Microsoft revealed that the ARM version of Windows 8 will not run x86 legacy Windows applications at an investor
Microsoft also revealed that they will be no x86 compatibility mode in the ARM-version of Windows 8, a feature which was widely assumed based on prior Microsoft statements.
"We've been very clear since the very first CES demos and forward that the ARM product won't run any X86 applications," Sinofsky said responding to an analyst question.
That will be news to Intel's software boss Renée James which experienced an unusual public tongue lashing from Microsoft following James' reporting that Windows 8 ARM would not run x86 code. Microsoft called the comments "misleading".
"What we announced yesterday for the first time was that when you write a Metro style application, all the tools are there to enable you in any of the languages that we support to automatically support ARM or X86." said Sinofsky.
Which isn't the same thing. Sinofsky went on to claim that offering such support would have ramifications for battery life and attempted to describe the compatibility rift as an opportunity for application developers.
"If we allow the world of X86 application support like that, or based on what we call desktop apps in our start yesterday, then there are real challenges in some of the value proposition for system on a chip, you know, will battery life be as good, for example?" he asked.
"And then if we do let them run, we just brought the perceived negatives of some of the ecosystem."
Rather more likely they would instantly earn the enmity of their life-long Wintel partner, Intel themselves.
Sinofsky's full response can be seen in Microsoft's transcription here (Microsoft Word format).