DirectX10 is exclusive to Windows Vista and is not slated to be supported by any other platform. This will ensure that the next-gen games will be available on Windows Vista before any other platform.
The new display driver or graphics model in Windows Vista, WDDM (Windows Display Driver Model), is the main reason for DirectX10’s exclusivity to the operating system. It may come as a surprise to know that the graphics driver model hasn’t changed much since Windows NT4 – WDDM is the first major revamp of the system and is designed for scaling high-capability graphics.
DirectX10 depends on these improvements in the graphics model and so, it leverages the virtualization and architectural improvements of WDDM, in both the APIs as well as the underlying infrastructure.