Abstract: Systems and methods in accordance with embodiments can be used to re-write data to a rotatable storage medium. When a position of a write element is not within a threshold during a data write operation, an indication of data written while the position of the element was not within the threshold can be maintained. When the device including the rotatable storage medium is free from other data transfer operations, the data written while the element was not within the threshold can be re-written. In this manner, data that may be considered less reliable due to the misplacement of a write element during a data write operation can be re-written such that the data can be placed closer to a data track centerline.

Abstract: To account for head misplacement while servowriting, adjustments to thresholds used during writing and/or trimming of servo information can be used. A threshold can be used to disable servowriting when it is determined that servo information will not be written and/or trimmed at a desired location or within a threshold distance of a desired location. In multiple pass servowriting, a threshold can be adjusted for a pass or step or portion thereof using a position-error during a corresponding operation. For example, the position-error while trimming a first servo burst can be determined. Using the position-error, the threshold can be adjusted. The adjusted threshold can be used while writing a corresponding second servo burst. The threshold can be increased in a direction opposite to the determined position-error and decreased in the direction of the determined position-error. In this manner, the probability that the two bursts will identify a desired location can be increased.

Abstract: A rotatable media storage device operates using multiple disk spin-speeds, e.g., a reduced spin-speed and a nominal spin-speed. A disk is spun up to a reduced spin-speed and an initial data transfer is began while the disk spins at the reduced spin-speed, if an amount of work that has been requested is below a threshold. The disk is spun up to a further spin-speed (e.g., a nominal spin-speed), which is greater than the reduced spin-speed, and the initial data transfer is began while the disk spins at the further spin-speed, if the amount of work that has been requested is above the threshold. Alternative embodiments using multiple disk spin-speeds are also provided.

Abstract: Embodiments of the present invention determine the offset of a first burst of a burst pair from a centerline. This can be used to determine the desired offset position for a second burst of the burst pair. The target signal to provided the data storage unit for writing the second burst can take into account the transfer function of the controller and the physical plant so as to more accurately write at the desired offset position.

Abstract: Template patterns in accordance with the present invention can be applied to improve printed media self-servo writing by reducing PES noise and SAM error-rate at an outer diameter of a reference surface of a disk. In one such template pattern, zig-bursts within a servo wedge describing radial positioning are replaced with pulses at an inner diameter of the reference surface such that head skew at the inner diameter is a limiting factor for pattern frequency at the inner diameter. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: Methods in accordance with the present invention can include determining a position of a head along a stroke by locating one or more marker-zones printed to a reference surface of a disk. The one or more marker-zones can be printed to a portion of the reference surface as one or more pulses from a template pattern that can further comprise a plurality of chevrons. In one embodiment, each pulse can trace the motion of the stroke along at least a portion of the radius of the reference surface. A pulse can identify a marker-zone edge when the pulse disappears at some radius from the center of the disk. By moving the head along the stroke, the marker-zone edge can be detected and a gross position determined. A fractional position can be determined by measuring a phase of a chevron located at substantially the same radial location as the edge.

Abstract: Template patterns in accordance with the present invention can include one or more maker-zones printed to a reference surface of a disk for determining gross-position along a stroke of a read head connected with a rotary actuator. The one or more marker-zones can be printed or otherwise written to a portion of the reference surfaces as one or more pulses. In one embodiment, each pulse can trace the motion of the stroke along at least a portion of the radius of the reference surface. A pulse can identify a marker-zone edge when a di-bit (a transition pair representing a pulse) disappears at some radius from center of the disk. At a radius closer to the center of the disk, the di-bit can abruptly reappear so that the pulse is continued. The interruption in the radial continuity of the magnetized pulse defines the marker-zone and can be any length.

Abstract: A method for retrieving critical data determined to be requested by a host device in the near future and stores it in cache. A hard drive retrieves and provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. The critical data may be related to power-on of the computer, such as boot sector FAT system data. Thus, the cache of the present invention may use old data rather than new data or the last data accessed.

Abstract: A hard drive retrieves critical data determined to be requested by a host device in the near future and re-allocates the critical data on the hard drive medium. The hard drive provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. The critical data can be written to reserved areas of the media that provide desirable read characteristics. In this aspect, the present invention may trade drive capacity and/or media write speed for media read speed. The critical data maybe re-allocated and placed in sequential order, thereby saving time from seeking to different locations over the media. Critical data may stored in FLASH memory, providing quicker data access while consuming less power.

Abstract: A method for retrieving critical data that is determined to very likely be requested by a host device in the near future and storing it in FLASH. The hard drive provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. The critical data may be related to power-on of the computer, such as boot sector FAT system data. The critical data maybe re-allocated and placed in sequential order, thereby saving time from seeking to different locations over the media. Critical data may stored in FLASH memory, providing quicker data access while consuming less power. While the hard drive is in low power states, other data can be written to FLASH in order to conserve energy.

