Abstract: A diagnostic apparatus for testing devices such as computer systems, and computer system components such as disk drives or printers. The device comprises a main unit, the main unit having a central processing unit for executing instructions, issuing commands, and receiving data from a first device. The apparatus also has a first peripheral unit coupled to the main unit, the first peripheral unit having ports for interfacing with the first device, the first peripheral unit being interchangeable with a second peripheral unit for interfacing with a second device. The apparatus also comprises a first non-volatile memory unit coupled to the main unit, the first non-volatile memory unit comprising a first set of tests for the first device, the first non-volatile memory unit being interchangeable with a second non-volatile memory unit comprising a second set of tests for a second device. These interchangeable parts are provided so that the user may test various types of hardware.

Abstract: A filter capable of having its damping and frequency parameters independently varied. The filter can be represented in either a digital or an analog computation network. The network comprises four multipliers for multiplying by a frequency term twice and a damping factor twice. In addition, the network comprises two unit delay blocks for temporarily storing previous signal input values for zeros or output values for poles. These stored values are used in computing subsequent outputs. The multipliers are configured with adders and subtractors to compute a next output value as a combination of a current input, a weight -2+2df+f.sup.2 --wd.sup.2 f.sup.2 times the most recent saved value and a weight 1-2df+wd.sup.2 f.sup.2 times the previous saved value. Moreover, unity gain at DC can be achieved.

Abstract: A method and apparatus for generating and viewing a transition between a first and second sequence of images on a computer controlled display system.

Abstract: Electronic paper which has two sides, reverse of one another, which can be flipped over in response to user generated flip commands is described. When a piece of electronic paper is flipped over, a number of transition views of the paper are generated to give the user the impression that the paper is actually being turned over to reveal a reverse side. Different information can be stored on either side, and the composition of either side can be linked so that changes made to the graphic information on one side affects the graphic information on the other side. In addition, when the amount of graphic information on the reverse side of the paper exceeds the amount of available space normally available on the reverse side when the paper is flipped over, approximately the same amount of space available on the top side, the reverse side is expanded to fit the quantity of information to be displayed on the reverse side.

Abstract: Method and apparatus for accurately determining the charge state of a battery is disclosed. The charge state is derived from the battery voltage, which is corrected for errors introduced by temperature and series resistance. Error from series resistance is minimized by either making an open circuit voltage measurement, or by making a plurality of voltage measurements under known load conditions, calculating the series resistance from these measurements, and calculating an equivalent open circuit voltage, compensating for the voltage drop caused by the series resistance of the battery. Errors introduced by temperature induced shifts in battery voltage are corrected by reading the battery temperature and correcting the battery voltage to a reference temperature. The battery voltage corrected for temperature and series resistance effects is used to compute charge state by table look up or algebraically.

Abstract: A memory system where a cache miss is fielded with a retry access to main memory, but instead of waiting for the microprocessor to resynchronize and re-initiate the memory cycle, the memory cycle is started immediately. The speed of the tag array is specified so that the status of the cache, hit or miss, is known at the same time that the microprocessor's memory cycle start signal is known to be valid. The addresses are then latched and the memory cycle is started in anticipation of the retried cycle. The access time of memory is then overlapped with microprocessor resynchronization and memory cycle reinitialization. By using this technique, clock cycles are needed for the initial cycle, additional clock cycles are needed to perform the resynchronization, and additional clock cycles are needed for the retried cycle since the data is already waiting from memory. The above-described improvement is implemented by decoupling the direct connection of the memory array from the address bus.

Abstract: A modular enclosure for personal computer systems, and methods for assembly of an enclosure. The enclosure substantially comprises a base, a unitary internal frame, a front and a back panel, and a U-shaped top cover. Frame-mounting snaps and cruciform members located on forward and rear portions of the frame mate to complimentary receiving openings in the base. Front and rear panels are mounted to the base, frame, and top cover by a plurality of panel-mounting snaps and hooks. A base electromagnetic interference (EMI) shield at the periphery of the shield having a plurality of planar tabbed fingers with hemispherical domes formed therein is then fitted and secured to the base such that the lateral edges of the fingers are recessed below a peripherally extending rim on the base. Thereafter, the internal frame is snapped into place upon the base, and a rear panel having an EMI shield fitted and secured to the base and frame by panel-mounting snaps and hooks.

Abstract: A hidden, releasable latch for a molded plastic enclosure having a first panel abutting a second panel along a seam. The first panel has a pressure bump on its inside surface a first distance from the seam, and a projecting tang on its inside surface at a further distance from the seam. The second panel has a tab from its inside surface projecting inside, parallel and spaced from the inside surface of the first panel, the tab contacting the pressure bump, and capturing the projecting tang in a hole within the tab. The tab is flexible enough for slight deflection during the capturing of the tang by the hole during an assembly process, and the releasing of the tang by movement of the tab from pressure from the pressure bump during a disassembly process.

