Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones. A disk locked clock is synchronized relative to a servo data rate of the servo zone the head is over. A first reader/writer gap is measured in cycles of the disk locked clock at a first servo track in the first servo zone. A second reader/writer gap is measured in cycles of the disk locked clock at a second servo track in the second servo zone. The first and second reader/writer gaps are normalized to generate a normalized first and second reader/writer gaps. A third reader/writer gap is estimated in cycles of the disk locked clock at a third servo track in the second servo zone based on the normalized first and second reader/writer gaps.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors that define a plurality of servo tracks, wherein the servo sectors comprise a plurality of servo bursts. A radial velocity of the head is detected relative to the servo tracks. At least two of the servo bursts are read to generate servo burst signals, and the servo burst signals are adjusted in response to the radial velocity of the head. A position error signal is generated for the head in response to the adjusted servo burst signals.

Abstract: A method, apparatus and a data storage device are provided for implementing data track pitch adjustment for data written on a recordable surface of a storage device under operational vibration conditions. An operational vibration disturbance spectrum is detected during a write operation and the data track pitch is selectively adjusted based on the detected operational vibration disturbance spectrum. The adjusted track pitch information is saved and used during a read operation.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by a plurality of servo sectors, wherein each servo sector comprises a plurality of servo bursts, and each servo burst comprises a predetermined phase. After positioning the head over one of the servo tracks, a servo burst in one of the servo sectors is read to generate a read signal, and a sine and cosine component are extracted from the read signal. At least one of the sine and cosine components is rotated by an angle based on a radial location of the head. A position error signal for the head is generated in response to the rotated component.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, the disk including a plurality of servo sectors wherein each servo sector comprises at least one servo burst. A read signal emanating from the head is sampled while reading a servo burst in a servo sector to generate a plurality of sample values. A quality metric is generated in response to a plurality of sample values of a servo sub-burst representing part of the servo burst. When the quality metric does not exceed a threshold, the servo sub-burst sample values are excluded when generating a position error signal (PES) representing a position of the head over the disk. When the quality metric exceeds the threshold, the servo sub-burst sample values are included when generating the PES. The head is then positioned over the disk in response to the PES.