摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A disk drive is disclosed comprising a disk having a plurality of servo tracks defined by servo sectors, and a head actuated over the disk. The disk drive further comprises control circuitry comprising a servo control system operable to position the head over the disk. A disturbance is induced in the servo control system, and while positioning the head over the disk, a data track is accessed. The disturbance induced in the servo control system causes the data track to be non-circular relative to a rotation axis of the disk such that the non-circular data track crosses multiple of the servo tracks over a revolution of the disk.
摘要:
A disk drive is disclosed comprising a disk and a head actuated over the disk. A burst metric is generated in response to a burst read signal. The burst metric comprises at least one of an alpha metric comprising a ratio of a first burst amplitude of a first phased based servo burst measured at a first radial offset to a second burst amplitude of a second phased based servo burst measured at a second radial offset, a harmonic metric comprising a ratio of a first harmonic of the burst read signal as the head is moved radially over the disk to a higher harmonic of the burst read signal as the head is moved radially over the disk, and a spiral track crossing metric comprising a first and second interval each representing a partial duration of the read element crossing a spiral track.
摘要:
A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks defined by a plurality of servo sectors. An estimated track ID is generated representing an estimated radial location of the head. A high order Gray code in a first servo sector is detected, and errors in the high order Gray code are corrected using the estimated track ID to generate a corrected Gray code. The corrected Gray code is decoded into a first part of a detected track ID. A low order track code is detected in the first servo sector, and the low order track code is decoded into a second part of the detected track ID. The first part of the detected track ID is combined with the second part of the detected track ID.
摘要:
A data storage device with improved data storage densities, coupled with lower hard error and write-inhibit events is described. A feed-forward write inhibit (FFWI) method enables data tracks to be written more densely. Alternatively, the FFWI method may reduce the hard error and write inhibit events to improve data storage performance. A concept of virtual tracks enables the FFWI method to be applied to the writing of circular data tracks with non-circular servo tracks, or to the writing of non-circular data tracks with PES data from circular servo tracks—in both cases, improvements to performance and/or storage densities are enabled. The FFWI method may also be applied to the case of both non-circular servo and data tracks.
摘要:
A data storage device with improved data storage densities, coupled with lower hard error and write-inhibit events is described. A feed-forward write inhibit (FFWI) method enables data tracks to be written more densely. Alternatively, the FFWI method may reduce the hard error and write inhibit events to improve data storage performance. A concept of virtual tracks enables the FFWI method to be applied to the writing of circular data tracks with non-circular servo tracks, or to the writing of non-circular data tracks with PES data from circular servo tracks—in both cases, improvements to performance and/or storage densities are enabled. The FFWI method may also be applied to the case of both non-circular servo and data tracks.
摘要:
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.