Abstract: A magnetic thin film recording medium is provided for longitudinal recording of magnetic flux transitions, with the read-back signals enhanced due to a substantial reduction in media noise. The reduced noise level is the result of a unique vacuum deposition process for applying an underlayer to a substrate, prior to deposition of the magnetic thin film. In particular, the underlayer is deposited in a low temperature plasma process under increased pressure of argon or another inert gas and at reduced deposition rates, thus to create voids or interstitial areas which substantially isolate individual grains from their neighboring grains. The subsequently deposited magnetic thin film replicates the crystalline structure and orientation of the chromium underlayer, for relatively isolated grains in the recording layer. This results in lower media noise levels, approaching or equalling those characteristic of particulate media.

Abstract: An etching and fluorinating treatment is disclosed for modifying the surface properties of magnetic data storage media and sliders for magnetic data transducing heads. Media enclosed within a plasma chamber is first exposed to an argon plasma for cleaning, then exposed to a plasma mixture including argon with either fluorine or carbon tetrafluoride, maintained at a pressure of approximately half of atmospheric pressure, at a temperature of about 100.degree. C. An electrical field is generated for forming argon, carbon and fluorine ions. The argon ions etch the carbon overcoat of the disc, while the carbon and fluorine ions combine with the carbon to form extended chain fluoropolymers, and also penetrate the carbon layer. Sliders are treated in a plasma mixture of argon and CF.sub.4. During such treatment, carbon and fluorine ions penetrate exposed surface areas of the slider, and form a reaction product of solid lubricant film.

Abstract: Magnetic recording media are controllably textured, particularly over areas designated for contact with data transducing heads. In connection with rigid media, the process includes polishing an aluminum nickel-phosphorous substrate to a specular finish, then rotating the disc while directing pulsed laser energy over a limited portion of the radius, thus forming an annular head contact band while leaving the remainder of the surface specular. The band is formed of multiple individual laser spots, each with a center depression surrounded by a substantially circular raised rim. The depth of the depressions and height of the rims are controlled primarily by laser power and firing pulse duration. The shape of individual laser spots can be altered by varying the laser beam inclination relative to the disc surface. On a larger scale, the frequency of firing the laser in combination with disc rotational speed controls the pattern or arrangement of laser spots.

Abstract: A method and related system for use with a disk drive are disclosed for adjusting the current level emanating from a read/write head during recording of data onto a disk to compensate for differences in read/write head and disk relationships. Also, a method and related system are disclosed for determining the optimum slimming constant to be utilized to minimize data pulse peak shifts to compensate for differences in read/write head and disk relationships.

Abstract: Ceramic head pad materials which exhibit superior toughness and lubricating material characteristics over known materials, particularly in the areas of toughness resilience, damping, solid lubricity, reduced brittleness and chipping (without a change in bulk hardness), and improved thermal expansion, result from optimizing the amount of strontium oxide (SrO) and included in a calcium titanate ceramic. In particular, a ceramic material with approximately 5% to 7% SrO in a calcium titanate matrix (with approximately 6% SrO being the optimal concentration), may be utilized to realize the aforestated improved toughness and lubricating characteristics.

Abstract: A disc drive includes a stationary frame and vertical spindle shaft, and a hub rotatable relative to the spindle shaft and supporting one or more magnetic discs. A motor for rotating the hub includes an annular stator integrally secured to the spindle shaft, and a rotor assembly integral with the hub. The rotor assembly includes an annular magnet and an annular back iron, with the magnet being spaced apart from the stator to define an air gap. The magnet includes four longitudinally disposed arcuate poles of equal size, separated from one another by flux gaps. Each of the poles has a medial region and first and second end regions on opposite sides of the medial region. The medial region is selectively magnetized to a level less than the level to which the end regions are magnetized, creating a flux gap and torque profile for the magnet particularly effective in reducing torque ripple.

Abstract: Magnetic recording media are controllably textured, particularly over areas designated for contact with data transducing heads. In connection with rigid media, the process includes polishing an aluminum nickel-phosphorous substrate to a specular finish, then rotating the disc while directing pulsed laser energy over a limited portion of the radius, thus forming an annular head contact band while leaving the remainder of the surface specular. The band is formed of multiple individual laser spots, each with a center depression surrounded by a substantially circular raised rim. The depth of the depressions and height of the rims are controlled primarily by laser power and firing pulse duration. The shape of individual laser spots can be altered by varying the laser beam inclination relative to the disc surface. On a larger scale, the frequency of firing the laser in combination with disc rotational speed controls the pattern or arrangement of laser spots.

Abstract: A rotary actuator for a magnetic disc drive includes a stationary arcuate permanent magnet and a thin, arcuate voice coil formed of a single winding of aluminum wire. Both the magnet and voice coil are curved about a pivot axis of a rotating shaft supporting a movable head arm assembly of the rotary actuator. The coil is integral with the head arm assembly, and pivots the head arm assembly responsive to electrical current introduced into the coil. Opposite ends of the pivot shaft are received into fixed race bearings supported by spaced apart upper and lower bearing plates, one of which is slightly elastically deformed to secure the shaft by their restoring force. Leaf springs provide a biasing force against the selected bearing plate and cooperate with parallel, spaced apart flexure members in the selected bearing plate to compensate for thermal expansion coefficient mismatch.

Abstract: A method for determining the micro impact energy capacity of a disk drive's ceramic heads and its thin film disks. The impact energy capacity of disk drive heads (typically composed of ceramic materials) and disks (higher capacity disks use thin film media) provides a measure of quality and durability of the heads and media. The method includes dropping an indentor of a known weight on a sample surface, measuring the identation surface area and length, increasing the weight and repeating the previous steps at different areas o the surface until surface cracking occurs. The various measurements are plotted to produce a stress-strain curve, the area of which comprises the micro energy capacity of the surface.

