The device interface represents a virtual adapter; it is used to create resources. ID3D11Device2 adds new methods to those in ID3D11Device1.
interface ID3D11Device2 : public ID3D11Device1
Header: Declared in d3d11_x.h (d3d11_2.h on other Windows platforms).
Library: Use d3d11_x.lib (d3d11.lib on other Windows platforms).