Abstract: A voltage discharge circuit discharges the voltage across a charge storage device, such as a capacitor, at an output of a power supply. The discharge circuit may be used, for example, in a contrast power supply for an LCD panel. The discharge circuit uses one or more switches to control the coupling between the output capacitor and a discharge element, such as a resistor. When the power supply is enabled, the discharge resistor is not coupled to the output capacitor, so that the discharge circuit does not significantly affect the operation of the power supply. When the power supply is disabled, the switches couple the discharge resistor to the output capacitor to discharge any accumulated voltage at a relatively fast rate. For a contrast power supply for an LCD display, a switching power supply is preferred.

Abstract: A termination circuit for RGB signal lines provides a high frequency termination impedance that matches the impedance of a monitor cable and monitor termination, without adversely affecting the monitor-sense circuitry of an ASIC that generates the RGB video signals. When used with a VGA ASIC designed to work with 150 .OMEGA. pull-down sense resistors on the RGB lines, the circuit provides the proper 75 .OMEGA. AC termination impedance required for VGA lines while producing the 150 .OMEGA. DC termination required for proper monitor sense operation.

Abstract: A central processing unit ("CPU") activity monitor and method provides CPU activity information. The CPU activity monitor includes a timer and an activity event counter for receiving a plurality of mode signals from the CPU, a cache miss signal from a cache memory system, and a clock signal from a clock. An activity-to-inactivity value defines when the CPU transitions from an active state to an inactive state. An activity threshold defines when the CPU transitions from an inactive state to an active state.

Abstract: System and method for constructing and customizing icons for use in a graphical user interface (GUI) is disclosed. A GUI is provided with a set of available user interface components that may be selected and combined by a user to create new icons or to modify existing icons. Each icon comprises a plurality of components and each component may be represented by a set of primitives, or component objects. With respect to each component, a user may select an object from the set of objects to represent the component and the selected objects are combined to create a coherent icon used for representing applications, functions and documents in an operating system or applications program. The combination of the component objects is performed based on sets of rules associated with the individual components, which rules dictate the positioning, scaling, graphical combination and available coloring of the component.

Abstract: A dual footprint for servicing either of two types of microprocessor packaging systems. A first footprint capable of receiving and servicing a first type of microprocessor packaging system, for example, a tape carrier package microprocessor package, is formed within a second footprint capable of receiving and servicing a second type of microprocessor packaging system, for example, a pin grid array microprocessor package. In a preferred form, the two footprints are electrically interconnected and the first footprint is offset by a selected angle from the second footprint to allow increased connectivity between the two footprints.

Abstract: A hard-disk drive tray assembly includes an adapter, a tray, and a bezel. The adapter and tray are designed with slots and protrusions such that the adapter can be secured to the tray without the use of tools, screws, or nuts. The bezel pivots horizontally about the tray and comprises at least one incorporated inserter/extractor lever thereby allowing a user to insert and extract the hard-disk drive tray assembly using just one hand. The bezel has a built-in handle which allows a user to securely grasp onto the hard-disk drive tray assembly during transportation from one location to another. Furthermore, the bezel comprises a translucent or transparent LED display window for providing an external means of visually monitoring the typical LED status indication light which is integral to the hard-disk drive without having to run additional wiring from the hard-disk drive to an externally mounted LED light.

Abstract: A computer system includes a microprocessor that is electrically connected to a first synchronous bus operating in synchronism with a first clock signal at a first clock frequency. A second synchronous bus operates in synchronism with a second clock signal at a second clock frequency and provides electrical communication to a number of peripheral devices. An asynchronous bus provides data communication between the first and second synchronous bus using handshaking signals so that the first and second clock signals operate independently of each other. The operating frequency and other parameters of the microprocessor and the first synchronous bus can be changed without requiring any changes to the second synchronous bus so that the microprocessor and the first synchronous bus can take advantage of advances in technology while allowing the second synchronous bus and the associated peripheral devices to remain compatible with previous versions of the computer system.

Abstract: A circuit utilizes a toggle flip-flop, a D flip-flop and combinatorial logic to generate a clock signal which can be enabled or disabled without creating spikes or shortened pulses in the clock signal. The circuit receives an input clock signal and an input clock enable signal. The circuit generates an output clock signal which is an enabled/disabled version of the input clock signal, controlled by the input clock enable signal. The circuit thus provides the operational advantages of enabling or disabling, with a single control signal, groups of logic circuits triggered by a common clock signal.

Abstract: A telephone line monitoring circuit for a MODEM monitors the TIP and RING lines of the telephone line. A first circuit of the monitoring circuit detects when a local phone goes off-hook while the MODEM is on-hook by sensing a decrease in a differential voltage between the TIP and RING lines. A second circuit detects the pick up of a local phone while the MODEM is off-hook by detecting a change in the impedance between the TIP and RING lines. A third circuit detects the hang up of a remote phone connected with the MODEM while the MODEM is off-hook by detecting a temporary break in the DC loop between the central office and MODEM. A snoop circuit monitors the telephone line for DTMF signals while the MODEM is on-hook. The snoop circuit becomes AC coupled to the telephone line when enabled, and does not apply a significant load to the telephone line.

