Abstract: A magnetic disk drive includes redundant data written at a plurality of out of phase angular locations to reduce the latency and enhance performance during a read operation. The loss of recording capacity is reduced by increasing the data density to achieve the same soft error rate standard required for single recording. Dual recording also allows different recording codes to be used at the duplicated locations to thereby have the more highly stressed code words occur at different locations in the data to further reduce the possibility of an error. The redundant recording can be used in one portion of the media and normal recording used in another media portion to enable selection of the recording technique in accordance with the type of data being stored. The size of the normal and redundant recording portions can be controlled by the format operation and the user of the disk drive can intervene to designate the size of the redundant and normal media recording portions effected during the format operation.

Abstract: A method and apparatus is disclosed for adaptively controlling the biasing current applied to magnetoresistive (MR) read heads within a magnetic disk drive to provide optimized bias for each head/disk/channel component combination. An optimized bias current for each head is ascertained and stored on the disk surface at the time of manufacture. During each power up operation the values are transferred to random access memory which is accessed during the execution of each head switch command to apply bias current in accordance with the optimized value to the active MR head. Periodic reoptimization and updating of the stored values is effected by general error measurement circuitry that forms a part of the device control system and is invoked to perform the reoptimization upon the occurrence of an event such as a predetermined duration of power on operation subsequent to the last reoptimization procedure.

Abstract: To reduce disk drive power consumption, a reduced disk rotational velocity idle mode is used wherein in-situ components of the drive calibrate the landing (or take-off) speed of each head/disk combination and establish a transition speed incrementally above the highest landing speed to assure that the heads both fly above the confronting disk surfaces and avoid substantially all the asperities projecting from the disk surfaces. This can be accomplished using digital harmonic ratio flyheight (HRF) measurement techniques. This system optimizes the power savings to the characteristics of the particular drive. The power saving can be imposed in stages, initially to maintain the capability of quick return to operating conditions and a final stage that realizes maximum power savings. The transition speed is recalibrated periodically, which enables monitoring of the device for degradation or future imminent failure as sequential transition speeds change.

Abstract: A disk drive includes a cast base upon which is mounted the disk stack-spindle assembly and the actuator assembly and a cover that is loosely received by the cast base to form the head-disk enclosure. The cover is secured and sealed to the cast base by a malleable metal foil tape that surrounds the enclosure and continuously overlies the interface between cover and base. The tape complies with the surface irregularities and does not creep, to provide permanent shielding and sealing between base and cover. Further, cables exiting the enclosure may be sealed using a piece of double sided adhesive which is interposed between cable and casting followed by application of the malleable foil tape thereover. Thus in a compact device, no significant thickness is added to the enclosure wherein a maximum available height is used to house the stack of disks while providing noise and EMC shielding in addition to securing and sealing the cover.

Abstract: High density magnetic disk storage and semiconductor module technologies are combined to provide a disk drive using a standard multilayer ceramic substrate as the disk drive base support member to support spindle and actuator assemblies including 1 inch diameter disks. The ceramic substrate has components and very large scale integration (VLSI) chips mounted directly thereon to avoid use of one level of packaging and presents standard pins to mount the drive using standard sockets to afford economy and reliability.

Abstract: In a disk storage device dedicated servo system, a reference track is written in the outer guardband of the servo surface and each of the data surfaces. Supplemental position error signal (PES) values are obtained from the difference of servo and data surface samples at a plurality of locations around the disk and stored for access during read/write operations. The supplemental PES values are combined with the dedicated surface PES values to yield a composite PES that more accurately follows the data track centerline of the disk surface being addressed. The supplemental PES values are also periodically updated. To provide a more accurate correction of the composite PES, two consecutive supplemental values are used and an interpolation is calculated to provide a continuously changing supplemental PES value for modification of each sector actuator drive pulse between the two current supplemental PES values.

