Abstract: Example storage medium servo patterns, data storage devices, and methods to provide servo tracks with continuously varying frequency in a data storage device are described. The data storage device may include storage media, such as magnetic disks, having servo sectors that define servo tracks, where adjacent servo tracks have continuously varying frequency as the head moves from one servo track to the next. As the head is actuated over the storage medium, a target track frequency may be determined based on the radial position of a target servo track and the channel frequency may be set to the target track frequency to follow the target servo track.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: select a sector on the corresponding disk surface to which to write data, wherein the sector is selected in accordance with a data erosion mitigation pattern; and output, while the head is positioned proximate to a preceding sector that precedes the selected sector, a laser pre-bias current to a laser-generating component of the head, wherein the laser pre-bias current is sufficient to induce significant data erosion on the preceding sector.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to apply a pre-bias current to the assistive energy emitter at a first value while the selected head is positioned proximate to one or more spiral patterns on the corresponding disk surface. The one or more processing devices are further configured to apply the pre-bias current to the assistive energy emitter at a boosted value while the selected head is not positioned proximate to the one or more spiral patterns, wherein the boosted value is greater than the first value.

Abstract: Various illustrative aspects are directed to a data storage device including one or more disks, an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface among the one or more disks, the selected head comprising a write element and an assistive energy emitter, and one or more processing devices configured to, individually or in combination: apply an assistive energy current to the assistive energy emitter while refraining from applying a write current to the write element, and vary a level of the assistive energy current over time while refraining from applying the write current to the write element.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: select a sector on the corresponding disk surface to which to write data, wherein the sector is selected in accordance with a data erosion mitigation pattern; and output, while the head is positioned proximate to a preceding sector that precedes the selected sector, a laser pre-bias current to a laser-generating component of the head, wherein the laser pre-bias current is sufficient to induce significant data erosion on the preceding sector.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The selected head comprises a write element and an assistive energy emitter. The one or more processing devices are configured to apply an assistive energy current to the assistive energy emitter while refraining from applying a write current to the write element.

Abstract: Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuating mechanism comprising one or more heads, and configured to position the one or more heads proximate to disk surfaces of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: determine a first burst value based on an averaged value of a first set of one or more bursts; determine a second burst value based on an averaged value of a second set of one or more bursts; generate a position error signal (PES) based on the determined first burst value and the determined second burst value; and control a position of at least one head among the one or more heads based on the PES.

Abstract: Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuating mechanism comprising one or more heads, and configured to position the one or more heads proximate to disk surfaces of the one or more disks; and one or more processing devices. The one or more processing devices are configured to: determine a first burst value based on an averaged value of a first set of one or more bursts; determine a second burst value based on an averaged value of a second set of one or more bursts; generate a position error signal (PES) based on the determined first burst value and the determined second burst value; and control a position of at least one head among the one or more heads based on the PES.

Abstract: Various illustrative aspects are directed to a data storage device comprising: a voice coil motor (VCM) and one or more processing devices, configured to actuate the VCM, switch on measuring a back electromotive force (BEMF) from the VCM for intervals of an initial BEMF measurement that are free of spikes in the initial BEMF measurement, and process a measured BEMF signal from the intervals of the initial BEMF measurement that are free of spikes in a change of current term of the initial BEMF measurement.

Abstract: Various illustrative aspects are directed to a data storage device comprising: a voice coil motor (VCM) and one or more processing devices, configured to actuate the VCM, switch on measuring a back electromotive force (BEMF) from the VCM for intervals of an initial BEMF measurement that are free of spikes in the initial BEMF measurement, and process a measured BEMF signal from the intervals of the initial BEMF measurement that are free of spikes in a change of current term of the initial BEMF measurement.

Abstract: Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surface; and one or more processing devices, the head comprising: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform spiral write operations of spiral patterns comprising a plurality of sync marks with the head on the corresponding disk surface, wherein the spiral write operations are performed at: a plurality of values of laser pre-bias current, write backoff, and/or start disk phase; detect pattern signal amplitudes of the spiral patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based on the pattern signal amplitudes of the spiral patterns.

