Abstract: A multiprocessor system comprises concurrent display of video data reflecting the operation of two processors in discrete portions of a single display screen with a user interface adapted for interaction with both processors. One processor controls the entire display while allocating a portion of the display screen for the use of the other processor which processor emulates a target processor system, for example, the IBM PC. To fully emulate another target processor system requires emulation of its screen facility and abstractions used in the display operations of the targeted system. The one processor is a general purpose host computer system having a central processor with real resources including I/O devices, main memory, a video display for displaying information on the display screen of the display and user input means, e.g. a keyboard and a mouse, to the host computer to provide input to the display screen.