How will Intel EM64T work, and what software is there to take advantage of 64-bit extensions?
Development of a broad “ecosystem”, ranging from processors, chipsets and tools to operating systems (O/S), applications, utilities and drivers is expected to take some time to develop. Platforms with Intel EM64T can be run in three basic ways (note: a 64-bit capable BIOS is required for all three scenarios): 32-bit O/S and 32-bit applications (Legacy Mode): No software changes are required, however the user gets no benefit from Intel EM64T. 64-bit O/S and 32-bit applications (Compatibility Mode): This usage requires all 64-bit device drivers. In this mode, the O/S will see the 64-bit extensions, but the 32-bit application will not. Existing 32-bit applications do not need to be recompiled, and may or may not benefit from the 64-bit extensions. The application will likely need to be recertified by the vendor to run on the new 64-bit extended O/S. 64-bit O/S and 64-bit applications (64-bit Mode): This usage requires 64-bit device drivers. It also requires applications to be modified for
