Multi-stage actuator disk drives, methods, and computer program products for seeking and then maintaining a transducer on track

A method of controlling seeking of a transducer that is adjacent to a rotatable data storage disk in a disk drive, the disk drive having a secondary actuator for positioning the transducer over a second range of movement, and a primary actuator for positioning the secondary actuator over a first range of movement that is larger than the second range of movement, the method comprising:

• controlling the secondary actuator to move the transducer toward a target track on the disk while seeking;
• controlling the primary actuator to move the secondary actuator toward the target track while simultaneously controlling the secondary actuator to maintain the transducer on the target track, wherein controlling the secondary actuator comprises extending the secondary actuator, and controlling the primary actuator comprises moving the secondary actuator toward the target track while retracting the secondary actuator until the secondary actuator is retracted to about a predetermined location within the second range of movement;
• determining whether a seek distance for a subsequent seek from the target track to another track is at least a threshold distance;
• and
• selectively allowing the subsequent seek when the seek distance is determined to be at least the threshold distance, and delaying the subsequent seek, when the seek distance is determined to be less than the threshold distance, until the secondary actuator is retracted to within a predetermined offset from a predetermined location within the second range of movement.

A method of controlling seeking of a transducer that is adjacent to a rotatable data storage disk in a disk drive, the disk drive having a secondary actuator for positioning the transducer over a second range of movement, and a primary actuator for positioning the secondary actuator over a first range of movement that is larger than the second range of movement, the method comprising:

• controlling the secondary actuator to move the transducer toward a target track on the disk while seeking;
• controlling the primary actuator to move the secondary actuator toward the target track while simultaneously controlling the secondary actuator to maintain the transducer on the target track;
• determining whether a seek direction for a subsequent seek from the target track to another track is toward the initial track;
• and
• selectively allowing the subsequent seek when the seek direction is determined to be toward the initial track, and delaying the subsequent seek, when the seek direction is determined to be away from the initial track, until the secondary actuator is retracted to within a predetermined offset from a predetermined location within the second range of movement.

A disk drive comprising:

• a data storage disk;
• a transducer configured to read data from the disk and/or to write data to the disk;
• a secondary actuator that is configured to position the transducer relative to the disk over a second range of movement;
• a primary actuator that is configured to position the secondary actuator relative to the disk over a first range of movement that is larger than the second range of movement;
• and
• a controller that is configured to seek the transducer to a target track on the disk by controlling the secondary actuator to extend the secondary actuator from a predetermined location within the second range of movement and move the transducer toward the target track, and controlling the primary actuator to move the secondary actuator toward the target track while simultaneously controlling the secondary actuator to retract the secondary actuator to the predetermined location while maintaining the transducer aligned with the target track, and is further configured to initiate at least one of reading and writing data on the target track of the disk before the secondary actuator is retracted back to the predetermined location.

A disk drive comprising:

• a data storage disk;
• a transducer configured to read data from the disk and/or to write data to the disk;
• a secondary actuator that is configured to position the transducer relative to the disk over a second range of movement;
• a primary actuator that is configured to position the secondary actuator relative to the disk over a first range of movement that is larger than the second range of movement;
• and
• a controller that is configured to seek the transducer to a target track on the disk by controlling the secondary actuator to move the transducer toward the target track, and controlling the primary actuator to move the secondary actuator toward the target track while simultaneously controlling the secondary actuator to maintain the transducer on the target track, wherein the controller is configured to extend the secondary actuator to move the transducer toward the target track, and configured to control the primary actuator to move the secondary actuator toward the target track while retracting the secondary actuator until the secondary actuator is retracted to about a predetermined location within the second range of movement, and is further configured to determine whether a seek distance for a subsequent seek from the target track to another track is at least a threshold distance, and configured to selectively allow the subsequent seek when the seek distance is determined to be at least the threshold distance, and to delay the subsequent seek, when the seek distance is determined to be less than the threshold distance, until the secondary actuator is retracted to within a predetermined offset from a predetermined location within the second range of movement.

A disk drive comprising:

• a data storage disk;
• a transducer configured to read data from the disk and/or to write data to the disk;
• a secondary actuator that is configured to position the transducer relative to the disk over a second range of movement;
• a primary actuator that is configured to position the secondary actuator relative to the disk over a first range of movement that is larger than the second range of movement;
• and
• a controller that is configured to seek the transducer to a target track on the disk by controlling the secondary actuator to move the transducer toward the target track, and controlling the primary actuator to move the secondary actuator toward the target track while simultaneously controlling the secondary actuator to maintain the transducer on the target track, and is further configured to determine whether a seek direction for a subsequent seek from the target track to another track is toward the initial track, and configured to selectively allow the subsequent seek when the seek direction is determined to be toward the initial track, and delaying the subsequent seek, when the seek direction is determined to be away from the initial track, until the secondary actuator is retracted to within a predetermined offset from a predetermined location within the second range of movement.

A computer program product for controlling seeking of a transducer that is adjacent to a rotatable data storage disk in a disk drive, the disk drive having a secondary actuator for positioning the transducer over a second range of movement, and a primary actuator for positioning the secondary actuator over a first range of movement that is larger than the first range of movement, the computer program product comprising computer program code embodied in a computer-readable storage medium, the computer program code comprising:

• computer program code that is configured to control the secondary actuator to move the transducer toward a target track on the disk while seeking;
• computer program code that is configured to control the primary actuator to move the secondary actuator toward the target track and to simultaneously control the secondary actuator to maintain the transducer on the target track;
• computer program code that is configured to extend the secondary actuator;
• computer program code that is configured to move the secondary actuator toward the target track while retracting the secondary actuator until the secondary actuator is retracted to about a predetermined location within the second range of movement;
• and
• computer program code that is configured to determine whether a seek distance for a subsequent seek from the target track to another track is at least a threshold distance, and configured to selectively allow the subsequent seek when the seek distance is determined to be at least the threshold distance, and to delay the subsequent seek, when the seek distance is determined to be less than the threshold distance, until the secondary actuator is retracted to within a predetermined offset from a predetermined location within the second range of movement.