Abstract: An intelligent disk drive includes a controller which embeds user data address information into error correction code check symbols written to the data storage disk. The address information is not written to disk, but address errors are detected by decoding the error correction code check symbols during read operations. Disk space is saved while maintaining robust address error detection.

Abstract: A method and apparatus for operating geography-altering machinery such as a track-type tractor, road grader, paver or the like relative to a work site to alter the geography of the site toward a desired condition. A first digital three-dimensional model of the desired site geography, and a second digital three-dimensional model of the actual site geography are stored in a digital data storage facility. The machine is equipped with a position receiver to determine in three-dimensional space the location of the machine relative to the site. A dynamic database receives the machine position information, determines the difference between the first and second site models and generates representational signals of that difference for directing the operation of the machine to bring the actual site geography into conformity with the desired site geography.

Abstract: A format for embedded servo track identification fields in rotating disk data storage units such as magnetic disk drives. The present invention uses the concept of tri-bits (i.e., three code bits per logical bit) to encode track identification information in servo wedges of embedded servo disk drive systems. More specifically, two particular sets (and their equivalents) of tri-bit codes have been discovered to have optimum characteristics for providing a phase coherent encoding of a Gray code that is simple to translate into straight binary code. The properties of such tri-bit encoding limit error propagation to a single bit, which allows for very reliable track identification during movement of a head transducer across tracks (i.e., "seeks"). A full range of Gray scale codes is available since more than two consecutive logical "0"s can be reliably decoded when encoded using such tri-bits.

Abstract: A method and apparatus for estimating internal brake energy in a fluid cooled brake of the type used in large work machines from easily sensed machine operating parameters. The temperature of the coolant is sensed before and after it passes through the brake. The coolant flow rate through the brake is determined from one or more additional sensed parameters, for example engine speed. The sensed parameters are used in a thermodynamic model of the brake which generates estimates of internal brake temperature (TEIB) and the amount of power absorbed by the brake (BRKP). Signals representing TEIB and optionally BRKP are generated to provide indications of brake operation and/or health. The model is executed on a digital computer either on-board the vehicle or at a remote location.

Abstract: A disk drive head disk assembly having a compact configuration includes an actuator assembly with an E-block mounted to a base plate through a three point mounting system. The second ridges in a generally cylindrical opening and includes means for forcing a mounting post against the first and second ridges. The E-block has a flex cable mounting surface and wedge: shape extension adapted to receive a portion of said flex cable forming an oblique angle with the flex cable mounting surface. A flex circuit is attached to the base plate and includes a ribbon-like flex cable and an L-shaped member adapted to receive the flex cable with snap-on clamps adapted for mounting the flex cable to the E-block.

Abstract: A method and apparatus are disclosed for monitoring similar machine components loaded in parallel to produce trend information useful in diagnosing and predicting component degradation or failure. The invention is illustrated for engine cylinder exhaust port and manifold temperature measurements. In one embodiment split exhaust manifolds are each provided with a sensor to produce signals indicating the exhaust temperature. A computer-based trending module receives the parallel temperature information, periodically determines a difference between the temperatures, and averages the differential temperature readings over a predefined trend period to generate a trend values. A trend based on a plurality of the trend points is generated and monitored for changes which indicate the possible degradation of one of the measured components.

Abstract: A magnetic memory disk storage system has a pair of storage disks rotatably mounted in a housing. A head actuator assembly is pivotably mounted adjacent to the storage disks and includes a plurality of load beam assemblies for placing read/write heads adjacent to the disk surfaces. Each of the load beam assemblies has a load beam, a magnetic recording slider adjacent an outboard end of the load beam, an actuator arm welded to the inboard end of the load beam and two alignment ears on the actuator arm. A pivot bearing assembly extends through pivot holes through the load beam assemblies for pivotable support of the head actuator assembly. The load beam assemblies are clamped together with the alignment ears on all of the load beam assemblies being in alignment. A torque washer next to the nut which clamps the parts on the bearing assembly includes a hole for resisting torque and preventing twisting of the load beam assemblies.

Abstract: A method and apparatus for operating geography-altering machinery such as a track-type tractor, road grader, paver or the like relative to a work site to alter the geography of the site toward a desired condition. A first digital three-dimensional model of the desired site geography, and a second digital three-dimensional model of the actual site geography are stored in a digital data storage facility. The machine is equipped with a position receiver to determine in three-dimensional space the location of the machine relative to the site. A dynamic database receives the machine position information, determines the difference between the first and second site models and generates representational signals of that difference for directing the operation of the machine to bring the actual site geography into conformity with the desired site geography.

