Could and should Microsoft change the heart of Windows Phone?

Could and should Microsoft change the heart of Windows Phone?

Summary: Could and should Microsoft replace the Windows Embedded Compact kernel in Windows Phone with the MinWin/NT kernel? A new voice (and former Microsoft Distinguished Engineer) weighs in.


There have been a number of rumors circulating for months that Microsoft is planning to make some very major revisions with Windows Phone 8, codenamed "Apollo." Specifically, the word is Microsoft is going to switch out the kernel of the operating system -- the Windows Embedded Compact code -- and replace it with "Windows 8" in Apollo next year.

Exactly what "Windows 8" in this context meant was up for debate. But a new voice has weighed in on the matter in the past week, and his theory deserves exploration. Hal Berenson, a former Distinguished Engineer at Microsoft, who left the company last year to become President of True Mountain Group, LLC which provides technology and management consulting, has a blog post worth reading, entitled "Windows Phone 8 and Windows 8: Cousins or Siblings."

As Berenson noted, Microsoft wouldn't want to put Windows in its entirety inside a phone. Nor would the company necessarily want to dump all of the "Windows Phone OS" customized bits that currently layer on top of the kernel.

What the Softies instead are doing, some believe, is substituting Windows Embedded Compact for parts of "MinWin," which is the detangled core Windows kernel/file system/networking stack code -- also known by its shorthand as "Cutler's NT." (Cutler as in Dave Cutler, the father of Windows NT.)

Berenson -- who was a Distinguished Engineer in Security and Identity at Microsoft and also a former Digital Equipment engineer -- explained the impact MinWin has had on resource use in Windows:

"Windows CE has a reputation for being small and modular, Windows has a reputation for being big and bloated. But Windows itself is about 6 years into an effort to completely restructure and clean up the code base, its resource requirements have actually shrunk over the last two releases (Win7 and Win8), and Windows 8 is very much focused on the low power/constrained resources environment that characterize both tablet and phone devices.

"Indeed I am running the Windows 8 developer preview on a tablet that is less powerful and has no more memory than the current generation of smartphones and even at this early stage it is as responsive as those devices.  In some regards, such as boot time, it is actually faster!  So could a WinNTk-based Windows Phone 8 run well on a 1Ghz CPU with 512MB of RAM?  Of course it could.  What about 800Mhz?  Almost certainly.  256MB?  Well, now I start to wonder.  It is pretty clear that Microsoft is focusing on enabling low-cost smartphones from Nokia and others as a key part of its strategy.  The question is, what does a low-cost smartphone’s specs look like in the fall of 2012?  And how big a target is RAM for cost reduction? And how much savings can you really get using Windows CE over WinNTk."

In his post, Bernson detailed the cost-saving and compatibility reasons that moving to a MinWin/NT kernel makes sense for Microsoft. His arguments are all compelling. But just because it can be done, will it?

Berensone noted in his post that a number of the Windows Phone team are former Windows developers, engineers and managers. "There are definitely a lot of Microsoft people, both current and former, who want it (the switch to a MinWin/NT core) to happen," he said.

(Berenson didn't mention the work Microsoft Research has done to investigate replacing the Embedded Compact kernel with NT via a project codenamed "Menlo." But I think the Menlo work adds even more fuel to the fire.)

I had been thinking that the fact that Windows 8 is unlikely to be released to manufacturing until mid-2012 made it unlikely Microsoft could take its core and deliver a new Windows Phone OS release based on it before the end of 2012. However, if Microsoft is using "only" the MinWin core -- which is basically done and not changing with Windows 8 -- perhaps a Windows Phone 8 "Apollo" release in the latter half of 2012 is still a realistic goal.

I asked Berenson whether he expected the change in kernels, if and when it happens, to disrupt users and developers much. His reply:

"Switching to the NT kernel should have no impact on existing WP7 applications as those apps have no direct access to Windows CE.  This really should be a very seamless move for both applications and end-users.  The ODMs (original design manufacturers) and carriers are really the only ones who have significant work to do since drivers or any other native mode software they wrote will need to be ported or rewritten. But things written with Silverlight/.NET/XNA should just work.  I guess there might be a caveat for apps that use some esoteric feature that Microsoft decides to deprecate, but since most such features would only have been exposed in Mango I doubt Microsoft would have exposed them at all if they didn't plan on carrying them over to WP8."

He also said he wouldn't be surprised to see the convergence of kernels result, over time, in WinRT (the new Windows 8 runtime) becoming the primary development model for both Windows PCs/tablets and phones.

So far, Microsoft still isn't publicly acknowledging the Apollo codename or anything about the coming OS release. On November 7, members of the Windows Phone team are expected to tout the new crop of Mango phones out in time for this holiday season and some of the new apps available for them during a New York City VIP event.

Topics: Windows, Microsoft, Mobility, Operating Systems, Software


Mary Jo has covered the tech industry for 30 years for a variety of publications and Web sites, and is a frequent guest on radio, TV and podcasts, speaking about all things Microsoft-related. She is the author of Microsoft 2.0: How Microsoft plans to stay relevant in the post-Gates era (John Wiley & Sons, 2008).

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  • RE: Could and should Microsoft change the heart of Windows Phone?

    I'd be very surprised to see MinWin in Apollo.
    More likely Windows Phone 9 circa 2013 will be a MinWin based phone, also capable of running WinRT apps *re-covers crystal ball*
    • RE: Could and should Microsoft change the heart of Windows Phone?

      possible, then again nobody thought MSFT would ship mango before the first year aniversary of wp. and everybody was wrong.
  • RE: Could and should Microsoft change the heart of Windows Phone?

