It is amazing that the Apple fans have no clue how systems work. Microsoft develops at a lower level, systems-wise, than any other company. What languages, for example, have been released by Apple over the past 10 years? AppleScript?

Microsoft invests a lot at the low level, including O/S design. Yes, they can learn from Apple (and have) on UI design but give me a break on languages and O/S. The Microsoft guys have far more experience and innovation than Apple ever would.

For the sake of argument, Microsoft is copying Apple. But Apple announced the transition to Intel in 2005. Microsoft had WOW64 for some time before that. Wikipedia says WoW64 was even in a limited edition of Windows 2000. So there goes Microsoft copying Apple… again..

At any rate, this sounds nice in theory, but I would imagine in practice it would be pretty complex. The ACM would probably be a beastly undertaking. Consider, too, that older versions of Windows themselves had components that may not be installed by default… say IIS, or Message Queueing, etc. I would think that simply providing a VM of the older OS would be a much simpler and lower-overhead (in terms of development) solution, and they should put all their virtualization efforts to make that as high-performance as possible. With RDP app publishing and/or something like Coherence from Parallels, it could be a relatively seamless experience, even graphically–RDP supports desktop composition for Vista, so even if the hardware itself for the host doesn’t support Aero, you can get it as long as the client hardware supports it. And with Microsoft’s acquisition of Calista, RDP will improve considerably. I hope they aren’t thinking of it only in terms of VDI solutions!