Abstract: A virtual addressing buffer circuit has improved address mapping and control flexibility for improved physical resource management and a unique opportunity for forward-compatible system design. The virtual addressing buffer formats the output address utilizing a format register as a combination of the new address bits and the original input address bits. The ability to format the output address enables the user to replace certain address bits without requiring that the entire address be replaced. The virtual addressing buffer controls the output of several command signals to external circuits to indicate how the system should respond to the address output from the virtual addressing buffer. The command signals are controlled by a command register and are output from the virtual addressing buffer only when an address match has been verified.

Abstract: A graphics image management system registers each image in a graphical database which can be used to select and organize the images to generate a display record identifying images which meet certain user defined criteria. Each record contains a filename and contains an index name that does not need to be unique. The graphic image management system also includes a mechanism for displaying representations of each image on a display screen. The displayed graphic images can be scrolled in a picture browser window in any order as determined by the database. Index names may be used for selection of a graphical image in a combo box. In addition, a descriptive phrase can be associated with each image in order to further identify the image and these phrases can be searched to locate a particular image.

Abstract: An interface apparatus provides an auxiliary interface between an electronic base unit and a circuit card. The auxiliary interface apparatus may, for example, provide an RF interface between a notebook computer and a PCMCIA circuit card. The auxiliary interface apparatus comprises an auxiliary base connector attached to the base unit, an auxiliary card connector attached to the circuit card, and an actuator device. The actuator device moves the auxiliary base connector between a first position, in which the auxiliary base connector does not make contact with the auxiliary card connector, and a second position, in which the auxiliary base connector does make contact with the auxiliary card connector. The actuator device preferably comprises a rack and pinion device, where the auxiliary base connector is attached to the rack. A pinion gear engages with the rack to move the auxiliary base connector between the first position and the second position.

Abstract: A small computer system interface (SCSI) disk array subsystem has removable disk drive units that can be removed while the subsystem has power applied to it and is operational. In order to prevent malfunctions of other disks in the disk array, and in order to prevent rapid fluctuations in the current in the power circuits of the subsystem, the power and the data and control signals are applied to the inserted disk drive unit in a phased sequence. Initially, the ground of the disk drive unit is connected to the ground of the subsystem along with precharge power which connects the power buses of the disk drive unit to the power buses of the subsystem through resistors so that capacitances connected to the power buses of the disk drive unit are charged gradually through the resistors rather than abruptly. Thereafter, power is applied directly from the power buses of the subsystem to the power buses of the disk drive unit.

Abstract: A pressure-actuated pointing device (PAPD), especially adapted for application in a personal, laptop, or notebook computer, is finger-activated and is used to control the displacement of a cursor on a graphics screen. The PAPD includes at least one rigid finger pad rigidly mounted to and supported by a flexible stem. The stem, in turn, is rigidly mounted to a base plate with the finger pad positioned flush with a forward-facing surface of a computer enclosure. A system operator applies pressure to the finger pad in order to displace the cursor on the graphics screen. The magnitude of the applied positive pressure gradient and point of pressure application on the finger pad determine the magnitude and direction of the cursor's displacement on the graphics screen.

Abstract: A method for restriping a striped disk array in a computer system without requiring the removal of the system from normal operation provides an efficient method to expand the disk array and incorporate the new storage into the striping scheme. When the operating system is not requesting access to the hard disk subsystem, the data is repositioned. The data on the array need not be backed-up onto alternate media before the array is expanded. Once new storage space is installed, the data is repositioned from disk to disk under the control of a disk controller until a stripe of the new array is expanded. Pointers stored in non-volatile memory maintain the location of the next free location and the next data block to be repositioned. The pointers are also used by the disk controller to locate the files during the array expansion process. The process is repeated until all of the data is relocated in the expanded array. After the relocation is complete, empty storage at the end of each disk remains.

Abstract: A cache control system generates an alternate cache control signal to unload a CPU driven bus control signal without interfering with the bus control of the other processors in the system. The alternate cache control signal removes most of the loading from the control signals of the CPU. One feature of the cache control system enables an increase in the external cache capacity of the computer system by increasing the number of synchronous SRAM chips which can be controlled by the system. Another feature enables an increase in the system performance time for memory accesses from the external cache by decreasing delays in the receipt of cache control signals.

Abstract: System and method for constructing and customizing icons for use in a graphical user interface (GUI) is disclosed. A GUI is provided with a set of available user interface components that may be selected and combined by a user to create new icons or to modify existing icons. Each icon comprises a plurality of components and each component may be represented by a set of primitives, or component objects. With respect to each component, a user may select an object from the set of objects to represent the component and the selected objects are combined to create a coherent icon used for representing applications, functions and documents in an operating system or applications program. The combination of the component objects is performed based on sets of rules associated with the individual components, which rules dictate the positioning, scaling, graphical combination and available coloring of the component.