US 2003/0197971 A1 · Adaptive index reference position qualification in a disc drive

Abstract

Method and apparatus for performing a seek operation to move a data transducing head from an initial track to a destination track on a rotatable recording surface. A servo control circuit operates to sweep the head across the recording surface. Servo data from an intermediary track are transduced to obtain a detected angular position value for the head with respect to the recording surface. When the detected angular position value differs from a predicted angular position value for the head, the servo control circuit initiates an index qualification routine at the conclusion of the seek. The qualification routine involves transducing the servo data from the destination track to verify the accuracy of the predicted angular position value. In this way, the effects of spurious (false) index signals obtained from the servo data transduced during the seek operation are minimized, and unnecessary reinitializations of the servo control circuit are avoided.

Claims20

Dependent claims

A method for performing a seek operation to move a head from an initial track to a destination track on a rotatable recording surface, comprising:

transducing servo data from an intermediary track between the initial track and the destination track as the head sweeps across the recording surface to obtain a detected angular position value for the head with respect to the recording surface;
declaring an unsafe condition when the detected angular position value differs from a predicted angular position value for the head;
and
performing an index qualification routine after the head reaches the destination track to verify accuracy of the predicted angular position value.

1 more element

A data storage device, comprising:

a rotatable data recording surface on which servo data are stored to define a plurality of concentric tracks;
a controllably moveable data transducing head adjacent the recording surface;
and
a servo control circuit configured to carry out a seek operation to move the head from an initial track to a destination track;
wherein during the seek operation the servo control circuit provides a detected angular position value for the head from servo data transduced from an intermediary track between the initial track and the destination track during the seek operation, maintains a predicted angular position value for the head determined from servo data transduced prior to the seek operation, and declares an unsafe condition during the seek operation when the detected angular position value differs from the predicted angular position value;
and
wherein at the conclusion of the seek operation the servo control circuit performs an index qualification routine on the destination track to verify accuracy of the predicted angular position value.

4 more elements

Dependencies are inferred from the claim text.

Adaptive index reference position qualification in a disc drive

Life of this patent

Adaptive index reference position qualification in a disc drive

Life of this patent

Abstract

Claims20