Abstract: A digital computing system is disclosed having a monolithic microprocessor, a versatile input/output subsystem, a multi-medium memory subsystem, and a video display subsystem with audio generating capability. In the memory subsystem, a balanced mix of dynamic RAM, P-channel MOS ROM and N-channel MOS ROM are included to minimize cost without sacrificing performance. In the video display subsystem, a monolithic video display processor performs all RAM access functions, in addition to composite video generation. The resultant composite video signal, which may include audio and external video information, can be applied directly to a video monitor or RF modulated for use by a television receiver.