Abstract: An apparatus and method for optimizing detection thresholds used to identify addresses of tracks in a disc drive having a head and a disc upon which a plurality of tracks are defined, the tracks including track address fields in which track address information is stored. A comparator is provided which generates track address sequence signals in response to a corresponding plurality of readback signals obtained as the head is maintained in a fixed relationship to a selected track. A demodulator identifies erroneous track address sequence signals therefrom and increments a count in an accumulator for each detected, erroneous signal. A detection threshold circuit sequentially provides the comparator with a set of detection thresholds from a population of detection thresholds, each of which are used in turn by the comparator.

Abstract: An apparatus and associated method are disclosed for optimizing the data transfer performance of a disc drive in which user data is stored in data blocks arranged on tracks of at least one rotating disc. When a selected, uninterrupted amount of time passes since the most recently performed disc drive operation, the disc drive enters an idle mode and selectively evaluates the data blocks for uncorrected read errors. During the idle mode, at such time that a selected data block is found having an uncorrected error, a sequence of corrective operations are performed in an attempt to resolve the error and the selected data block is reallocated when at least selected one of the corrective actions are unsuccessful.

Abstract: An apparatus and method for impact response testing of materials such as magnetic discs of a disc drive. The apparatus of the present invention supports a target disc in cooperative relationship with a sub-millimeter impact test ball such that the test ball can be dropped on selected portions of the target disc from selected heights above the target disc. The apparatus permits the method of observing the characteristics of a detent made in the target disc, by use of a high resolution surface profiler, and interpolating the observed characteristics to analytical standards which, for a given test ball size and drop height, indicate the dynamic hardness of the target disc at that test location. A vacuum is used to support the test ball above the disc, and a vacuum release valve is provided to negate the vacuum and release the test ball.

Abstract: An apparatus and method for merging the disc pack, E-block and magnet of a disc drive, the disc pack conveyed to a first selected position in a merge assembly station and moved to a merge slide assembly where calibration measurements of disc pack height and squareness are made at a reference position. The merge slide assembly moves the disc pack from the reference position to a shuttled position, the E-block is moved to an E-block nest assembly where the load arms of the E-block are spread in response to the calibration measurements, and the discs of the disc pack are interweaved between opposing read/write heads of the E-block. A magnet slide assembly positions the magnet to straddle the E-block. The disc pack, E-block and magnet are moved together, maintaining the merged interrelationship, to the basedeck and fastened to the basedeck.

Abstract: Apparatus and method for providing a linearized position error signal in a disc drive. A first servo position error signal is generated by the disc drive as a selected combination of servo burst signals received as a disc drive head passes over servo burst fields of a selected track, the first servo position error signal having a magnitude indicative of the position of the head relative to the selected track. A second servo position error signal is also generated by the disc drive as a selected combination of the servo burst signals, the magnitude of the second servo position error signal being different from the magnitude of the first servo position error signal for at least a portion of the width of the selected track.

Abstract: Apparatus and method for improving vibration and mechanical shock response of a system through the use of discrete-time sliding mode control with variable parameters are disclosed. A servo circuit for positioning a control object (such as a head of a disc drive) includes a reference generator generating position and velocity references, an observer generating position and velocity estimates, and circuitry for determining position and velocity errors therefrom. Variable position and velocity gains are applied to the position and velocity errors, respectively, the position and velocity gains varying with respect to at least the magnitudes of the position errors.

Abstract: An apparatus and method for recovering from read errors detected by a read channel (70) in a sequence of data read from a disc (18) of a disc drive (10) by using read channel quality indicators to determine the appropriateness of using error correction in combination with other corrective actions utilized in the recovery process. Upon the detection of an uncorrected error in the retrieved data, the disc drive (10) enters a read error recovery routine wherein one or more corrective actions (102, 122) are applied in an effort to resolve the error. One of the channel quality indicators comprises a channel quality measurement (108, 128) determined as the sum of the square of the sampled data bit error values recovered during the read operation.

