Abstract: Apparatus and method for improved positional control in a disc drive servo loop, wherein the actual velocity of rotary actuator is sensed from the motion-induced back-emf generated by movement of a coil of the actuator through the magnetic field of a voice coil motor. A current sense resistor is used in conjunction with the coil to provide closed loop control of the current applied to the coil. Signals indicative of the voltages across the serial combination of the coil and current sense resistor are provided to a velocity sense circuit, which determines the velocity of the coil by generating and subtracting out values for the dc voltage drops across the coil and the current sense resistor and the ac voltage drop across the coil. A compensation routine is provided to compensate for variations in temperature of the coil during operation.

Abstract: An actuator assembly includes a first actuator arm and a second actuator arm, each having a first end and a second end, a support member, and a bearing assembly coupled to the arms and the support member, and supporting the arms and support member for rotation about an axis. The bearing assembly has a first portion abutting the first actuator arm and second portion abutting the second actuator arm, with the first and second arms being secured against movement away from each other by the bearing cartridge. Also provided is a retainer for preventing rotation of the first actuator arm about said axis relative to the second arm. The retainer may comprise first and second fasteners provided at opposite sides of the axis. In an alternative embodiment, the retainer comprises a leaf spring having a notch provided therein on the first and second actuator arms, and a fastener member provided on the support member.

Abstract: A microprocessor-controlled-circuit applies pulses to a standing motor whose rotor position is to be determined. The time required for the injected current to reach a predetermined threshold in a comparator is measured. The pulses are long enough to effectuate an accurate measurement, but not so long that the rotor moves. The pulse is applied twice to each phase, once with a positive polarity and once with a negative polarity, for a total of six measurements. The positive and negative rise times are subtracted from each other to determine whether the positive or negative current rise time was greater. Based upon the differences in the readings for all of the phases, the position of the rotor is known. There are differences in which the difference is zero or negligible. There are at least two methods to determine rotor position when there are ambiguities in the sign of the difference.

Abstract: A disc drive includes a disc drive motor and a chassis for providing a substantially contaminant-free cavity. The disc drive motor includes a fixed member coupled to the chassis and a rotor rotatable about the fixed member for rotating a magnetic storage disc in the contaminant-free cavity. A bearing interconnects the fixed member and the rotor. A viscous pump seal is located between the contaminant-free cavity and the bearing. The viscous pump seal includes a first pump surface carried by one of the fixed member and the rotor and a second, grooved pump surface carried by the other of the fixed member and the rotor. The first and second pump surfaces are separated by a gap. The viscous pump seal inhibits transfer of contaminants from the bearing to the contaminant-free cavity.

Abstract: The invention is a miniature disc drive system. In the preferred embodiment of the invention, a positioner for positioning a transducer includes an actuator arm having the transducer mounted at one end and a voice coil motor (VCM) mounted at the other end. A pivot is centrally located along the actuator arm, whereby the VCM, when activated, can rotate the transducer over a disc or discs having approximately 45 mm diameters. The VCM is preferably a moving voice coil-type having a voice coil attached to the actuator arm and two magnets positioned above and below the voice coil such that the voice coil can freely move between them. One magnet is mounted to a base portion of a housing which encloses the entire disc drive system. The other magnet is mounted to roof portion of the housing. Thus, the housing is integrated into the active components of the disc drive and permits a significant size reduction to be achieved.

Abstract: The substrate of a magnetic recording medium is laser textured employing a dual fiber-optic laser delivery system which enables separate control of nucleation and crystallization. An embodiment of the invention includes laser texturing glass, ceramic and glass-ceramic substrates without microcracking to form a texture comprising uniform protrusions.

Abstract: An improved disc clamping system for the elements of the disc stack in a disc drive to increase resistance to radial shifting of the disc stack elements. The increased resistance to radial shifting is achieved by increasing the coefficient of friction between adjacent disc stack elements, and the increase in the coefficient of friction is accomplished by controllably texturing the contact surfaces of various disc stack elements or combinations of disc stack elements. Surface texturing processes particularly suited to specific disc stack elements are disclosed.

Abstract: A low particulating circuit board for a disc drive flex assembly, and a method for forming the same, are disclosed. The circuit board comprises a conductive metal substrate which has sufficient thickness to provide mechanical support and backplane suppression for the circuit board and to efficiently sink heat generated by preamplifier circuitry housed by the circuit board. The substrate has dielectric layers formed on the top and bottom surfaces thereof, the dielectric layers comprising an epoxy interleaved with nonparticulating fibers, such as tetrafluorethylene (TFE) fibers. Traces and pads are provided on the dielectric layers to provide the necessary electrical connections for the preamplifier circuitry. A plurality of circuit boards are formed from a panel and subsequently cut therefrom. Particulate generation is minimized through the use of the metal substrate, as well as recession of the substrate and the solder masks to reduce the amount of material cut during the cutting operation.

Abstract: A low profile mechanism for biased driving of driven roller in tape cartridge includes a rotor-on-the-outside motor placed on a reciprocating base plate and moved by the base plate to engage a drive roller with a predefined control force. The drive roller is translatable such that it conveys all or part of the control force to the driven roller of a supplied tape cartridge.

