Disk drive device and method for error recovery procedure therefor
View Patent ↗Embodiments of the present invention help to achieve a read error recovery, and suppress decreases in the capacity of the disk drive device and degradation in performance. In one embodiment, a hard disk drive (HDD) performs following control without use of repeatable run-out (RRO) compensation information on a magnetic disk in a normal reading process. When an error occurs in a normal reading process, the HDD moves a read element to a position different from a target position of the normal reading process. At the position where the read element has been moved, the read element reads out the RRO compensation information. In a recovery procedure for the reading process where the error has occurred, the HDD performs following control with compensation by the servo compensation information read out by the read element.
1. A disk drive device comprising:
a head having a read element and a write element;
a disk on which servo sectors are discretely recorded in a circumferential direction and servo compensation information corresponding to the servo sectors is recorded in a radial position on which the read element performs a following operation in a normal writing process; and
a controller for performing following control with compensation by the servo compensation information in a normal writing process and for performing following control without using the servo compensation information on the disk in a normal reading process; wherein
the controller moves the read element to a different position from a target position of the normal reading process if an error has occurred in the normal reading process;
the moved read element reads out the servo compensation information at a position where the read element moved; and
the controller performs following control with compensation by the servo compensation information read out by the read element in a recovery procedure of the reading process in which the error has occurred.
2. The disk drive device according to claim 1 , wherein
in the following control in the recovery procedure, the controller uses servo compensation information radially adjacent to a target position of the reading process where the error has occurred.
3. The disk drive device according to claim 2 , wherein
the controller uses servo compensation information radially closest to the target position of the reading process in the following control in the recovery procedure.
4. The disk drive device according to claim 1 , wherein
the read element reads out servo compensation information corresponding to a servo sector immediately preceding to a target data sector of the reading process where the error has occurred; and
the controller performs compensation by the servo compensation information in servo control using the immediately preceding servo sector in the following control in the recovery procedure.
5. The disk drive device according to claim 1 , wherein
the controller changes a compensation amount which is based on servo compensation information in accordance with a distance between a target position of the reading process where the error has occurred and the servo compensation information to be used in the following control in the recovery procedure.
6. The disk drive device according to claim 5 , wherein
the controller decreases a compensation amount which is based on servo compensation information in accordance with increase of a distance between a target position of the reading process where the error has occurred and a target position of the servo compensation information to be used in the following control in the recovery procedure.
7. The disk drive device according to claim 1 , wherein
the controller performs a read retry using the servo compensation information before performing a read retry with a changed target position in the recovery procedure of the reading process where the error has occurred.
8. A method for a recovery procedure from a read error in a disk drive device comprising a head having a read element and a write element and a disk in which servo sectors are discretely recorded in a circumferential direction and servo compensation information corresponding to the servo sectors is recorded in a radial position on which the read element performs a following operation in a normal writing process, the method comprising:
performing following control with compensation by the servo compensation information in a normal writing process;
performing following control without using the servo compensation information on the disk in a normal reading process;
moving the read element to a different position from a target position of the normal reading process if an error has occurred in the normal reading process;
reading out the servo compensation information by the read element at a position where the read element moved; and
performing following control with compensation by the servo compensation information read out by the read element in a recovery procedure of the reading process in which the error has occurred.
9. A method according to claim 8 , wherein
in the following control in the recovery procedure, servo compensation information radially adjacent to a target position of the reading process where the error has occurred, is used.
10. A method according to claim 9 , wherein
servo compensation information radially closest to the target position of the reading process is used in the following control in the recovery procedure.
11. A method according to claim 8 , wherein
a compensation amount indicated by servo compensation information is changed in accordance with a distance between a target position of the reading process where the error has occurred and the servo compensation information to be used in the following control in the recovery procedure.
12. A method according to claim 11 , wherein
a compensation amount indicated by servo compensation information decreases in accordance with increase of a distance between a target position of the reading process where the error has occurred and a target position of the servo compensation information to be used in the following control in the recovery procedure.
13. A disk drive device comprising:
a head having a read element and a write element;
a disk on which servo sectors are discretely recorded in a circumferential direction and servo compensation information corresponding to the servo sectors is recorded in a radial position on which the read element performs a following operation in a writing process; and
a controller for executing a writing process in following control with compensation by servo compensation information for a writing process and a normal reading process to read data written in the writing process; wherein
the controller moves the read element to a different position from a target position of the normal reading process if an error has occurred in the normal reading process;
the moved read element reads out the servo compensation information for a writing process at a position where the read element moved; and
the controller performs following control with compensation by the servo compensation information for a writing process read out by the read element in a recovery procedure of the reading process in which the error has occurred.
14. The disk drive device according to claim 13 , wherein
in the following control in the recovery procedure, the controller uses servo compensation information for a writing process radially adjacent to a target position of the reading process where the error has occurred.
15. The disk drive device according to claim 14 , wherein
the controller uses servo compensation information for a writing process radially closest to the target position of the reading process in the following control in the recovery procedure.
16. The disk drive device according to claim 13 , wherein
the read element reads out servo compensation information for a writing process corresponding to a servo sector immediately preceding to a target data sector of the reading process where the error has occurred; and
the controller performs compensation by the servo compensation information in servo control using the immediately preceding servo sector for a writing process in the following control in the recovery procedure.
17. The disk drive device according to claim 13 , wherein
the controller changes a compensation amount which is based on servo compensation information for a writing process in accordance with a distance between a target position of the reading process where the error has occurred and the servo compensation information to be used in the following control in the recovery procedure.
18. The disk drive device according to claim 17 , wherein
the controller decreases a compensation amount which is based on servo compensation information for a writing process in accordance with increase of a distance between a target position of the reading process where the error has occurred and a target position of the servo compensation information to be used in the following control in the recovery procedure.
19. The disk drive device according to claim 13 , wherein
the controller performs a read retry using the servo compensation information before performing a read retry with a changed target position in the recovery procedure of the reading process where the error has occurred.