Patent ID: 7106547

Claim:
A method of determining embedded runout correction (ERC) values in a disk drive, wherein the disk drive includes a transducer, a disk and a servo control system, the transducer reads data from and writes data to the disk, the disk includes tracks, the tracks each include servo sectors, the ERC values provide compensation for repeatable runout (RRO) in the tracks, and a position error signal (PES) positions the transducer relative to the tracks, the method comprising: determining a first ERC value using the transducer to read a servo sector during a first revolution of the disk; determining a second ERC value using the first ERC value and the transducer to read the servo sector during a second revolution of the disk; determining an updated ERC value for the servo sector using the first and second ERC values; writing the updated ERC value to the servo sector; generating a third PES using the transducer to read the updated ERC value and servo bursts in the servo sector during a third revolution of the disk; and using the third PES to position the transducer as the transducer writes user data to a data field that is adjacent to the servo sector during the third revolution of the disk.