Abstract: A servo pattern for use on a data storage surface that includes at least one track to minimize position error during positioning of a transducer over the data storage surface. The servo pattern includes a plurality of servo burst fields of constant amplitude for defining a centerline of the track and for determining the position of the transducer. According to the present invention, at least one servo burst field comprises N segments, where N.gtoreq.2, and each of the N segments is written with constant amplitude. The amplitude of the at least one servo burst field is then determined as a function of the amplitudes of the N segments.

Abstract: In a subsystem for accessing addressable ECC-coded sectors of magnetic disk tracks subject to sector level redundancy group organization, a method is described for managing write updates to said sectors by maintaining a current set of all redundant sectors in a subsystem NVS buffer external to the DASD such that only a read access of the DASD sector to be modified need be made. This derives from the availability of the new record data and the old redundant sector information at the subsystem. The redundant sector is modified by logically combining the old redundant sector and the new and old data sectors and is saved to the buffer and asynchronously copied to DASD subsequently.

Abstract: A method and apparatus for generating very small split tables from an even smaller amount of information preferably stored on a medium in a system track. The present invention takes advantage of the fact that the pattern of split data cells is periodic. Each split table can be generated upon initial application of power from a relatively few parameters stored in the system track. A method is provided by the present invention for generating each split table based upon the zone number, the number of track wedges within the period of the repeat pattern, the rate at which data is to be written in the zone and two additional parameters. In addition, the present invention is a method and apparatus for increasing the efficiency of the medium by adjusting the size of each zone to minimize the number of split data cells stored on the medium. In accordance with the present invention, the size of each zone is selected based upon the length of the repeat pattern.

Abstract: In accordance with the present invention a storage device servo control system that positions a head relative to multiple tracks of a storage medium includes a servo signal filter that receives a readback signal from the head and produces filtered servo signal data samples, a servo demodulator that receives the filtered readback servo signal from the servo signal filter and produces a position error signal that indicates the head position relative to a track using a demodulation scheme selected in accordance with a track width profile of the storage device, and includes a servo controller that determines the demodulation scheme to be used by the servo demodulator and that processes the position error signal to maintain the head centered relative to the track.

Abstract: Servo pattern bursts are recorded with two frequencies that are detected using heterodyne detection with oscillators at the same frequency as the respective recorded frequencies. The two frequencies are selected to be orthogonal so the sensed servo pattern of one frequency is zero when detected with the detecting circuitry of the other frequency. The servo pattern bursts of the two frequencies are placed close together on the disk so they are sensed simultaneously so that, with orthogonality processing, a PES signal from a three phase pattern is sufficient to provide a robust linear signal, thereby eliminating one of the bursts from a quadrature pattern and reducing the disk surface area needed in each track for the servo pattern by 25% or more.

Abstract: Method and apparatus are disclosed for a data recording disk file having a head module with separate side by side read and write transducers for optimizing the switching of the head between reading information and writing information on the same track or cylinder. A function generator defines at least one control function for a servo control signal to drive an actuator to move the head module the approximate distance between the side by side write and read transducers, optimized to minimize the time between write and read, and optimized to move the head module the approximate distance between the side by side read and write transducers at the timing best suited to minimize the write transition time.

Abstract: A process and device for separating a mixture of substances by sorption of the components of the mixture on two different sorption agents with independently adjustable sorption properties. The process is characterized in that the mixture of interest is introduced into a gap between two surfaces of sorption agents. A gap medium in which the components of the mixture are soluble and/or dispersible and/or in which they can be evaporated is located between the facing surfaces of the sorption agents (1,2). Of the three different phases consisting of surfaces and gap medium at least two move in different directions at a substantially constant distance apart, and the separated components of the mixture located on the sorption means are extracted after passing through the separating section.

Abstract: Digital data is stored on a DASD by generating a parity block for a specified block of data items and storing the parity block at a selected location on the DASD. The parity block includes a parity computation calculated by applying a parity routine to the corresponding data. The parity block also includes a parity code that indicates either (1) the size of the corresponding data block, or (2) the number of data items contributing to the parity computation. The parity block may be stored adjacent to the corresponding data, or at an independent location. Among other things, the invention provides significantly increased robustness against data loss, and improved flexibility and efficiency in storing data.

Abstract: The present invention is directed to polyisocyanates containing a stabilizing amount of a carboxylic acid corresponding to the formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 represent hydrogen or C.sub.1 -C.sub.5 -alkyl andX and Y represent hydrogen, chlorine or methyl, with the proviso that when X=Cl, Y=H or CH.sub.3 and when Y=Cl, X=H or CH.sub.3.The present invention is also directed to the use of the stabilized polyisocyanates as binders for coating compositions, sealing compounds and adhesives.

Abstract: Colorants are obtained by reacting a dyestuff which is free from ionic groups and has.gtoreq.2 NH.sub.2 groups which are preferably arranged in such a manner that they do not participate in the resonance of the chromophore with such an amount of a (cyclo)aliphatic diisocyante so as to form an adduct that still contains at least two free NCO groups, and subsequently reacting this adduct with a (cyclo)aliphatic diamine, to form an adduct suitable for dyeing and pigmenting macromolecular substances, in particular for coloring PUR-based paints, coatings and laminates.

