Magnetic disk drive and magnetic disk medium

Abstract

Embodiments of the invention increase the convenience of a magnetic disk drive for portable use by shortening a period of time required to record a large amount of data, and by increasing the reproduction time, in the magnetic disk drive. In one embodiment, an area between servo data parts is interpolated by servo data parts, each of which stores a burst signal, so that the allocation density of a burst signal is made k times. At the time of write operation in which data is written, only the servo data parts are made use of to perform the servo control while a disk is driven at high rotational speed so as to reduce the recording time. At the time of read operation in which data is reproduced, the servo data parts are made use of to ensure the required precision of the servo control at low rotational speed that is 1/k of the rotational speed at the time of write operation. The reproduction at low rotational speed enables the reduction in power consumption.

1 - 11 . (canceled) 
     
     
         12 . A magnetic disk medium using a sector servo method, in which servo data and user data are formed in a track, wherein:
 said servo data includes:
 first servo data, a gap area having the specified length in which no data is written being located at a position adjacent to said first servo data; and 
 second servo data, data being allowed to be written up to a position adjacent to the second servo data; and 
   said first servo data or said second servo data is selectively written to the track.   
     
     
         13 . A magnetic disk medium according to  claim 12 , wherein:
 said first servo data is periodically located on the track to form each servo sector; and   said second servo data is located substantially at regular intervals between the first servo data and the adjacent first servo data thereof so that the second servo data forms each servo sector.   
     
     
         14 . A magnetic disk medium according to  claim 12 , wherein:
 at least one of said first servo data has the data size that is larger than the data size of the second servo data.   
     
     
         15 . A magnetic disk medium according to  claim 14 , wherein:
 said second servo data includes only a burst signal from among components of servo data.   
     
     
         16 . A magnetic disk medium according to  claim 12 , wherein:
 said gap area is adjacent to the front side of the first servo data with respect to the rotation direction of the magnetic disk medium.   
     
     
         17 . A magnetic disk medium according to  claim 12 , wherein:
 said gap area is formed as a gap part, the length of which is greater than or equal to the physical distance in the track direction between the write element for writing data, and the read element for reading data, of a read/write head for reading/writing information from/to the magnetic disk medium.