Patent ID: 7027256

Claim:
A magnetic disk drive having a reduction in repeatable runout (RRO) effects, comprising: a head disk assembly (HDA) including a rotating magnetic disk having distributed position information in a plurality of uniformly spaced-apart embedded servo sectors for defining data storage tracks, the plurality of embedded servo sectors for storing servo information including repeatable runout (RRO) cancellation values and RRO cancellation value error correction code (ECC) data at a servo data rate, the RRO cancellation value ECC data only for detecting and correcting errors in the RRO cancellation values, and each data storage track having a plurality of data sectors between the embedded servo sectors for storing user data at a user data rate that is different from the servo data rate, an actuator for positioning a transducer head in response to a control effort signal, the transducer head for periodically reading the distributed position information from the servo sectors and reading data from the data storage tracks; and a sampled servo controller for periodically adjusting the control effort signal during a track-following operation based on the distributed position information and the RRO cancellation values.