Christian Stueble stueble@amaunet.cs.uni-dortmund.de writes:
I think Fiasco/L4 uses memory mapped I/O, not separated I/O?
Memory-mapped I/O (that is, I/O via memory accesses in the virtual address space) and I/O via the separate 16-bit I/O address space (with in/out instructions; ``port I/O'') are completely separate from each other. It is not possible to map the port address space into the virtual memory, and that means it is not possible to replace port I/O with memory-mapped I/O. That's why, the kernel needs to support port I/O.
Michael