Abstract: A mounting system for attaching head suspension assemblies to actuator mounting arms of a disc drive actuator. The mounting system of the invention comprises mounting plates for the head suspension assemblies that include bosses inserted in cooperative holes in the actuator head mounting arms. Mounting discs of shape memory allow, in martensitic phase, having outer diameters selected for cooperation with the inner diameter of the bosses, are press-fitted into the bosses. The mounting discs are then heated to transform the material of the mounting discs to the austenitic phase. This transformation causes the outer diameter of the mounting discs to increase with sufficient force to deform the bosses of the mounting plates into interference fit with the holes in the actuator head mounting arms.

Abstract: An important and central aspect of the present invention is the use of expanded amorphous aluminum silicate (EAAS) as a vehicle for a chlorite salt. This vehicle, when exposed to moisture, will release chlorine dioxide (ClO.sub.2) for purposes of deodorization or microbial suppression. Thus, where a particular area or volume is to be deodorized or made less microbally contaminated, the EAAS-chlorite salt (most preferably sodium chlorite) is placed in the area or volume to be treated and moisture is permitted to interact with the material. The result of the moisture is to permit the chemical reaction (presumably acidification) of the chlorite salt to yield chlorine dioxide gas. While normal EAAS has some inherent acidity, the inherent acidity is low enough so that, even when a chloride salt is encapsulated in the EAAS and the resultant mixture exposed to moisture, ClO.sub.2 release is very slow and over an extended period. Under most conditions, a more rapid release of ClO.sub.

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 including a composite disc spacer that maintains the discs in a fixed radial relationship to the spindle motor hub. The composite disc spacer includes a wedge member which supports a plurality of axially extending fingers which include inwardly and outwardly facing surfaces that bear against the spindle motor hub and against the bores of the discs to maintain the discs in a fixed concentric relationship to the spindle motor hub. The composite also has a spacer that extends about the wedge member to provide fixed relative axial spacing of the discs. The wedge member and the spacer interlock to facilitate handling of the composite disc spacer during assembly.

Abstract: A low inductance electrical spring connector for a disc drive interconnecting the conductors of a flex circuit support and seal apparatus to conductive traces on a PCB, the electrical spring connector having a dielectric housing with a plurality of spaced-apart insulator portions, and a plurality of conductive spring contacts disposed between the insulator portions. The dielectric housing forms an open ended insertion cavity disposable below the flex circuit support and seal apparatus. First ends of the conductive spring contacts are solderable to conductive traces on the PCB, while second ends of the conductive spring contacts are contact surfaces disposed in the insertion cavity. Inserting the conductors of the flex circuit adjacent the contact surfaces into the insertion cavity causes the contact surfaces to engage the conductors of the flex circuit to secure the flex circuit support and seal apparatus while providing electrical contact between the head-disc assembly and the printed circuit board.

Abstract: An improved attachment of an actuator E-block of an actuator apparatus to a cartridge bearing assembly for a hard disc drive, the actuator apparatus having an E-block with a central bore having a pair of cartridge bearing alignment edges and a relief area, the cartridge bearing alignment edges disposed within the central bore to engage the cartridge bearing assembly. Mounting members extend through the wall of the E-block into the central bore to apply a frictional load there against and a compressive load against the cartridge bearing assembly sufficient to maintain contact between the cartridge bearing alignment edges of the E-block and the cartridge bearing assembly.

Abstract: An improved crash stop apparatus having an inner crash stop that pressingly engages the actuator assembly of a disc drive when the read/write heads of the actuator assembly approach a desired inner extent of radial travel to prevent further movement of the read/write head beyond the inner extent of travel and furthermore having an outer crash stop that pressingly engages the actuator assembly when the read/write heads approach a desired outer extent of radial travel. The crash stops each have a pin rigidly mounted at a proximal end and having a cantilevered distal portion which is disposed in the path of travel of the actuator. An elastomeric member is disposed between the impacting actuator and the pin. The elastomeric member and cantilevered pin provide a two-stage braking impulse to decelerate the actuator, wherein the first stage compresses the elastomeric member and wherein the second stage deflects the cantilevered pin.

