Apparatus system and method for variable data density patterned media

A system for patterned media having variable data density, the system comprising:

• a write head configured to write information by creating a magnetic field to orient a bit in one direction or the other;
• a hard disk drive comprising at least one disk;
• the disk having a patterned media recording surface comprising a plurality of sectors;
• wherein each sector comprises
• a synchronization region configured to generate a signal in a read head, the signal having a predetermined frequency and phase;
• a first data region wherein the data is positioned with a first data density configured to generate a signal with a first frequency;
• at least a second data region positioned to place the first data region between the synchronization region and the at least one second data region, wherein the data comprising the second data region is positioned with a second data density configured to generate a signal with a second frequency, wherein the second data density is less than the first data density compensate for a cumulative phase error to the write head;
• a write clock configured to synchronize a frequency and phase of the write head with the predetermined frequency and a phase of the synchronization region;
• and
• a frequency module configured to modify the frequency of the write clock after a period of time determined in response to at least one physical characteristic of the disk.

A computer readable storage medium encoded with a computer readable program, wherein the computer readable program when executed on a computer causes the computer to:

• sense a signal in a read head, the signal having a predetermined frequency identifying a first frequency and a second frequency, the first frequency resulting from a first density of a first data region, the second frequency resulting from a second density of a second data region, wherein the second data density is less than the first data density compensate for a cumulative phase error to a write head;
• synchronize a frequency and a phase of a write clock with a predetermined frequency and phase of a synchronization region;
• and
• modify the frequency of the write clock after a period of time determined in response to at least one physical characteristic of the disk.

A method for writing patterned media having variable data density, the method comprising:

• sensing a signal in a read head, the signal having a predetermined frequency identifying a first frequency and a second frequency, the first frequency resulting from a first density of a first data region, the second frequency resulting from a second density of a second data region, wherein the second data density is less than the first data density compensate for a cumulative phase error to a write head;
• synchronizing a frequency and phase of a write clock with the predetermined first frequency and a phase of a synchronization region;
• modifying the frequency of the write clock after a period of time determined in response to at least one physical characteristic of the disk;
• and
• writing the patterned media with the write head.

An apparatus for patterned media having variable data density, the apparatus comprising:

• means for sensing a signal in a read head, the signal having a predetermined frequency identifying a first frequency and a second frequency, the first frequency resulting from a first density of a first data region, the second frequency resulting from a second density of a second data region, wherein the second data density is less than the first data density compensate for a cumulative phase error to a write head;
• means for synchronizing a frequency and phase of a write clock with the predetermined frequency and a phase of a synchronization region;
• and
• means for modifying the frequency of the write clock after a period of time determined in response to at least one physical characteristic of the disk.