Storage device and servo information writing method
View Patent ↗A storage device receives and holds a storage medium that is subjected to first servo writing processing for writing servo information, a Gray code of which is offset, from an inner cylinder or an outer cylinder to a predetermined cylinder and, after the first servo writing processing, subjected to second servo writing processing for writing servo information from an opposite direction to the predetermined cylinder and in which Gray codes are written to be offset not to overlap in the first or second servo writing processing and the pieces of servo information having different mark patterns are written in the first servo writing processing and the second servo writing processing. The storage device acquires cylinder information and mark patterns from the servo information written in the held storage medium and controls a position of a head based on the acquired cylinder information and mark patterns.
1. A storage device comprising:
a storage medium that is subjected to first servo writing processing for writing servo information from one of an inner cylinder and an outer cylinder to a predetermined cylinder and, after the first servo writing processing, subjected to second servo writing processing for writing servo information from other one of the inner cylinder and the outer cylinder to the predetermined cylinder, the servo information written in the first servo writing processing and the servo information written in the second servo writing processing being written to overlap each other near the predetermined cylinder in the first servo writing processing and the second servo writing processing;
a head that reads out the information written in the storage medium; and
a head-position control unit that reads out the servo information written in the storage medium using the head and controls a position of the head using the read-out servo information,
wherein the servo information written in the first servo writing processing and the servo information written in the second servo writing processing have different mark patterns and
the head-position control unit acquires cylinder information and the mark patterns from the servo information written in the storage medium and controls the position of the head based on the acquired cylinder information and mark patterns.
2. The storage device according to claim 1 , wherein
the predetermined cylinder is set near a yaw angle 0 degree, and
the head-position control unit controls, with an area near the yaw angle 0 degree as an unused area, the head to track-skip the boundary.
3. A storage device comprising:
a storage medium that is subjected to first servo writing processing for writing servo information from one of an inner cylinder and an outer cylinder to a predetermined cylinder and, after the first servo writing processing, subjected to second servo writing processing for writing servo information from other one of the inner cylinder and the outer cylinder to the predetermined cylinder, the servo information written in the first servo writing processing and the servo information written in the second servo writing processing being written to overlap each other near the predetermined cylinder in the first servo writing processing and the second servo writing processing;
a head that reads out the information written in the storage medium;
a head-position control unit that reads out the servo information written in the storage medium using the head and controls a position of the head using the read-out servo information; and
an estimator that estimates a position of the head from an electric current supplied to the head,
wherein in seeking the position of the head, when the estimator determines that the head crosses over the predetermined cylinder, the head-position control unit changes timing for detecting the servo information written in the storage medium to narrow timing and controls the position of the head.
4. The storage device according to claim 3 , wherein the servo information written in the first servo writing processing and the servo information written in the second servo writing processing each has frame numbers of special patterns near the predetermined cylinder.
5. A storage device comprising:
a storage medium that is subjected to first servo writing processing for writing servo information from one of an inner cylinder and an outer cylinder to a predetermined cylinder and, after the first servo writing processing, subjected to second servo writing processing for writing servo information from other one of the inner cylinder and the outer cylinder to the predetermined cylinder, the servo information written in the first servo writing processing and the servo information written in the second servo writing processing being written to overlap each other near the predetermined cylinder in the first servo writing processing and the second servo writing processing;
a head that reads out the information written in the storage medium;
a head-position control unit that reads out the servo information written in the storage medium using the head and controls a position of the head using the read-out servo information; and
an estimator that estimates a position of the head from an electric current supplied to the head,
wherein in seeking the position of the head, when the estimator determines that the head crosses over the predetermined cylinder, the head-position control unit controls the position of the head using position information estimated by the estimator, without performing position control using the servo information written in the storage medium.
6. A servo information writing method comprising:
performing, on a storage medium, first servo writing processing for writing servo information from one of an inner cylinder and an outer cylinder to a predetermined cylinder; and
after the first servo writing processing, performing, on the storage medium, second servo writing processing for writing servo information from other one of the inner cylinder and the outer cylinder to the predetermined cylinder,
the servo information written in the first servo writing processing and the servo information written in the second servo writing processing being written to overlap each other near the predetermined cylinder in the first servo writing processing and the second servo writing processing
wherein the servo information written in the first servo writing processing and the servo information written in the second servo writing processing have different mark patterns.
7. The servo information writing method according to claim 6 , wherein the predetermined cylinder is set near a yaw angle 0 degree.
8. The servo information writing method according to claim 6 , wherein the servo information written in the first servo writing processing and the servo information written in the second servo writing processing each has frame numbers of special patterns near the predetermined cylinder.
9. A servo information writing device comprising:
a servo writing unit that writes servo information from any one of an inner cylinder and an outer cylinder to a predetermined cylinder, and writes servo information in a storage medium, in which the servo information is written, from other one of the inner cylinder and the outer cylinder, to the predetermined cylinder,
wherein the servo information written from the one of the inner cylinder and the outer cylinder and the servo information written from the other one of the inner cylinder and the outer cylinder have different mark patterns.
10. The servo information writing device according to claim 9 , wherein
the servo writing unit writes the servo information from any one of the inner cylinder and the outer cylinder to a predetermined cylinder near a yaw angle 0 degree, and
writes the servo information in the storage medium, in which the servo information is written, from other one of the inner cylinder and the outer cylinder, to the predetermined cylinder near the yaw angle 0 degree.
11. The servo information writing device according to claim 9 , wherein the servo information written from the one of the inner cylinder and the outer cylinder and the servo information written from the other one of the inner cylinder and the outer cylinder each has frame numbers of special patterns near the predetermined cylinder in the storage medium.