Abstract: An apparatus and method for performing real-time, closed loop write verification in a disc drive having a rotatable magnetic disc and a head having read and write elements. During a write operation, the disc drive generates a write current signal indicative of input data to be written to the disc. The write current signal is applied to the write element, which generates a time-varying magnetic field to simultaneously induce a readback signal in the read element through magnetic coupling of the read element to the write element, and to magnetize the disc to write the input data to the disc. The readback signal induced in the read element is used to reconstruct a set of output data which is used to verify accuracy of the input data.

Abstract: A method and apparatus are disclosed for optimizing operational performance of a disc drive. The disc drive is provided with an integrated temperature measurement circuit which provides a temperature measurement signal indicative of operational temperature of the disc drive. The integrated temperature measurement circuit is formed as part of an application specific integrated circuit (ASIC) housing additional circuitry used by the disc drive during operation. A parametric configuration circuit, operably coupled to the integrated temperature measurement circuit, identifies selected parameters for use by the disc drive to optimize disc drive performance, the parameters arranged as a plurality of parameter sets corresponding to a plurality of predefined operational temperature ranges.

Abstract: An apparatus and method are disclosed for optimizing the operational performance of a disc drive having a head adjacent a rotatable disc, a servo circuit which controls the position of the head and a read channel for decoding read signals from the head to reconstruct data previously stored on the disc. The read channel includes a channel quality monitor which generates a channel quality measurement indicative of read channel quality, the channel quality measurement determined from error values associated with the data reconstructed by the read channel from the read signal. An optimum value for a selected parameter affecting disc drive performance is selected by determining an associated quality measurement value for each of a plurality of parameter values, and selecting the optimum value for the parameter in relation to the associated quality measurement values. Preferably, each associated quality measurement value is determined in less than one revolution of the disc.

Abstract: Method and apparatus for predicting future failure of a disc drive head from degradation in a head readback response characteristic, such as electrical resistance, readback signal amplitude, asymmetry or nonlinearity. During manufacturing, the disc drive determines and store a baseline level for a selected readback response characteristic of the head indicative of head performance as data are read back from a disc. During subsequent data processing use, the disc drive subsequently periodically determines a subsequent level for the readback response characteristic of the head. The possibility of a future failure of the drive is next predicted in relation to a difference between the baseline level and the subsequent level for the readback response characteristic of the head. An indication of the possibility of the future failure is provided to allow a host device to reallocate data stored on the disc before the failure of the head.

Abstract: Apparatus and method for providing microactuator positional control in a disc drive having a rotatable disc on which a plurality of tracks are defined and an actuator assembly which supports a head adjacent the tracks. An actuator motor is used to provide primary positioning of the head through the controlled application of current to a coil of the actuator motor. A microactuator, opposite the actuator motor coil, has a pair of microactuator coils wound about respective magneto-striction beams so that, in response to drive currents passed through the microactuator coils, a selected one of the magneto-striction beams increases in length and the remaining magneto-striction beam decreases in length. The magneto-striction beams act upon a pivot assembly coupled to the head to displace the head to a final desired position adjacent the disc.

Abstract: An apparatus and associated method for providing a strain relief in support of a medial portion of a terminal end of an electrical wire that is used in the construction of an actuator coil for a disc drive assembly. The strain relief apparatus has a base that is attached to the actuator assembly, an upstanding post around which the electrical wire is wrapped to provide a frictional engagement between the wire and the post, and a flange depending from a distal portion of the post to urge the wire onto the post and retain the wire about the post during routing of a distal portion of the terminal end that is associated with manufacturing steps of electrically connecting the actuator coil to the disc drive control system. In a preferred embodiment the strain relief has a pair of posts so that each terminal end is wrapped individually about one of the posts. In an alternative preferred embodiment the strain relief has a single post about which both terminal ends are wrapped.

Abstract: Disclosed is a high pressure injection molding system employing one or more plastic injection molding workstations including split molds, a single plastic extruder coupled to a heated manifold capable of delivering fluid plastic to multiple workstations, and wherein final lockup of the split mold halves results in application of compressive forces effective to maintain the split mold halves in nominal position during high pressure injection molding conditions. Operational movement is performed by use of a single remote pumping station utilizing pressure compensated pumps, accumulators and manifolds. The independent mold workstations allow independent operation while providing efficency of operation for the hydraulic system and extruder system.

Abstract: A disc drive is provided with rotatable discs and an actuator assembly having heads adjacent the discs. A flex circuit assembly providing electrical connection between the heads and the disc drive circuitry comprises flex strips routed on the actuator assembly from the heads and a flex affixed on the actuator assembly. A flex support snubber mounted on the side of the actuator assembly has a body portion with a plurality of arms extending therefrom. Each pair of the arms form a groove so that the arms are disposed above and below discs while the discs extend into the grooves. A plurality of slits are interposed between the grooves to support the flex strips therein. An opposite end of the flex support snubber curves to form a U-shaped snubber bend for turning and guiding a dynamic portion of the flex.

Abstract: Apparatus for protecting a disc drive from damage due to non-operational mechanical shocks, the disc drive comprising a rotatable disc having an inner radius and an outer radius and a controllably rotatable actuator adjacent the disc. A snubber is provided adjacent the disc, the snubber having a body portion rigidly affixed with respect to the disc and snubber arms connected to the body portion. The snubber arms extend from the body portion towards the disc and above and below the elevation of the disc, with each snubber arm having a distal end located at a position adjacent the disc between the inner and the outer radii of the disc and towards the. outer radius of the disc. The height of each snubber arm limits deflection of the disc at the outer radius of the disc as a result of mechanical shock forced supplied to the disc drive assembly.

