Abstract: Aspects of the invention include a method and apparatus to optimize the location of data on a disc drive storage system by optimizing the physical location of the file to allow the read ahead memory cache to operate more efficiently. In one aspect, the disc drive uses a reserved area on the media to hold files during the optimization process. In another aspect, the drive includes an optimization table that stores optimized file access data to further enhance the drive performance.

Abstract: A high-saturation magnetization composite soft magnetic film can be deposited by magnetron co-sputtering of two or more kinds of materials using targets which have a lower saturation magnetization than that of a single target, which otherwise will be used to produce the resulting composite soft magnetic film. The composite film has a substantially uniform composition and thickness.

Abstract: A disc sequencer incorporating parallel state machines to support both pipelined and non-pipelined read modes is disclosed. The parallel state machines include a first state machine and a second state machine for controlling whether data are read from a disc media and transferred to a buffer via a channel interface coupled to a read/write channel. Data may be read through the read/write channel in either pipelined or non-pipelined mode. If an operational state of either state machine is active, then the transfer of data between a read/write head accessing the media and the buffer is enabled. The operational state of the first state machine is dependent on the operational state of the second state machine such that if the second state machine is active, the operational state of the first machine will go active on the following clock period.

Abstract: A method and apparatus for detecting and recovering from head instability in a magneto-resistive (MR) transducer head of a disc-drive system. A head-instability-recovery circuit is described for use in disc drive to recover from a head-instability condition of an MR transducer head. This circuit includes a controller and a current source that supplies current to the MR head. The current source is controlled to supply a nominal amount of current to the MR head when operating in a normal mode, and to supply one or more current bursts having a current above the nominal supply current in order to recover from the head-instability condition. Also described is a method for recovering from a transducer-instability condition of an MR transducer of a disc drive, including detecting a situation that indicates a head-instability-recovery operation is desired, and performing the head-instability-recovery operation.

Abstract: Ultra smooth as-deposited composite nickel coatings for use in an information storage system are provided. The composite nickel coatings include an electrolessly deposited nickel layer formed on a sputter deposited nickel layer. The composite nickel coatings have an as-deposited surface roughness of less than about 10 Å. Embodiments include formation of the composite nickel coating on a disk, followed by deposition of an underlayer and magnetic layer thereon to form a magnetic recording medium.

Abstract: An anti-ferromagnetically coupled (AFC) magnetic recording medium having improved thermal stability and signal-to-medium noise ratio (SMNR), comprising: a non-magnetic substrate having at least one surface; and a layer stack overlying the at least one surface, the layer stack comprising at least one layer pair composed of first and second superposed, crystalline ferromagnetic layers spaced-apart by a crystalline non-magnetic spacer layer providing anti-ferromagnetic coupling (AFC) between the first and second ferromagnetic layers; wherein the lattice constants of the crystalline non-magnetic spacer layer are substantially matched to the lattice constants of each of the first and second crystalline ferromagnetic layers for obtaining a desired crystalline orientation and microstructure of said ferromagnetic layers without significantly degrading the interface exchange energy density J of the AFC.

Abstract: A method of handling multiple resonance frequencies in a disc drive includes monitoring a position error signal (PES) for an actuator arm, generating a plurality of feedforward compensation signals from the PES using a plurality of bandpass filters, and applying the compensation signals to a servo control signal. Each filter has a center frequency that is set to a problematic resonance frequency. The method may also include identifying the problematic frequencies by, for example, commanding a movement of the actuator arm, collecting data points for the PES that are associated with the movement, and performing a digital fourier transform of the data points to identify resonant frequencies. Other methods of identifying problematic frequencies include analyzing PES zero-crossing data, or using principal component analysis.

Abstract: An apparatus and method are disclosed for improving data recovery operations in a disc drive employing a redundant sync data block format. The disc drive includes a rotatable disc and a controllably positionable head which is used to store user data in a plurality of data blocks on tracks of the disc. Each data block includes a user data field to store user data, a first sync field and a redundant, second sync field, the sync fields storing first and second sync words, respectively, which establish symbol boundaries used by a read channel of the disc drive. User data are recovered from a selected data block by initiating a delay of selected duration during which a first portion of the selected data block passes proximate the head, allowing the second, remaining portion of the selected data block to be read at the completion of the delay.