Abstract: Various illustrative aspects are directed to a data storage device, comprising: one or more disks; an actuator assembly comprising a head, and configured to position the head over a corresponding disk surfaces; and one or more processing devices, wherein the head comprises: a write element; a laser unit; and a fly height control element, and wherein the one or more processing devices are configured to: iteratively perform write start operations of write start patterns with the head on the corresponding disk surface, at a plurality of values of at least one of laser pre-bias current, and write backoff; detect pattern signal amplitudes of the write start patterns on the corresponding disk surface; and determine a relation of write backoff to laser pre-bias current for the head, based at least in part on the pattern signal amplitudes.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media comprising a plurality of tracks. A first pattern of magnetic transitions is written to a first segment of a first track. Preparation is made to write a second pattern of magnetic transitions to a second segment of a second track adjacent the first segment of the first track. When the second pattern matches the first pattern, a write boost is configured to a first setting, and when the second pattern does not match the first pattern, the write boost is configured to a second setting. The second pattern of magnetic transitions is then written to the second segment of the second track using the configured write boost.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media comprising a plurality of tracks. A first pattern of magnetic transitions is written to a first segment of a first track. Preparation is made to write a second pattern of magnetic transitions to a second segment of a second track adjacent the first segment of the first track. When the second pattern matches the first pattern, a write boost is configured to a first setting, and when the second pattern does not match the first pattern, the write boost is configured to a second setting. The second pattern of magnetic transitions is then written to the second segment of the second track using the configured write boost.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media. A write boost is configured to a first setting, and a first pattern of magnetic transitions is written to a first servo field of a servo sector on the magnetic media using the first setting for the write boost. The write boost is configured to a second setting different from the first setting, and the first pattern of magnetic transitions is written to a second servo field of the servo sector on the magnetic media using the second setting for the write boost.

Abstract: A data storage device is disclosed comprising a head actuated over a disk. The head is used to read servo information from the disk and generate a position error signal (PES) representing a position of the head over the disk. A control signal is generated based on the PES and a triangle-shape dither signal, and the head is positioned over the disk using the control signal.

Abstract: Systems and methods are disclosed for accessing data on a storage system. An apparatus, such as a data storage device or a computing device, may include a memory configured to store data. The apparatus is configured to determine an importance level for a file to be stored in the storage system. The data storage system includes one or more private storage clouds and one or more public storage clouds. The apparatus is also configured to generate a set of recovery data chunks based on the file and the importance level. The apparatus is further configured to store the set of recovery data chunks in the set of public storage clouds. The apparatus is further configured to store at least a portion of the file in the private storage cloud.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a spin torque oscillator (STO). A first bias signal is applied to the STO during a first interval preceding a write operation to write data to the disk, wherein the first bias signal causes the STO to protrude toward the disk. After the first interval, a second bias signal is applied to the STO during a second interval spanning at least part of the write operation, wherein an amplitude of the first bias signal is in the range of 1.1 to 1.5 times an amplitude of the second bias signal.

Abstract: Systems and methods are disclosed for accessing data on a storage system. An apparatus, such as a data storage device or a computing device, may include a memory configured to store data. The apparatus is configured to receive a request for a file stored in a storage system. The storage system includes a private storage cloud and a set of public storage clouds. The apparatus is also configured to determine whether the file is retrievable from the set of public storage clouds. If the file is retrievable from the set of public storage clouds the apparatus may determine whether access to the set of public storage clouds is faster than access to the private storage cloud and may retrieve the file from one or more of the private storage cloud and the set of public storage clouds.

Abstract: Systems and methods are disclosed for accessing data on a storage system. An apparatus, such as a data storage device or a computing device, may include a memory configured to store data. The apparatus is configured to receive a request for a file stored in a storage system. The storage system includes a private storage cloud and a set of public storage clouds. The apparatus is also configured to determine whether the file is retrievable from the set of public storage clouds. If the file is retrievable from the set of public storage clouds the apparatus may determine whether access to the set of public storage clouds is faster than access to the private storage cloud and may retrieve the file from one or more of the private storage cloud and the set of public storage clouds.