Abstract: A rotating-shaft hydrodynamic bearing assembly adapted for use in a rotating disk data store. The bearing assembly combines a plurality of spaced-apart radial journal bearings with a two-faced axial thrust plate to provide stiffness against runout at high rotational velocities. Fluid pressure is controlled on both sides of every fluid dement by bounding all radial fluid bearing layers and the dual thrust bearing layers with circumferential undercuts coupled to ambient pressure through a plurality of fluid-filled passages in the rotating shaft. Outward-biased surface-relief patterns are disposed in both axial thrust bearing layers to increase hydrostatic pressure and prevent cavitation in the non-bearing thrust-plate peripheral layer. The fluid bearing layers are disposed in a continuous pressure-controlled fluid film sealed at both ends by surface tension, thereby eliminating sources of air-bubble entrapment.

Abstract: A disk drive for use with an embedded head positioning servo system is disclosed. The disk drive includes a disk on the surface of which spaced-apart servo bursts are prerecorded in servo sectors. Successive servo bursts are read by a read/write head which produces oscillating signals having variable magnitude peaks. A timing circuit provides a timing signal, synchronized with the occurrence of the servo sectors, which defines, in time, a servo signal window, during which time a servo burst is being read by the read/write head. A detector circuit measures the magnitudes of each of the peak signals of a servo burst occurring in the servo timing window. The median peak value for a burst is stored, a next burst is detected and measured and the median peak value for that burst is stored. By comparing the median peak magnitudes of successive servo bursts, a servo error signal for use in correcting any error in head position relative to a desired track centerline is produced.

Abstract: The use of tertiary ethers as blowing agent allows the preparation of lower density foams from many types of polymeric materials.

Abstract: A process for making high-purity foam moldings without the use of organic blowing agents involves the use of inorganic gases such as carbon dioxide, nitrogen, air and other pneumatogens.The process involves the simultaneous impregnation and purification of the polymers with or without foaming. If foaming is not done in the extractor, the polymeric particles can be foamed in pre-expanders or expanded and molded in downstream equipment.

Abstract: The evaporative casting of molten metals has been shown to produce casting having smooth surfaces with significantly less sign of carbon deposits thereon by using a polystyrene containing a high temperature peroxide, tert-butyl cumyl peroxide.

Abstract: The thermal shrinkage and pyrolysis rate of plastic foam moldings are successfully controlled by coating the expandable plastic beads used in the preparation of the moldings with varying amounts of substantially water-insoluble inorganic siliceous materials. The plastic foam moldings are useful as patterns in an evaporative casting process, wherein the molding is vaporized and replaced by molten metal.

Abstract: Tetrahydrofuran has been polymerized and copolymerized to form polymers of 1000 to 10,000 molecular weight using fuming sulfuric acid with a cocatalyst selected from salts of Group VA metal halides and superacid salts. The cocatalyst salts may be, for example, NaPF.sub.6, NaSbF.sub.6, and LiO.sub.3 SCF.sub.3.

Abstract: The process of enabling foam moldings to expand further than otherwise by impregnating the expanded sheet with inorganic gases such as carbon dioxide, nitrogen, air and other pneumatogens prior to reheating to effect expansion.

Abstract: Purification of tetrahydrofuran from the dehydrocyclization of 1,4-butanediol in the presence of an organic acid catalyst has been accomplished by the extractive distillation of crude tetrahydrofuran containing water using monopropylene glycol as an extractive solvent.

Abstract: The process of making foam moldings without the use of organic blowing agents involves the use of inorganic gases such as carbon dioxide, nitrogen, air, solid carbon dioxide and other pneumatogens. Because of the rapidity with which these gases diffuse out of the polymer particles, it is necessary to pre-expand the particles and then reimpregnate the particles with the same or different gas.

Abstract: In the suspension polymerization of styrene monomers in water using suitable suspension stabilizers, the only modifier needed has been found to be organotin compounds in amounts from 10 to 1000 ppm based on monomer. The product beads have a narrow bead size distribution.

Abstract: The process of enabling foam moldings to expand further than otherwise by impregnating the expanded sheet with inorganic gases such as carbon dioxide, nitrogen, air and other pneumatogens prior to reheating to effect expansion.