Today at Microsoft’s WinHEC event in Shenzhen, China, the company announced that it’s working with Qualcomm to bring the full Windows 10 experience to future devices powered by Snapdragon processors. Terry Myerson, executive vice president of the Windows and Devices Group at Microsoft, is “excited to bring Windows 10 to the ARM ecosystem” and looks forward to bringing “Windows 10 to life with a range of thin, light, power-efficient and always-connected devices,” which may include anything from smartphones to tablets to ultraportable laptops to servers. These new Snapdragon-powered devices should support all things Microsoft, including Microsoft Office, Windows Hello, Windows Pen, and the Edge browser, alongside third-party Universal Windows Platform (UWP) apps and, most interestingly, x86 (32-bit) Win32 apps. They should even be able to play Crysis 2.

This announcement fits nicely with Microsoft’s “Windows Everywhere” doctrine and should come as no surprise. It’s not even the first time we’ve seen Windows running on ARM processors. Microsoft’s failed Windows RT operating system was a modified version of Windows 8 that targeted the ARMv7-A 32-bit architecture. It grew from Microsoft’s MinWin effort to make Windows more modular by reorganizing the operating system and cleaning up API dependencies.

This work first surfaced in Windows Server 2008, which could be installed with a stripped-down, command-line only interface that did not include components such as Internet Explorer that were not necessary for specific server roles. Windows RT also leveraged the newer Windows Runtime (WinRT) API that offered several new features such as digitally signed app packages distributed through the centralized Windows Store and the ability to run apps within a sandbox. It also made it easier for software developers to target multiple CPU architectures. However, Microsoft’s rework of Windows was not yet complete, leaving Windows RT with a bunch of legacy Win32 code that went unused. It also could not run Win32 desktop apps, severely limiting the number of available apps to only those using WinRT and distributed through the Windows Store.

MinWin and its derivatives have continued to evolve over the past few years after getting a major boost in 2013 when Microsoft reorganized its disparate software platforms into the singular Operating Systems Engineering Group. The end result is Windows 10, a modular OS that can run on anything from low-powered IoT devices to high-performing workstations and servers. Its foundation is OneCore, MinWin’s direct descendant, that includes only the operating system kernel and components essential for any hardware platform. OneCore UAP (Universal App Platform) is another major module for Windows 10 whose groundwork was laid during the creation of Windows Phone and Windows RT. It provides support for Universal Windows Apps and Drivers, along with more advanced features such as the Edge browser and DirectX. On top of these modules, Microsoft can add modules that target specific device families (desktop, mobile, Xbox, HoloLens, etc.) that provide specialized features and shells.

Also included in OneCore UAP is Universal Windows Platform (UWP). An extension of the WinRT API used in Windows 8, it allows developers to create universal apps that are CPU architecture agnostic and can run on multiple devices, seamlessly adapting their user interface and input methods to the hardware they’re running on. With UWP, the architecutre independence is achieved by having pre-compiled versions for each platform available from the Store, which will then download and install the correct version for the individual device. The major change with today's announcement over Windows RT and UWP is that x86 apps will be able to run on Qualcomm's ARM-based SoCs, along with support for all of the peripherals that are already supported with Windows 10. This alone is a huge change from Windows RT, which would only work with a small subset of peripherals.

Microsoft is also focusing on having these devices always connected through cellular, which is something that is not available for many PCs at the moment. Support will be available for eSIM to avoid having to find room in a cramped design to accomodate a physical SIM, and Microsoft is going so far as to call these "cellular PCs" meaning they are expecting broad support for this class of computer, rather than the handful available now with cellular connectivity.

The ability to run x86 Win32 apps on ARM will come through emulation, and to demonstrate the performance Microsoft has released a video of an ARM PC running Photoshop.

This of course raises several questions, few-if-any of which Microsoft is willing to answer. Intel has long exerted strong control over the x86 ISA, limiting or outright preventing competitors like NVIDIA from implementing x86 support. So how Microsoft and Qualcomm are able to (for lack of a better way to put it) get away with this is a big question. Certainly there's no indication right now that this has Intel's formal blessing.

The key points here are that this is a form of software emulation - Microsoft even calls it as much - and that only 32-bit x86 support is being offered. On the former, this means that there's no hardware execution of x86 instructions taking place - though Microsoft and Qualcomm are certainly lining up instructions as best they can - which avoids many of the obvious patent pitfalls of doing x86 in hardware, and puts it in the same category as other x86 emulation mechanisms like DOSBox and QEMU. Meanwhile only supporting 32-bit x86 code further rolls back the clock, as the most important of those instructions are by now quite old, x86 having made the jump to 64-bit x86-64 back in 2003. So it may very well be that it's easier to avoid any potential legal issues by sticking with 32-bit code, though that's supposition on our part. In any case it will be interesting to see what instructions Microsoft's emulator supports, and whether newer instructions and instruction set extensions (e.g SSE2) are supported in some fashion.

Of course, the performance of this solution remains to be seen. x86 is not easy or cheap to emulate, and an "emulator" as opposed to a Denver-like instruction translation makes that all the harder. On the other hand, while maximizing x86 compatibility is great for Microsoft and Qualcomm, what they really need x86 for is legacy applications, which broadly speaking aren't performance-critical. So while x86 on a phone/tablet ARM SoC may not be fast, it need only be "good enough."