Abstract: An apparatus for minimizing axial and radial displacement of discs in a disc drive having a spindle motor hub rotatable about a central axis. The hub includes a substantially cylindrically shaped mounting surface at a selected radius about the central axis. The disc spacer comprises a substantially circular body having an inner surface at a first radius greater than the radius of the mounting surface, and a plurality of inwardly-facing spindle contact features projecting from the body. Each of the spindle contact features has a spindle contact surface at a second radius less than the radius of the mounting surface, with the spindle contact surfaces being operably configured to bear against the mounting surface when the disc spacer is coupled to the spindle motor hub. Preferably, intermediate portions of the body between adjacent spindle contact features deform to urge the spindle contact features toward the mounting surface.

Abstract: A disc mounting system for mounting the discs of a disc drive in a fixed radial relationship to the hub of a spindle motor. The disc mounting system includes a compression spring member located between adjacent discs in the disc stack. The compression spring member has a circular cross-section, and forms a wave shape such as a sinsoidal wave shape encircling the hub of the spindle motor. When the discs are positioned in an intended relationship relative to the hub, high and low peaks on the compression spring member engage chamfers adjacent the bore of the discs, and act to center the discs relative to the spindle motor hub to prevent shifting of the discs relative to the spindle motor hub due to applied mechanical shocks and differential thermal expansion of disc stack elements.

Abstract: An apparatus and method for detecting rotational vibration applied to a disc drive having an actuator supporting a head adjacent a rotatable disc. A spindle motor has a set of driver coils which rotate the disc through electrical commutation, and a set of velocity sense coils which sense the rotational velocity of the motor in relation to voltages established across the sense coils. Rotational vibration is detected in relation to changes in the rotational velocity of the disc. A data transfer operation between the disc and a host device is interrupted when the magnitude of the rotational vibration exceeds an acceptable level. A servo circuit compensates for the application of rotational vibration to the disc drive by adjusting current applied to the actuator in relation to the changes in the rotational velocity of the disc.

Abstract: An apparatus and method for reducing the number of interconnections in a disc drive through microactuator control and write current signal superpositioning. The disc drive includes a rotatable disc on which a plurality of tracks are defined and an actuator assembly supporting a read/write head having a write element. An actuator motor provides coarse (primary) positional control of the head and a microactuator disposed adjacent the head provides fine (secondary) positional control. A filter circuit is operably coupled between the write element and the microactuator and receives, by way of a common set of conductors, a combined signal comprising high frequency write current signals superimposed upon lower frequency microactuator control signals. The filter circuit filters the combined signal so as to pass the low frequency microactuator control signals to the microactuator and pass the high frequency write current signals to the write element.

Abstract: An apparatus for latching an actuator of a disc drive at a park position in the presence of applied mechanical shocks. An inertial latching system includes a contact feature coupled to and moveable with the actuator and a stationary surface along and in contact with which the contact feature moves to and from a park position. An inertial latching element is moveable in response to applied mechanical shock from an unlatched position to a latched position, with the inertial latching element normally biased to the unlatched position. The inertial latching element includes a moveable contact surface which, when the inertial latching element is in the latched position, is disposed at an angle relative to the stationary surface, thus forming a narrowing path which prevents the contact feature from moving away from the park position in a critical direction.

Abstract: A separator apparatus for separating flush effluent from an oil and gas well following a fracture stimulation process, the separator having a vessel that maintains the effluent at a selected liquid level, an inlet is connected to the vessel at a location below the liquid level so that the effluent enters the vessel at a location therebelow. A plurality of baffles within the vessel slow the effluent so that solids settle out to a drain which is periodically opened to transfer the solids to an appropriate disposal. An upper outlet permits the venting of gases that percolate from the liquid constituent, a backpressure valve disposed in communication therewith to maintain a positive pressure within the vessel. A liquid drain withdraws the liquid constituent from the vessel at a rate determined by a level assembly.

Abstract: A method of reducing debris within an E-block of an actuator assembly in a disc drive is provided. A manufactured E-block is first provided for tooling. The E-block has a central bore with an inner diameter and a bore surface. A hardening member is then provided with an outer diameter that is larger than the inner diameter of the bore surface. The hardening member is pressed through the central bore so that the hardening member compresses and deforms the bore surface. As the hardening member deforms the bore surface, the bore surface becomes substantially smooth and hard.

Abstract: A snubber for a plurality of discs in a disc drive has a pivoting body with extending portions having angled surfaces that abuttingly engage the discs in a closed position of the pivoting body, the angled surfaces alternatively clearingly disengaging the discs in an open position of the pivoting body. A spring member biases the pivoting body to the closed position, and a solenoid when electrically energized imparts an opposing rotational force to urge the pivoting body to the open position. In the closed position the angled surfaces provide a two-point contact in support of each disc, the surfaces supporting the disc on each side of the disc to provide a fixed support of the disc at the edge thereof.

Abstract: An apparatus and method for converting a pulse-width modulation (PWM) signal to an analog voltage signal. A current source is provided to supply electrical charge at a controllable rate to a ramp capacitor which, during successively occurring cycles of the PWM signal, alternatively receives electrical charge from the current source and discharges previously received electrical charge. A first sampling capacitor receives electrical charge from the ramp capacitor to output a feedback voltage to a feedback circuit to adjust the rate of electrical charge supplied by the current source, with the charge transferred to the first sampling capacitor determined in relation to the charge stored on the ramp capacitor over an entire PWM cycle. A second sampling capacitor receives electrical charge from the ramp capacitor to output the analog voltage, with the charge transferred to the second sampling capacitor determined in relation to the duty cycle of the PWM signal.