Eh supposedly it's COM, but from what I read, Microsoft occasionally tampers with the interface slightly, so it's not perfect COM.schapman said:due to microsft using COM, i cant see any prob coding for dx7 w/ the dx9 sdk.. you "should" be able to code all the way back to dx5 or earlier right.. that is, if MSOFT does com right. one of the main points of using com is that u release it, but cant change it after... just add to it