At this point, we have established that the 64-bit PC computing world is really very different from 32-bit PC computing.  It’s not just a matter of the processors being faster.  Whereas with 32-bit PCs, you could count on having an x86 instruction set at the bottom, that’s not the case with 64-bit PCs, where you can have either an Itanium EPIC processor underneath, or an x64 processor.  So, what is Microsoft doing about 64-bit computing?  Let’s consider operating systems, developer tools, and applications . . .