Abstract: A method for detecting air-contamination within a hydrodynamic bearing used with a disc drive comprises in one embodiment, a method to detect air-contamination with hydrodynamic fluid by measuring operating signals of the disc drive between different external air pressure conditions (including ambient) on the hydrodynamic bearing and comparing the operating signals to predetermined threshold values. In another aspect, the invention provides an air-contamination detecting apparatus adapted to detect air-contamination within the fluid of a hydrodynamic bearing. In another aspect, the invention provides a method to determine air-contamination within hydrodynamic bearings using the change in disc drive input/output signals responsive to air-pressure changes on the hydrodynamic bearings.

Abstract: A bearing system in which an axially stiff narrow gap fluid dynamic gas bearing is preloaded by an axially less stiff larger gap fluid dynamic bearing. As an example two fluid dynamic bearings are provided spaced apart along a shaft, one of the bearings comprising a fluid dynamic bearing, the other comprising an air bearing. The fluid dynamic bearing has a larger gap, while the air bearing has a relatively small gap. The overall working surface area of the air bearing may be twice as much or more than the working surface area of the fluid bearing.

Abstract: The counterplate and/or sleeve are modified to reduce or eliminate distortion in the counterplate in a laser welded fluid bearing design. It is known to directly weld the counterplate which lies across the end of the shaft and the thrust plate to a wall or shoulder of the sleeve in which the counterplate is fit. The radial stiffness of the sleeve is weakened by cutting grooves or the like at or near the interface between the sleeve wall and the counterplate, or on the outer diameter of the sleeve wall to essentially weaken the sleeve wall. This weakening of the sleeve wall prevents bowing or distortion of the counterplate being imposed by the sleeve.

Abstract: A very thin lubricant coating is applied to one or both of the facing surfaces defining the gap of a hydrodynamic bearing to prevent wear of these surfaces. The lubricant film is necessarily very thin, in the range of about 10 Å to 1000 Å, so that the film is thin enough that it does not materially affect the performance of the hydrodynamic bearing gap which is about typically 1-10 &mgr;m. The thin lubricant film could be a perfluoropolyether (PFPE) or a mixture of PFPE or a phosphazine derivative. To improve the adhesion and lubricating performance, functional PFPE can be used. For pure metallic surface like steel, phosphate esters can also be used because of its affinity with the metallic surface, e.g., ferrous. For example, the film could be PFPE, or a mixture of PFPE and a phosphazine derivative. The lubricant should be chosen to be thermally stable, and non-reactive with the typical ambient environment.

Abstract: The present invention is related to a disk drive hub/back iron configuration that resists distortion upon changinging temperature of the disk drive. The hub/back iron configuration thus prevents distortion of the disks, reducing HDI problems.

Abstract: A system and method for improving the durability and reliability of recording media used in hard drives is disclosed. A protective overcoat made by depositing a diamond like carbon (DLC) layer over a magnetic layer and then depleting the DLC protective layer of hydrogen before it is coated with a Perfluoropolyethers (PFPE) using an in-situ vapor lubrication technique.

Abstract: A patterned media having recordable and non-recordable regions is initialized by first erasing (e.g. DC magnetizing) at least a portion of the recordable regions. At least one offset may then be determined. The at least one offset may compensate for a read to write delay in the electronics and/or at least one delay caused by the space separation between a read and a write head. A plurality of position error signal (PES) bursts may then be written on at least a portion of the recordable regions. During the write process, the previously written PES bursts are read and used to determine PES signals (e.g. servo signals) in order to guide the write head while writing new PES bursts. Magnetically written gray code may then be written on the media. The magnetically written gray code may be used to define a track number for the data tracks with no eccentricity.

Abstract: A method for non-destructive measurement of dynamic coercivity is disclosed. In this method, magnetic media is DC erased by applying a forward DC magnetic field to the magnetic media such that the magnetic moments in the magnetic media are substantially aligned. A specified number of reversed magnetic field pulses are then applied to the magnetic media in a direction opposite to the forward DC magnetic field, wherein the intensity of the reversed magnetic field pulses is less than the remanent coercivity of the magnetic media. The broadband medium noise of the magnetic media is measured. The intensity of the reversed magnetic field pulses is then repeatedly and incrementally increased and applied to the write head for the specified number of pulses, the intensity of the reversed magnetic field pulses eventually exceeding the remanent coercivity of the magnetic media. For each intensity level of the reversed magnetic field pulses, the broadband medium noise is again measured.

Abstract: The active vibration suppression of a slider suspension arm is achieved by including as part of the suspension arm two bimorph piezoelectric elements. A first bimorph piezoelectric element is attached to the top of the suspension arm and acts as a sensor. A second bimorph piezoelectric element is attached to the bottom of the suspension arm and acts as an actuator. The actuator is controlled as a function of a voltage measured by the sensor so that the actuator damps periodic vibrations occurring in the suspension arm.

Abstract: A magnetic data recording medium substrate has a contact zone and a data zone. The contact zone is textured by forming multiple texturing features, each having a bell-shaped profile resembling a Gaussian curve. The features preferably are formed by pulsed laser energy applied to a glass substrate, or to an aluminum nickel-phosphorous substrate coated with a glass layer. As compared to previous laser texturing approaches, the laser beam is less narrowly focused to provide a beam impingement area with a diameter of at least three microns, forming texturing features with diameters of at least three microns. The texturing features preferably are uniform in height and diameter, and may be symmetrical or have asymmetrical aspects, so long as bell-shaped profiles are present in the direction of travel of the recording medium, relative to transducing heads.

