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Windows 8 to support ARM, System on a chip, architectures

microsoft.com

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Re: Windows 8 to support ARM, System on a chip, architectures

#71

Post by redthrowaway »

Hacktivist wrote: post #63
redthrowaway wrote: post #32

Earlier quoted context omitted.

Why? Putting Android on the iPhone I get, but I don't see too many hackers out there wanting to flip off Apple by installing Windows , of all things. To put it another way, how many macbook pros are running Win7 solo, aka w/o bootcamp or VMware?

When the Intel Macs were initial released there was a contest to install Windows XP on it natively (before bootcamp was even announced.) Enough people donated to the prize pool that the winner walked away with 14,000 dollars.

I hadn't heard that. Thanks for the anecdote.

Re: Windows 8 to support ARM, System on a chip, architectures

#72

Post by bradhe »

_b8r0 wrote: post #36

I've noticed a lot of speculation about how they will translate code between X86, X86_64 and ARM. Well, the simple answer is not to translate at all. MS have been pushing managed code via things like Silverlight and .NET for some time. My tuppence worth: Windows 8 on ARM won't support legacy x86 code, but will run .NET, Silverlight and any other managed code shamalamadingdong it needs to run. I can see Windows 8 on x…

>Windows 8 on ARM won't support legacy x86 code

On one hand I doubt this as MS has a penchant for backwards compat and there is an emulation layer for EVERYTHING in Windows as is.

On the other hand, I'm seeing them move away from their backwards compat religion and CISC to RISC sounds fucking horrifying to me.

Re: Windows 8 to support ARM, System on a chip, architectures

#73

Post by _b8r0 »

jallmann wrote: post #70
_b8r0 wrote: post #36

I've noticed a lot of speculation about how they will translate code between X86, X86_64 and ARM. Well, the simple answer is not to translate at all. MS have been pushing managed code via things like Silverlight and .NET for some time. My tuppence worth: Windows 8 on ARM won't support legacy x86 code, but will run .NET, Silverlight and any other managed code shamalamadingdong it needs to run. I can see Windows 8 on x…

> Windows 8 on ARM won't support legacy x86 code, but will run .NET. I can see Windows 8 on x86 supporting legacy code Hmm, I don't believe so. That'd introduce fragmentation that Microsoft's typical users (mom and pop) should not have to deal with. Also that'd be a pretty drastic policy shift for Microsoft seeing the pains they've gone to maintain compatibility with older software. My guess is that, at the very leas…

> wtracy suggested the possibility of JITing x86 to ARM, that's ballsy and it'd be awesome if Microsoft pulls that off.

JITing x86 - ARM might not even be fully necessary for most modern apps. It might be possible to do some sort of interception and JIT-style translation for certain parts of code but it might also be possible to provide a DLL level compatibility layer as fallback. That way when DLL functions are called they're called natively, and the main module executes via JIT.

I'm not suggesting that would be easy, it'll be balls to the wall hard, but that's the only thing I that immediately springs to mind that wouldn't come with a massive performance penalty.

The fragmentation argument is valid and an excellent point to make, however we don't really know who this is being targeted at or the defined primary use cases at this point. If Microsoft can fck up the user experience so badly with Vista and Windows 7 Starter, they can fck up the user experience with ARM and not worry too much. It might also be worth bearing in mind that if a recompile is needed, it's going to be in the next Visual Studio, which will support a lot more managed code features through the CLR than unmanaged code on x86_64 (by which I mean the CLR supports more languages and has fairly tight integration - if you use C++ in Visual Studio you're probably using less of Visual Studio overall than if you're writing ASPX in C#).

Re: Windows 8 to support ARM, System on a chip, architectures

#74

Post by _b8r0 »

bradhe wrote: post #72
_b8r0 wrote: post #36

I've noticed a lot of speculation about how they will translate code between X86, X86_64 and ARM. Well, the simple answer is not to translate at all. MS have been pushing managed code via things like Silverlight and .NET for some time. My tuppence worth: Windows 8 on ARM won't support legacy x86 code, but will run .NET, Silverlight and any other managed code shamalamadingdong it needs to run. I can see Windows 8 on x…

>Windows 8 on ARM won't support legacy x86 code On one hand I doubt this as MS has a penchant for backwards compat and there is an emulation layer for EVERYTHING in Windows as is. On the other hand, I'm seeing them move away from their backwards compat religion and CISC to RISC sounds fucking horrifying to me.

I absolutely agree with you about the penchant, but I know first hand from Microsoft employees that the backwards compatibility issue is a complete pain in the arse. Supporting ARM on managed only paves the way to ditch unmanaged code in x86_64 in the future. Supporting native unmanaged code might require a recompile and some testing, but might be possible (given the Xbox 360) but then you're going to have trouble with x86_64 only references in your code. Implementing some sort of x86 -> ARM is going to be a nightmare of epic proportions, Rosetta-type technologies be damned.

