Patent ID: 7660065

Claim:
A method for writing positioning information, in a plurality of generally round, consecutive tracks on a disk-shaped recording medium, the positioning information being used for positioning a head provided for writing information to the disk-shaped recording medium or reading information written in the disk-shaped recording medium, comprising: writing first positioning information on one track of the disk-shaped recording medium, and writing second positioning information on or adjacent to a portion of the track, the second positioning information overlapping the first positioning information in the track position to define an overlapping portion, wherein if the first and second positioning information are at least partially offset in the radial direction of the medium, the head is directed from the second positioning information to the first positioning information as the head reads the positioning information in the overlapping portion, and wherein a number of sectors that form said overlapping portion of one track of the positioning information is changed according to a magnitude of a stepped portion occurring at a starting point of the overlapping portion.