Abstract: A disk drive rotary actuator has a head arm rotatable about a pillar. The pillar has abutments engaging a rolling member located in a recess in the head arm. The rolling member and pillar provide a space between abutment surfaces through which a flexure plate passes. A spring holds the pillar and arm together with the rolling member between them.

Abstract: A multi-task system employs a single interrupt occurring at fixed time intervals to initiate the control functions. The actuator control, servo control and spindle control routines are operated on a priority basis so that if a control function having a high priority is not ready to be executed, the processor immediately performs execution of the next available control function. More particularly, the spindle control process is operated in the foreground with the actuator control and servo control routines operated on an interrupt basis of the spindle control routine. Upon receipt of the interrupt signal, priority is first given to an actuator control routine for execution. Upon completion of the actuator control routine, or if the actuator control is not ready to be executed, access is given to a servo control routine. At the conclusion of the servo control routine, the interrupt exits to the spindle control routine.

Abstract: The method disclosed is generally directed to a process for controlling the velocity of an actuator arm assembly during a load from a ramp. A process in accordance with the invention includes applying an alternating current to the VCM to eliminate frictional effects. An increasing current is applied to the VCM. The increasing current is an increasing function of time in one embodiment of the invention and is determined such that the heads are loaded at a predetermined velocity. In one embodiment, the predetermined velocity is 1 in/sec.

Abstract: An apparatus that compensates for the asymmetry and the baseline shift in the signal generated by a magnetoresistive head. The apparatus stores a first correction factor for the baseline shift, a second correction factor for correcting the amplitude of the positive portion of the signal and a third correction factor for correcting the amplitude of the negative portion of the signal. The first correction factor for correcting for baseline shift is added to the signal generated by the magnetoresistive head to generate a baseline corrected signal. The baseline corrected signal is then monitored for positive and negative excursions from the baseline and the positive excursions are multiplied by the second correction factor and the negative excursions are multiplied by the third correction factor for generating a compensated signal.

Abstract: A disk drive having a novel head-gimbal assembly (HGA) which is attached to an actuator arm of an actuator assembly. The HGA includes a read/write head, a flexure, and a suspension arm. The suspension arm has a first end including the flexure supporting the read/write head, and a second end including a hole having an attached swaging member extending through it. The swaging member includes a baseplate and a swaging boss which interface at an annulus region. A circular hole is formed through a top surface of the baseplate and extends downward partially through the swaging member. A non-circular hole, concentric with the circular hole, is formed through a bottom surface of the swaging boss, and extends upward partially through the swaging member. The non-circular hole has a smaller diameter than the circular hole. The shape of the non-circular hole may be any geometric shape such as a two-lobbed swaging hole, a three-lobbed swaging hole, an elliptical hole or a hexagonal hole.

Abstract: A digital communication apparatus (20) transmits sectors of digital values that include error correction values used to detect and correct errors within the sector. Each sector consists of a number of blocks (70, 72, 74) and the error correction values of each block (70) are useful in correcting up to a maximum number of erroneous digital units (78, 84) in that block (70). The digital communication apparatus (20) encodes the blocks of digital units to transmit them through a channel (32) and then decodes the channel's representation of those encoded blocks, where the channel's representation occasionally contains burst errors.

Abstract: A digital peak detection system digitizes analog signals and provides absolute values to a series of one cycle delays, and to a sequence of comparator stages. Each digital sample is parallel compared to a number of preceding samples equal to the number of active comparator stages. Control signals activate comparator stages to determine sample comparison window length, including lengths exceeding the number of samples between recorded peaks. Peak detection is optimized using a variable gain amplifier whose gain is updated based upon amplitude difference between actual and desired peak samples. When sample amplitudes are smaller than a qualifier threshold, a countdown timer increases amplifier gain after lapse of a programmed time without detecting a qualified pulse. Gain is also updated when the analog to digital converter saturates. Initial gain values can be programmed, and gain stored at the end of a servo mode for future use in reducing gain control loop convergence time.

Abstract: A disk drive in which a movable latch locks the data transducer assembly to prevent movement due to shock. The movable latch cooperates with an actuator by engaging an actuator extension arm. The movable latch also engages a stationary magnet with one of two latching magnets. The movable latch arm is mounted to a shaft which extends into a sealed casing which incorporates a plunger. The plunger is located in a chamber filled with viscous fluid which is not subject to migration or outgassing from the chamber. The viscous fluid provides resistance to sudden movements of the plunger. Latch release is achieved by application of low continuous force to the actuator arm by a voice coil motor.

