I'm... not really sure Microsoft will release Windows 7...
One basic problem is that of compatibility. Microsoft's compatibility of NT5 to Windows ME / 98 was actually rather good. Microsoft's compatibility of NT5 to NT6... or Windows 2000/Xp to Vista... is horrible. Seriously, in many cases W.I.N.E. offers better compatibility than Vista.
The result of trying to maintain
NT5 compatibility meant an drastic rise in the system resources Vista required. Windows 7 changes the underlying kernel and Operating System yet again. The result is that attempting to maintain compatibility of NT5
AND NT6 applications is going to cause Windows 7 to be even more bloated in system resources.
There are some technically viable methods to get around the system resources problem. The one I outlined, and favor myself, is for the NT5 and NT6 Operating Systems to be virtualized behind the NT7 Operating System... so that when you need to load, say Microsoft Office 2003, you can choose to load it in the NT5 kernel / OS, which is moved into main memory and hardware access, while the NT7 kernel / OS is unloaded.
Other methods could include Opening up the Source code of the NT5 and NT6 code bases so that W.I.N.E. technology can be used to integrate NT5 and NT6 technology into several OTHER platforms. Microsoft of course won't do this, but it is a technically viable option.
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The compatibility problem of Windows 7 to previous versions of Windows... that are not going to just magically disappear, are worsened by Microsoft seeming to be looking at a further market segmentation of forced product differentiation.
Basically, if you think that the
Vista versions are segmented artificially, you ain't seen nothing... yet. Microsoft could make a move to force people to pay up for NT5 and NT6 compatibility... and to big name clients like General Motors? That might be the push they need to say "hello Linux" and just walk away.