Abstract: A method for performing background disk sector analysis for drives, including drives dedicated to redundancy and/or fault recovery techniques, in an intelligent, microprocessor based disk array. The method directs the microprocessor to wait a specified time and test for disk activity. In the absence of disk activity, the disk controller is directed to generate a read request for a disk memory location within the array. A return code following the array is checked to determine if the read failed, indicating a disk drive media failure. The disk controller is then notified if a failure occurs. The processor again checks for disk array activity and in the absence of activity issues a read request for successive locations within the array, thereby reading all disk memory locations within the array.

Abstract: An apparatus for determining cacheable address and write-protect memory address regions in a computer system which includes a programmable single-ended limit register and a single comparator to determine each such region. A programmable limit register associated with each respective memory address region defines a boundary limit for each of the respective memory regions. A single address comparator associated with each respective limit register determines whether a memory address developed by the computer system resides between the respective boundaries provided by the value stored in the respective programmable limit register and a predefined address. The use of a single limit register and a single address comparator for each memory address region reduces the gate count and decreases the input buffer loading in the logic circuitry.

Abstract: A computer system uses a random access memory to store memory characteristic information, such as noncacheable status. The memory is coupled to the processor address lines to produce an output representative of the memory address block, the output used as appropriate, for example by the noncacheable address input of a cache controller. Latches are used to store programming mode, write or read operation and data values. The reading and writing of the random access memory is performed without disturbing the main memory.

Abstract: To isolate a computer housing structure from vibration created by an internal cooling fan, the fan is provided with a pair of specially designed resilient vibration isolation members. In one embodiment, the vibration isolation members each comprise a spaced pair of pocketed end portions having generally triangular cross-sections and joined by a thin strip of resilient material. These end portions are fitted onto the corners of the fan's rectangular outer frame which is then pushed forwardly into a rectangular mounting frame, the pocketed isolation member end portions serving to space the inserted fan frame apart from the mounting frame. The rear side of the mounting frame is then secured to an inner side surface of the computer housing structure. In another embodiment, a pair of elongated resilient vibration isolation members are removable mounted on opposite outer side edge portions of a rectangular mounting frame into which the rectangular fan frame is removably inserted.

Abstract: A tower unit for a personal computer wherein the tower unit is a generally rectangular box having a generally rectangular interior chassis. The interior chassis includes a first set of interiorly extending mounting flanges and tabs which are positioned and aligned on opposing chassis walls to mount one or more drives at an upwardly facing angle in order to allow the user visual and manual access to the drives for ease of operation. A similar combination of interiorly directed tabs and flanges are formed in the opposing side walls of the frame near the bottom of the tower unit chassis in order to mount a plurality of hard disk drives in horizontal positions. The frame includes a front frame panel which combines with the front bezel to provide a gripping area which cooperates with another gripping area formed in the rear bezel to allow the tower unit to be easily moved about.

Abstract: A pointing device according to the present invention includes a trackball embedded in the case of a computer display. The trackball is placed adjacent to the display and the select buttons for the trackball are located on the backside of the display case behind the trackball. The user guides the trackball with his thumb and pushes the select buttons on the backside of the case with his index and middle fingers, allowing the user to operate the pointing device with only one hand. Alternatively, the trackball is embedded in the corner of the keyboard of a desktop system, with the select buttons on the opposite side of the keyboard behind the trackball. With the keyboard standing on legs, the user's fingers can reach the two select buttons opposite the trackball to operating the pointing device.

Abstract: A disk array controller includes a local microprocessor, a bus master interface, a compatible interface, buffer memory and a disk interface. The controller includes a DMA controller between the microprocessor, the bus master interface, the compatibility interface and the buffer memory. DMA controllers are also provided between the disk interface and the buffer memory. One of these DMA channels includes an XOR engine used to develop parity information used with the disk array. The various DMA controllers are cycled to allow access to the buffer memory and the disk interface.

Abstract: A flexible pull tab and a surface mount connector attached on opposite sides of a flexible printed circuit board is disclosed. The flexible pull tab is folded back so that the tab ends touch to ensure easy gripping for removal of connector perpendicular to the connector.

Abstract: A light pipe used for backlighting liquid crystal displays has a planar front surface and a stair-stepped or faceted back surface. Light is injected from the ends of the light pipe from cold- or hot-cathode, apertured, fluorescent lamps. The cold-cathode lamps are preferably insulated to raise their operating temperature. The back surface has a series of planar portions parallel to the front surface connected by facets, which are angled so that the injected light reflects off the facets and through the front surface. A reflector having a planar, highly reflective, highly scattering surface or a sawtoothed or grooved upper surface in located adjacent to and parallel with the light pipe back surface to reflect light escaping from the back surface back through the light pipe to exit the front surface. The axis of grooves is preferably slightly skewed from the facet axis to reduce moire pattern development.

