Patent ID: 7522372

Claim:
A magnetic storage medium including a longitudinal servo track, the servo track comprising: magnetic flux transitions forming detectable servo marks, the servo marks forming a tone field of repeating servo marks oriented at a first azimuth angle, whereby the tone field provides a metric reference for dimensional measurements between features of the servo track, wherein the tone field servo marks are phase encoded with information associated with a longitudinal position of the servo track by displacing selective servo marks of the tone field to create longitudinal characters; and servo frames of the tone field having a mid-frame synchronization mark incorporated within the tone field, wherein the mid-frame synchronization mark is distinguishable from the tone field, and for each servo frame the number of servo marks in the tone field of the servo frame along a longitudinal direction of the servo track before the mid-frame synchronization mark and after the mid-frame synchronization mark varies with lateral position of the servo track.