Abstract: A recordable medium according to some embodiments includes a servo control field having a bit patterned media (BPM) pattern. The pattern includes a plurality of isolated magnetic islands or dots arranged in a down-track orientation and in a cross-track orientation. A phase of dots arranged on the medium in the servo control field varies in a first cross-track direction. The dots arranged on the medium may include a first phase pattern that has a first phase gradient in the first cross-track direction and a second phase pattern that has a second phase gradient, different from the first phase gradient, in the first cross-track direction. The dots may include a plurality of dot composites including a plurality of dots.

Abstract: Methods and structures for recovering from an off-track position error in a dynamically mapped storage device. In a dynamically mapped storage device data is dynamically mapped to a physical location on the recordable media. Thus, when a write fault occurs, such as an off-track position error, the data may be re-written and re-mapped at a different location on the recordable media. In a dynamically mapped storage device data may be reordered into a sequential stream of contiguous physical data blocks. Random host data blocks may be mapped into sequential physical data blocks on the recordable media. Further, the sequential reordering of the data blocks may ensure that no data is present in tracks or sectors directly ahead of the track of sector being written. Further, the system has the ability to store multiple revolutions of host supplied data within the disk drive memory buffer and maintain the information in memory while writing it to the recordable media.

Abstract: A method allocating firmware objects between different types of memory in a product model based on a frequency of access of each firmware object in trace data. The allocated firmware objects and trace data are used to simulate the performance of the product model. Memory access statistics obtained during the simulation may be used to analyze product model performance in the frequency and time domains.

Abstract: In a servo control loop, phase detection between a clock signal and servo burst fields on a movable storage media is carried out with compensation for the effects of frequency variation in the timing of servo burst fields.

Abstract: Detection of head disk interference is provided by monitoring a hard disk drive characteristic related to disk rotation rate. A number of characteristics can indicate HDI. These include the magnitude of decreases in rotation rate, changes in the time-derivative (time-rates of change) of rotation rate or other changes in time-profiles of rotation rate, changes in spin motor current, differences between maximum and minimum values of spin motor current, changes in the time-derivative (time-rates of change) of spin motor current or other changes in time-profiles of spin motor current or combinations or indicators thereof. These approaches to detecting HDI provide several potential advantages. Detection of HDI can be achieved relatively early in a test or other procedure, can be performed relatively rapidly, can distinguish HDI from at least some other anomalies and can indicate the location and/or magnitude of HDI occurrences.

Abstract: Methods of machining a single piece hub with integral upper and lower female cones includes providing a single piece hub with upper and lower conical voids having respective narrow ends proximal each other and respective wide ends distal each other. Surfaces of the voids are machined using a tool provided from a single side of the hub that is dimensioned to fit through an opening defined by the interface between the narrow ends of the conical void. The tool can be moved parallel to a rotational axis for accessing conical surfaces of both voids and perpendicular to the rotational axis while contacting the surfaces so as to produce a final machined surface.

Abstract: A system is capable of detecting a “large” shock. In contrast to just any shock, a large shock exceeds some threshold of magnitude or duration and may generate particles and/or the deposit of particles on a recording head, which can result in write errors. Responsive to detection of a large shock, the system can take corrective action, such as executing one or more corrective action seeks after detection of the large shock or executing a series of corrective actions seeks during a certain number of load operations after detection of the large shock. RAW verifications may be performed to confirm correct write operation of the recording head after such corrective action.

Abstract: Tracing of test information from a hardware device for debugging is formatted for transmission via a high-speed serial protocol. Data from various components in the hardware device is transmitted to an external test board using high speed serial ports. The number of serial ports needed for data transfer is significantly less than a complimentary parallel port configuration. Additional functional blocks on the chip process the data for high speed serial output. The functional blocks format information into subchannels, arbitrate data, append protocol, perform data integrity checks, and serialize the data. The additional blocks built on the chip to support the serial ports consume less chip space than the space consumed by the number of parallel ports required to provide equivalent data transfer rates. The process operates in near real time and may use time stamping to correlate and reconstruct data from different information sources.

Abstract: A method and apparatus for receiving data at a non-solid state storage device, which includes a store cache and a storage medium. The received data is written to the store cache and transferred from the store cache to the storage medium. In response to receiving a signal at the storage device that is indicative of a power off condition of a data source device from which the data was received, at least a portion of the data remaining in the store cache is transferred to the storage medium prior to powering off the storage device.

Abstract: Methods and structures for providing on-the-fly head depopulation in a dynamically mapped storage device. In a dynamically mapped storage device in which all user supplied logical blocks are dynamically mapped by the storage device controller to physical disk blocks, features and aspects hereof allow on-the-fly head depopulation to protect data when a subsection of a storage device, such as a head of surface is failing. When the storage device detects that a head is failing, data may be migrated off the failing subsection into other subsections (e.g., a different head or surface) using mapping features and aspects hereof. Thus, the data on the failing subsection is still available should the subsection or head eventually fail.