Abstract: An inverting power supply (10) having first and second charging capacitors (22, 24) that are alternately connected to a positive power source (12) and a negative output terminal (18) which is to be maintained at a negative voltage with respect to a common ground for the power source and the power supply. Switches (34, 36) connect a positive plate of each charging capacitor to the power supply positive terminal during alternate half cycles of a two-phase clock (20) and charge is bled from the positive plates by switching transistors (46, 50) during the other half cycle to enable charge to be transferred via diodes (52, 54) from the negative output terminal to negative plate of the charging capacitors during the other half cycle.

Abstract: Apparatus and method for dynamically programmiing the magnitude of read bias and write currents in a disc drive head. A digital input value is provided to a register of a digital to analog converter, the digital input value indicative of the desired magnitude of the head current. A multiplier of the digital to analog converter multiplies the digital input value by a reference voltage to generate an output voltage. The differential voltage between the reference voltage and the output voltage controls the source to drain resistance of a transistor connected in series with a preamp voltage source of a preamp circuit. By inputting different digital input values, the source to drain resistance of the transistor, and hence the magnitude of the current generated by the preamp voltage source, are precisely controlled. The magnitude of the head current is provided as a multiple of the magnitude of the current generated by the preamp voltage source.

Abstract: A disc drive is disclosed having servo information written to one or more discs of the disc drive at a frequency that varies for each of the tracks defined on the disc, the servo information read by and used to control the position of an associated head of the disc drive. The servo information is preferably constant density and arranged as a plurality of servo strips extending radially from an inner to an outer diameter of the disc, each servo strip comprising a plurality of servo fields, the servo fields defining the tracks on the disc.

Abstract: A snubber assembly for a disc drive having a plurality of rotatable discs and an actuator assembly supporting read/write heads for flying support above the data surfaces of the discs, the snubber assembly being positioned outboard to the outer perimeters of the discs in a disc clearing position when the disc drive is in the operational mode. The snubber assembly has a plurality of snubber members that nest the discs to limit the deflection of the discs when the snubber assembly is moved to a disc nesting position. A latch member secures the actuator assembly when the snubber assembly is moved to the disc nesting position. In the preferred embodiment, ramp members extend from the snubber members to lift the heads from the data surfaces when the snubber assembly is moved to the disc nesting position.

Abstract: An apparatus and method are disclosed for determining a maximum magnitude of bias current that can be safely applied to a head of a disc drive. The disc drive comprises a head disposed adjacent a rotatable disc having a recording surface on which data are magnetically stored, a preamplifier circuit which selectively applies bias currents to the head, and a head bias current selection circuit, operably coupled to the preamplifier circuit, which first determines the maximum magnitude of bias current that can be applied to the head in relation to a maximum power dissipation rating of the head and voltage measured across the head when at least one initial bias current of selected magnitude is applied to the head. Thereafter, a range of bias currents having different magnitudes less than or equal to the maximum magnitude are selected and evaluated to select an optimum magnitude for subsequent use by the drive.

Abstract: A method and apparatus are disclosed for improving data transfer rate performance in a multi-drive array configured as a redundant array of inexpensive discs (RAID). The array comprises at least first and second disc drives each comprising a rotatable disc on which a plurality of tracks are defined. An array controller is operably coupled to the disc drives to stripe data across the first and second disc drives using a common bus architecture. Logical block addresses (LBAs) are assigned to each of a plurality of data blocks of the tracks of the drives and are grouped into a number of zones, each zone having nominally the same number of LBAs. Data are thereafter transferred to and from the drives on a zone-basis, so that a block of data of determined size is divided between the first and second disc drives at a selected ratio so that a greater percentage of the block of data is written to the first zone as compared to the second zone.