Abstract: The present invention provides a method to determine and to locate the position of the imbalance torque of an actuator in a disc drive. There are several steps performing different functions in the method. The first step of the method performs the function of obtaining a difference in the voice coil motor (VCM) current of the disc drive in the X orientation and in the Y orientation with the VCM current of the disc drive when the disc drive is placed flat. The second step performs the function of obtaining the square of each difference in VCM current. The third step performs the function of obtaining the imbalance by adding the square of the VCM current and subsequent square root of the addition. The valve of the imbalance torque is obtained by multiplying the imbalance with the torque constant. The fourth step performs the function of obtaining a division value of the VCM current in the X orientation or in the Y orientation with the VCM current of the disc drive when the disc drive is placed flat.

Abstract: An apparatus and method for securing an information storage disc within a disc drive incorporates a rotatable spindle hub and a clamping ring. The clamping ring is positioned between an inner edge of the information storage disc and the rotatable spindle hub. The clamping ring is a strip of resilient sheet material and defines a series of serpentine shaped curves that alternatively contact the inner edge of the information storage disc and a sidewall of the rotatable spindle hub. The clamping ring applies a radial force to the information storage disc. In some cases the clamping ring may define a series of equally spaced apart, radially extending, tabs from the top and bottom edges of the clamping ring. The tabs from the top edge contact the top surface of the information storage disc at an inner diameter of the information storage disc. The tabs from the bottom edge contact the bottom surface of the information storage disc at an inner diameter of the information storage disc.

Abstract: A facing target sputtering apparatus, comprising: inner and outer spaced-apart, concentric, and coextensive tubular cathodes open at each end, with the inwardly facing surface of the outer cathode and the outwardly facing surface of the inner cathode; a first pair of ring-shaped magnet means extending around the outwardly facing surface of the outer cathode at the ends thereof, with a first polarity magnetic pole facing the outwardly facing surface; a second pair of ring-shaped magnet means extending around the inwardly facing surface of the inner cathode at the ends thereof, with a second, opposite polarity magnetic pole facing the inwardly facing surface; and a substrate positioned in spaced adjacency to an end of the inner and outer cathodes; wherein: magnetic flux lines from the first and second pairs of magnet means uni-directionally pass through portions of an annularly-shaped space between the ends of the inner and outer cathodes, and during sputtering operation, plasma is substantially confined t

Abstract: A magnetic recording head having an air bearing surface for confronting a surface of a rotating disc and comprising a pole tip and a generally rounded and substantially planar body attached to the pole tip is disclosed. The width of the pole tip defines a track width of data written to the rotating disc. The generally rounded shape of the top pole body is such that top pole magnetization gradually changes its direction and follows the edges of the body. Further, the pole tip has low remanence, gradual spin structure and no domain walls formed near the pole tip.

Abstract: Abnormal nodule formation during electroless plating, e.g., of amorphous NiP “seed” layers utilized in the manufacture of magnetic recording media, is eliminated or substantially reduced by performing the electroless plating process in an apparatus employing polymeric or polymer-based materials which are substantially resistant to degradation upon prolonged contact with the electroless plating bath at an elevated temperature, i.e., release of soluble, low molecular weight, carbon-containing species which are incorporated in the electroless plating deposit and act as nucleation centers for abnormal growth leading to nodule formation. Suitable degradation-resistant polymeric materials for use as fittings, piping, racks, tanks, etc. of the electroless plating apparatus include fluorine-containing hydrocarbons and fluorocarbons.

