Providing d3d10 for xp has nothing to do with gdi, they have a way to use different rendering contexes (like they do for opengl
).While d3d10 as an intergrated part of the OS (with all the interprocess sharing features) needs quite some work, providing a core implementation where it can be used as a dedicated api (like opengl) requires minimal work from microsoft
.They just want to force upgrade to vista and since there is no real competition on the OS market yet they do w/e they like ;p