This is the cache/memory management unit (CMMU) for systems with the original 88100 CPU. It implements demand-paged virtual memory management with a 16KB cache memory (64KB on 88204) on a VLSI chip. To implement the maximum of 256KB/256KB I/D cache on a 88100 system, eight 88204 CMMUs had to be used. It was also possible to build a system without any CMMU at all, as done e.g. on several embedded systems, which resulted in a system unable to use VM.