Abstract: The depth of focus of a lens focusing system for laser texturing a magnetic recording medium is increased by reversing the lens system. Lens reversal provides symmetrical energy distributions in both negative and positive defocus ranges. An embodiment includes a lens focusing system comprising a planoconvex lens, wherein the laser light beam is passed into the planar surface and out through the convex surface to impinge upon a substrate. Another embodiment includes a multiple lens focusing system comprising an aplanatic meniscus lens and a companion doublet, wherein the laser light beam is sequentially passed into a concave surface of the aplanatic meniscus lens and through the companion doublet lens.

Abstract: The invention provides for encoding position information for zone number, subtrack number and sector number, with less number of bits. The invention also provides for redundant position information to accurately determine the position of the transducer head.

Abstract: A method and apparatus for compensating for repeatable run-out errors in a disc drive is disclosed. The compensation is created by determining transfer function values for a servo loop in the drive as well as a sequence of repeatable run-out values for a portion of a disc. The repeatable run-out values are divided by respective transfer function values to produce compensation values that are inverse transformed to produce time-domain compensation values. These time-domain compensation values are injected into the servo loop to compensate for repeatable run-out errors.

Abstract: A disc drive system having at least one hard disc of approximately 48 mm diameter having concentric tracks is supported by a hub positioned in a centrally located aperture of approximately 12 mm diameter. The disc is rotated at a constant speed by a brushless DC motor attached to the hub. A transducer means for communicating information with the hard disc is moved relative to the disc surface by a positioning means. The positioning means includes a voice coil motor for selectably and accurately positioning the transducer means over the tracks on the hard disc. The disc drive system is enclosed in a housing means constructed from ferrous material having a base portion and a shell portion. The positioning means has a shaft about which the positioning means rotates. To provide a small, rugged assembly, the shaft is mounted at each end between the shell portion and base portion of the housing. Additionally, the shaft of the brushless DC motor is mounted in the same manner.

Abstract: A method to create an improved hydrodynamic bearing which is relatively insensitive to changes in load and rotational speed is provided, wherein the hydrodynamic bearing is useful in a spindle motor for a disc drive or the like which is stiffer than known standard spindle motors so that the stability of the system and specifically of the actuator arm and transducer relative to the rotating disc is optimized. The hydrodynamic bearing can also be used as a bearing cartridge or as the cartridge that may be incorporated into a spindle motor or the like, where the bearing includes a shaft and at least two independent bearings each comprising a thrust plate supported on the shaft and a counter plate incorporated in a sleeve which is capable of relative rotation around the shaft.

Abstract: A disc drive system includes a rotatable disc, an actuator arm, and a suspension load beam connected to the actuator arm. A head positioning mechanism includes a motor attached to the suspension load beam. A gimbal has a first end attached to the motor, and a slider carrying a transducing head is attached to a second end of the gimbal. Control Circuitry generates electrical control signals to operate the motor to selectively position the transducing head proximate a predetermined radial location on the rotatable disc.

Abstract: A disc drive microactuation system finely positions a transducing head carried by a slider adjacent a selected radial track of a rotatable disc. An electromagnetic microactuator having a stator and a rotor operatively connected to the slider is provided on a substrate. The rotor is movable with respect to the stator to effect fine movement of the slider. A magnetic shield layer is provided on the substrate for shielding the electromagnetic microactuator.

Abstract: A bimetallic part is formed from metals or comprises metals with different thermal expansion coefficients. A first element defines the part and defines one surface of the bearing gap and has a first coefficient of expansion and a second element is wholly or partially inserted into and constrained within the first element and having a different coefficient of thermal expansion so that as the temperature changes, the stress created by the differential expansion of the two elements will cause the overall part to deform elastically as a function of temperature. This deformation will cause the gap, the elements being properly selected, to narrow as temperature rises (and viscosity falls) and to widen as temperature falls (and viscosity rises).

Abstract: In a disc drive, a position error signal (PES) can be generated that is insensitive to the read element's magnetic and physical geometry and micro-track profile, and that has a spatial domain periodic frequency that corresponds to a frequency region of the micro-track profile that facilitates a high magnitude response. The servo pattern for generating this PES includes a first servo burst pair (A,B) and a second servo burst pair (C,D) of servo burst members, each pair written as normal and quadrature channels.

Abstract: A disk drive system includes a base, a disk stack rotatably attached to the base, and an actuator assembly movably attached to the base. A ramp assembly includes a set of ramps for loading and unloading the transducing elements to and from the disks in the disk stack. The ramp assembly is attached to the base. The ramp assembly has a series of fixed ramps which are either formed as one integral unit or formed of separate portions. The actuator assembly includes a set of arms. Attached to each arm is a suspension. Attached near the free end of each of the suspensions is a transducer. Also attached to the suspension is a load tang. The load tang rides over the surface of the ramp when the transducers are loaded to or unloaded from a disk surface. The load tang includes a plastically deformable portion which may be irreversibly deformed during assembly of the drive and more particularly, deformed when all of the heads are unloaded from the disk to the ramp assembly for the first time.

Abstract: A soldering member includes an elongated heating element for soldering a series of connectors. The elongated heating element of the soldering member is flexibly supported via a rigid base for adjusting the orientation of the heating element to align with a series of connectors rigidly supported for soldering. A method of using the soldering member is also described.