Abstract: A cold trap assembly having Peltier Junction assembly is provided to reduce the head stiction between a disc drive head and a disc. The Peltier Junction assembly includes a cold region which has a temperature lower than the ambient temperature of the disc drive. Vapors from outgassing components in the disc drive condense on the cold region, thereby reducing the amount of vapors which may condense on the disc surface.

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 system is disclosed which may be used for collecting television channel tuning data, household purchase data, VCR channel usage data and the like; on site at a plurality of preselected households, wherein the system concentrates and transmits the collected data to a central site in a fault tolerant manner, transparent to the occupants of the household. The novel system features a hub and spoke architecture for effecting communications between the central site and each household (remote site). The hub and spoke architecture at each remote site comprises a hub unit, and a set of spoke meters. The hub unit is adapted to be coupled, in a variety of ways, to a set of metering devices, one or more of which is coupled to one or more television receivers and/or cable television converters. Not all of the metering devices need be coupled to the television receiver or cable converter, e.g., stand alone purchase meters and wands may be coupled to the hub. The meters may be polled systematically, e.g.

Abstract: A static electricity discharge device for a magnetic head formed by providing a recess to expose one of the conductors connected to the head's magnetic circuits. Static electricity buildup on the conductors discharges through the exposed portion of the conductor rather than through the pole pieces of the magnetic circuits.

Abstract: A self-loading negative pressure air bearing slider is formed having side vents. The side vents allow for repeatable manufacturing of the basic slider in fewer steps while retaining the desirable features of high stiffness and substantially constant flying height found in negative pressure air bearing sliders.

Abstract: A method and apparatus for placing a ferrite core in the slot of a pad of a ferrite head. A circular magnet is mounted below a non magnetic table on a slider slidable along a line. The pad is clamped on the table with its slot exposed and aligned along the line and the center of the magnet. When the ferrite core is placed on the table near the magnet, it stands on edge, aligned along a radial line of flux from the magnet. As the magnet is slid towards the slot, the core follows the center of the magnet, aligned along the centerline of the slot following the radial line of flux. The core slides into the slot and is thereafter bonded to the pad.

Abstract: A flexible head connector with a ground plane for connecting a daughter board to a mother board.

Abstract: Two thick film resistors calibrate the output of the feedback light detector circuit for monitoring the light power of a laser diode. The output is connected to the power control circuit for the laser diode. Calibration of the feedback output during manufacture permits replacement of the laser diode/feedback light detector combination in the field without recalibration of the power control circuit.

Abstract: Quarterwave chokes mounted on the ends of a quartz lamp about the power leads to the lamp and further mounted on the interior cavity wall of a microwave oven. The chokes permit connection of the quartz lamp to a power source via power leads passing through the cavity wall without allowing microwave energy to escape from the cavity along the power leads.

Abstract: A high vacuum compatible X-Y positioning stage having an air bearing is provided. A pair of moveable carriages is mounted interior to an airtight chamber. Constraints allow movement of each carriage to only one horizontal direction, the directions of each carriage being orthogonal. Air inlet and outlet ports enter the chamber through apertures, and are mounted on the carriages and are moveable therewith. Airtight, flexible bellows form an airtight seal between the chamber and air ports at the apertures. Pressurized air communicated through the ports to the carriage is constrained to exit the carriage via small orifices about the exterior thereof to form an air bearing. The air is constrained to exit the airtight chamber through a passageway mounted in the carriage and leading to the outlet port. A stage is mounted on one pair of ports. The other pair is mounted in a fixed position. The stage is moveable in an X-Y plane vis-a-vis the fixed position on a compensated air bearing.

Abstract: Apparatus is disclosed for processing sparse vectors in a tandem or parallel processing environment. Sparce vectors are those vectors stored in memory with their zero-valued operands deleted. They have a corresponding order vector of bits whose state indicates the order of zero and non zero operands in a corresponding expanded vector. The apparatus fetches the order vectors n bits at a time, n corresponding to the number of tandem processors, and counts the number of one bits. This number of operands is then fetched from memory. The apparatus aligns and orders the fetched sparse vector operands, inserts zero operands where appropriate, and forwards the resulting portion of the expanded vector to the tandem processors for processing.

Abstract: A microwave oven having the control panel mounted on the door. The control panel includes a plurality of pushbutton switches for the user to push to control the speed, time, etc. for variable cooking in the microwave oven. The switches communicate to an electronic controller also mounted on the door. The controller converts user input into signals that control the various operating components of the oven, such as the magnetron. The controller is connected with these components via a flexible printed circuit cable which bridges the space between the door and the oven near or through the hinge area of the oven.