Abstract: A method for ascertaining a position of a read/write head relative to a reference position on a rotatable disk in a computer disk drive. The method includes reading amplitudes of a set of servo bursts embedded in tracks of the disk and classifying the servo bursts into a converging servo burst set and a detection servo burst set around the reference position. The method also includes forming a position error signal by normalizing a detection servo burst signal with a converging servo burst signal. The converging servo burst signal is formed from amplitudes of the converging servo burst set at the position of the read/write head. The detection servo burst signal is formed from amplitudes of the detection servo burst set at the position of the read/write head. The position error signal represents an offset from the reference position.