Windows XP 64-Bit Edition requires the installation of 64-bit drivers only. Some device drivers are modified to allow installation of 64-bit and 32-bit drivers from the same .inf file. These modifications also prevent installation of the wrong driver on the wrong platform. The extension .ia64 is used in the .inf file of these drivers to identify the installation files and sections in the .inf file that can be installed on the 64-bit platform. Previous versions of Windows do not recognize the .ia64 extension, and ignore any .inf file entries that contain it.
