Operating Systems Memory-Mapped 1/0 Disadvantages e Most computers nowadays have some form of caching of memory words. Caching a device control register would be disastrous(blind to device ready) Selective disable caching adds extra complexity. G If there is only one address space then all memory modules and all lo devices must examine all memory references to see which ones to response to. Most modern computers have a dedicated high-speed memory bus, so O device have no way of seeing memory addresses as they go by on the memory bus. Gao Haichang, Software School, Xidian UniversityOperating Systems Gao Haichang , Software School, Xidian University 11 Memory-Mapped I/O Disadvantages  Most computers nowadays have some form of caching of memory words. Caching a device control register would be disastrous (blind to device ready). Selective disable caching adds extra complexity.  If there is only one address space, then all memory modules and all I/O devices must examine all memory references to see which ones to response to. Most modern computers have a dedicated high-speed memory bus, so I/O device have no way of seeing memory addresses as they go by on the memory bus