Abstract: A circuit arrangement and methods for sensing whether line terminator devices are present at terminal ends of high speed communications pathways, and enabling a switching terminator in accordance therewith, are disclosed. In one embodiment, the communications pathway comprises a Small Computer System Interface (SCSI) bus comprising internal and external bus segments and bus control lines, including a reset line consisting of internal and external reset line segments. First and second system reset signals are supplied from a central processor unit (CPU) to various system components. Line terminator devices may or may not be coupled to the ends of the internal and external bus segments. The first system reset signal is directed to first and second transistors coupled together in an "upside down" collector-to-emitter configuration comprising a two-quadrant bidirectional switch which opens upon assertion of the first system reset signal.

Abstract: Housings for personal computers are assembled at a first site and then shipped in bulk to one or more configuring sites. At the configuring sites, electrical components are inserted into the housing, and the thus-configured computers are packaged in individual containers, along with packing material. Each container has an openable vertical wall. If the computers need to be reconfigured, the openable wall of the container is opened, and one or more of the electrical components are removed and/or replaced horizontally through that opened wall without having to remove the computer or packing material from the container.

Abstract: A scanning method for receiving a signal in a frequency hopped communication system that transmits a packet having N segments that are encoded with an error correction code that allows recovery of a packet even if e segments are erasures. A receiving station continuously scans the first p (1.ltoreq.p.ltoreq.e+1) channels, testing each channel for the existence of a transmission. If detected, a segment is received, and then the receiving station sequences through the remaining channels, receiving the segments if possible, and then applying error correction to the complete transmission. This technique of scanning the first several channels, receiving the first unimpaired segment, and thereby gaining the ability to recover all unimpaired segments enables the full theoretical power of a coded, slow frequency hopped system to be realized.

Abstract: An arbitrary curve formulated as a quadratic B-spline with a plurality of second order Bezier curves is approximated. Applying a forward differencing to the parametric equation of the second degree Bezier curves, a second order difference coefficient is derived. By defining the error from approximating the curve with forward differencing as the distance between the approximated point on the curve and the midpoint between the end points of the curve, the second order differential coefficient is directly proportional to the error. Additionally, the error resulting from increasing the number of parametric intervals for the forward differencing is proportional to the original error. It follows from the relationship established for the second order differential coefficient, the number of parametric intervals, and the error threshold that the user specifies, the number of parametric intervals is determined.

Abstract: A printed circuit board is installable into a slot of a cardedge connector such that contacts of the connector ride along electrically conductive, raised pads of the card. Each pad includes frontal edge segments which are inclined generally rearwardly toward a center axis of the pad so that if any of the contacts are laterally offset with respect to the center axis of its respective pad during installation, the offset contact will be re-directed toward the center axis in response to making engagement with one of the frontal edge segments.

Abstract: The display system includes at least one central processing unit (CPU) which is coupled through appropriate input/output (I/O) circuitry to input devices, such as a keyboard, digital pad, mouse and/or trackball. The CPU is coupled to a hard disk drive for the storage of programs and data, and may also be coupled to a network through which the CPU may communicate with a variety of other system resources and devices. The CPU is further coupled to a display device such as a CRT or liquid crystal display, on which the present invention is displayed. The windows include defined areas having window features such as menu bars, command options, text, icons and/or button functions to be executed by the CPU. The help system includes an access window having topics, index and look for button functions for selection by a user. Through the use of the topics, index or look for functions, a help inquiry is defined which results in the CPU generating and displaying a presentation window on the display.

Abstract: In a computer system having an input device for controlling a position of a cursor on a display screen, a method of compensating for a physical orientation of the input device relative to the display screen. Initially, the physical orientation of the input device in relation to the display screen is determined. If the input device has been rotated, a first set of values corresponding to movement in the X axis is swapped with a second set of values corresponding to movement in the Y axis. Next, the sign of the first set of values corresponding to the Y axis is changed. Thereby, a horizontal movement indicated by the rotated input device produces a horizontal movement of the cursor. Likewise, a vertical movement indicated by the rotated input device corresponds to a vertical movement of the cursor.

Abstract: Signal transactions are conducted between nodes coupled to a bus, without causing bus deadlock during split transactions. Deadlock avoidance is achieved by rendering a node effectively unavailable at such times to serve as a bus slave for a new bus master. When the "locking" node serves as a transaction source, deadlock is avoided by deasserting, during a split transaction, a buffer-available signal, which is used normally to indicate receiver buffer availability. Additionally, when the "locking" node serves as a transaction destination, deadlock is avoided by deasserting a bus-ownership request signal, which is used normally for requesting bus ownership. After completion of the split transactions, such signals may be unmasked.

Abstract: Apparatus for converting representations of color pixels in a twenty-four bit color format to representations in a fifteen bit color format including an individual circuit for data representing each component of a color, each of the individual circuits including apparatus for selectively incrementing the value the five highest order bits of a value representing a component of a color, apparatus responsive to a value of the lowest order bits of a value representing a component for providing a signal to cause the apparatus for selectively incrementing the five highest order bits, and apparatus for selectively enabling the apparatus responsive to a value of the lowest order bits depending on a desired pattern of pixels.