Abstract: The vapor drain is a device that permits steady state control of the composition of the atmosphere within a substantially sealed enclosure. For any fabricated enclosure the will be sources of vapor phase molecules: molecules evaporating from a deliberately installed lubricant reservoir, molecules outgassed from components, and molecules diffusing in from the outside world. The purpose of the vapor drain is to minimize the second two classes of molecules in the composition of the enclosure atmosphere as they are considered to be contaminants. An example application is a rigid disk magnetic data storage device which requires a monomelecular layer of lubricant on the disk and slider surfaces. The vapor drains suppresses the contaminant population by capturing a portion of all three sources of molecules in the vapor phase.

Abstract: A system and method for controlling the movement of a member, particularly the heads of a disk file, to a specified position in a predetermined path, makes use of an electromagnetic responsive to control signals and to position reference information and a transducing means for reading such information to produce a position signal. The position signal is sampled regularly and, together with the actuator control signal, used to update a velocity estimator. During the deceleration phase of the movement, a new actuator control signal is generated at each sample time from the square of the estimated velocity divided by the computed distance-to-go to the specified position.

Abstract: A method of assembling a disk file comprises merging a pre-assembled actuator assembly and disk stack assembly prior to attaching them to a common base. The relative axial positions of the actuator assembly and disk stack assembly are measured and adjusted to align head arms with collapsed suspensions with the inter disk spaces. Once aligned the two assemblies can be moved together and the heads released.

Abstract: A voice coil actuator comprising a carriage assembly and a magnet assembly includes a cylindrical shorted turn resiliently mounted in the magnet assembly. The shorted turn is thereby allowed limited movement in a direction parallel to its own axis. In this way, the reaction force on the magnet assembly, caused by the movement of the carriage assembly during operation of the actuator, can be absorbed by the shorted turn.

Abstract: A lubricant reservoir for a vapor transport type rigid magnetic disk drive lubricant system includes a metal heat sink that presents a finned surface at the side exposed to the outside environment. A second surface within the sealed head-disk enclosure cooperates with a thermal heat transfer resisting wall portion to form a duct. A lubricant reservoir is retained against the heat sink surface within the duct. The reservoir assembly is secured to the head-disk enclosure wall by mounting tape that not only seals the enclosure, but thermally isolates the reservoir assembly from the enclosure wall.

Abstract: In a disk drive providing amplitude sampling data detection, the amplitude of an analog read back signal is sampled at data clock intervals. The resulting analog values are converted to digital equivalent values. The digital equivalent values are each compared to an expected digital values that is representative of the data that was originally recorded on the disk, to thereby generate a different value. The resulting collection of difference values are magnitude segregated, and then stored in a plurality of registers, for later use in providing a histogram that is a measure of the disk drive's read error rate.

Abstract: A structure and organization for a magnetic disk drive provides for optimizing the volumetric storage density within a device form factor by optimizing the number of disks. The spindle and dual rotary actuators are respectively supported at each side by a pair of support plates that are separated and supported by not only the spindle and actuator shafts, but also the voice coil motor core pieces and tie plates which carry shock mounts. This head-disk assembly is shock mounted in the lower part of a two part enclosure wherein the enclosure parts are aligned and separated by elastomer guides and the separation covered by a compliant tape to complete the enclosure. Both actuators use a common servo surface while one actuator carries upwardly facing transducers and the other downwardly facing transducers so that each arm extending between disks mounts, but a single suspension-transducer assembly to reduce interdisk spacing.

Abstract: The present invention relates to a magnetic head suspension in a magnetic disk storage with a record carrier moved relative to the magnetic head and separated therefrom by an air cushion. The head suspension assembly with suspension arm 3, flexure 19 and slider 30 is fixed to an arm portion 1 at a point where arm portion 1 is provided with a ramp 2. This ramp eliminates prebiasing the suspension arm 3. The free end of the suspension arm 3 is provided with a raised portion 5. The elements 25, 26 fixing the tongue 27 to the flexure 19, in particular the bracket 25 with the attached tongue 27 on which the slider 30 is arranged, are substantially recessed in the raised portion 5 of the suspension arm 3. As a result, there is a noticeably reduced overall height.

