A method of writing product servo sectors to a disk of a disk drive is disclosed. A plurality of spiral tracks are written to the disk, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. During the product servo writing process, the sync marks in the spiral tracks are read to generate a coarse timing recovery measurement, and the high frequency signal in the spiral tracks is read to generate a fine timing recovery measurement. The coarse and fine timing recovery measurements are processed to synchronize a servo write clock used to write the product servo sectors to the disk. In one embodiment the control circuitry within the disk drive synchronizes the servo write clock by reading the spiral tracks, and in an alternative embodiment an external product servo writer synchronizes the servo write clock by reading the spiral tracks.

Servo writing a disk drive by synchronizing a servo write clock to a high frequency signal in a spiral track

A disk drive is disclosed servo written from spiral tracks by generating a time-stamped sync mark detect signal processed by timing recovery firmware. A plurality of spiral tracks are written to the disk, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. The head internal to the disk drive is used to read the spiral tracks, and a time-stamped sync mark detect signal is generated when one of the sync marks is detected. The time-stamped sync mark detect signal represents a time when the sync mark was detected relative to a servo write clock. A difference between the time-stamped sync mark detect signal and an expected time is computed in firmware to generate a coarse timing recovery measurement used to synchronize the servo write clock. The servo write clock and the head internal to the disk drive are used to write product servo sectors along a substantially circular target path.

Servo writing a disk drive from spiral tracks by generating a time-stamped sync mark detect signal processed by timing recovery firmware

Disclosed is a method for generating a repeatable runout (RRO) compensation value set for a circular track on a magnetic medium on a surface of a disk in a disk drive. The magnetic medium has a plurality of previously written spiral servo tracks for providing position information during a self servo-writing operation. In the method, servo burst patterns are written at a plurality of radial locations on the magnetic data storage surface during circular tracking operations using the spiral servo tracks, and respective position error signals generated during the circular tracking operations are stored. The servo burst patterns at the plurality of radial locations define a circular data track. The RRO compensation value set for the circular data track may be generated based on the respective stored position error signals generated during the circular tracking operations for writing the servo burst patterns at the plurality of radial locations.

Determining repeatable runout cancellation information using PES information generated during self servo-writing operations

A method and apparatus is disclosed for adjusting the track density over the disk radius by changing the slope of spiral tracks used to servo write a disk drive. A plurality of spiral tracks are written to the disk wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. A slope of the spiral tracks over a first radial segment of the disk is substantially steeper than the slope of the spiral tracks over a second radial segment of the disk. The head internal to the disk drive is used to read the spiral tracks in order to write product servo sectors to the disk to define a plurality of data tracks. The steeper slope of the spiral tracks over the first radial segment causes a track density of the data tracks to be lower over the first radial segment compared to the track density of the data tracks over the second radial segment.

Adjusting track density over disk radius by changing slope of spiral tracks used to servo write a disk drive

A method and apparatus is disclosed for writing product servo sectors to a disk of a disk drive to define a plurality of data tracks. The disk drive comprises the disk and a head actuated over the disk. The disk comprises a plurality of spiral tracks which are read using the head to synchronize a write clock and to generate a position error signal (PES) according to a PES algorithm used to maintain the head along a first servo track while writing product servo sectors along the first servo track. The PES algorithm is adjusted to seek the head to a second servo track, and the head is used to write product servo sectors along the second servo track.

Adjusting track density by changing PES algorithm when servo writing a disk drive from spiral tracks

A method and system for self-servo writing a disk drive by transferring a servo reference pattern by magnetic printing onto at least one storage surface of a reference disk, wherein a resulting printed reference pattern includes embedded servo information providing servo timing and transducer head position information; assembling the disk drive including the steps of installing at least said disk into the disk drive and enclosing said disk and the data transducers within a housing sealed against particulate contamination from an eternal ambient environment; reading the printed reference pattern from said disk via at least one transducer head to generate a readback signal; sampling the readback signal at a sampling rate to generate a sampled signal; processing the sampled signal waveform specturm to generate a recovered signal including the embedded servo information and a fundamental frequency of the sampled signal; using the servo information from the recovered signal to precisely position and maintain the data transducers at concentric track locations of disk storage surfaces; and self-writing disk drive servo patterns onto the storage surfaces at the concentric track locations with the data transducers in accordance with disk drive servo pattern features.

Mike Moser

Papers

Self-writing of servo patterns in disk drives