Windows 8 on ARM won't run x86 apps Microsoft admits

Windows 8 ARM PCs will not, in fact, have full app compatibility with software designed for x86 Windows 7 and 8 computers, Microsoft has confirmed, instead demanding that developers port their titles over to the new architecture. Despite earlier suggestions that seemed to indicate otherwise, Windows president Steven Sinofsky clarified during an analyst Q&A this week that while new apps coded for the Metro UI will work on both x86 and ARM tablets, laptops and other computers, existing software will not.

In doing so, Sinofsky arguably used a little verbal slight of hand to work around a previous – apparently misconstrued – statement. Earlier in the week, the exec said that legacy apps from Windows 7 machines would work on Windows 8, something which many assumed meant both x86 and ARM devices. In fact, Sinofsky pointed out, so far there haven't been any ARM Windows 7 machines, and we were incorrect to assume he was talking about ARM support.

He also argues that Microsoft has "been very clear since the first CES demos and forward that the ARM product won't run any x86 applications." Nonetheless, back in May the company described Intel's suggestion of that as "factually inaccurate" and "misleading" though wouldn't say exactly how that was the case.

According to Sinofsky, Microsoft's concern is that x86 apps aren't designed with power frugality in mind, something ARM tablets and notebooks are likely to at least partially prioritize. Security is also a concern: "if we do let them run, we just brought the perceived negatives of some of the ecosystem" he explains, "so, people say, great, now it's easy to port viruses and malware and we'll port those."

Avoiding viruses is certainly one way of stopping common criticisms of Windows tablets; that is, that they require more maintenance than iPad or Android Honeycomb rivals. In Sinofsky's strategy, x86-based Windows 8 models would be a very different proposition for consumers than ARM-based variants, with Metro being the "opportunity" glue for developers in-between.

QUESTION: Thank you. I was wondering if you could talk a little bit — you mentioned yesterday that legacy applications will be able to run on Windows 8 regardless of the chipsets that people are choosing. I was just wondering if you could talk to us a little bit about how that will happen. Does there have to be some emulator or app virtualization? But if you can kind of walk us through what you're doing there.
STEVEN SINOFSKY: Sure. I don't think I said quite that. I think I said that if it runs on a Windows 7 PC, it'll run on Windows 8. So, all the Windows 7 PCs are X86 or 64-bit.

We've been very clear since the very first CES demos and forward that the ARM product won't run any X86 applications. We've done a bunch of work to enable that — enable a great experience there, particularly around devices and device drivers. We built a great deal of what we call class drivers, with the ability to run all sorts of printers and peripherals out of the box with the ARM version.

What we talked about yesterday was — 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. I think that's the key part of everything that we'll run.

It is very interesting. I kind of want to encourage folks to think a little bit about it because, obviously, there are technical reasons and technical capabilities that could allow several approaches.

You know, if you start from the premise that Windows on ARM is a good thing and that the role of an operating system is to abstract out hardware for software developers, which is essentially the definition of an operating system, and then let the unique value of that hardware shine through. And that's something that Windows does fairly uniquely. It's constantly working to let innovations in hardware shine through in the operating system so that they all can show their uniqueness.

The challenge is very interesting. 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? Well, those applications aren't written to be really great in the face of limited battery constraints, which is a value proposition of the Metro style apps.

So, we have to be careful that we don't remove the value proposition for those applications. On the other hand, people would say, oh, but you have to let them run because then there's that whole ecosystem. And then if we do let them run, we just brought the perceived negatives of some of the ecosystem. So, people say, great, now it's easy to port viruses and malware and we'll port those.

So, we've taken the approach that we're going to build a bunch of rich capabilities in the operating system that allow devices and peripherals and a broad range of form factors all to run and working with multiple ARM partners on the ARM side, and then Intel and AMD on the system on a chip side, but then focus on the Metro style applications as the opportunity.

And so if you're a developer across the street, you look at it, your opportunity just grew because it's an Intel-based world and the AMD-based world plus the ARM-based world for Metro style apps, so it's the whole run rate of all of those.

[via InfoWorld and via The Register]