Method and apparatus for positioning head using spiral servo pattern in a disk drive

A disk drive comprising:

• a disk medium on which spiral servo patterns are recorded;
• a head including a read head which reads data from the disk medium and a write head which writes data to the disk medium;
• a head moving unit which moves the head radially over the disk medium;
• a unit which reproduces burst signals of a particular shape from the spiral servo patterns read by the read head while the head is scanning circumferential regions on the rotating disk medium which correspond to concentric tracks;
• a generator which generates position data associating servo burst signals contained in concentric servo patterns constituting the concentric tracks with the burst signals of the particular shape;
• a position error calculating unit which uses the position data to perform a position error calculation required to position the head on one of the concentric tracks;
• and
• a controller which uses a result of the calculation performed by the position error calculating unit to control the head moving unit and thus positioning of the head,
• wherein the generator divides each of the burst signals of the particular shape into a plurality of regions in a circumferential direction to generate position data associating amplitudes obtained from the respective regions with position signals A and B reproduced from the servo burst signals and used to calculate an error in a position with respect to a center line of each of the concentric tracks and position signals C and D reproduced from the servo burst signals and used to calculate an error in a position with respect to an adjacent track boundary.