> What does the I/O hole correspond to in the system? PCIe mmio mapped space. 32-bit devices must have addresses below 4G so X86 systems have a physical memory map that looks like: 0 - 2G: RAM 2G-4G: MMIO 4G-end of memory: RAM end of memory-infinity: 64-bit MMIO Depending on how much MMIO there is different systems put the dividing line at other addresses than 2G. -Tony
