1. Field of the Disclosure
The present invention relates in general to disk drives and, in particular, to a system, method and apparatus for synchronizing writing on bit patterned media.
2. Description of the Related Art
In some disk drives with bit patterned media, there is an offset of a few micrometers between the read head and the write head. The read head provides a timing reference using the patterns on the servoing track. Due to the nature of the pattern generation process between the inner and outer diameters of the disk, the regularity of the patterns is not consistent over the range of the read-write offset. This creates a problem for synchronizing the write signal with the patterns on the write track.
Conventional solutions to this problem include measuring the phase difference between the write and read tracks on the master disk, and storing this information in a look-up table in memory. A similar process determines the optimal write phase with a different method and stores it in memory. Still another solution measures the write phases for track groups and stores the information as a look-up table. The look-up table may be stored in a single, dedicated section of the media. However, in use, the look-up table must first be read into memory. Thus, continued improvements in synchronizing writing on bit patterned media are desirable.