Abstract: A method of in situ stabilizing a composite lubricant in order to reduce or subtantially eliminate phase separation of the components of the composite lubricant, comprising sequential steps of: (a) providing a substrate including a surface; (b) applying a thin layer or film of the composite lubricant to the substrate surface, the composite lubricant comprising at least two lubricant components which are normally mutually immiscible; and (c) treating the thin layer or film of composite lubricant solely with UV radiation for an interval sufficient to reduce or substantially eliminate phase separation of the at least two normally mutually immiscible lubricant components. Embodiments of the invention include magnetic and magneto-optical (MO) media including stabilized composite lubricant layers formed in situ according to the inventive process.

Abstract: A write head comprises a yoke including a top pole and a bottom pole, the top pole including a layer of insulating material, a layer of a first magnetic material positioned on a surface of the layer of insulating material, the first magnetic material having a first end positioned adjacent to an air bearing surface of the write pole, and a layer of a second magnetic material positioned on the surface of the layer of insulating material, the second magnetic material having a lower magnetic moment than the first magnetic material and being positioned to conduct magnetic flux between the return pole and the layer of first magnetic material. The method of constructing the write head and a disc drive including the write head are also included.

Abstract: An extraction device for removing a connector plug from a disc drive socket including first and second lever plates having a length extending between opposed first and second ends and a width extending between opposed sides and the first and second lever plates being pivotally connected between the first and second ends to form lever handles and lever arms. The lever arms include opposed fingers spaced along the width of the lever plates between opposed sides. The lever arms include a slot between fingers, a width of which is sized to enclose a length of the connector plug. A spring biases the lever arms of the first and second lever plates towards one another and the lever plates being movable against a spring bias to open the lever arms to remove a connector plug. A method for removing a connector from a disc drive socket including aligning an extraction device with the connector plug and operating the device to remove the connector plug.

Abstract: A slider body configuration, or slider, for carrying a data transducer in cooperative relationship with a rotating data storage disc. The slider includes a plurality of landing pads which serve to minimize the contact area between the slider and the discs when the heads are parked in contact with the discs, and the landing pads project from surfaces which are farther removed from the disc surface than the air bearing surfaces, thus minimizing the size and strength of any liquid miniscus formed between the slider and the disc when the slider and disc are in contact. By recessing the bases of the landing pads from the air bearing surfaces, the effect of the landing pads on the separation between the data transducer and the discs is minimized.

Abstract: An actuator having a relatively low mass for supporting flexible head suspension assemblies to read data from or write data to discs. The actuator includes an actuator body adapted to rotationally coupled to a base chassis of the disc drive and a yoke assembly including yoke arms extending from the actuator body. The actuator includes at least one rigid actuator arm rigidly supporting the flexible head suspension assemblies. The rigid actuator arm includes multiple arm plates supported in spaced relation to provide a thickness of the actuator arm for lateral stiffness.

Abstract: An actuator arm for a rotary actuator assembly of a disc drive comprises a substantially planar sheet of pliable material defining a longitudinal actuator arm having longitudinal edges, a distal end supporting the transducer, a proximal end supporting an actuator coil. Strut means integral with the sheet extends substantially normal to the plane of the sheet along at least a portion of at least one longitudinal edge and the proximal end of the arm to provide rigidity to at least a portion of the arm. In one embodiment, an integral strut portion defines a support for the actuator coil. In another embodiment, integral strut portions extend along opposite longitudinal edges to a location proximal the distal end to define a rigid portion between the strut portions and a flexible suspension region distal to the rigid portion.

Abstract: Apparatus in a disc drive for transferring data between a rotatable disc and a host computer. An analog pre-processor integrated circuit device incorporates circuitry to carry out analog processing functions including write current driving, readback signal amplification, prewrite compensation, frequency-domain filtering, and equalization. A digital post-processor integrated circuit device incorporates circuitry to carry out digital signal processing functions including Viterbi detection, decoding, error detection and correction, buffering, host interface functions, and data encoding and serialization. The analog pre-processor is preferably mounted within the interior environment of the disc drive to an actuator assembly that supports a head adjacent the disc. The digital post-processor is preferably supported on a printed circuit board mounted to an exterior surface of the disc drive.