Just a note of support for Richard -- having I/O use the native APIs directly rather than via emulation or other wrappers is a good idea, because the emulations / wrappers usually add restrictions that are not present in the native API.  This is also the reason why we dropped going through stdio -- it did not give enough control over buffering and made integration with (UNIX native) file descriptors complex.  Integration with native I/O primitives on Windows seems sense in the light of e.g. PEP 3156.