US 6,091,564 A · Disk drive with calibration bursts that are recorded on a spiral and method of recording the same

Abstract

A disk drive with a disk having a servo pattern including a special "calibration track" wherein a plurality of calibration burst pairs are recorded on a spiral centerline to define null points that are radially shifted from a burst pair centerline by precise, predefined or subsequently measured, fractional track amounts to collectively provide accurate information about servo signal values generated as a function of real displacement. The calibration burst pairs beneficially allow for calibrating the PES signal after the drive is removed from the servowriter during a manufacturing phase called Intelligent Burn-In. The calibration bursts are recorded on a spiral to reduce the recording time and are preferably written in data regions so that they are disposable and may be selectively written over with data to maximize storage space. Some or all of the calibration burst pairs may be retained for a subsequent recalibration.

Claims21

Dependent claims

A disk drive comprising:

a base;
a disk;
means for rotating the disk;
a head stack assembly coupled to the base;
a read transducer carried by the head stack assembly over the disk;
a servo control loop for controlling the position of the read transducer;
a first servo burst pair that is written on a circular path and is located in a first servo sector to define a first burst pair centerline, the burst pair centerline defining a track;
and
a first calibration burst pair for calibrating the read transducer that is written on a spiral centerline, is located in a first data region between servo sectors, and is radially displaced from the track by a known radial displacement,
wherein a plurality of calibration burst pairs are written on a spiral centerline and are radially displaced from the track by a corresponding plurality of known radial displacements.

7 more elements

A method of writing servo system calibration bursts in a disk drive having a revolving disk with a recording surface, an actuator, and a write transducer mounted on the actuator, wherein the actuator is moved by a servo track writer, the method comprising the steps of:

(a) positioning the actuator with the servo track writer at a first desired reference location over the recording surface of the revolving disk;
(b) moving the actuator with the servo track writer at a constant radial velocity such that the write transducer passes over a first spiral band on the recording surface of the revolving disk;
(c) recording a first succession of calibration bursts in data regions of the revolving disk as the write transducer passes over the first spiral band;
(d) positioning the actuator with the servo track writer at a second desired reference location over the recording surface of the revolving disk;
(e) moving the actuator with the servo track writer at the constant radial velocity such that the write transducer passes over a second spiral band on the recording surface of the revolving disk;
and
(f) recording a second succession of calibration bursts in the data regions of the revolving disk as the write transducer passes over the second spiral band to form a succession of calibration burst pairs that are positioned at radial locations along a spiral centerline in the data regions of the revolving disk.

4 more elements

A method of writing servo bursts in a disk drive having a revolving disk with a recording surface, an actuator, a read transducer mounted on the actuator, and a write transducer mounted on the actuator, the method comprising the steps of:

(a) recording a plurality of servo burst pairs on concentric circles for use in positioning the actuator relative to concentric data tracks;
and
(b) recording a succession of calibration burst pairs on a spiral centerline for use in calibrating a response characteristic of the read transducer while track following on the plurality of servo burst pairs.

Dependencies are inferred from the claim text.

Disk drive with calibration bursts that are recorded on a spiral and method of recording the same

Life of this patent

Disk drive with calibration bursts that are recorded on a spiral and method of recording the same

Life of this patent

Abstract

Claims21