In any case, Windows 10’s ability to scale and adapt to essentially any hardware platform is a remarkable feat of engineering, and it’s what makes today’s joint announcement with Qualcomm possible. The first devices with Snapdragon SoCs running the full Windows 10 experience should be available in the second half of 2017.

It will be interesting to see what shape these devices take and which companies produce them. Some new lower-cost, full-featured Windows 10 tablets would be a welcome addition, and Qualcomm has its eyes on the low-powered server market too with its Centriq product family. A Windows 10 smartphone with a Snapdragon SoC is also likely, but with Windows Phone 8 holding less than 1% global market share, according to Gartner, Microsoft is essentially starting from scratch. Will the benefits of universal apps be enough to lure software developers and users of other Windows products away from Android and iOS? Can Windows 10 reestablish Microsoft as a major player in the smartphone market, or is the hole it has dug over the past decade too deep?

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  • JMC2000 - Friday, December 9, 2016 - link

    Seriously, what am I reading here?
  • jwcalla - Thursday, December 8, 2016 - link

    This is really only interesting for laptops but Intel has that market pretty much cornered already. Even with Chromebooks ARM has gone nowhere. And why would I buy an ARM Windows laptop that has to do emulation to run x86, and suffer the performance and power penalty?

    And nobody cares about running x86 apps or Windows 10 on a phone or tablet. Hopefully people have gotten over that lie by now.
  • stephenbrooks - Thursday, December 8, 2016 - link

    If they'd done something like this 10 years ago and implemented it consistently (plus dealt with having adaptable UIs between phones and larger screens), it could have worked. But there have been so many mis-fires (Windows 8 UI, WinRT) by now...
  • Krysto - Thursday, December 8, 2016 - link

    Probably because of price. Intel's chips have gotten incredibly expensive for the performance they offer.

    Core M in $1,000-$1,500 laptops, for instance, is a ridiculous proposition. ARM would be much better suited there, and it may even run better.

    And the Celeron/Pentium notebook market should be wiped out by ARM-based laptops. If it's not then, OEMs are just brain dead masochists who don't know what's good for them and their customers.
  • TheinsanegamerN - Thursday, December 8, 2016 - link

    Clearly, people DO like running windows 10 on a tablet, unless you vcompletely missed how well the surface line is doing.

    As for why someone would want an ARM laptop, the vast majority of consumers dont need a powerhouse machine. Things like web browsers and office applications, and based on the video photoshop, all run really well. Unless you are a gamer, ARM on windows would satisfy your needs well. So you can buy a machine that is cheaper and gets better battery life then the x86 powered machine, since intel no longer has sole control of that market. So cheaper, better battery life, no discernible performance difference, seems like a few good reasons.

    For laptops, ARM is also more efficient and easier to implement, which means higher profit margins and more sales. OEMs like AMD would have a better chance of succeeding in an ARM world, as intel wouldn't have a stranglehold on the ARM arket like they do x86.
  • jwcalla - Thursday, December 8, 2016 - link

    The Surface tablet is really just a smaller ultrabook that can also play Angry Birds. Its appeal is mostly for those who are looking for a laptop function. Even then, it hasn't sold much.

    I think it's great to see ARM in laptops but as far as I have seen, ARM companies (and ARM itself) seem completely uninterested in entering that market. Maybe Qualcomm will be different. But we have ARM Chromebooks and x86 Chromebooks and x86 clearly dominates that market, and this is on a platform where the ARM stuff is 100% native, not run through emulation. Maybe with Android apps coming to Chromebooks ARM will have a leg up there. But it seems to me that OEMs are -- for one reason or another -- attached to Intel.

    When it comes to power usage, laptops are in a competitive market. I'm not sure I'd want to waste CPU cycles on emulation when I can just get an x86 laptop. Price would have to be dramatically favorable to make up for the hits to performance and battery. And for those who simply want to browse the web and check Facebook, they'd be better off getting a Chromebook.
  • name99 - Thursday, December 8, 2016 - link

    "Clearly, people DO like running windows 10 on a tablet, unless you vcompletely missed how well the surface line is doing."

    Just to throw out an example of how people see what they want to see:
    The Surface line ("doing well" according to the commenter above, and much of the internet) sells 1 million units a quarter.
    The Apple Watch ("struggling" and "a flop" according to much of the same internet) has been selling three x that number (a million a month) and is likely to shift to two million a month with the new models.

    Keep that in mind next time any of you feel the urge to make wild statements about how various products are doing...
  • sorten - Thursday, December 8, 2016 - link

    You're comparing watch sales to mobile computer sales? The standards for success are different.
  • FunBunny2 - Thursday, December 8, 2016 - link

    -- The Apple Watch ("struggling" and "a flop" according to much of the same internet) has been selling three x that number (a million a month)

    you, or your source(?), is making that up. Apple doesn't tell anyone how many Watch are sold. lots of folks look at chicken guts to tell them how many.
  • doggface - Friday, December 9, 2016 - link

    1 surface 4 pro = ~$2k
    1 apple watch = ~$400

    I would hope they sell at least 2 times as many

    More to the point, cheaper ($500-800) tablets are no longer really available because intel aren't making atoms for tablets anymore. Hello market that is underserved.

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