Abstract: A housing and ejection mechanism for PCMCIA electronic "smart cards" is disclosed. The ejection mechanism comprises a pair of cooperating lever arms and springs. When a "smart card" is inserted into the housing, the two lever arms pivot into the housing, extending an ejection spring. As the spring is pulled back by means of the lever arms, insertion of the card requires only slightly more force than would be needed to connect a "smart card" with its socket were no spring present. Full insertion of the card leaves the two lever arms coupled, but with only one of the lever arms locked in position. When the user triggers the ejection process, the two levers are mechanically separated and one of them applies the full spring force to the "smart card", freeing it from its socket and starting to push it out of the housing. After the first arm frees the "smart card" from its socket, it frees the second lever arm from its latch. The two lever arms then cooperate to push the "smart card" further out of the housing.

Abstract: The de-skewer utilizes a delay line to generate a set of delayed versions of an input clock signal. A bank of flip-flops compares pulses within the delayed clock signals to a synchronization pulse provided within an input data signal. A detector receives outputs from the flip-flops and selects the delayed clock signal having the least amount of skew based on the values of the output from the flip-flops. A multiplexer outputs the selected delayed clock. The de-skewer provides a simple, open-loop circuit for eliminating skew between parallel transmission paths. The de-skewer is ideally suited for eliminating skew from sources which do not vary significantly as a function of time. In particular, the de-skewer is well-suited for use in a data transmission system providing short bursts of high data rate transmissions. A double-edged de-skewer is also described which is capable of generating a pair of clock signals for use in eliminating duty cycle distortion.

Abstract: A data compression process and system that identifies the data type of an input data stream and then selects in response to the identified data type at least one data compression method from a set of data compression methods that provides an optimal compression ratio for that particular data type, thus maximizing the compression ratio for that input data stream. Moreover, the data compression process also provides means to alter the rate of compression during data compression for added flexibility and data compression efficiency. Furthermore, a system memory allocation process is also provided to allow system or user control over the amount of system memory to be allocated for the memory intensive data compression process. System memory allocation process estimates the memory requirement to compress the input data stream, and allocates only that amount of system memory as needed by the data compression for memory allocation efficiency.

Abstract: A method for manipulating an inked object with a pointing device on a pen based computer system includes receiving an ink stroke made with a pointing device, displaying the ink stroke on a screen of the computer system and creating a representative stroke within the computer system from the ink stroke. Upon the receipt of a user-initiated command, the representative stroke is first manipulated and then the ink stroke is manipulated in accordance with the representative stroke. Only the ink stroke is displayed on the screen. Examples of manipulation of the inked object include sizing, distorting, and deleting segments of the inked object. The method of the present invention is preferably practiced as a computer implemented process on a pen-based computer system.

Abstract: A technique for analyzing and interpreting user inputs to a computer, such as strokes, key depressions, or voice signals to a hand-held, pen-based computer system. Inputs to the system are received at a user interface, such as a dual function display/input screen from users in the form of pen strokes or gestures. A database stores the input data strokes and hypotheses regarding possible interpretations of the strokes. Recognition of the input strokes and recognition of higher level combinations of strokes (forming characters and words, etc.) is performed using recognizers, or recognition domains, each of which performs a particular recognition task. A controller is provided for controlling the hypotheses database and for scheduling the recognition tasks in the recognition domains. Arbitration resolves conflicts among competing hypotheses associated with each interpretation. The recognition domains, or recognizers generate two or more competing interpretations for the same input.

Abstract: A method and apparatus for automatic alignment of manipulated objects in two-dimensional and three-dimensional graphic space. The present invention provides an alignment field gradient which emanates from objects surrounding the manipulated object(s). As a user manipulates an object, the present invention attracts the manipulated object into an aligned position and orientation with another object(s) in the displayed three-dimensional display space. The present invention provides alignment of all combinations of vertices, edges and planar faces for three-dimensional polyhedral objects and for all combinations of vertices and edges for two-dimensional polygonal objects.

Abstract: An apparatus and method for protecting the state of a state machine from an unstable clock signal. The apparatus of one embodiment includes a state register having an input and a first output which provides an output signal corresponding to the state of the state machine and a set or reset input coupled, through a logic circuit, to the first output. The logic circuit is coupled to receive a signal indicating the unstable state of the clock signal. The logic circuit is coupled to receive a signal indicating the unstable state of the clock signal. The logic circuit feeds back the output from the first output to the set or reset input to maintain the state in the state register while the clock signal is unstable. An embodiment of the method comprises storing a state in a state register, receiving a first signal indicating an unstable state of the clock signal and feeding back the output from the state register to the set or reset input while the first signal indicates the unstable clock exits.

Abstract: An apparatus and method for processing video data for compression/decompression in real-time. The apparatus comprises a plurality of compute modules, in a preferred embodiment, for a total of four compute modules coupled in parallel. Each of the compute modules has a processor, dual port memory, scratch-pad memory, and an arbitration mechanism. A first bus couples the compute modules and a host processor. Lastly, the device comprises a shared memory which is coupled to the host processor and to the compute modules with a second bus. The method handles assigning portions of the image for each of the processors to operate upon.