Abstract: A machine-implemented method for detecting and resolving conflict between a plurality of objects on trajectories in space. A two-dimensional representation is generated which depicts the trajectory of one of the objects and the times remaining until conflict of said one object with front and back limiting trajectories, respectively, of at least one other of the objects. An indication of potential conflict is displayed on said representation when the trajectory of said one object is between the front and back limiting trajectories of said other object. The front and back limiting trajectories for each such other object are calculated by enclosing a preselected protected airspace about said one object in an imaginary parallelogram having one set of sides parallel to the trajectory of said one object and the other set of sides parallel to relative velocity of such other object with respect to said one object.

Abstract: A method and circuitry for suppressing additive transient disturbances in an analog differential input signal, such disturbances being due, for example, to thermal asperity transients caused by an MR transducer contacting a moving storage surface. The input data signal is algebraically summed with a corrective feedback signal for providing as output signal. The output signal is fed back to a circuit including an envelope detector and differentiator and converted into another signal that is the derivative of an amplitude envelope corresponding to the output signal. Nonlinear signal-adaptive filter means converts said other signal into the corrective feedback signal, which substantially replicates the additive transient disturbance and is subtracted from the data input signal to render the output signal substantially free of the transient disturbance.The input, output and corrective signals are preferably differential signals.

Abstract: A high resolution lithographic mask having a desired pattern is generated and used to replicate the pattern onto a film in a one-step process.A film of phase-changeable material in one state is provided on a conductive substrate. By scanning tunneling microscope techniques, the state and thereby the conductivity or other property of the material in selected areas of the film is changed to a second state to provide from the film a mask having a desired pattern defined by crystalline areas. Amorphous material need not be removed from the mask.To replicate the pattern on another film, the latter is placed on another conductive substrate; the mask is positioned with its patterned side within electron tunneling distance of said other film; and the pattern is replicated in a single step by applying a voltage between the mask and other film.

Abstract: Submicron structures are written on a surface by positioning in nanometer range proximity, preferably within current tunneling range, of the surface a scanning tip of a material that emits atoms upon application of an applied voltage of low magnitude. While the tip is maintained within said range, it is moved relative to the surface, and a series of short voltage pulses are concurrently applied between the tip and surface. These pulses cause atoms of tip material to directly transfer to the surface and concurrently cause remaining atoms of tip material to migrate to the tip and continuously reform the tip and maintain its sharp configuration, thereby insuring uninterrupted writing ability. Various tip materials exhibiting low field evaporation potentials may be used; however, gold is preferred if deposition is to be under ambient conditions. Heating the tip enhances the ability of the material to emit atoms. The deposited structures may be selectively sensed or erased by application of appropriate voltages.

Abstract: An improved apparatus and method for detecting the polarization state of an optical wavefront is disclosed, which is especially suitable for use in an integrated magneto-optic recording head. An optically transparent waveguide structure transmits TE and TM modes of the wavefront propagated as a beam coupled into the waveguide by a TE/TM grating coupler. In the waveguide structure is a periodic structure comprising a birefringent mode separator that splits the propagating beam into TE and TM modes. The mode separator comprises an array of uniformly spaced volumes of identical configuration. Photosensitive devices detect the intensity of the light contained within each of the separated beams. The signals from these photosensitive devices are used to determine the state of polarization of the optical wavefront. The periodic structure may, if desired, comprise regions of alternating birefringence, such as a Bragg grating, either in a waveguide layer or a cladding layer.

Abstract: A highly sensitive apparatus for sensing the position of a movable member comprises an optical directional coupler providing four external ports. Light from a short coherence length diode laser is injected into the first port. The coupler serves as a beam splitter to direct one portion of the injected light to the member via the second port and a single mode optical fiber. Part of this one portion is reflected concurrently from the member and from the adjacent polished coating at the end face of said fiber back into said fiber and optically coupled via the third port to a photodetector to provide a signal whose amplitude is indicative of the position of the member, based upon the relative phase of said concurrent reflections.The other portion of the injected light is optically coupled to and via the fourth port to another photodetector for providing, as a reference, a signal proportional to the intensity of the injected light.

Abstract: A high performance, low power analog to digital converter is designed in BIFET technology utilizing the high gain, high performance of a bipolar comparator and the low power of a CMOS latch and CMOS encoding logic circuits. Using a FET dynamic latch, metastability is avoided, significantly reducing soft error rate.