Abstract: A fabrication method and structure for a cobalt alloy thin film magnetic recording media uses an underlayer of sputter deposited chromium having a thickness of 50 to 200 angstroms which presents the (100) plane of the chromium atoms at the surface upon which the cobalt alloy magnetic thin film layer is to be deposited. The cobalt alloy hexagonal close packed atomic structure is sputtered onto the chromium underlayer and epitaxially grown such that the (110) plane of the cobalt alloy structure is parallel to the media surface. This disposes the cobalt magnetic layer structure to have the C axis (easiest axis of the magnetization) parallel to the media surface to optimize horizontal recording density.

Abstract: A disk drive structure is shown which maximizes the axial length available for mounting disks within a predetermined height such as dictated by a form factor. A cast aluminum box frame is used which supports the spindle and actuator assemblies and forms a part of the head disk enclosure in cooperation with a drawn metal cover. The box frame captures the spindle and actuator shafts at each end to ensure maximum overall assembly stiffness and minimize the axial length required by the structure supporting the spindle. The box casting geometry is angled to establish the casting/cover joint region at a location beyond the zone of tangency of the disks nearest the form factor so that only the thinner cover is interposed in the region where the disks most closely approach the form factor. The cover and box frame are sealed and secured to one another by a thin compliant tape that does not contribute stress to the box frame during thermal cycling.

Abstract: A lubricant film for a thin-film disk is disclosed. The lubricant film comprises a monolayer of fixed lubricant bonded to the surface of the thin-film disk and a mobile lubricant in contact with the layer of fixed lubricant. The monolayer of lubricant film is applied to the thin-film in a method comprising applying a lubricant composition to the surface of a thin-film disk, then heating the thin-film disk at a sufficient temperature for a sufficient time to bond or fix a portion of the lubricant composition to the disk; to evaporate a portion of the lubricant composition from the surface of the disk; and to dispose a portion of the lubricant composition as a mobile lubricant in contact with the fixed lubricant.

Abstract: A disk drive within the dimensional confines of a form factor can optimize volumetric density by using the full height dimension to house disks, but must thereafter utilize the remaining space for electrical components. The structure shown uses a stack of parallel cards with an interface card on the rear end wall to provide the principal drive control and data circuits exterior of the head-disk assembly (HDA). The motor driver circuitry is mounted on a flat flexible cable and is secured to the front wall at the opposite end of the drive in heat transfer relation. The heat generating motor drive circuits are physically isolated from the data/control circuits by the frame and HDA while some of the printed circuit cards are secured to the frame in a manner that enhances rigidity; the allocation of modules to the cards anticipates flow of data and control signals to minimize the number of connections and signal delays that impair performance.

Abstract: The magnetic disk drive chemical breather filter of the present invention affords protection with respect to chemical vapors and gases in addition to trapping particulate pollutants. The chemical filter as described, protects against both organic vapors and inorganic gases. In addition particulate filters are interposed between the chemical filters and both the exterior atmosphere and internal atmosphere. The combined filter is isolated from both external and internal atmosphere by extended length diffusion passages. Both difffusion passages are composed of multiple parallel paths to prevent the blockage of any single path from impairing the functioning of the filter. Chambers formed at each side of the combined filter medium and access thereto by the diffusion passages at the center of one chamber and the periphery of the other enables the length of the air passage through the filter medium to be equal irrespective of the portion of the filter through which the air flow passes.

Abstract: A recirculating filter system is provided for a sealed magnetic disk drive by providing a cartridge housing that mounts a filter medium closely adjoining the disk stack and substantially concentric therewith. The frame that mounts the filter medium also serves as a baffle or diverter to deflect air impelled by rotation of the disks to the rear of the filter medium. The remaining sides of the housing contact the cover or enclosure to define a dead box behind the filter medium wherein the velocity head of the air flow is converted to a potential head. Air impelled along the surface of the medium, at the side confronting the disk stack, provides some aspiration. A plenum formed at the radial outward side of the filter medium enables effective use of the entire medium surface. The recirculating air filter cartridge is not only compact within a corner of the cover or enclosure, but also is easily manufactured as a result of the simple filter medium configuration.