Abstract: An I/O port interrupt mechanism includes a source register connected to the port for reporting sources of interrupts arising within the port, an interrupt mask register connected to the source register and operable to configure the I/O port for generation of interrupts, and an interrupt controller connected to the output of the source register and operable to hold off interrupts arising within the I/O port.

Abstract: Apparatus and a method are disclosed for reducing the transmission power required when a host computer displays video information on a remote video display. A video memory is located in close proximity to the display so that the display can be periodically refreshed in the normal manner from the local memory. Consequently, the host computer need only transmit information regarding the portions of the local memory that have changed since the last data transmission. Since the information for the entire local memory is not transmitted each time the memory must be updated and in particular, each time the display must be refreshed, the required data transmission rate between the host and the display is greatly reduced from the rate normally required with prior art apparatus and, consequently, the power consumption is reduced.