Abstract: A head suspension load beam for a disk file has a slender base portion shaped like a plate, one end of which is secured to a head actuator arm, and the other end of which supports a head. The base portion is reinforced by bending a side margin portion in the longitudinal direction of the base portion at substantially right angles to the plane of the base portion, and further by providing reinforcement ribs, the height of which does not exceed the height of the bent side margin portion, almost parallel to the side margin portion. A head suspension load beam of another embodiment of this invention is reinforced by bending the side margin portion substantially parallel with the plane of the base portion or further toward the plane of the base portion, instead of using reinforcement ribs.

Abstract: A bit-serial division method for computing the value v/u, where v and u are each n-bit vectors that are elements in a finite Galois field GF(2.sup.n) consisting of 2.sup.n elements. The n-bit components of each element in the field are coordinates of the element in a canonical basis of the field. Vector u is converted from canonical basis to a dual basis. Vector u in dual basis also comprises n bits in the finite field ordered according to an index i that takes on values from 0 to (n-1). All bits n of the converted vector u are loaded into a shift register in parallel, then converted from dual basis back to canonical basis to produce a single bit output w.sub.0 from a lookup table which generates bitwise the inverse of the n-bit vector u. The bits in the shift register are shifted (n-1) times to generate successive additional single bit outputs w.sub.i with said lookup table. Then each bit w.sub.i is multiplied by the vector v and a corresponding element c.sub.

Abstract: A method is disclosed for repositioning an adsorbate atom or molecule on a substrate surface by moving the tip of a STM to a position adjacent the atom to be moved and subsequently increasing the attraction between the tip and atom by moving the tip closer to the substrate, and then, while the atom remains bound to the surface, moving the tip laterally to drag the atom to a desired position on the surface. The tip is then moved away from the substrate, reducing the attraction between the atom and tip and leaving the atom bound at the desired position.The atom may be repositioned in close proximity to an atom of the same or another type on the same or a different substrate to create a desired multi-atom structure or synthesize a molecule.

Abstract: An improved digital phase-locked device and method for synchronizing incoming data (8) with a local clock (24) includes registers (12a,12b) which, when alternately triggered during each successive selection cycle, trap the states of waveforms supplied by a delay element string (11). A transition detector (13) detects transitions in these waveforms and provides to a selection means (17, 18, 19) a plurality of outputs, each corresponding directly to a respective clock position. Registers 19a, 19b of the selection register are alternately triggered by clock signals. Selection register 19 provides a window (SW) defining the maximum number of unique clock positions adjacent a then present clock position within which bit patterns are examined for determining whether any of the clock positions then within the window constitutes a valid local clock selection choice.

Abstract: Phase discrimination and data separation method and apparatus for on-track error recovery by shifting input data in time relative to a clock to improve recovery of error bits due to bit shift in a disk storage system having a servo clock syncronized to a disk's rotational speed and a refernce clock which must be synchronized to the servo clock to insure that the data previously written onto the disk will be retrieved correctly during read back. Data encoded in (1,7) or denser codes can be recovered because of fewer transitions in a phase discriminator and therefore a shortened phase discrimination cycle in a feedback loop to avoid interference into the following correction. Readback data pulses for address mark (AM) search operations are standardized while a PLL is phase locked to the servo data, reducing or eliminating misdetection of AM due to delay skew or pulse width variations. Sequential logic avoids race conditions.

Abstract: High availability is achieved in a multiprocessor system by grouping the processors into two clusters operating on different clock and power boundaries. In each cluster is an array containing a substantially identical copy of the system information relating to the operation of the processors. Each processor has a local port for accessing the local array and a remote port for accessing the remote array. When an update is made on the system information, it is made on both the local and remote arrays with the remote update performed transparently.

Abstract: A method and means is described for correcting multiple error bursts in data recorded on a storage medium in blocks, comprising a plurality of subblocks. After reading the data, decoded block check syndromes are algebraically summed with estimated block check syndromes to provide a set of syndromes for a code for locating subblocks having an error burst. This set of syndromes is decoded to identify each subblock having an error burst. Concurrently block level syndromes are computer to identify the locations and values of errors within the subblocks having error bursts. During writing, the data in all subblocks of a block is encoded and block level syndromes are generated for these subblocks. These block level syndromes are multiplied by a series of preselected weighting factors (.alpha..sup.1 . . ..alpha..sup.1(B-1)) according to the location index 1 of the sublock within the block and as multiplied, each is stored in a different one of B buffers.

