Method and apparatus for forming servo patterns on a magnetic-recording disk

1. A method for forming servo patterns on a magnetic-recording disk, said method comprising:

moving a magnetic-recording head in an opposite direction to a pattern development direction, when there is a faulty servo pattern from which data cannot be read by a read element of said magnetic-recording head;

positioning a write element of said magnetic recording head on a track where said faulty servo pattern was formed and forming a reserve servo pattern at a different circumferential location from a circumferential location of said faulty servo pattern;

moving said magnetic-recording head in said pattern development direction;

positioning said read element on said track where said faulty servo pattern was formed and forming a new servo pattern in said pattern development direction by said write element at said circumferential location of said faulty servo pattern on a track disposed between said track where said faulty servo pattern was formed and an outside diameter of said magnetic-recording disk, based on data read from said reserve servo pattern by said read element;

moving said magnetic-recording head in said pattern development direction, when said faulty servo pattern exists, and checking in said pattern development direction whether there is another faulty servo pattern on tracks disposed between said track where said faulty servo pattern was formed and an outside diameter of said magnetic-recording disk; and

then moving said magnetic-recording head in said opposite direction to said pattern development direction.

2. The method recited in claim 1 , said method further comprising:

when there is a faulty burst pattern of a plurality of burst patterns of said faulty servo pattern from which data cannot be read by said magnetic-recording head, forming at said different circumferential location a plurality of reserve burst patterns corresponding to said plurality of burst patterns of said faulty servo pattern.

3. The method recited in claim 1 , wherein said reserve servo pattern is formed so as to be distinguishable from at least one other servo pattern.

4. An apparatus for forming servo patterns on a magnetic-recording disk, said apparatus comprising:

a control circuit, said control circuit configured to control timing to form a servo pattern and configured to control a position of a magnetic-recording head when forming said servo pattern; and

wherein said control circuit is configured:

to move said magnetic-recording head in an opposite direction to a pattern development direction, when there is a faulty servo pattern from which data cannot be read by said read element;

to position a write element on a track where said faulty servo pattern was formed and to form a reserve servo pattern at a different circumferential location from a circumferential location of said faulty servo pattern;

to move said magnetic-recording head in said pattern development direction;

to position said read element on said track where said faulty servo pattern was formed and to form a new servo pattern in said pattern development direction by said write element at said circumferential location of said faulty servo pattern on a track disposed between said track where said faulty servo pattern was formed and an outside diameter of said magnetic-recording disk, based on data read from said reserve servo pattern by said read element;

to move said magnetic-recording head in said pattern development direction, when said faulty servo pattern exists, and to check in said pattern development direction whether there is another faulty servo pattern on tracks disposed between said track where said faulty servo pattern was formed and an outside diameter of said magnetic-recording disk; and

then to move said magnetic-recording head in said opposite direction to said pattern development direction.

5. A method for forming servo patterns on a magnetic-recording disk, said method comprising:

moving a magnetic-recording head in an opposite direction to a pattern development direction, when there is a faulty servo pattern from which data cannot be read by a read element of said magnetic-recording head;

positioning a write element of said magnetic recording head on a track where said faulty servo pattern was formed and forming a reserve servo pattern at a different circumferential location from a circumferential location of said faulty servo pattern;

moving said magnetic-recording head in said pattern development direction;

positioning said read element on said track where said faulty servo pattern was formed and forming a new servo pattern in said pattern development direction by said write element at said circumferential location of said faulty servo pattern on a track disposed between said track where said faulty servo pattern was formed and an outside diameter of said magnetic-recording disk, based on data read from said reserve servo pattern by said read element; and

storing a radial and circumferential position on said magnetic-recording disk where said faulty servo pattern exists.

6. The method recited in claim 5 , said method further comprising:

inspecting servo patterns, wherein said inspecting skips said radial and circumferential position on said magnetic-recording disk where said faulty servo pattern exists.

7. The method recited in claim 5 , further comprising:

identifying said radial and circumferential position on said magnetic-recording disk where said faulty servo pattern exists as a location not to be used for writing and reading data.