Abstract: An integrated circuit cell module for performing precise time measurements for use in applications such as disk drive controllers. The combination of the cell module and a hard disk controller chip creates a complete hard disk controller in a single chip without the need for external analog components normally required for classic phase lock loop hard disk controllers. A problem in designing such a unified chip is that it must be digital in nature. Therefore, the maximum resolution with which signals generated by the disk drive (Rddata signals) can be measured and signals generated by the controller for writing to disk (Wrdata signals) can be generated is dependent on the clock which drives the controller chip. In hard disk controllers, the data rate is such that the minimum distance between adjacent Rddata or Wrdata pulses is approximately 100 ns which would require an oscillator having a speed which would be impractical in a design.

Abstract: A data compression method which recognizes the adverse conditions of duochrominance-isoluminance and nonlinear color distribution. A mxn block of pixel data is examined to compute two colors and a bitmap which best represent the block generally using a luminance partitioning technique. The original data and the compressed data are examined to determine if the resultant decompresssed image will contain artifact associated with duochrominance-isoluminance or nonlinear color distribution. If these artifacts will occur in the decompressed data, the decompressed data is not used but rather the block is represented by storing the color of each pixel. This method produces compressed images of excellent quality.

Abstract: An adaptive compression/decompression method for color video data with an anti-aliasing mode. 4.times.4 blocks of pixel data are examined to determine which one of four compression techniques should be used on each block. User settable thresholds can be used to shift the types of compression used. Highest compression is obtained when more data is stored in run length blocks of single colors and lowest compression when more data is stored as two colors with a 32-bit bitmap for each 4.times.4 block. One type of compression used provides anti-aliasing.

Abstract: A clock circuit for generating two clock signals, one (CLK) having stretched clock phases on a cycle by cycle basis, and the second (2X CLK) being a clock signal having a frequency twice the frequency of the first clock signal which is phase and edge coherent with the first clock signal, including the stretched clock phases. The circuit inputs a signal generated by an oscillator which is twice the frequency of the CLK signal which is then used to generate the CLK signal for use by a microprocessor, either phase of which can be stretched on demand, while the second 2X CLK signal remains phase coherent with the microprocessor CLK signal.

Abstract: A video display apparatus for composing video signals for a raster scanned display on a line-by-line basis. Objects are stored in a video RAM and are packed in the RAM without regard to their location on the display. A separate dispatch table contains information on each object and commands. A dispatcher operates on this information, allowing lines of data and commands to be extracted from the RAM as each video line is composed in a buffer.

Abstract: A printer using meltable solid ink pellets loaded into a reservoir in which a holder with an attached solid ink pellet is inserted through a doorway for access to the reservoir and a release mechanism within the reservoir releases the ink pellet from the holder by engagement of the ink and release mechanism. The holder surrounds the pellet on all but one end and includes keyed projections on the holder for matching to keyed slots on said doorway, such that only a matching keyed holder will pass through said doorway. The keyed projections on the holder are used to open the doorway. The release mechanism includes a bore for receiving and restraining the pellet against rotation of the holder, or can include a thin chisel for severing the connection of the pellet to the holder.

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 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.

Abstract: A substantially spherical ball to be used in a cursor controlling mouse. The mouse ball is formed from a composition of silicone having zirconium dust dispersed uniformly throughout. The zirconium provides the added weight necessary to keep the ball rolling on a working surface, but is not sufficiently conductive to short electrical components in mouse. The uniform composition provides for the mouse ball to have its gravitional center coincident with its geometric center to inhibit cursor jitter when the mouse is manually moved.

Abstract: A logic cell is described having four inputs, four outputs, a control store, means for multiplexing the four inputs onto two leads and logic means that operate in response to the signals on the two leads and signals from the control store to product output signals which are applied to the four outputs. Illustrative logic functions provided by the logic means include a cross-over or identity function, a change in the routing direction of an input signal, NAND and XOR gates and a D-type flip-flop. The selection of two of the four inputs as well as the selection of the particular logic function that is implemented is controlled by control bits stored in the control store. Numerous such logic cells are arranged in a two-dimensional matrix such that each cell has four nearest neighbor cells, one to its left (or to the West) one to its right (or to the East), one above it (or to the North) and one below it (or to the South).

Abstract: An improved handle and latch assembly for a portable personal computer. The computer includes a cover. To open the cover, the user grasps the handle and pushes it a slight distance toward the computer. The handle is slideably coupled to the cover of the personal computer. A locking member is moveably disposed within the cover. A pair of locking hooks extend out of the cover and engage with slots in the keyboard section of the computer. When the handle is moved inward, it contacts the locking member and moves it, thereby releasing the hooks, and allowing the cover to be opened.

Abstract: An apparatus and method is disclosed for reducing flicker in an interlaced computer generated raster-scanned display. Several circuits and methods are described for implementing vertical filtering. In general, the data for a given pixel on the nth, nth+1, nth+2 . . . nth+N line is read from memory and convolved to provide data for a given pixel on a display line before pixel data for other pixels along these lines is read from memory.

Abstract: A method for building an inverse color look-up table in a color graphics system. The inverse color look-up table accepts as an address input RGB color information and provides as a data output index information for indexing a color look-up table. The method initializes an array of data elements, each of said data elements for storing said index information, each of said data elements corresponding to a color position in RGB color space. A first index value is stored in the array, the first index value corresponding to an index for the color look-up table. The first index value is stored in a first of the data elements, the first data element corresponding to a color represented by the first index value in the color look-up table. An address of the first data element is also stored in a queue means. For a second of the data elements, it is determined whether the second data element has been assigned an index value.

Abstract: Methods and apparatus are provided for performing multi-gauge arithmetic operations in a microprocessor CPU. Special purpose instructions facilitate parallel processing of individual bytes or half words of data words without requiring that the processor's mode be separately controlled. A byte/half word mode flag is provided to control the "width" of narrow gauge operation. Add partial, substract partial and compare partial instructions operate on corresponding bytes or half words of two operands and return independent byte or half word results. Multiply partial instructions multiply byte or half word multiplicands by a common multiplier and return independent byte or half word products. The multi-gauge arithmetic operations of the present invention have particular application to graphics processing where repetitive operations are performed on large arrays of pixel data.