Abstract: A first embodiment of the present invention comprises a housing for a docking station for use with a portable computer. The docking station provides the portable computer with increased display and data storage capabilities. In use, a portable computer is inserted into the docking slot of the docking station. Additionally, a large cathode ray tube display is place on top of the housing for the docking station in typical user scenario. As docking and undocking must not be hindered by the presence of a large display on top of the housing for the docking station, the housing is provided with internally mounted cross beams that distribute the weight of the display around a computer supporting skeleton and through a set of support columns into the surface the housing for the docking station is resting upon. This reinforcing cross beams and columns structure allows the housing for the docking station to support without deformation relatively large displays without being excessive in weight of size.

Abstract: A digital encryption structure allows the varying of the computational overhead by selectively reusing, according to the desired level of security, a pseudorandom encoding sequence at the transmitter end and by storing and reusing pseudorandom decoding sequences, associated with one or more transmitters at the receiver end. A public initialization vector is combined with a secret key to produce a deterministic sequence from a pseudorandom number generator. This pseudorandom sequence in turn, is used to convert plaintext to ciphertext. The sequence may be selectively reused by storing the sequence to a transmitter memory cache and iteratively reading the sequence from memory according to a counter which controls the level of security of the encryption system. The ciphertext is decrypted on the receiver end by invertibly combining the ciphertext with the same pseudorandom sequence used by the transmitter to originally encode the plaintext.

Abstract: A method and apparatus for approximating a value distributed between two endpoints. The method and apparatus are embodied in a rendering device for calculating pixel shading values for the display of 3-D graphical images. The method approximates a function P(w)=(1-w)A+wB, where w is a provided interpolation weight between 0 and 1, A is a first endpoint value and B is a second endpoint value. The method causes exact evaluation for the cases where P(0)=A and P(1)=B.

Abstract: In a method for manipulating a selected object on a computer display of a computer system through the use of a pointing device and a screen based icon, the types of manipulation may include rotating and/or scaling the selected objects. The method includes the step of selecting a manipulating tool having a designated "axle" mark that serves as its center of rotation. The pointing device is directed towards a "handle" portion of the manipulating tool that is spaced apart from the axle to "grab" the handle. The pointing device is then used to rotate the handle about the axle. The computer system then manipulates the selected object by an amount that is a function of the angular distance that the handle is rotated about the axle user interface includes a screen based icon.

Abstract: A method for rapidly transferring serial data in a two conductor busing arrangement in which one conductor is utilized to transfer data and the other conductor is utilized to transfer clock signals, and in which a plurality of components are connected to the two conductors, at least one of which is capable of acting as a bus master including the steps of providing clock signals on the clock conductor which are active on both edges, placing a special signal on the data conductor to indicate the start of an operation, placing address data on the data conductor to indicate an address on the data conductor, placing data on the data conductor to indicate the type of transfer to be made, acknowledging the receipt of the address by a component being addressed, transferring data on the data conductor, placing a special signal on the data conductor to indicate the end of the data transfer, transferring a signal indicating a parity count, and placing another special signal on the data conductor to indicate the end of t

Abstract: An apparatus and method useful for the efficient display of images on a computer display screen a display area description language is provided for describing and manipulating portions of a raster display screen. The area description language is comprised of a set of instructions and masks that define the areas and manipulations for a particular display. The area description language is used to define the location, dimension and contents of areas within a logical display grid. Each area description command is comprised of three components. First, each command has an associated scan count. The scan count defines which scan line or lines will be operated upon by the command. Secondly, each command has at least one instruction. The command instruction is used to define the location and the dimension of the area being defined by the command. The third component that may or may not exist in each command is a mask.

Abstract: A user interface element having a plurality of user interface elements for marking, finding, organizing, and processing data within documents stored in an associated computer system are described. Each element typically has an appearance which is uniquely related to the data or the function the element is designed to represent or perform, respectively. In their simplest form, these elements are only used to mark data within a document. Each element, however, can also be programmed to cause the computer to perform some function in association with the marked data, such as printing the data or mailing the data to someone. A user can select particular data within a document using an element and have that data associated with the element in memory. Data marked with common elements can be found by searching for a particular representative element in memory. Users can create their own elements, program elements with their own desired functionality, and modify existing elements.

Abstract: A method for encoding compressed graphics video information and decoding such information. The method consists of enriching the video information in zeros through shifting and Exclusive ORing video image with itself. A number of methods are attempted in the shifting and Exclusive ORing process in order to determine the method which yields the optimum zero enriched image. The zero enriched image is then encoded and the encoded information stored. Upon retrieval, the information is decoded and an Exclusive OR and shifting process is done to obtain the original video information.