Predictive methods and systems for sampling data read from a rotating storage medium

A read and write system comprising:

• a mark detection module configured to generate i) a first mark indicator when first servo data is read from a storage medium, and ii) a second mark indicator when second servo data is read from the storage medium;
• an offset estimation module configured to estimate a first distance or an offset angle based on i) a first location of the storage medium, and ii) a period between times when the first mark indicator and the second mark indicator are generated, wherein the storage medium is rotated about the first location, and wherein the offset estimation module is configured to estimate the first distance or the offset angle based on one of
• i) a previous estimate of the first distance, or a previous estimate of the offset angle,
• ii) a least mean squares estimate of a difference between i) the period, and ii) a previous period between a third mark indicator and a fourth mark indicator, and
• iii) a regression analysis performed based on a predetermined number of periods between respective pairs of mark indicators;
• and
• a frequency adjustment module configured to adjust a sampling frequency at which user data is read from the storage medium based on i) the first distance, or ii) the offset angle.