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.

Abstract: To reduce the whirling air vortices which are normally formed at the disc tip, the outer edge of the disc surface may be gradually thinned down to a sharp tip. An alternative approach, the disc tip is gradually reduced in width and rounded at its outer edge. A flow obstruction may be incorporated in the shroud adjacent the edge of the disc tip. This obstruction may comprise a small substantially rectangular insert extending from the inner edge of the housing. Or, the inner surface of the portion of the housing adjacent the ends of the disc may incorporate grooves therein. These grooves, which are roughly herringbone in shape, and would have their center near either the edge of disc in a single disc environment or mid-way between the disc in a two disc environment.

Abstract: In one example, a FDB motor having a top-cover attached, EM biased bearing system is provided. The motor includes a shaft and rotor disposed for relative rotation, and an axial limiter for restricting axial movement of the rotor with respect to the shaft, wherein the axial limiter is wet or lubricated during contact. The limiter is spatially fixed with respect to one of the shaft or the rotor and disposed with an axial end surface opposing a surface portion spatially fixed with respect to the other of the shaft or the rotor to form a gap therebetween. The gap may be filled with a fluid such as bearing lubricant, thereby providing a lubricated or wet contact surface to restrict axial movement of the shaft and rotor. Additionally, one or both surfaces may include a groove or slot to provide circulation of fluid through the gap.

Abstract: An apparatus for detecting defects on a disk surface includes a light source that generates a light beam and a beamsplitter that splits the light beam into a first light beam portion and a second light beam portion. The first light beam portion illuminates the surface of the disk and produces a reflected light beam. An acoustic-optic deflector deflects the reflected light beam and the second light beam portion producing a deflected output beam having a deflection angle. A detector detects an incident beam translation signal corresponding to reflected light beam angular deflection and acoustic-optic deflector beam angular deflection from the deflected output beam.

Abstract: Remotely communicating data between computers or devices across a wide area network for purposes of redundancy or collaboration. A service brokers the transfer of data between an initiating computer and a destination device, thereby establishing a peer-to-peer architecture by which data of the initiating computer can be stored remotely on the destination device. The process begins as the initiating computer issues a request for permission to store the data remotely on an identified destination device. The permission is granted if the initiating computer properly identifies the destination device using information, such as a network address or a password, that is privately communicated between the users of the destination device and the initiating computer. Accordingly, substantially any computer user having access to the Internet can achieve remote backup of data and remote collaboration of data with the assistance of a trusted third party who also is registered with the service.

Abstract: A method and system for interleaving storage of data streams on a rotating storage medium of a data storage device comprise dividing the storage medium into a plurality of logical zones. Each logical zone of the plurality of logical zones extends radially from an inner diameter of the storage medium to an outer diameter of the storage medium. Data from a first stream of data is written to a first logical zone of the plurality of logical zones for up to an amount of time corresponding to the rotational speed of the storage medium and the size of the first logical zone.

Abstract: Adjusting a servo control system includes identifying a gain crossover frequency for the servo control system, generating a sensitivity function for the servo control system, measuring a sensitivity peak in the sensitivity function, comparing a frequency of the sensitivity peak to the gain crossover frequency, and adjusting the servo control system in response to the comparison of the frequency of the sensitivity peak to the gain crossover frequency.

Abstract: Methods and structures for dynamic multiple indirections to improve reliability and performance of a dynamically mapped storage devices. 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 provide for dynamically altering the number of replicated copies (multiple mapped indirections) of user data stored on the storage device. Performance information regarding operation of the storage device may be gathered by the storage device controller such that where physical capacity of the storage device permits and as degrading reliability is detected, additional copies (multiple indirections) of stored user data may be written to the mapped storage device. Increased multiple indirections improves reliability by decreasing the probability of data loss in response to various failure modes of the storage device.

Abstract: Methods and associated apparatus to reduce electrical power consumption in an information channel may include identifying times at which to restore power to elements in the information channel, and restoring power to the elements at the identified times. Times for each element are identified based on a recovery time for that element to reach a sufficiently stable operating point before a transition to an active mode of operation. By maximizing the length of time individual elements may stay in the reduced power mode, power savings may be maximized without negatively affecting information channel performance.

Abstract: Methods and structures for providing patches or updates to embedded ROM firmware simply and inexpensively while avoiding imposition of execution or memory fetch overhead. A patch memory includes locations storing addresses and optional alternate data values. Read/fetch operations addressed to a firmware ROM memory are applied in parallel to the patch memory. All locations of the patch memory may be compared in parallel to the supplied address to determine if a match is found in patch memory. If no match is found, the read/fetch memory cycle completes normally retrieving data from the ROM memory. If a match is found, the alternate data value is applied to the data bus in place of the ROM memory data retrieved. Any ROM location may therefore be patched regardless of whether the location stores instruction or data.