Abstract: A method for compensating for position and component induced variations in the acceleration and deceleration capabilities of a voice coil actuator in a disc drive, comprising the steps of dividing the discs radially into a plurality of zones, testing the acceleration and deceleration capability of the disc drive in each zone by performing specially controlled seeks in both inward and outward directions in each zone, comparing the result of these specially controlled seeks with a calculated nominal or desired result, and calculating a compensation factor for each zone which is applied by the servo system to all subsequent seek and track following operations.

Abstract: A disk caddy is disclosed which prevents particles generated during the process of securing a disk caddy lid to a disk caddy housing from reaching a stored disk. The disk caddy includes a barrier extension, which extends from the lid in one embodiment of the invention. The barrier extension is located towards the end of the lid and, in one embodiment, inserts into a slot in the housing which is otherwise intended to receive a disk.

Abstract: A method for pattern-etching thick alumina layers in the manufacture of thin film heads (TFH) by using compatible metallic mask layers and an alumina etchant. The deep alumina etching enables the formation of scribe-line grooves of street and alleys across the wafer for sawing and machining of sliders. These grooves eliminate most alumina chipping due to stress and damage introduced by the sawing and machining operations.

Abstract: The invention is a miniature disc drive system. In the preferred embodiment of the invention, a positioner for positioning a transducer includes an actuator arm having the transducer mounted at one end and a voice coil motor (VCM) mounted at the other end. A pivot is centrally located along the actuator arm, whereby the VCM, when activated, can rotate the transducer over a disc or discs having approximately 45 mm diameters. The VCM is preferably a moving voice coil-type having a voice coil attached to the actuator arm and two magnets positioned above and below the voice coil such that the voice coil can freely move between them. One magnet is mounted to a base portion of a housing which encloses the entire disc drive system. The other magnet is mounted to roof portion of the housing. Thus, the housing is integrated into the active components of the disc drive and permits a significant size reduction to be achieved.

Abstract: Method and apparatus for compensating for errors in the location of servo frames in a disc drive, the servo frames providing control inputs to a servo loop of the disc drive. Each servo frame includes an additional compensation field to which a compensation term is written, the compensation term indicative of the average radial error in the location of the servo frame. The compensation term is determined by measuring the radial distance between adjacent servo frames over a plurality of revolutions of the disc and averaging these measured radial distances. The compensation terms are thereafter used in conjunction with position information from the servo frames to control the position of the head. The compensation term facilitates the elimination of repeatable, random errors in the locations of the servo frames, causing the head to nominally follow a circular path about the disc, regardless of the errors in the locations of the servo frames.

Abstract: An intelligent status monitoring, reporting and control module is coupled to a SCSI bus that interconnects a cluster of SCSI-compatible data storage modules (e.g., magnetic disk drives). The status monitoring, reporting and control module is otherwise coupled to the cluster of SCSI-compatible data storage modules and to power maintenance and/or other maintenance subsystems of the cluster for monitoring and controlling states of the data storage modules and power maintenance and/or other maintenance subsystems that are not readily monitored or controlled directly by way of the SCSI bus. The status monitoring, reporting and control module sends status reports to a local or remote system supervisor and executes control commands supplied by the local or remote system supervisor. The status reports include reports about system temperature and power conditions. The executable commands include commands for regulating system temperature and power conditions.

Abstract: A control system for a film deposition apparatus having a plurality of processing chambers. The control system includes a plurality of control processors, each of the plurality of processors including a memory, being coupled to a subset of the plurality of chambers and controlling processing in said subset of the plurality of chambers. Each processor includes a data structure, provided in said memory, having configuration data for said plurality of processing chambers, and control routines for controlling processing in the apparatus. In a second aspect, the system includes a facility for determining the position of the substrate in the system. The transport system of the deposition apparatus includes hardware position sensors which indicate the presence or absence of a substrate at said sensor. The facility determines the position of substrates when the output of one or more of the hardware sensors is unavailable.

Abstract: A hydrogenated carbon film for magnetic thin film recording media is manufactured by alternating current magnetron sputtering in an atmosphere containing argon and a hydrocarbon gas. Targets mounted side-by-side cyclically sputter and discharge charge buildup according to an alternating current. Shielding between the targets directs electrons toward the anode at a given time.

Abstract: A transducer support assembly supports a transducer relative to a disc in a disc drive. The transducer support assembly includes a slider coupled to the transducer and a suspension assembly supporting the slider. The suspension assembly includes a bias member configured such that, upon relative movement of the disc and the suspension assembly toward one another a sufficient distance, the bias member contacts the disc and exerts a bias thereagainst before a remainder of the suspension assembly contacts the disc.

Abstract: A magnetic recording medium having low medium noise and suitable for high density magnetic recording is produced with a bicrystal cluster magnetic layer on a glass or glass-ceramic substrate. An underlayer which is formed with a (200) crystallographic orientation induces the formation of a bicrystal cluster microstructure in a magnetic alloy layer epitaxially grown on the underlayer.

Abstract: An optical storage system includes an optical disc for storing information in an optical reading format. An optical transducer is carried on a slider proximate a data surface of the optical disc and is used for transducing information on the disc surface. A mesa is provided on an air bearing surface of the slider and electrical conductors are provided which extend around the mesa.