Abstract: A battery charge controller and fuel gauge which accurately monitors the voltage, temperature, and charge and discharge current of a rechargeable battery, and calculates the battery's charge capacity and charge level. Each time the battery is fully discharged, any calculated charge level remaining is divided by subtracted from the previously calculated charge capacity. When the battery is fully charged, the charge level is set equal to the charge capacity. During subsequent charge and discharge, the current is converted to a coulomb count and added or subtracted from the charge level to maintain an accurate charge level. Fast charge inefficiency due to temperature is considered by subtracting a temperature proportional factor before the charge level of the battery is updated. The charge level, voltage and temperature are used to determine the optimal fast charge termination point to achieve full charge and prevent temperature abuse and overcharge.

Abstract: An improved cover assembly for the electrical connectors of a notebook computer. The notebook computer of the present invention is adapted to be connected by electrical connectors with an expansion base. The improved cover assembly includes a cover plate hinged to the housing of the notebook computer movable relative to the housing between an uncovered position and a retained position. The cover plate includes a slidable door being sized so as to allow connection of a preselected connector of the notebook computer. The improved cover assembly can be adapted to allow the notebook computer to be connected to the expansion base while the remaining notebook computer electrical connectors are covered to reduce the amount of undesirable foreign matter in the open ended connectors that can reduce connection performance.

Abstract: A method for communication between multiple processors using registers that are accessed by four register select lines which are translated from the original system address. The address translation is performed off of the main processor board to reduce loading effects on the local bus and reduces the pin count of processor board. A signal representing which of the processors is currently active is used as a pseudo address line for the purpose of the translation. The original addresses of the I/O registers may be either input/output or memory mapped.

Abstract: An apparatus 10 is employed for controllably separating a top sheet of paper 52 from a stack of paper 50 and delivering this top sheet of paper 52 to a printer. A rubber wheel 26 is maneuvered into contact with the top sheet of paper 52 and is rotated in a first direction to urge the top sheet of paper 52 toward a rear surface of a tray 12 in which the stack of paper is positioned. The top sheet of paper 52 contacts the rear surface and bows upward, away from a remaining portion of the stack of paper 50. This bowing action serves to separate the top sheet of paper 52 from the sheets of paper immediately below it. Thus, once the top sheet of paper 52 is separated, the diretion of rotation of the rubber wheel 26 is reversed so as to remove the top sheet of paper 52 and deliver it to the printer.

Abstract: An image reproduction machine has an outlet opening through which successive image-imprinted paper sheets are forwardly discharged by a spaced series of exit roller sets. The discharged sheets are delivered into an open-topped housing well area having a horizontal bottom surface with a back edge forwardly and downwardly offset from the outlet opening, and a ramped surface extending downwardly and rearwardly from the horizontal surface back edge. A deflector bar adjacent the outlet opening has first downwardly projecting portions that engage each discharging sheet and temporarily corrugate and stiffen it in a manner assuring that its front end portion will forwardly clear the rear horizontal surface edge before bending down to its level. These downwardly projecting portions are interdigitated with the exit roller sets and positioned to perform their temporary corrugation function without crinkling the discharging sheets.

Abstract: An automatic switch actuator is disclosed which may be used to test press-to-actuate type switches--for example, the key actuated switches of a computer keyboard. In the illustrated embodiment of the invention, a system of electrically operated valves are used to apply four different fluid pressures to selected pistons of an array of pneumatic cylinders. Each cylinder is mechanically connected to a plunger which is oriented so as to contact a selected key in an array of keys (i.e., a keyboard).

Abstract: A surface mountable insulation displacement type connector for electrically coupling an end portion of a connector ribbon to a spaced series of surface mounted electrically conductive contact pads on a printed circuit board has an elongated base portion through which the central body sections of a longitudinally spaced series of metal contactor pins transversely and slidably extend. The pin body sections have bifurcated, barbed top end portions disposed above a top side of the connector base portion, and transversely enlarged bottom end portions disposed below the bottom side of the base portion. The base portion is secured to the circuit board by soldering the bottom pin end portions to the baord contact pads, with the slidable mounting of the pin body sections automatically compensating for board surface height variations in the region of the surface contact pads.

Abstract: Portable electronic devices, such as personal computers, are provided by this invention which include hinged housing compartments containing a monitor and a keyboard as well as at least one extendable flap for extending the keyboard surface to more closely approximate a full size keyboard. These devices are much easier to type on and do not sacrifice functionality of compactness. Extendable supports are provided to retain the flap in a substantially planar orientation.

Abstract: To isolate a computer housing structure from vibration created by an internal cooling fan, the fan is provided with a pair of specially designed resilient vibration isolation members. In one embodiment, the vibration isolation members each comprise a spaced pair of pocketed end portions having generally triangular cross-sections and joined by a thin strip of resilient material. These end portions are fitted onto the corners of the fan's rectangular outer frame which is then pushed forwardly into a rectangular mounting frame, the pocketed isolation member end portions serving to space the inserted fan frame apart from the mounting frame. The rear side of the mounting frame is then secured to an inner side surface of the computer housing structure.

Abstract: Method and apparatus for determining nets among nodes in a circuit board that includes applying a potential to a reference conducting surface oriented with respect to the board; measuring a parameter of an electrical response at a node of interest; and comparing the measurements to determine a plurality of nets among the nodes. The tentative net list developed from the measured parameters is then verified using continuity testing.