fɔːɹ sˈɪstəm ˈɑːɹkɪtˌɛktʃɚz ɪnwˌɪtʃ pˈoːɹt aɪ slˈæʃ ˈoʊ ɪz ɐ dɪstˈɪŋkt ɐdɹˈɛs spˈeɪs fɹʌmðə mˈɛmɚɹi ɐdɹˈɛs spˈeɪs, ɐn ˈaɪəmˌuː ɪz nˌɑːt jˈuːzd wɛn ðə sˌiːpˌiːjˈuː kəmjˈuːnᵻkˌeɪts wɪð dɪvˈaɪsᵻz vˈaɪəɹ aɪ slˈæʃ ˈoʊ pˈoːɹts.
For system architectures in which port I/O is a distinct address space from the memory address space, an IOMMU is not used when the CPU communicates with devices via I/O ports.