Abstract: A system for transferring information to and from a magnetic disk is disclosed wherein the information may be encoded on a data track in a large number of polarization orientations in comparison to conventional bidirectional recording schemes. In one embodiment of the present invention, it is contemplated that a single segment may be polarized in eight different orientations, each of which being distinguishable from each other by a read/write head. Polarization of a segment in one of eight different orientations significantly increases the amount of information which can be stored in any given segment relative to conventional systems which are polarized in only one of two orientations. Thus, the amount of information which may be stored on a disk may be increased without having to alter the linear or radial density of the disk.

Abstract: A system and method for forming servo patterns on magnetic medium is disclosed. A magnetic film coated with a layer of styrene-acrylonitrile is stamped with a nickel stamper reproducing the negative image of the stamper pattern on the styrene-acrylonitrile. Ions are then accelerated towards the surface of the styrene-acrylonitrile, which stops the ions in the areas where the styrene-acrylonitrile is thick and allows the ions to penetrate through to the magnetic layer in the areas where the styrene-acrylonitrile is thin. The ions, which penetrate through to the magnetic layer, interact with the magnetic layer altering the magnetic layer's structure reducing its coercivity (Hc) and remnant moment (Mrt). This reproduces the stamped styrene-acrylonitrile pattern on the magnetic layer. The styrene-acrylonitrile is then removed by oxygen plasma etching the surface leaving behind a patterned magnetic medium.

Abstract: A sputtering apparatus for depositing layers of material onto a substrate includes a vacuum chamber, a first target and a second target positioned within the vacuum chamber. A source of power is placed in electrical communication with the first target and the second target. A switch alternately connects the source of power between the first target and the second target. The first target and the second target are different materials. The switch connects power to the first target when the transport mechanism positions the substrate near the first target and the switch connects power to the second target when the transport mechanism positions the substrate closer to the second target.

Abstract: A combination glide test/burnishing head can be utilized in a glide test/burnishing system. The combination glide test/burnishing head includes two piezo-electric elements, which can be utilized in a passive mode as sensors for detecting contacts between the glide test/burnishing head and asperities on the surface of a magnetic recording disc. Contact between the glide test/burnishing head and disc asperities results in generation of a defect detection signal, which can be utilized by associated test logic to define the location of the detected asperities on the disc surface. The piezo-electric elements of the glide test/burnishing head can also be utilized in an active mode to cause yaw variation in the flight attitude of the glide test/burnishing head, in turn causing a burnishing pad on the glide test/burnishing head to be moved radially into contact with a detected disc asperity.

Abstract: A glide test head assembly glide test head assembly in which the mounting orientation of the piezo element has been modified. The glide test head assembly mounts the piezo element with one of its major surfaces coincident with the surface of the laterally-extending wing on which it is mounted. The mounting orientation of the piezo element allows the piezo element to be mounted fully on the laterally-extending wing of the glide test head assembly, raising the resonant frequency of the piezo element, decreasing the glide test head assembly's sensitivity to excitation caused by air flow disturbances, and increasing the reliability of glide test results.

Abstract: According to the present invention spindle bearings are assembled with at least one annular gimbal to compensate for undesired components of bearing compression force. Specific devices and methods are directed to compensating for either (a) operational force variations such as those caused by temperature variation or (b) assembly-related force variations such as those caused by misalignment.

Abstract: A glide test head assembly optimized for glide avalanche testing. The glide test head assembly of the present invention includes air bearing surfaces formed with a negative crown, or slightly concave surface. The negative crown of the air bearing surfaces of the inventive glide test head lowers the hydrodynamic pressure between the glide test head assembly and a spinning disc for given disc rotational speeds, enabling the glide test head assembly to fly at a lower heights at a greater linear velocity, and thus with increased stability. The increased flying stability of the inventive glide test head assembly improves the correlation between true flying height and disc/head contact detection for glide avalanche testing.

Abstract: A glide test head which includes a pillar or column member positioned on the lower surface of the laterally-extending wing that mounts the piezo element of the glide test head, and extends toward the disc surface being tested. The preferred location of the column member is near the trailing and outermost edges of the laterally-extending wing. The dimensions of the column member and the flying attitude of the glide test head are selected to make the lowermost surface of the column member the closest contact point of the entire test head during test operation, and to contribute minimal effect on the overall hydrodynamic operation of the glide test head. In a related aspect of the invention, it is envisioned that the test system in which the inventive glide test head is implemented will spin the disc under test at a greater than normal speed, thus increasing the throughput of the test system.

Abstract: A storage media is provided. The surface of the media is made to vary by an insubstantial amount relative to a datum to provide for improved flyability of a head over the surface.

Abstract: A multiple disk drive storage system includes a latch assembly for positively latching a head positioning actuator arm when the head is positioned on a load/unload mechanism at the outer perimeter of the disks. Latching and unlatching cycles of the latch assembly are effected by interaction of the actuator arm motion and a latch arm retention magnet structure. In the latch position, the actuator arm is mechanically captured by a hook shaped latch head at one end of the movable latch arm, so that, even in a power off condition the actuator arm is positively latched by the combination of the actuator arm motion limitations, the latch head shape, the latch arm motion limitations and a bias spring urging the hooked latch head into a permanent, static latch with the actuator arm. The opposite end of the latch arm is provided with a magnetic mass which is attracted and held by the retention magnet.