Abstract: The present invention is directed to polyurethane ureas which may be obtained by the reaction of a hydrophilic NCO prepolymer, which has been prepared from a polyhydroxy component based on about 9 to 100% by weight of a polyether containing about 30 to 100% by weight of ethylene oxide, or a mixture of this hydrophilic NCO prepolymer and a hydrophobic NCO prepolymer, the mixture containing .gtoreq.30% by weight of the hydrophilic prepolymer, with an aldimine or ketimine-containing hardener mixture in the presence of water and organic solvents, approximately 30 to 70% of the NCO groups of the prepolymers being reacted with the amino groups of the hardener and the remainder reacting with water.The present invention is also directed to a process for the preparation of these polyurethane ureas and to coated substrates prepared from these polyurethane ureas.

Abstract: The present invention is directed to a process for the production of light-stable, solvent-resistant polyurethane urea elastomer coatings by the reactive coating process wherein NCO prepolymers are reacted with 4,4'-diamino-C.sub.1 -C.sub.4 -tetraalkyldicyclohexylalkanes containing up to 4 carbon atoms in the alkyl group with continuous mixing and continuous discharge of the reaction mixture.

Abstract: The invention disclosed herein is concerned with a process for mixing a plurality of viscous rapidly reacting, fluid materials and an apparatus with which to perform this process. In this process the fluid materials are initially introduced into a mixing chamber and mixed with a gas, preferably in such a way that an angular momentum is imparted to the mixture. The mixture is then fed into a static mixer which has a short residence time spectrum. The apparatus comprises a cylindrical mixing chamber with a gas inlet and at least one nongaseous fluid material inlet arranged to direct flow tangentially to the interior surface of the mixing chamber. Other inlets may be provided downstream of these initial inlets but before a static mixing apparatus with which said mixing chamber communicates. An outlet is provided downstream of said static mixing apparatus which preferably has intersecting baffle plates, a low pressure loss and a short residence time spectrum.

Abstract: The invention disclosed herein is concerned with a process for mixing a plurality of viscous rapidly reacting, fluid materials and an apparatus with which to perform this process. In this process the fluid materials are initially introduced into a mixing chamber and mixed with a gas, preferably in such a way that an angular momentum is imparted to the mixture. The mixture is then fed into a static mixer which has a short residence time spectrum. The apparatus comprises a cylindrical mixing chamber with a gas inlet and at least one nongaseous fluid material inlet arranged to direct flow tangentially to the interior surface of the mixing chamber. Other inlets may be provided downstream of these initial inlets but before a static mixer with which said mixing chamber communicates. An outlet is provided downstream of said static mixer which preferably has intersecting baffle plates, a low pressure loss and a short residence time spectrum.

Abstract: The present invention relates to a process for the production of polyurethane ureas from a prepolymer which contains isocyanate groups and a mixture of hardeners containing amino groups, in the presence of water, and optionally in the presence of solvents, characterized in that the mixture of hardeners comprises compounds corresponding to the following general formulae:H.sub.2 N--R--NH.sub.2 (A)h.sub.2 n--r--n .dbd. r.sub.1 (b)andR.sub.1 .dbd. N--R--N .dbd. R.sub.1 (C)whereinR represents a divalent aliphatic, cycloaliphatic or araliphatic group having from 2 to 18 carbon atoms and optionally also containing --O-- or ##STR1## (wherein X represents H, --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7 or --C.sub.4 H.sub.9) andR.sub.

Abstract: A method and apparatus for the point plotting and rearrangement of graphical data from a coded source into a buffer for raster type display. The execution of a graphic order in a stored program controllable graphics terminal are represented by a line generating a sequence of X Y coordinate values, which values are to be plotted or displayed. The points are plotted into a work organized memory array in the form of topologically adjacent rectangular subarrays. These subarrays are then transformed into linear arrays. In order to conserve memory they directly replace the previous topologically adjacent subarrays in the memory. The linear arrays may then be accessed a word at a time and applied to the raster display.

Abstract: The instant invention relates to thermoplastic polyurea powders, optionally containing urethane groups, characterized byA. a smooth, substantially spherical or lenticular surface,B. an average particle diameter of 5 to 1,000.mu., preferably 10 to 200.mu.,C. a urea group content, and, optionally, a urethane group content, of 8 to 30% by weight,D. an ionic group content of 0.01-0.15 milliequivalents per gram of solids, preferably 0.02-0.1 milliequivalent per gram andE. 0.1 to 10% by weight, preferably 0.2 to 5% by weight, of an organic dye incorporated in the polymer molecule by way of at least one urethane and/or urea group,And the process of manufacture thereof.

Abstract: A substrate to be used as a support for a release coating is provided with a powdery release support with a release agent which is substantially non-tacky by applying on the support an aqueous solution, dispersion or paste containing a lactam compound which is water soluble, swells in water or forms a paste with water, drying the resulting coating. The process comprises treating the release agent, drying the release agent, applying a polyurethane coating over the release support and then removing the polyurethane coating from the release support. The release agent is selected from lactams and addition compounds of lactams with water, oximes, amines, monofunctional or polyfunctional alcohol or thioalcohols and mixture thereof.