Magnetic disk device and method
View Patent ↗According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, and a controller. The magnetic disk has a plurality of tracks. The magnetic head performs reading and writing from and to the magnetic disk. The controller controls write operations to a first region and a second region of the magnetic disk in different manners. The second region is narrower in track pitch than the first region.
1. A magnetic disk device comprising:
a magnetic disk having a plurality of tracks;
a magnetic head that performs reading and writing from and to the magnetic disk; and
a controller that controls write operations to a first region and a second region of the magnetic disk in different manners, the second region being narrower in track pitch than the first region, wherein
the controller
calculates a decrease in the track pitch and generates, from the decrease, write control information for each of the first region and the second region, and
controls the write operations according to the write control information.
2. The magnetic disk device according to claim 1 , wherein
the controller determines whether or not the magnetic head is located on a write-target track among the plurality of tracks, through a comparison between a position of the magnetic head and a writable range, and
the second region includes a narrower writable range than the first region.
3. The magnetic disk device according to claim 1 , wherein
the controller refrains from prohibiting a write operation to the first region, and prohibits a write operation to the second region.
4. The magnetic disk device according to claim 1 , wherein
the controller controls the write operations to the first region and the second region in different manners in a unit of track.
5. The magnetic disk device according to claim 1 , wherein
the controller controls the write operation to the first region in a unit of area smaller than one track.
6. The magnetic disk device according to claim 1 , wherein
the magnetic disk stores the write control information.
7. The magnetic disk device according to claim 6 , wherein
the magnetic disk includes a servo area, and
the servo area stores the write control information.
8. The magnetic disk device according to claim 1 , further comprising
a non-volatile memory different from the magnetic disk, wherein
the non-volatile memory stores the write control information.
9. The magnetic disk device according to claim 1 , wherein
the controller measures eccentric components of two adjacent tracks among the plurality of tracks, and calculates the decrease in the track pitch from the eccentric components of the two adjacent tracks.
10. A method of controlling a magnetic disk device, the magnetic disk device comprising a magnetic disk having a plurality of tracks; a magnetic head that performs reading and writing from and to the magnetic disk, the method comprising:
controlling write operations to a first region and a second region of the magnetic disk in different manners, the second region being narrower in track pitch than the first region, wherein
the method further comprising
calculating a decrease in the track pitch;
generating, from the decrease, write control information for each of the first region and the second region; and
controlling the write operations according to the write control information.
11. The method according to claim 10 , further comprising
determining whether or not the magnetic head is located on a write-target track among the plurality of tracks, through a comparison between a position of the magnetic head and a writable range, wherein
the second region includes a narrower writable range than the first region.
12. The method according to claim 10 , further comprising
refraining from prohibiting a write operation to the first region, and prohibiting a write operation to the second region.
13. The method according to claim 10 , wherein
the controlling comprises controlling the write operations to the first region and the second region in different manners in a unit of track.
14. The method according to claim 10 , wherein
the controlling comprises controlling the write operation to the first region in a unit of area smaller than one track.
15. The method according to claim 10 , wherein
the magnetic disk stores the write control information.
16. The method according to claim 10 , wherein
the magnetic disk includes a servo area, and
the servo area stores the write control information.
17. The method according to claim 10 , wherein
the magnetic disk device further comprises a non-volatile memory different from the magnetic disk, and
the non-volatile memory stores the write control information.
18. The method according to claim 1 , further comprising:
measuring eccentric components of two adjacent tracks among the plurality of tracks; and
calculating the decrease in the track pitch from the eccentric components of the two adjacent tracks.