Magnetic disk device and controlling method of the same

A magnetic disk device comprising:

• a first magnetic disk, a second magnetic disk, and a plurality of third magnetic disks, which are rotatable;
• a first magnetic head capable of seeking in a radial direction of the first magnetic disk to write data to and read data from the first magnetic disk;
• a second magnetic head capable of seeking in a radial direction of the second magnetic disk to write data to and read data from the second magnetic disk;
• a plurality of third magnetic heads capable of seeking in a radial direction of each of the third magnetic disks to write data to and read data from each of the third magnetic disks;
• and
• a controller which controls rotation of the first magnetic disk, the second magnetic disk, and the plurality of third magnetic disks, and controls seek of the first magnetic head, the second magnetic head, and the plurality of third magnetic heads, wherein
• the controller
• writes a guide spiral pattern to the first magnetic disk by the first magnetic head,
• writes a first final spiral pattern of a predetermined frequency including a sync mark in each predetermined cycle to the first magnetic disk by the second magnetic head while tracking the written guide spiral pattern by the first magnetic head and the second magnetic head following the first magnetic head,
• writes a servo pattern which is a reference to positioning control of seek of the second magnetic head, to the second magnetic disk by the second magnetic head while tracking the written first final spiral pattern by the second magnetic head,
• writes a plurality of adjustment patterns including a sync mark in each predetermined cycle with different frequencies, to each of the third magnetic disks by each of the third magnetic heads, while tracking the written servo pattern by the second magnetic head and each of the third magnetic heads following the second magnetic head,
• reads each of the written adjustment patterns by each of the third magnetic heads and detects the number of signal components of the sync mark included in the read signal of each of the third magnetic heads,
• selects a frequency of an adjustment pattern from which the detected number larger than or equal to a threshold value is obtained, among the read adjustment patterns, as a write frequency of each of the third magnetic heads,
• writes a plurality of second adjustment patterns including a sync mark in each predetermined cycle with the same frequency as each of the selected write frequencies, to each of the third magnetic disks by each of the third magnetic heads, while tracking the written servo pattern by the second magnetic head and each of the third magnetic heads following the second magnetic head, and
• writes a servo pattern which is a reference to positioning control of seek of the each of the third magnetic heads, to each of the third magnetic disks by each of the third magnetic heads while tracking each of the written second final spiral patterns by each of the third magnetic heads.

A method of controlling a magnet disk device comprising a plurality of rotatable magnetic disks;

• a plurality of magnetic heads capable of seeking in a radial direction of each of the magnetic disks to write data to and read data from each of the magnetic disks;
• and a controller controlling the rotation of each of the magnetic disks and the seek of each of the magnetic heads,
• the method comprising:
• writing a plurality of adjustment patterns including a sync mark in each predetermined cycle with different frequencies, to each of the magnetic disks by each of the magnetic heads;
• reading each of the written adjustment patterns by each of the magnetic heads, and detecting the number of signal components of the sync mark included in the read signal of each of the magnetic heads;
• selecting a frequency of an adjustment pattern from which the detected number larger than or equal to a threshold value is obtained, among the read adjustment patterns, as a write frequency for each of the magnetic heads;
• writing a plurality of spiral patterns including the sync mark in each predetermined cycle with the same frequency as each of the selected write frequencies, to each of the magnetic disks by each of the magnetic heads;
• and
• writing a servo pattern which is a reference to positioning control of seek of each of the magnetic heads, to each of the magnetic disks, by each of the magnetic heads, while tracking each of the written spiral patterns by each of the magnetic heads.