Re: People don't buy x86 because of Performance or anything
"a problem with recent (since 2000) versions of Windows."
Are you serious?
To the best of my recollection, Windows 98 and Windows NT (3.1?) , to name but two, both had the non-transportable installed OS image issue, which would be mid to late 1990s. IE the OS as installed generally reflected the hardware present at install time (apart from anything else, there usually wasn't enough disk space to keep *all* the available drivers on the system, users wanted that space for more important things in the 1990s).
Windows PE isn't an OS, it is (as you clearly recognise) little more than an extended boot loader, a grown up version of DOS that can run a subset of Windows apps and drivers, and (once again) all it needs is to support the hardware present at install time.
Or maybe I'm misunderstanding something?
Biting the hand that feeds IT