Re: Windows 8 to support ARM, System on a chip, architectures

#75

Post by rbanffy »

TeHCrAzY wrote: post #64
rbanffy wrote: post #46

Earlier quoted context omitted.

> it would be more difficult to write an x86 emulator for ARM Building an x86 emulator is easy. Building one that can run Windows 8 software at speeds comparable to then current Intel or AMD x86 processors will probably be impossible. There is no such performance gap between ARM and x86.

Would the opposite be easier? It might make sense to offer comparability for Windows|ARM executables on Windows|x86, so if you want to hit both platforms, you'd be doing it in ARM. I can see ARM being great for corporate desktops: .net LOB apps work, IE will work, Office will work etc.

Sure, but one key advantage of Windows is that it has a huge legacy of software that already targets x86 and that would have to be recompiled/reoptimized to ARM.

The performance of a built-for-speed x86 is very forgiving. Eclipse runs well enough on my Core i5, but I suspect it would have problems on an energy-efficient ARM.

Re: Windows 8 to support ARM, System on a chip, architectures

#76

Post by rbanffy »

runjake wrote: post #68
rbanffy wrote: post #62

Earlier quoted context omitted.

> Managers cared about portability. Tell that to those who wanted to run Office and Visual Studio on their Alpha boxes...

I don't get it, are you trolling? You're talking about over a decade ago, back when NT on Alpha was relevant. A lot changes in 10 years.

I am saying that a lot more than the base OS has to be ported. That includes, of course, Visual Studio, Office, games, utilities, 3rd-party titles, browser plugins (so you can do net banking), device drivers (so you can scan, print, use a smartcard reader). Windows benefits from a huge complex ecosystem that will have to move with Microsoft.

It took years before AMD64 was fully supported and it's semicompatible with ancient x86. ARM is a completely different beast. I am pointing out Microsoft tried to make this move before and failed.

When Apple did it (and they did it twice), the carrots were huge performance gains. This carrot implies a loss of performance. Unless hardware makers start flooding the market with Windows 8-compatible ARM machines, 3rd parties may opt to stay within the comfy confines of x86/AMD64.

It is a very tricky move.

Also, since most of what a Linux distro offers (and that includes OpenOffice, editors, IDEs, languages, games) already runs on ARM, this move would also benefit the competition that's already positioned to benefit from this without the need to convince 3rd parties to jump along. I imagine Microsoft will impose restrictions on what OS and software you will be able to install on those machines to counter that.

It will be fun to watch.

Re: Windows 8 to support ARM, System on a chip, architectures

#77

Post by kenjackson »

rbanffy wrote: post #76
runjake wrote: post #68

Earlier quoted context omitted.

I don't get it, are you trolling? You're talking about over a decade ago, back when NT on Alpha was relevant. A lot changes in 10 years.

I am saying that a lot more than the base OS has to be ported. That includes, of course, Visual Studio, Office, games, utilities, 3rd-party titles, browser plugins (so you can do net banking), device drivers (so you can scan, print, use a smartcard reader). Windows benefits from a huge complex ecosystem that will have to move with Microsoft. It took years before AMD64 was fully supported and it's semicompatible with…

As you know, they've apparently already ported Office (or are at least well on their way).

The carrot in this case is battery life. And I think the markets will turn out to be different ones. The ARM machines will largely be tablets and netbooks. The Intel SoCs will have poorer battery life, but better perf. That's where you'll have VS and such.

Of course .NET apps will run across both. And the Windows Marketplace will largely be .NET apps.

They failed at this before, because there was no motivation to succeed. Alpha, MIPS, Itanium, were all DOA. But they did help ensure that the Windows kernel was portable.

Re: Windows 8 to support ARM, System on a chip, architectures

#78

Post by Niten »

runjake wrote: post #37
wtracy wrote: post #26

Earlier quoted context omitted.

MS has learned from their experience with Windows on Alpha. Even when they released XP for x86-64, they initially wouldn't sell it at retail for fear that people would get confused and buy the wrong one. I'm betting they have some compatibility magic cooked up that we haven't seen yet. Emulation has already been suggested. How about the possibility of having a launch hook that recompiles x86 machine code to ARM machi…

Their "magic" is .NET and MSIL.They explicitly stated they aren't virtualizing or emulating x86 code during the session.

No, they explicitly stated that their demonstration did not consist of virtualized or emulated x86 Windows. That doesn't at all rule out a dynamic translation layer for x86 apps.
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