Abstract: A method and apparatus for processing, in a signal processing channel, digital values corresponding to a digitized incoming analog signal representative of coded binary data. Using a state-dependent sequence detection algorithm appropriate functional expressions of digital sample values are precomputed at each cycle of the digitizing clock for a preselected number of bits ahead of the current bit. Preselected ones of these expressions are compared against corresponding thresholds to provide respective binary decision outputs that, with state values corresponding to the current state, determine state values for the next state and decode one bit of coded binary data at each clock cycle. Programmed values generated for the thresholds may be adaptively modified according to changes in sample values in the incoming analog signal relative to corresponding expected sample values. Different thresholds are used for positive and negative phases of the analog signal shape to accommodate signal shape asymmetry.

Abstract: A method and means for setting the free-running frequency of a voltage controlled oscillator (VCO) without requiring laser trimming or the like is described. The VCO forms part of an interconnected phase-locked loop (PLL) and frequency-locked loop (FLL). At system power on, the PLL is automatically disabled and a digital-to-analog (DAC) in the PLL is set to a value corresponding substantially to the center of a preselected lock range. The FLL, which includes a second DAC, then operates to generate a bias voltage for incrementing or decrementing the VCO output frequency until the VCO pulse count stored in a register equals an expected count; whereupon the VCO will be set at its free-running frequency. When the PLL is enabled, a phase error generator generates a digital phase error signal from the input data. A digital integrator converts the phase error signal to a digital frequency error signal.

Abstract: A clamp includes an annular member that acts through a spacer ring to clamp a stack of rigid disks in spaced parallel relationship to a hub having a portion supporting the lower end of the stack. The annular member has a plurality of uniformly spaced radial slots to define a plurality of substantially identical tapered leaf springs. Each leaf spring terminates at its wider end in a common solid hoop-shaped rim that overhangs and contacts the spacer ring along a circular line in the same horizontal plane as, and near, the centroid of the cross-sectional area of the rim when the clamp is uncompressed. Upon application of a compressive force in an axial direction concurrently to the small innermost ends of all said leaf springs, the rim pivots at and along said circular line to substantially eliminate radial load transmitted via the spacer ring to the top disk when clamping the stack to the hub.

Abstract: A method is disclosed for correcting multibyte errors in a magnetic medium on which data is recorded in variable length blocks that comprise subblocks of data bytes and corresponding check bytes and include error correction code (ECC) for which ECC syndromes are generated during reading. A sequence of N sequential parity check bytes is written at the end of each block. After ECC syndromes are generated during reading, parity syndromes are generated by comparing parity check bytes computed from data bytes and check bytes as read with the parity check bytes as written. When a long-burst error occurs, a pointer points to the first of the N consecutive bytes in a block that could have been influenced by the error burst. After correcting correctable errors in all subblocks not affected by the N bytes identified by the pointer, and adjusting the parity syndromes for errors thus corrected, the adjusted parity syndromes are used to correct the errors in the N bytes indicated by the pointer.

Abstract: A unique method for recording, reading and erasing data bits in a data storage device is described. Using extended scanning tunneling microscopy (STM) techniques, a tunneling electron current by resistive heating selectively melts discrete areas of a state-transformable film; then heat is dissipated rapidly, writing data bits by changing the film in said areas from a first state to a second state wherein an electronic property, such as conductance, work function or band gap, in said areas is changed.Again, using extended STM techniques, the effect of this changed electronic property of said film on the tunneling current is measured for reading the written data bits. Minimizing the effect of blemishes on the material is effected, during operation in STM constant current mode by measuring dI/dV or dI/ds, and during operation in STM variable current (constant gap) mode by measuring (dI/dV)/I or (dI/ds)/I.

Abstract: A sharp point (5) is brought so close to the surface of a sample (4) to be investigated that the forces occurring between the atoms at the apex of the point (5) and those at the surface cause a spring-like cantilever (7) to deflect. The cantilever (7) forms one electrode of a tunneling microscope, the other electrode being a sharp tip (8). The deflection of the cantilever (7) provokes a variation of the tunnel current, and that variation is used to generate a correction signal which can be employed to control the distance between said point (5) and the sample (4), in order, for example, to maintain the force between them constant as the point (5) is scanned across the surface of the sample (4) by means of an xyz-drive (3). In certain modes of operation, either the sample (4) or the cantilever (7) may be excited to oscillate in z-direction. If the oscillation is at the resonance frequency of the cantilever (7), the resolution is enhanced.