Disk drive and method of retracting head thereof
View Patent ↗Embodiments of the present invention relate to retracting a magnetic head of a disk drive device to a retract position in accordance with a fall state, and to suppressing the performance degradation due to erroneous fall determinations as well as occurrence of damage by a head-disk crash. According to one embodiment of the present invention, in a Hard Disk Drive (HDD), a servo controller moves a head slider to a cylinder at the side of a ramp at a predetermined timing that a fall determiner determines that it is falling and an unload controller starts an unload process. This shortens the time between determination by the fall determiner that it is falling to retraction of the head slider to the retract position. Furthermore, it prevents increase of the erroneous determinations by relaxing the fall determination condition for safety. Also, it shortens the time that the head slider returns to the initial position before the seek in case that it is not determined that it is falling.
1. A disk drive comprising:
a head for accessing a data region of a disk;
a detector;
a moving mechanism for supporting and moving the head; and
a controller for controlling the moving mechanism to move the head to a retract position outside of the data region in response to a detection result of the detector for detecting that an acceleration of the detector reaches a first reference, and further for controlling the moving mechanism to carry out a seek operation of the head toward a radial position which is closer to the retract position than a current position of the head, in response to another detection result of the detector reaching a second reference prior to reaching the first reference.
2. The disk drive according to claim 1 , wherein the controller changes the second reference according to the position of the head at the time of starting the seek operation.
3. The disk drive according to claim 1 , wherein the controller changes the first reference and the second reference according to a command from an external controller.
4. The disk drive according to claim 1 , wherein the controller changes the first reference according to a command from an external controller, and further changes the second reference according to the first reference.
5. The disk drive according to claim 1 , wherein the controller starts to move the head to the retract position before the detection result of the detector exceeds the first reference when an error occurs in the seek operation.
6. The disk drive according to claim 5 , wherein the controller ceases an error recovery procedure and starts to move the head to the retract position when the detection result of the detector reaches the first reference on the way of the error recovery procedure for the error.
7. The disk drive according to claim 5 , wherein the controller starts to move the head to the retract position in response to the occurrence of the error.
8. The disk drive according to claim 1 , wherein the controller returns to a process before the seek operation without moving the head to the retract position, if the detection result does not reach the first reference.
9. A method for retracting a head in a disk drive comprising;
providing a disk drive with a detector;
obtaining a detection result of the detector for detecting an acceleration of the detector;
determining that the disk drive is falling in response to the detection result reaching a first reference;
moving the head to a retract position outside a data region of a disk in response to the determination that the disk drive is falling; and
conducting a seek of the head toward a radial position which is closer to the retract position than a current position of the head, in response to the detection result of the detector reaching a second reference prior to reaching the first reference.
10. The method according to claim 9 , wherein the moving the head to the retract position is not performed, and returning to a process before the seek, if the detection result does not reach the first reference.
11. The method according to claim 9 , wherein the moving the head to the retract position is started before the detection result exceeds the first reference, if an error occurs in the seek.
12. The method according to claim 11 , wherein an error recovery procedure for the error is ceased, and the moving the head to the retract position is started, if the detection result of the detector reaches the first reference on the way of the error recovery procedure for the error.
13. The method according to claim 11 , wherein the moving the head to the retract position is started in response to the occurrence of the error.