Abstract: A magnetic disc drive includes a rigid housing, a plurality of data storage discs rotatably mounted in the housing, and a carriage for supporting and placing transducing heads in selected dispositions with respect to the rotating discs. An actuator or voice coil motor drives the carriage, and is fixed in the vertical direction to the housing by three posts extended upwardly of a deck portion of the housing and engaging the bottom of the actuator. A metallic plate mounted integrally to the actuator and a viscoelastic polymeric layer are interposed between the actuator and the deck adjacent the posts. The posts are sufficiently flexible to permit a limited horizontal displacement of the actuator with respect to the housing, responsive to movement of the carriage. The displacement causes shear strain in the viscoelastic layer whereby the layer tends to absorb and dissipate most of the energy of vibration.

Abstract: A ceramic head pad material which exhibits superior toughness and lubricating material characteristics over known materials, particularly in the areas of toughness/resilience, damping, solid lubricity, reduced brittleness and chipping (without a change in bulk hardness), and improved thermal expansion, results from optimizing the amount of strontium oxide (SrO) in a calcium titanate ceramic. In particular, a ceramic material with approximately 5% to 7% SrO in a calcium titanate matrix (with approximately 6% SrO being the optimal concentration), may be utilized to realize the aforestated improved toughness and lubricating characteristics.

Abstract: A thin film magnetic head including top and bottom pole tips having reversed trapezoidal cross sections. Mirror image symmetry across a gap region may be achieved. The top and bottom pole tips may be formed using a photolithographic process using positive photoresist including post bake and flood exposure steps.

Abstract: A disc drive servo head having two thin film transducers, one of which is disabled from reading by lapping away its pole tips. The coils of the disabled transducer are oppositely wound from the usable transducer's and induce an equal and opposite signal from background noise, such as generated by adjacent data heads during write. The signals from the disabled tranducer coils are combined with the signals from the usable transducer during reading of servo data to concel background noise.

Abstract: A balancing apparatus for balancing a high precision magnetic disk drive includes a plate having a circular aperture in which three mounting surfaces grip a precision mounting ring on the disk pack to be balanced. The plate is mounted on a pivoting platform so that the pack can be lowered into the aperture, gripped by the mounting surfaces and then flipped into a horizontal position for balancing such that an operator has access to the disk pack to add balancing weights through the circular aperture.

Abstract: A process for assembling the I core and C core element of a ferrite magnetic transducer core includes the steps of depositing by sputtering a gap material on the gap face of one core element. A magnetic material of the type which can be bonded to ferrite by heat and pressure is then sputter deposited on the gap material. The surface of the magnetic material is then juxtaposed to the gap face of the other element and heat and pressure below a pint which may affect the ferrite's magnetic characteristics is used to diffusion bond the two elements to each other. It is possible to use a layer of Sendust Fe-Si-Al high permeability alloy or other high permeability material as the magnetic material deposited on the gap material if this enhancement of the core is desired. In any case, higher than customary clamping pressure along with lower than customary temperature is used to effect the bond.

Abstract: The integrity of a disk drive from a flyability standpoint is tested by applying a write signal of known frequency to the read/write transducer and monitoring the playback signal from the transducer. The playback signal is processed to separate a modulation component which represents air bearing disturbance.

Abstract: A disk for testing the sliders and their supports used in rigid magnetic disk drives has at least one asperity formed of a fluorocarbon resin. Such a test disk when mounted on a spindle and rotated allows testing the mechanical performance of the sliders carrying the data transducing heads in a disk memory by flying the sliders to be tested on the test disk and observing their performance when flying over the resin asperity. A method for producing the asperity involves depositing a drop of a fluorocarbon resin solution on the area of the disk wherever an asperity is desired, drying the solution to leave a small mound of the resin where the drop was deposited, and the no curing the resin by baking. The height of an asperity can be varied by machining or by varying the concentration of the fluorocarbon resin in the solution.

Abstract: An Ni-P (Nickel-Phophorous) undercoating is provided under particulate (spin-coated) magnetic media. Particulate media, largely due to the way it is applied to the disk, is less expensive than thin film media. Described are the systems and methods to utilize the undercoat for particulate media.

Abstract: An improved spindle motor flex cable and related mounting arrangement are provided for use in a computer disk drive unit to couple a disk drive spindle motor to associated drive electronics. The flex cable comprises a flexible ribbon base with multiple conductors at one side thereof, wherein the flex cable is supported on a substantially sealed disk drive housing with the conductor side presented generally toward the housing. An inboard end segment of the flex cable is folded back upon itself for outward exposure of inboard conductor ends to permit facilitated connection as by soldering to spindle motor leads protruding from the housing. An outboard end segment of the flex cable extends beyond a side margin of the disk drive housing to expose outboard ends of the conductors for connection as by soldering to a connector fitting oriented to face away from the housing for easy plug-in connection or the like to drive electronics located, for example, an adjacent circuit board.

Abstract: .[.A vent cap has.]. .Iadd.A low diffusion disk drive breather vent for communicating air between the interior and the exterior of a sealed disk drive housing through a vent passageway, .Iaddend.a long, narrow air communication passage .[.covering the vent outlet of a sealed disk drive. The passage reduces.]. .Iadd.provided to reduce .Iaddend.diffusion of water vapor .[.into the disk drive.]. .Iadd.through the passage.Iaddend..