Multitrack servo marks with perpendicular and longitudinal magnetic fields
AssigneeSeagate Technology LLC
InventorsRiyan Mendonsa, Puskal Prasad Pokharel, Walter R. Eppler
Life of this patent
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Abstract
A servo sector on a disk is read via first and second readers that both span two or more user data tracks. The servo sector has a crosstrack width that spans the two or more user data tracks. The first reader provides a first signal based on detecting a total longitudinal field of the servo sector. The second reader provides a second signal based on detecting a total perpendicular field of the servo sector. A position error of the first and second readers is detected using. A value of the first signal can be used to detect a position error, detect a track-to-track phase error, and/or detect a Gray code error of a track ID field of the servo sector.
Claims20
A method, comprising:
- reading a servo sector on a disk via a first reader that has a first effective width spanning two or more user data tracks, the servo sector having a crosstrack width that spans the two or more user data tracks, the first reader providing a first signal based on detecting a total longitudinal field of the servo sector;
- reading the servo sector via a second reader that has a second effective width spanning the two or more user data tracks, the second reader providing a second signal based on detecting a total perpendicular field of the servo sector;
- and
- detecting a position error of the first and second readers using a value of the first signal obtained while traversing a burst field of the servo sector.
A method, comprising:
- reading a servo sector on a disk via a first reader that spans two or more user data tracks, the servo sector having a crosstrack width that spans the two or more user data tracks, the first reader providing a first signal based on detecting a total longitudinal field of the servo sector;
- reading the servo sector via a second reader that spans the two or more user data tracks, the second reader providing a second signal based on detecting a total perpendicular field of the servo sector;
- and
- detecting a track-to-track phase error of the servo sector using a value of the first signal obtained while traversing a preamble of the servo sector.
A method comprising:
- reading a servo sector on a disk via a first reader that spans two or more user data tracks, the servo sector having a crosstrack width that spans the two or more user data tracks, the first reader providing a first signal based on detecting a total longitudinal field of the servo sector;
- reading the servo sector via a second reader that spans the two or more user data tracks, the second reader providing a second signal based on detecting a total perpendicular field of the servo sector;
- and
- correcting a Gray code error of a track ID field of the servo sector using a value of the first signal obtained while traversing the track ID field.
Dependencies are inferred from the claim text.