Abstract: An accurate and time-efficient method and system for self-servowriting wherein at least one reference value used to position the transducer is updated for some, but not all, of the tracks to be written. The reference value(s) is dependent upon a predefined indicium of transducer position, such as the amplitude of the readback signal obtained from a written track when the transducer is positioned on the track. In a first embodiment, updating of the reference value(s) is performed at every Nth track written, where N is a fixed number or range of numbers determined by an expected track-to-track variation of the indicium. The servowriting system may be designed to dynamically increase or decrease N during servowriting in response to actual variations in the indicium. According to a second embodiment, updating is only performed when needed, e.g. when the variation of the measured indicium between two written tracks (not necessarily adjacent tracks) exceeds a predefined threshold value.

Abstract: Off-track time shift estimates are determined and used in order to write subsequent trigger patterns on a storage medium at different track pitches. Various procedures for determining an off-track time shift estimate are provided. These procedures include measuring time intervals between a related set of trigger patterns and another trigger written on the storage medium; measuring time intervals between a motor index and a particular trigger pattern at two different radial locations; measuring the difference in the center location of two trigger patterns written at different radial locations; and microjogging a recording transducer during the interval between two different trigger patterns.

Abstract: Off-track time shift estimates are determined and used in order to write subsequent trigger patterns on a storage medium at different track pitches. Various procedures for determining an off-track time shift estimate are provided. These procedures include measuring time intervals between a related set of trigger patterns and another trigger written on the storage medium; measuring time intervals between a motor index and a particular trigger pattern at two different radial locations; measuring the difference in the center location of two trigger patterns written at different radial locations; and microjogging a recording transducer during the interval between two different trigger patterns.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for random errors. Random errors may be caused by variations in disk velocity and therefore, one technique for correcting for random errors includes reducing velocity jitter. Additionally, random errors can be corrected by improving interval control during the propagation of trigger patterns used in writing timing information on storage media. Further, random errors, in the writing of timing information, can be corrected during a single revolution of the storage media. This eliminates additional rotations, thereby providing a large capital cost savings.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for systematic errors due to geometric effects. A correction is made for varying systematic errors, such as when the recording head has spatially separate read and write elements. Further, servopattern rotation due to residual or unmeasured systematic errors is reduced by using a once per revolution clock index derived from the motor drive current waveform or any other sensor. In one aspect of correcting for systematic errors in the writing of timing patterns on a storage medium of a storage device, a time interval between a trigger pattern written at a first-radial position of the storage medium and a rotational index is measured. The rotational index is related to the rotational orientation of the storage medium with respect to a fixed frame of the storage device.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: Improvements in placement of timing patterns in self-servowriting include detecting and correcting for media defects. A detector is used to detect whether a trigger pattern is within an expected location on the storage medium. If the trigger pattern is not detected, then a physical defect may be present. Thus, in one example, a false trigger pattern is generated. Additionally, a determination is made as to whether a trigger pattern is within an expected trigger pattern region. When the trigger pattern is not within the expected range, then a valid interval window may be modified to adjust the expected trigger pattern region.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for systematic errors due to geometric effects. A correction is made for varying systematic errors, such as when the recording head has spatially separate read and write elements. Further, servopattern rotation due to residual or unmeasured systematic errors is reduced by using a once per revolution clock index derived from the motor drive current waveform or any other sensor. In one aspect of correcting for systematic errors in the writing of timing patterns on a storage medium of a storage device, a time interval between a trigger pattern written at a first radial position of the storage medium and a rotational index is measured. The rotational index is related to the rotational orientation of the storage medium with respect to a fixed frame of the storage device.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: Improvements in placement of timing patterns in self-servowriting include detecting and correcting for media defects. A detector is used to detect whether a trigger pattern is within an expected location on the storage medium. If the trigger pattern is not detected, then a physical defect may be present. Thus, in one example, a false trigger pattern is generated. Additionally, a determination is made as to whether a trigger pattern is within an expected trigger pattern region. When the trigger pattern is not within the expected range, then a valid interval window may be modified to adjust the expected trigger pattern region.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for random errors. Random errors may be caused by variations in disk velocity and therefore, one technique for correcting for random errors includes reducing velocity jitter. Additionally, random errors can be corrected by improving interval control during the propagation of trigger patterns used in writing timing information on storage media. Further, random errors, in the writing of timing information, can be corrected during a single revolution of the storage media. This eliminates additional rotations, thereby providing a large capital cost savings.

Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for random errors. Random errors may be caused by variations in disk velocity and therefore, one technique for correcting for random errors includes reducing velocity jitter. Additionally, random errors can be corrected by improving interval control during the propagation of trigger patterns used in writing timing information on storage media. Further, random errors, in the writing of timing information, can be corrected during a single revolution of the storage media. This eliminates additional rotations, thereby providing a large capital cost savings.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: Methods and systems for self-servowriting a data storage medium are disclosed, including servoing to propagation bursts of a propagation pattern located in tracks other than an immediately preceding track. Reference levels used to position a recording head are accordingly kept in a usable dynamic range necessary to keep servo track spacing constant across the medium. The methods and systems are disclosed in connection with a rotary actuator having spaced read and write heads. Similar methods are disclosed for writing trigger or timing bursts of the propagation pattern.

Abstract: Improvements in placement of timing patterns in self servo writing include correcting for random and systematic errors due to geometric effects. In a disk drive having a recording head with separate read and write elements, a method for determining separation between the elements and for correcting for such errors as a function of skew angle between the head and the disk. Errors resulting from misalignment and non-parallelism of the elements as well as misalignment of the head on it its actuator are also detected and corrected. Errors due to changes in rotational velocity of the disk and misplacement of timing patterns with respect to adjacent timing patterns are detected and corrected. In general, a single revolution process may be used to both write and detect random errors on each track and corrected on subsequent tracks.

Abstract: A mechanism for servowriting on a storage medium of a storage device. The storage device has a transducer and a servo loop for positioning the transducer with respect to the storage medium. At least one transition is written on a track of the storage medium, while servoing on other transitions previously recorded on the storage medium. A reference waveform is derived as a function of a closed loop response of the servo loop and a position error waveform. The position error waveform corresponds to one or more position errors of the transducer relative to the previously recorded transitions. The reference waveform is usable in writing subsequent tracks on the storage medium. Using the reference waveform for writing subsequent tracks provides a substantial rejection of mechanical disturbances by the servo loop.

Abstract: Improvements in placement of timing patterns in self servo writing include correcting for random and systematic errors due to geometric effects. In a disk drive having a recording head with separate read and write elements, a method for determining separation between the elements and for correcting for such errors as a function of skew angle between the head and the disk. Errors resulting from misalignment and non-parallelism of the elements as well as misalignment of the head on it its actuator are also detected and corrected. Errors due to changes in rotational velocity of the disk and misplacement of timing patterns with respect to adjacent timing patterns are detected and corrected. In general, a single revolution process may be used to both write and detect random errors on each track and corrected on subsequent tracks.

Abstract: An accurate and time-efficient method and system for self-servowriting wherein at least one reference value used to position the transducer is updated for some, but not all, of the tracks to be written. The reference value(s) is dependent upon a predefined indicium of transducer position, such as the amplitude of the readback signal obtained from a written track when the transducer is positioned on the track. In a first embodiment, updating of the reference value(s) is performed at every Nth track written, where N is a fixed number or range of numbers determined by an expected track-to-track variation of the indicium. The servowriting system may be designed to dynamically increase or decrease N during servowriting in response to actual variations in the indicium. According to a second embodiment, updating is only performed when needed, e.g. when the variation of the measured indicium between two written tracks (not necessarily adjacent tracks) exceeds a predefined threshold value.

Abstract: During a write revolution of a storage medium, a transition is written on the storage medium while servoing on another transition previously recorded on the storage medium. During that write revolution, a position error signal corresponding to the position error of the transducer relative to the previously recorded transition is determined.