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if you mean direct port I/O, then no, you don't do this in windows.

There are a few drivers and bit of code around this board for directly accessing I/O. My favourite is UserPort which I have posted here before, search for it on here, or you can also google for it.

Of course, these things are all use at your own risk, since Windows and direct port I/O are not really the most compatible things to play with.

Edit: I found my original post:

http://board.flatassembler.net/topic.php?p=17732#17732

Of course, you mean it isn't done from Usermode (ring3).

Lots of info and source code for various versions of Windows:
http://www.lvr.com/parport.htm

That is why I liked UserPort, it has two main features features: 1) allows direct access from ring3 without OS overhead and 2) can be set on a process-by-process basis and/or global allow/restrict by individual port numbers. It has an okay UI also.

what's the point of doing port I/O from ring3 ?

I use it with my JTAG programmer (on the parallel port), without the OS overhead it is 10+ times faster.