Computer workstation with interrupt signaling arrangement

Abstract From the Canadian patent

A computer workstation including a processor one or, more input/output units, such as disk devices or network interfaces, a program memory and a video memory which contains video information displayed on a video monitor. An arbitration circuit selects among the processor and input/output units for transfers to and from the program memory and video memory. A master control circuit controls timing of transfers to and from the program and video memories, and periodically enables video update transfers of video information from the video memory to video control circuits, which control the video monitor. While a video update is in progress, the master control circuit holds off other transfer …