Abstract: The present invention includes a process and composition for reducing acidity in beans. The composition of the present invention may be sprayed onto the beans, or alternatively, the beans may be dipped in the composition to effectively reduce the acidity therein. The composition is characterized by a solution containing from about 1 to 2 percent by weight of Phosphorous Pentoxide, from about 0.25 to about 2 percent by weight of a non-anionic surfactant, about five to about 40 percent by weight of a solution of about 45 percent potassium hydroxide, and from about 55 to about 80 percent by weight of deionized water.

Abstract: The present invention provides a process and apparatus for autothermal aerobic thermophilic treatment of high strength and high temperature wastes. In accordance with the process of the present invention, waste material is injected into a reactor vessel having thermophilic microorganisms to form a volume of bulk liquid in the reactor vessel. An oxygen-containing gas is also injected into the reactor vessel in such manner as to transfer oxygen into the reactor bulk liquid for utilization by the thermophilic microorganisms in aerobic treatment of the waste material.

Abstract: An apparatus and method for optimizing the gain of a disc drive servo circuit are disclosed, the servo circuit controllably positioning a head adjacent tracks of a disc of the disc drive. A model reference seek is performed using sinusoidally derived reference current, velocity and position signals to move the head from an initial track to a destination track, during which position error is accumulated over a plurality of time periods associated with the seek. The position error is normalized in relation to the length of the seek. A gain adjustment value is next determined in relation to a difference between the normalized position error and a nominal position error associated with a nominal value of gain for the servo circuit, a scale factor being applied to the difference to control the convergence rate of the gain. The gain is thereafter adjusted using the gain adjustment value.

Abstract: A guard for cables that extend alongside a coupling in a tubing string includes a base and a clamp member that are hingedly interconnected to fit about the coupling and portions of the cables beside the coupling. Hinge elements, formed on sections of the clamp member at opposite ends of the guard and received by hinge grooves formed in end members of the base, are connected together by a hinge rod and a projection on a rib connecting the base end members extends partially about central portions of the hinge rod to secure the hinge elements within the hinge grooves. Bolt grooves are formed in free ends of the base end members opposite hinge ends of the base members in which the hinge grooves are formed to receive the ends of a base portion of a u-bolt that is secured to the base by a projection formed on a rib connecting the base end members and extending partially about the base portion of the u-bolt.

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: Quenching and scrubbing are accomplished simultaneously in a single downflow apparatus which functions both as an adiabatic quencher and a packed bed scrubber. A special feature of the quencher/scrubber is a hot-cool interface which is effective in controlling corrosion.

Abstract: Method and apparatus for improving the operational response of a disc drive. Compensation routines are performed to adjust disc drive parameters in accordance with existing environmental conditions during an idle mode of operation of the drive. At such time that a selected, uninterrupted amount of time passes since the most recently performed disc drive operation, the disc drive enters the idle mode and performs a predetermined sequence of the compensation routines, after which the disc drive performs dithering in which heads of the disc drive are positioned about various locations with respect to the corresponding discs of the disc drive. A compensation table is provided setting forth the predetermined sequence of the compensation routines and the table is reordered so that the compensation routines are subsequently performed in a different sequence.

Abstract: A new and distinct variety of crape myrtle, Lagerstroemia indica, which is characterized by a low, dense, mounded shrub form that may reach three to four feet in height and width with age; stiff, ruby red young branches; ruby red new leathery foliage which quickly changes to green with age; crimson to ruby red flower buds; currant red to light red flowers; and no seed production. The new variety is also characterized by a long bloom period.

Abstract: A new and distinct variety of crape myrtle, Lagerstroemia indica, which is characterized by a vigorous, upright growth habit; leathery leaves which emerge dark crimson and quickly change to dark green; new branches that are crimson and remain so for four or more weeks; modest seed production; inflorescences which are 12 to 20 inches tall and 8 to 12 inches wide; flower buds which are crimson before opening; and cherry red flowers that are heavily ruffled, with occasional slight variegation. The new variety is also characterized by a long bloom period.