A switching system is provided to enable selective access from a work center W to any of a plurality of computers PC1-PC16. Connections are provided from .the work center W including a video monitor, a keyboard and a mouse through a selector S proximate the work center W and a single cable bus CB extending in parallel to a plurality of controllers C1-C4 proximate individual computers. The selector S associates a specific computer with identification signals that are provided through the cable bus CB to the controllers C1-C4 to selectively link the identified computer through one of the controllers C1-C4 and the selector S to the work center W. The selector S incorporates a display to identify the selected computer and a manual switch for computer selection. Signal adjustment, reset and autobooting capabilities are provided in the system.

A bus interface system for expanding the I/O capability of a portable computer utilizes a parallel port connector with master interface circuitry connected to the internal ISA I/O bus of the portable computer and driving a 25-conductor Centronics-type cable as an intermediate bus. The master interface circuitry is device-driver-transparent, and multiplexes address, data, and control information over a byte-wide avenue of the intermediate bus according to premapped state translation tables. In a preferred embodiment a single peripheral I/O device comprising a slave circuitry may be connected to the 25-pin port, and the slave circuitry demultiplexes the intermediate bus states, providing a synthesized sub-set of ISA states to drive the peripheral device. In another embodiment a docking box comprises a bus with multiple I/O ports, such as a network port, a COM serial port, and additional floppy and hard disk drives. Power circuitry is provided for driving a single connected peripheral device, and for recharging a docked portable computer.

A method and mechanism for automatically correlating a device to its appropriate driver within a computer system utilizing candidate matching. A device tree indicating devices coupled to a computer system is available from an operating system. Within the device tree are device nodes which specify a particular device's name (device name) and a property which indicates compatible device names (compatible names) to the particular device. Drivers for devices can be located in RAM, ROM, or in another storage media (such as disk drive). Drivers can include a data field indicating a driver name indicative of a corresponding device with which they operate. For a particular device, the system constructs a candidate list of drivers by comparing (1) the device name and (2) the compatible names from the device tree against all the driver names of data fields of all known drivers. The candidate list is sorted so that matches by device name and proper version number are higher priority. The system then sequentially attempts installation of the drivers from the candidate list to the particular device (based on priority order) to determine the appropriate driver (e.g., probing the device using diagnostic operations). Drivers are skipped that cause an error or that do not properly configure the device. The process can be repeated for all devices in the computer system. The process is dynamic in that it is operable on boot up and upon any system change that allows more drives to be recognized.

A method and system for generating command signals for a computer monitor or other equipment. The system includes at least one pressure responsive potentiometer and a device operatively connected with such potentiometer for generating a command signal indicating at least one of the direction, intensity and duration of pressure applied to such potentiometer. The method remotely controls a function of a computer monitor or other equipment in response to signals obtained from pressure sensitive potentiometers manipulated by a user. The method includes the steps of periodically iterating to detect signals present on such pressure sensitive potentiometers, comparing the signals detected on each iteration to determine at least one of the amount and direction of change, generating a control signal reflecting the information determined in the comparison step, then transmitting the control signal to the computer or other equipment in a form acceptable by such computer or other equipment to effect a change in the function being controlled. The control system includes a hand held device having a control disc readily manipulable by a digit of a hand holding the device. There is also disclosed a form of the hand held device in which position control signals as well as "clicking" and "dragging" operation signals can all be controlled with a single digit of the hand of a user.

In a computer system having a built-in pointing device, connection/disconnection of an external pointing device having a processor is detected upon activation of the computer system. A battery-backed-up memory in the computer system stores information representing a use mode of pointing devices. If the use mode is set in an "auto-selected mode" and the connection of the external pointing device is detected, the use of the internal pointing device is disabled and only the external pointing device can be used under the control by the processor included in the external pointing device. If the use mode is set in a "simultaneous mode", both the internal and external pointing devices can be used.