Abstract: A method for adapting acceleration and deceleration of a disc drive transducer during movements between initial and target tracks on a disc surface to the maximum current available to drive an actuator whereon the transducer is mounted. During acceleration of the transducer, while the actuator current is substantially a maximum, the current supplied to the actuator coil is measured and a scale factor is determined as the square root of the ratio of the maximum current supplied to the actuator and a nominal current from which a velocity profile, used to effect velocity control of the movement, has been predetermined.

Abstract: A disc drive assembly having a pair of disc packs supported for rotation by independent spindle motors and a single actuator having dual arrays of actuator arms supporting read/write heads for each disc pack. The actuator has dual opposing actuator coils which interact with dual opposing magnet assemblies so that a controlled voltage to the actuator coils creates a rotating force having translational vectors that act radially on the actuator and are opposingly disposed to stabilize the actuator.

Abstract: An apparatus of automatically measuring the dynamic imbalance of a disc stack of a disc drive assembly, the disc stack conveyed to a first selected position in a balance measure assembly station where a rotary positioner lifts and rotates the disc stack above a sensor to locate an electrical lead of the disc drive motor. The disc stack is positioned in a reference position to position the electrical leads a for powering the disc drive motor. The disc stack is then conveyed to a second selected position where a motor power assembly clamps and powers the motor and discs. A balance head assembly measures the magnitude and phase angle of the dynamic imbalance of the disc stack and records the measurement to a production control computer.

Abstract: An apparatus and associated method are described which change the mechanical response characteristics of an actuator arm in a disc drive such that damage to the disc drive resulting from mechanical shock is minimized. An actuator arm is provided which has a groove that extends along a side portion of the actuator arm. A side rail is attached to the side portion of the actuator arm, and is preferably T-shaped so that the side rail mates with the groove. The side rail can be constructed of a stiffening material and/or a damping material as desired to change the mechanical response characteristics of the actuator arm to reduce contact between the actuator arm and the disc surface which results from mechanical shock to the disc drive assembly. In the method of use, a groove is machined into a side portion of an actuator arm and then an actuator arm side rail is inserted into the groove.

Abstract: An apparatus and method are disclosed for reducing the effects of thermal asperities and other anomalous conditions on disc drive read operations. An improved data block format is provided having first and second sync fields in which sync patterns are stored, the first and second sync fields being separated by a selected distance within the data block. The sync pattern of the second sync field enables synchronization of a disc drive read channel to the user data in the data block when the read channel fails to be synchronized by the sync pattern of the first sync field. In one embodiment, control information used by the read channel to prepare for receipt of the user data is stored in a field between the first and second sync fields; in an alternative embodiment, a portion of the user data is stored between the first and second sync fields.

Abstract: An apparatus and method for automatically correcting the dynamic imbalance of a disc pack of a disc drive, the disc pack conveyed to a first selected position in a balance correction assembly station where a rotary positioner lifts and rotates the disc pack to a reference position for the attachment of weighted shims to the disc pack. A shim selector assembly delivers a selected shim, and an end effector transfers the selected shim to a shim attachment assembly. The shim attachment assembly rotates and spreads open the shim so that the disc pack can be receivingly engaged thereby, and the shim attachment assembly releases the selected shim to lockingly engage the disc pack. A flipping assembly reverses the disc pack for placement of another selected shim to the other end of the disc pack, as required.

Abstract: A core sampler apparatus for use at the end of a drill string of a drilling rig having a hollow barrel assembly for receiving a subterranean core sample, a shoe supported at a bottom end of the barrel assembly, and a connector member providing a pinned attachment of the barrel assembly to the drill string.

Abstract: An apparatus and method are disclosed for improving data recovery operations in a disc drive employing a redundant sync data block format. The disc drive includes a rotatable disc and a controllably positionable head which is used to store user data in a plurality of data blocks on tracks of the disc. Each data block includes a user data field to store user data, a first sync field and a redundant, second sync field, the sync fields storing first and second sync words, respectively, which establish symbol boundaries used by a read channel of the disc drive. User data are recovered from a selected data block by initiating a delay of selected duration during which a first portion of the selected data block passes proximate the head, allowing the second, remaining portion of the selected data block to be read at the completion of the delay.