Abstract: A method for retrieving critical data determined to be requested by a host device in the near future and re-allocating the critical data on the hard drive medium. The hard drive provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. Thus, the cache of the present invention may use old data rather than new data or the last data accessed. The critical data can be written to reserved areas of the media that provide desirable read characteristics. In this aspect, the present invention may trade drive capacity and/or media write speed for media read speed. The critical data maybe re-allocated and placed in sequential order, thereby saving time from seeking to different locations over the media. Critical data may stored in FLASH memory, providing quicker data access while consuming less power. While the hard drive is in low power states, other data can be written to FLASH in order to conserve energy.

Abstract: A hard drive retrieves critical data determined to be requested by a host device in the near future and stores it in a FLASH integrated circuit. The hard drive provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. The critical data maybe re-allocated and placed in sequential order, thereby saving time from seeking to different locations over the media. Critical data may stored in FLASH memory, providing quicker data access while consuming less power. While the hard drive is in low power states, other data can be written to FLASH in order to conserve energy.

Abstract: A hard drive retrieves critical data determined to be requested by a host device in the near future and stores it in cache. The hard drive provides the critical data to the requesting host upon receiving the request, thereby eliminating the time required to respond to the request due to media accessing. The critical data is retrieved upon the occurrence of a critical event. The critical data may be related to power-on of the computer, such as boot sector FAT system data. Thus, the cache of the present invention may use old data rather than new data or the last data accessed.

Abstract: The misplacement of a servo burst during a servowriting or self-servowriting process can be corrected by erasing and re-writing that burst. A servo pattern can be selected that has sufficient radial separation between bursts such that if a burst is re-written and trimmed there should be no damage to adjacent bursts. The radial separation can be selected to be greater than the width of the appropriate write element in order to allow for some misplacement of the element during the erasing and/or re-writing of the misplaced burst. Alternatively, a batch writing approach can be used to minimize the time needed to re-write misplaced bursts. In addition, WORF information of a track can be saved in memory for future servowriting and/or can be utilized to calculate a threshold for identifying servo bursts to be repaired. This description is not intended to be a complete description of, or limit the scope of, the invention.

Abstract: Systems are provided for limiting channel control values, such as servo automatic gain control (AGC) values and/or servo phase lock loop (PLL) values, within respective desired ranges. Keeping such values within desired ranges improves servo demodulation robustness.

Abstract: Methods are provided for limiting channel control values, such as servo automatic gain control (AGC) values and/or servo phase lock loop (PLL) values, within respective desired ranges. Keeping such values within desired ranges improves servo demodulation robustness.

Abstract: Servo demodulation systems including multiple servo demodulators are provided. A first servo demodulator is adapted to search for a servo address mark (SAM) pattern using a first set of servo demodulation detection parameters. A second servo demodulator is adapted to search for the SAM pattern using a second set of servo demodulation parameters, wherein at least one servo demodulation parameter in the second set is different than a corresponding parameter in the first set. Example servo demodulation parameters include staring automatic gain control (AGC) values and starting phase lock loop (PLL) values.

Abstract: Methods for searching for a servo address mark (SAM) pattern using multiple sets of servo demodulation detection parameters are provided. A SAM pattern is searched for using a first set of servo demodulation detection parameters. The SAM pattern is also searched for using a second set of servo demodulation parameters, wherein at least one servo demodulation parameter in the second set is different than a corresponding parameter in the first set. Example servo demodulation parameters include staring servo automatic gain control (AGC) values and starting servo phase lock loop (PLL) values.

Abstract: Methods are provided for improving servo-demodulation robustness, especially when used with a disk having zone bit recorded servo wedges. A servo address mark (SAM) pattern is searched for, within a servo wedge, at a first nominal frequency useful for searching for the SAM pattern if the servo wedge is within a first zone. The SAM pattern is also searched for, within the same servo wedge, at a second nominal frequency useful for searching for the SAM pattern if the servo wedge is within the second zone. A determination of which one of two zones a head is reading, can then based at least in part on which nominal frequency was used to successfully detect the SAM pattern.

Abstract: Systems are provided for improving servo-demodulation robustness, especially when used with a disk having zone bit recorded servo wedges. The systems include a first servo demodulator adapted to search for a servo address mark (SAM) pattern, within a servo wedge, at a first nominal frequency useful for searching for the SAM pattern if the servo wedge is within a first zone. The systems also include a second servo demodulator adapted to search for the SAM pattern, within the same servo wedge, at a second nominal frequency useful for searching for the SAM pattern if the servo wedge is within the second zone. A microprocessor can then determine which of the first and second zones a head is reading, based at least in part on which of the first and second demodulators detects the SAM pattern.