Abstract: Apparatus and related methods are described for adjusting servo gain. In an exemplary apparatus, a circuit determines a bias force error that occurs between an estimated bias force and an actual bias force on an actuator during movement by a servo motor. The circuit adjusts a servo gain in response to the bias force error, and regulates movement of the actuator by the servo motor in response to the servo gain.

Abstract: A disk drive has multiple disk surfaces and corresponding heads, each disk surface includes multiple regions, and each head is for recording on and playback of information from a corresponding disk surface. The data track density in a first region on a first disk surface is different than the data track density in a second region on a second disk surface, and the first and second regions are radially similarly situated regions. A method of sequentially accessing data in the first and second regions includes sequentially accessing data tracks in the first region and then sequentially accessing data tracks in the second region.

Abstract: Controlling seeking of a transducer includes accelerating the transducer to a seek velocity, generating a linearized switching curve defining a position and velocity of the transducer at which deceleration should begin, and controlling the velocity of the transducer in response to the current position and seek velocity of the transducer relative to the linearized switching curve. The linearized switching curve has a slope and an offset that are determined in response to the seek velocity and a current position of the transducer relative to a nonlinear switching curve.

Abstract: A method and disc drive are disclosed that employ dynamic buffer size allocation for handling multiple data streams, such as time-sensitive audio/video data. The method involves allocating a certain amount of required buffer space for each data stream to be handled without an interruption in recording or playing back the data stream. The method further involves reallocating the amount of required buffer space for each stream including any additional stream when one or more additional streams are to be added to the total number of streams being handled. The method also involves reallocating the amount of required buffer space for each stream including those streams that remain after any of the data streams being handled are terminated.

Abstract: A terminal voltage of an actuator motor is measured while the actuator motor is in a high impedance state. An internal voltage of the actuator motor is measured, and a back-EMF voltage of the actuator motor is estimated in response to the terminal voltage of the actuator motor and the internal voltage of the actuator motor. A drive current supplied to the actuator motor is controlled in response to the estimated back-EMF.

Abstract: A rate of occurrence of off-track write events is determined. A seek function control parameter for a head is adaptively adjusted based on the determined rate of occurrence of the off-track write events. Related circuits and devices are also discussed.

Abstract: An integrated circuit device having a plurality of embedded processor/controllers and a parallel emulation trace port coupled thereto to provide trace data for debugging the integrated circuit device. A serializer macro is provided within the integrated circuit device to serialize the parallel data from the emulation trace port in order to provide trace data from the IC device in a serial data stream instead of a parallel data stream. A high speed differential serial driver is used to provide the bandwidth required to support the data speeds associated with embedded processors running at high clock rates. An external serial to parallel converter is also provided to convert the high speed serial trace data back to parallel trace data such that the trace data can be input into an emulator in the normal manner. In one embodiment, two serializers are provided within the integrated circuit device to meet data throughput requirements, such as when the IC device has more than one embedded processor/controller.

Abstract: A disc drive has actuator servo-controls and signal processing electronics positioned on, and electrically connected to, a flex printed circuit board positioned on a top surface of a base along with the actuator assembly and the spindle motor of the disc drive. A power combo chip is also positioned on the flex printed circuit board that is positioned on the top surface of the base. A top cover is attached to the base to form an enclosed space. The actuator assembly and the spindle motor are within the enclosed space and the actuator servo-controls and signal processing electronics are outside the enclosed space.

Abstract: Techniques are described for reducing inductance in ball grid array (BGA) packages for integrated circuits (ICs). The BGA package comprises a set of contacts disposed near an outer edge of the BGA package that receives signal lines and isolated power and ground lines. One area of excess parasitic inductance within the BGA package is in the wire bonds that couple the set of contacts to the IC. The techniques described herein shorten the wire bonds in order to reduce the amount of parasitic inductance. The techniques include extending traces from a subset of the contacts inward into the BGA package toward the IC mounted. The wire bonds then couple the traces to the IC, thereby electrically coupling the subset of contacts to the IC. The presence of the traces substantially reduces lengths of the wire bonds relative to wire bonds that directly couple the set of contacts to the IC.

Abstract: An apparatus, system and method in which a plurality of interleavers are utilized with the outputs of the interleavers being combined to generate a single combined output are provided. In a preferred embodiment, at least two of the plurality of interleavers are of a different type. For example, in one exemplary embodiment, a first interleaver is an S-random interleaver with a second interleaver being one of an algebraic, convolutional, helical, pseudo random, or other type of interleaver. Combinational logic receives the output from each of the plurality of interleavers and combines the outputs to generate one combined output having a permuted order. By combining the outputs from a plurality of interleavers, a greater amount of randomness in the input data may be obtained as opposed to that of the known single interleaver systems.