Abstract: Video data in an encoded frame is reduced by adjusting orthogonal transform coefficients in the encoded frame during trick play operation such as fast forward or fast reverse. The orthogonal transform coefficients are adjusted by selecting essential orthogonal transform coefficients with high energy and non-essential orthogonal transform coefficients with low energy, maintaining or strengthening the essential orthogonal transform coefficients and attenuating or removing the non-essential orthogonal transform coefficients. In an MPEG bit stream, the encoded frame is an I-frame and the orthogonal transform coefficients are discrete cosine transform (DCT) coefficients.

Abstract: Embodiments of the present invention allow for media erasure. Various embodiments allow for controlling an actuator based on feedback signal measurements and disk phase to seek a head across a surface of a disk systematically for an erasure operation. Also, in various embodiments, a substantially repeatable seek motion of a head across a stroke may be determined, and launch points at which the head is launched over a disk in the seek motion for erasing at least a portion of the disk are determined based on disk phase.

Abstract: An anti-notch filter in a servo control loop is phase locked to a nonrepeatable runout component of a servo control loop signal. The phase locked anti-notch filter may thereby more effectively track time varying characteristics of the nonrepeatable runout component so that they can be at least partially reduced in the servo control loop signal.

Abstract: A disk drive capable of being configured into a plurality of data storage zones, wherein some of the zones have different performance characteristics than other zones; a method for performing such a zoning configuration; and, a host device utilizing such a disk drive. The disk drive comprises a disk having a plurality of sectors for storing data, a head for reading and writing the data, and a disk drive controller for controlling the head, wherein the plurality of the sectors are organized into the plurality of zones. In one embodiment of the present invention, the performance characteristics of the zones are dictated by configuration settings in the disk drive controller. The configuration settings may include settings for a plurality of parameters. In some embodiments of the present invention, the plurality of parameters comprises a CCT (command completion time) parameter, a Write Verify parameter, a Write Continuous parameter, a Read Continuous parameter, and an Error Re-allocation parameter.

Abstract: Methods according to some embodiments include writing servo patterns on a data storage medium including a plurality of timing patterns in response to phase correction values generated using a phase correction value (PCV) kernel having a length that is less than the number of timing patterns on the data storage medium.

Abstract: Bias force changes in a disk drive, including transient bias changes, are predicted and/or estimated. Bias compensation or change in bias compensation is calculated based on drive operating parameters such as seek length. Calculation can correspond to a modeled relationship of bias forces to seek length. Preferably, bias compensation calculation is adaptive and calculation parameters can be updated during normal read/write use of the disk drive.

Abstract: A system for generating resonance mode information associated with a servo track writer system comprising a drive VCM, a drive arm assembly, an external VCM, an external arm assembly, and a mechanical connection between the external arm assembly and the drive arm assembly. The system of the present invention comprises a controller, a position sensor, and a processor. The controller is adapted to apply an injection signal to the drive VCM such that the injection signal causes movement of the external arm assembly through the drive arm assembly and the pushpin. The position sensor is configured to generate an output signal indicative of a position of the external arm assembly. The processor generates the resonance mode information based on the injection signal and the output signal.

Abstract: Methods and structures for performing field flawscan to reduce manufacturing costs of a dynamic mapped storage device. In a dynamic mapped storage device in which all user supplied logical blocks are dynamically mapped by the storage device controller to physical disk blocks, features and aspects hereof permit flawscan testing of a storage device to be completed substantially concurrently with processing write requests for its intended application. A fraction of the storage device may be certified by an initial flawscan performed during manufacturing testing. Statistical sampling sufficient to assure a high probability of achieving specified capacity may be performed to reduce manufacturing time and costs in testing. Final flawscan of the remainder of the storage locations may be performed substantially concurrently with processing of write requests after the device is installed for its intended application.

Abstract: Embodiments of the present invention reduce the written-in run-out in servo data written to a storage medium. A set of servo controllers are evaluated and the controller having the best expected performance among the set is selected and employed. One embodiment of the present invention is a servo controller configured to select and employ a controller having a least amount of expected written-in run-out among a set of controllers. Another embodiment of the present invention is a method comprising a step for applying a set of controllers; and selecting a controller from the set of controllers with a least expected amount of written-in run out. Another embodiment of the present invention is a system comprising a servo controller for employing and selecting a disk controller that has a least expected amount of written-in run-out among a set of controllers.

Abstract: In a servo control loop, the rate of change of filter coefficients used by an adaptive filter to counteract external disturbances to head position is regulated in response to a characteristic of an acceleration signal. Regulating the rate of change of the filter coefficients may improve the stability of the servo control loop.