Patent ID: 8004784

Claim:
A frequency adjustment system for a rotating storage system, the frequency adjustment system comprising: an offset estimation module configured to estimate a distance between (i) data written to a rotating storage medium and (ii) a first center location about which the rotating storage medium rotates, wherein the data has been previously written to the rotating storage medium relative to a second center location, and wherein the second center location is different than the first center location; a frequency adjustment module configured to adjust a sampling frequency at which the data is read from the rotating storage medium based on the distance between the data and the first center location; and a mark detection module configured to generate (i) a first mark indicator when servo data is read from a first location of the rotating storage medium and (ii) a second mark indicator when the servo data is read from a second location of the rotating storage medium, wherein the offset estimation module is configured to (i) estimate the distance based on a period between the first mark indicator and the second mark indicator and (ii) estimate an offset angle for the data and an offset distance for the rotating storage medium based on the period, wherein the offset distance is defined between the first center location and the second center location, wherein the frequency adjustment module is configured to adjust the sampling frequency based on the offset angle and the offset distance, and wherein the offset estimation module is configured to estimate the offset angle and the offset distance based on at least one previous estimate of each of the offset angle and the offset distance.