I heard some rumours that Windows doesnt use the BIOS functions but use its own implementation of working with devices via I/O ports. I wonder is it truth?
Yes.
It's true for most 32-bit OSes. Bios functions are mostly 16-bit, so it causes problems/difficulties.
Bios is used for booting, but after that it's mostly ignored.
Thanks Tedd all the rumours seem to be truth... BIOS is used mainly by OS loader and then its functions are totally(!) ignored, am i right?
Yes.
But not 'totally(!)' :P There are a few system management things that some bioses do, but this isn't used by the os, it just works by itself.