    If I recall correctly didn't MS already have this discussion early on in Windows Phone development and then decide against it? From what I understand MinWin wasn't at that point, and still isn't, ready for prime time. I've heard other pundits speculate that this will not happen, if ever, prior to Windows Phone 9 at the earliest, which makes more sense to me if the code is still as unstable as rumor would have us believe
    • RE: Could and should Microsoft change the heart of Windows Phone?

      @blueyonder64 We must hear different rummors. Based on the developer preview and what I hear, MinWin is solid and will indeed be ready for primetime. Even so it might not make it until WP9 because of resource constraints and the time needed to take on 2 major overhauls. Windos 8 is large enough on its own. Throw in a WindowsPhone overhaul and risk increases dramatically.
      • It's stable on Intel...

        @Skippy99 : the Developer preview was released exclusively on x86 and smarthphones are ARM-only (even Nokia's Intel gamble was given the boot).<br><br>It won't be stable and ready for primetime on ARM until the Beta (end of February) or even later. <br><br>Alas, if you check Windows Phone 7 history you'll see that the team has always been one or two kernels behind. <br><br>When WP 7.0 was announced, it used Windows Embedded Compact 6.0 R2 (according to people who have jailbroken the system) when the cutting edge was R3. Mango (WP 7.5) is most certainly 6.0 R3, not 7.0. <br><br>So, thinking they will take a beta quality kernel for a mid 2012 development is nonsense. <br><br>WP7 schedule will most likely be as follows:<br> + Mango [6.0R3] : Oct 2011<br> + Tango [7.0] : March-April 2012<br> + Tango 2 [7.0R1] : Oct 2012<br> + Rango!? ("Apollo") [Win8] : March-April 2013
    • RE: Could and should Microsoft change the heart of Windows Phone?

      you're correct. early in wp dev. which is years ago. minwin is ready now.
  • RE: Could and should Microsoft change their heart on Windows Phone?

  • RE: Could and should Microsoft change the heart of Windows Phone?

    I think this is not such a big deal as people are making it. Some tech bloggers thinking that Apollo would mean the Windows 8 shell running on the phone. This is the low-level kernel we're talking about, which is actually a very small part of the OS.
    What will be interesting is what happens to the drive model. A unified driver model for Windows CE and Windows 8 would yield some cost savings for OEMs and may improve time-to-market.
    • RE: Could and should Microsoft change the heart of Windows Phone?

      @joeyw72 No it adds hardware support that the current platform lacks... That would be a big deal to a degree.
    • RE: Could and should Microsoft change the heart of Windows Phone?

      @joeyw72 I think that the driver model is perhaps the biggest single reason MS wants to move Win7 to run atop the NT kernel rather than continue with CE.

      Telling OEM's that they have to write drivers targetting two entirely different driver models is not attractive.

      On the other hand, the NT kernel has recently undergone HUGE investment in order to smooth its path to ARM and is now a well-understood entity from the perspective of modern ARM SOC vendors & driver writers.

      By moving WinPhone to run atop the NT kernel, WinPhone gets to ride the enormous investments from Microsoft and its silicon and OEM vendors.

      I hope I am wrong here, but I agree with others also, that we'll probably not see WinPhone support WinRT until WinPhone9.
  • RE: Could and should Microsoft change the heart of Windows Phone?

    MSFT needs to converge all its platforms under minwin, including wp and xbox if it is to make the promise of "everything runs windows" possible. These custom fragmented versions of windows that have been left behind the evolution race and custom purposed for niche projects need to die once and for all.
  • RE: Could and should Microsoft change the heart of Windows Phone?

    Nobody cares, the move towards a Mobile Platform means the move away from Microsoft Products.

    MS is still king of the Desktop but they are mostly irrelevant in the Mobile Space and it doesn't matter how good Windows Phone is because, nobody is using it or even cares to use it.

    I do think MS will try this though as they try to leverage their desktop platform in the mobile space. Hell, they are trying this now with Tablets and it isn't working for them there either.
    • RE: Could and should Microsoft change the heart of Windows Phone?

      @Peter Perry Many people are waiting for a Windows phone that meets their needs or requirements. There are also those of us that had contracts in place when WM& was released. I still expect the market share of the OS to increase in the next couple of years. It was not DOA nor has it's demise been written in the stars.
    • RE: Could and should Microsoft change the heart of Windows Phone?

      @Peter Perry

      I must be one of the thousands of nobodys out there using WP7.5 now with thousands of people buying it every day...
  • RE: Could and should Microsoft change the heart of Windows Phone?

    Microsoft absolutely has to unite Windows Phone with what they're doing in Windows 8 with Metro/WinRT. Otherwise they will have a split mobile strategy - which will fail.
  • Yes they should and I think WP8 will be it. They should have already.

    There was enough time from when they did the original WP7 reset to have done it then. Oh well better now than even later. MinWin adds so much to WP. Better security, better power management, better networking, better driver model, faster booting, better runtime perf. All this on for a platform that already far outperforms both ios and android in all these areas already. Bring it MS!
    Johnny Vegas
  • RE: Could and should Microsoft change the heart of Windows Phone?

    Good stuff MJ.
    Now we know who the real brains of Windows Weekly is.
  • RE: Could and should Microsoft change the heart of Windows Phone?

    That'd be one way to crush Apple. Be able to add-on a keyboard and a full-size screen to your phone, and -bam!- full-on desk-/lap- top equivalent. Able to do your MS Office work and probably run a few other Apps to boot. May not be a gaming rig, but for office work and functional portability, that'd be sweet.
  • easy

    They just need an old castle, with a tall tower, where they can extend a long lightening rod during the next violent thunderstorm.
  • RE: Could and should Microsoft change the heart of Windows Phone?

    So they're gonna cram a desktop OS into a phone. Does that mean UAC pop-ups for incoming calls?