Seagate Technology Incorporated

Maxtor Corporation

Ravi Hebbar

Justin Won

Bruce Douglas Buch

Timothy Francis Ellis

John Charles Purkett

Joshua Ward Christensen

Peter Stuart Harllee, Iii

Russel R Clemmons

Systems and methods are disclosed for writable servo zone overlap regions on a disc memory. An apparatus may comprise a controller configured to determine a servo gate (sgate) timing for an overlap zone including servo patterns of a first servo super zone and a second servo super zone of a disc memory, the sgate timing based on servo pattern timing for the first servo super zone and the second servo super zone. The controller may initiate writing to the overlap zone based on the sgate timing. The controller may also reduce the impact of servo pattern frequency change between zones by calculating a trajectory error prior to the crossing, and providing 1/X of the trajectory error into a servo feedback loop for a following X servo sampling points.

Writable servo overlap zones

A first portion of a track identifier is read from a first servo wedge of a track of a magnetic disk. A second portion of the track identifier is read from a second servo wedge of the track. The second portion includes least-significant bits of the track identifier that are also stored in the first portion. The first and second portions are combined to determine the track identifier for the first and second servo wedges, and the track is identified using the track identifier.

Magnetic disk servo wedges with partial track identifiers

An implementation of a system disclosed herein provides a method of compensating for a change in write position of a recording head due to a change in an operating condition of the recording head.

Write position compensation

A read trajectory and/or a write trajectory of a read/write head of a rotatable disk drive is adjusted using a compensation signal that compensates for a time-varying difference between the read trajectory and the write trajectory.

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Longmont, CO, United States of America

Ravi Hebbar