Method for determining read/write head position based on phase detection of a servo pattern

A hard disk drive, comprising:

• a disk controller;
• a read write (RW) head communicatively coupled to the disk controller;
• at least one disk having a servo pattern including a S-burst pattern on each half track of each track of the disk, in which all S-burst patterns disposed radially across the disk have a same phase relationship, and the servo pattern also including a P-burst pattern on each half track of each track of the disk following a corresponding S-burst pattern for each half track, in which P-burst patterns across two adjacent tracks have different phase relationship among the P-burst patterns across the two adjacent tracks in relation to a phase of the S-burst pattern;
• at least one read write (RW) head;
• and
• wherein the disk controller is operable to determine a RW head position based on the phase difference between a S-burst signal obtained from sensing at least one of the S-burst patterns and a P-burst signal obtained from sensing at least one of the P-burst patterns, in which the S-burst and P-burst signals are sensed as the RW head passes over the servo pattern.

A method operable to position read/write (RW) head radial position relative to a track within a magnetic disk, comprising:

• sensing a S-burst signal and a P-burst signal with the RW head, the S-burst signal and the P-burst signal associated with a servo pattern on the magnetic disk, the servo pattern including a S-burst pattern on each half track of each track of the magnetic disk, in which all S-burst patterns disposed radially across the magnetic disk have a same phase relationship, and the servo pattern also including a P-burst pattern on each half track of each track of the magnetic disk following a corresponding S-burst pattern for each half track, in which P-burst patterns across two adjacent tracks have different phase relationship among the P-burst patterns across the two adjacent tracks in relation to a phase of the S-burst pattern;
• determining a phase difference between the S-burst signal obtained from sensing at least one of the S-burst patterns and the P-burst signal obtained from sensing at least one of the P-burst patterns;
• determining the RW head radial position based on the phase difference between the S-burst signal and the P-burst signal;
• and
• repositioning the RW head is repositioned based on the determined RW head radial position and a desired RW head radial position.

A method operable to determine a radial position for a hard disk read write (RW) head, comprising:

• recognizing embedded gray coded location information on the disk;
• determining a track position of the RW head relative to the disk based on the embedded location information;
• sensing a S-burst signal and a P-burst signal with the RW head, the S-burst signal and the P-burst signal associated with a servo pattern on the magnetic disk, the servo pattern including a S-burst pattern on each half track of each track of the magnetic disk, in which all S-burst patterns disposed radially across the magnetic disk have a same phase relationship, and the servo pattern also including a P-burst pattern on each half track of each track of the magnetic disk following a corresponding S-burst pattern for each half track, in which P-burst patterns across two adjacent tracks have different phase relationship among the P-burst patterns across the two adjacent tracks in relation to a phase of the S-burst pattern;
• determining a phase difference between the S-burst signal obtained from sensing at least one of the S-burst patterns and the P-burst signal obtained from sensing at least one of the P-burst patterns;
• determining the RW head radial position based on the phase difference between the S-burst signal and the P-burst signal;
• and
• repositioning the RW head based on the determined RW head radial position and a desired RW head radial position.