Abstract: An apparatus for retaining a spindle motor during an outgassing test includes a body formed from an inert material and having an interior chamber for receiving a base of the spindle motor. Fasteners secure the spindle motor to the body to seal the interior chamber and prevent the spindle motor base from outgassing any compounds during the outgassing test. An electrical pad attached within the interior chamber contacts an electrical connector on the base of the spindle motor. An electrical wire attaches the electrical pad to a combination power source and motor controller for operating the spindle motor. The body and the attached spindle motor are placed within a test container and the electrical wire is passed through both the body and the test container for attachment to the power source and motor controller. The electrical wire includes an inert coating to prevent the electrical wire from impacting the results of the outgassing test.

Abstract: An method and apparatus for the assembly of motors utilizing curable adhesives. The method includes stations for: treating motor components with adhesive, assembling the motor components piece by piece, holding assembled motor components under compressive tension, overgramming components as needed, and an operational and life testing station. Integral to using the method are multi-position preload/cure fixtures. These fixtures include frame and base pieces. The frame holds assembled and adhesive treated motor components under compressive tension with spring loaded guide shafts during the curing process. The frame rests on the base. The base features nests which align the motor components for engagement with the guide shafts. The base also features a retractor bar to facilitate the insertion and removal of motor components. The base also features an overgramming means which supplies a brief overgramming pressure on the motor components to fully seat motor components.

Abstract: A method and apparatus for preserving loop fairness. Some embodiments include a dynamic half-duplex feature. One aspect includes a communications channel system and method for preserving loop fairness that includes a first channel node having one or more ports, each port supporting and attached to a fiber-channel arbitrated-loop serial communications channel. One of the ports will arbitrate for control of that port's attached channel, wherein control of the channel loop, once arbitration is won, a fairness-preserving apparatus causes control of the communications channel to be released based at least in part on whether a predetermined amount of use has occurred between the first port and the communications channel. In some embodiments, the predetermined amount of use includes a transfer of a first predetermined amount of data. In some embodiments, release of control of the channel is inhibited if less than a second predetermined amount of data remains to be transferred.

Abstract: A tape drive arrangement and method for driving a cartridge roller in a tape cartridge that advances tape in a tape cartridge. The tape drive has a drive motor and having a rotatable outer housing, and a cartridge roller contact surface around the outer housing of the drive motor. The drive motor is positioned within the tape drive so that the cartridge roller of a tape cartridge that has been inserted into the tape drive directly contacts the cartridge roller contact surface. The cartridge roller is directly driven by the drive motor upon rotation of the outer housing of the drive motor.

Abstract: In an arcuate scanner, a read head senses passage over a reference stripe recorded on a moving recording tape. Detection and logic circuitry respond to the read head signal to detect the reference stripe and determine an angular position of the read head with respect to an index associated with the arcuate scanner head assembly. Timing operations of the arcuate scanner and alignment of the arcuate scanner head assembly with regard to an information recording region on the tape are controlled in reference to the detection of the reference stripe.

Abstract: A contact start/stop architecture for disk drives overcomes problems introduced by low flying MR heads and textured landing zones. Takeoff velocity for heads vary from the textured landing zone to the data zone. Contact start/stop operations are controlled relative to a critical takeoff velocity between takeoff velocity in the data zone and takeoff velocity in the landing zone, which critical velocity is less than that required to achieve negligible contact between the head and disk surface while the head is within the landing zone, but greater than takeoff velocity within the data zone. An initial seek from the landing zone begins at critical takeoff velocity. The head drags along the disk surface in the landing zone, since it has not reached takeoff velocity within the landing zone, but will immediately be at fly height as soon as the head reaches the data zone, minimizing the total drag distance of the head in the landing zone.

Abstract: A detector in an informational handling system and a method of detection is provided. An input circuit is used to receive an input signal. A second circuit determines boundaries based on the input signal. However, at least two of the boundaries specified by the second circuit are monotonically related to each other. The detector can be implemented in a magnetic disc drive. A read circuit is operably coupled to the disc to read data stored on the disc. The read circuit includes an input circuit, a boundary calculation circuit, and a logic circuit operably coupled to one another. The input circuit serves to receive the data and provide an input to the boundary calculation circuit. The boundary calculation circuit calculates several boundaries based on the input. At least two of the boundaries are monotonically related. The boundary circuit provides an output to the logic circuit which provides a binary decision.

Abstract: A method of measuring the read-to-write offset of a track in a disc drive system having separate read and write elements measures the amplitude of a test signal across the width if a track. A test pattern is written to the track at a predetermined actuator offset, which will typically be zero. Next, the read element is incrementally moved across the width of the track to measure a maximum amplitude in the read signal from the read element. After the maximum amplitude has been determined, the read element is incrementally moved across the width of the track to find first and second actuator offset positions where the read signal has an amplitude approximately equal to a predetermined percentage of the maximum amplitude. A midpoint is calculated between the first and second actuator offset positions, and the read-to-write offset is equal to the difference between the midpoint and the predetermined actuator offset.

Abstract: A method for adaptively controlling the write inhibit signal in a disk drive apparatus. The disk drive apparatus include magnetic disks manipulated such that the total space that is to be allocated for storing data has been measured and recorded such that the tracks for storing data have been servo written at a wider spacing than a nominal track spacing. The drive's operational circuitry includes access to modified write inhibit threshold data that is based on the drive's nominal design track misregistration allowance, plus any track width increase gained by adaptively controlling the track pitch. The modified write inhibit threshold essentially facilitates an acceptable delay in activating a write inhibit signal. The data tracks on each of the magnetic disks have been servo written utilizing the wider track spacing while maintaining the track misregistration allowance that corresponds to the nominal track spacing.