotating medium;
trimming the first servo burst during a first pass of a second servowriting step of the write element; and
writing a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have a substantially common edge that can be used to determine the position of the write element during a subsequent pass over those servo bursts; wherein the second servo burst can be written before the first servo burst is trimmed.
14. A method according to claim 13 , further comprising:
using the trimmed edge of the first servo burst and an adjacent edge of the second servo burst to determine the position of the write element.
15. A method according to claim 13 , including at least one of:
having the width of the first servo burst after trimming be approximately the width of a track of servo data;
containing the first and second servo bursts in a servo wedge on the rotating medium;
having the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define the position of a centerline of a data track on the rotating medium; and
having the second pass of the second servowriting step occur before the first pass of the second servowriting step.
16. A method for writing servo information to a magnetic disk, comprising:
writing a first servo burst during a first servowriting step of a write head over a magnetic hard disk;
trimming the first servo burst during a first pass of a second servowriting step of the write head, the first servo burst being trimmed so as to have a trimmed edge in about a predetermined position on the magnetic disk; and
writing a servo burst during a second pass of the second servowriting step of the write head, wherein the trimmed edge of the first servo burst and an adjacent edge of the second servo burst define a position that can be used to adjust the radial location over the disk of the write head during subsequent passes over those bursts; wherein the second servo burst can be written before the first servo burst is trimmed.
17. A method for writing position information to a rotating medium in order to reduce repeatable runout, comprising:
writing a first servo burst during a first servowriting step of a write element over a rotating medium;
trimming the first servo burst during a first pass of a second servowriting step of the write element; and
writing a second servo burst during a second pass of the second servowriting step of the write element, wherein the first servo burst and second servo burst each have a substantially common edge that can be used to determine the position of the write element in order to reduce repeatable runout; wherein the second servo burst can be written before the first servo burst is trimmed.