System, method and apparatus for determining track pitch in a hard disk drive to satisfy the requirements of both off-track capacity and adjacent track erasure

A method of determining track pitch in a hard disk drive, comprising:

• (a) providing a hard disk drive;
• (b) measuring a 747 curve and determining an OTC track pitch of the hard disk drive;
• (c) measuring an ATI track pitch with a plurality of adjacent track writes;
• (d) fitting a logarithmic function to the ATI track pitch and data from the number of adjacent track writes;
• (e) calculating ATI track pitch for a desired number of adjacent track writes using a fitted function;
• and then
• (e) selecting a final track pitch from a greater of the OTC and ATI track pitches.

A method of determining track pitch in a hard disk drive, comprising:

• (a) providing a hard disk drive;
• (b) measuring a 747 curve and determining an OTC track pitch of the hard disk drive;
• (c) measuring an ATI track pitch with a plurality of adjacent track writes by measuring positions of adjacent tracks at which an on-track error rate is not worse than a given value after a targeted number of adjacent track writes in an ATI requirement;
• (d) fitting a logarithmic function to the ATI track pitch and data from the number of adjacent track writes;
• (e) calculating ATI track pitch for a desired number of adjacent track writes using a fitted function;
• and then
• (e) selecting a final track pitch from a greater of the OTC and ATI track pitches.