Abstract: A personal digital assistant module with a local CPU, memory, and I/O interface has a host interface comprising a bus connected to the local CPU and a connector at a surface of the personal digital assistant for interfacing to a bus connector of a host general-purpose computer, providing direct bus communication between the personal digital assistant and the host general-purpose computer. In an embodiment, the personal digital assistant also stores a security code. The personal digital assistant according to the invention forms a host/satellite combination with a host computer having a docking bay, wherein upon docking, a docking protocol controls access by the host to memory of the personal digital assistant based on one or more passwords provided by a user to the host. In another embodiment the personal digital assistant also has an expansion port connected to the local CPU, and expansion peripheral devices may be connected and operated through the expansion port.

Abstract: Timing is set for DRAM memory access in a computer by polling the DRAM memory banks, calculating capacitive load by accessing a prestored table of capacitive load versus DRAM size, and assigning wait states according to calculated capacitive load by accessing a prestored formula. In one embodiment, wait states are assigned in increasing increments for increasing total capacitive load. In an alternative embodiment, timing is assigned bank by bank. Control routines are preferably a part of a system BIOS.

Abstract: A system using a printer with a fuser-heater has control means for turning off the fuser-heater during times when no printing is required, while leaving the rest of the printing system operable. Time between print requests is monitored, and the fuser-heater is turned off when a preset time is reached without a print request. A next request turns the fuser-heater back on again. Data is accepted at a reduced rate while a heater warms up.

Abstract: 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.

Abstract: A system using a printer with a fuser-heater has control means for turning off the fuser-heater during times when no printing is required, while leaving the rest of the printing system operable. Time between print requests is monitored, and the fuser-heater is turned off when a preset time is reached without a print request. A next request turns the fuser-heater back on again. Data is accepted at a reduced rate while a heater warms up.