Windows Phone OS 7.0: What's inside?

In case anyone might think the Microsoft Research project codenamed Menlo could end up derailing Microsoft's current practice of using Windows CE/Windows Embedded Compact as the core of Microsoft's mobile OS in the near term, think again.

Windows Phone OS 7.0 is built from the same core building blocks as its Windows Mobile OS predecessors: A Windows CE/Embedded Compact layer at the base, with a bunch of mobile customizations on top. In other words, the Windows Phone team is an OEM of Windows CE/Embedded Compact. (And so is the Zune media player team.)

There still seems to be a bit of confusion as to which version of Windows CE is going to be in the first Windows Phone 7 devices that ship this year.

A May 3 Microsoft blog post states that the core of the Windows Phone OS 7.0 will be Windows Embedded Compact 7.0, codenamed "Chelan." The exact statement by Embedded Technical Evanglist Oliver Bloch: "By the Way, Windows Phone 7 is based on the Windows Embedded Compact 7 core."

However, Microsoft still has not released Windows Embedded Compact 7 (codenamed Chelan) to manufacturing as of today. And I'd think Microsoft would need to get the Windows Phone OS 7.0 to its phone partners real soon now if a fall/holiday launch this year is in the cards. If Chelan is the core of the Windows Phone OS 7.0, it would stand to reason that Microsoft has built the Windows Phone OS 7.0 on top of an unfinished version of the Embedded Compact core -- unless, of course, the OS for these phones is still a work in progress...

Who cares which version of Microsoft's embedded platform is inside? Well, Windows CE 7.0, the Chelan release, includes a handful of interesting capabilities not available in the current Windows Embedded product. WMPowerUser has a nice list of these Chelan features: Dual Core Support (SMP, ARMv6), IE 7 rendering of rich media plug-ins, DRM, Bluetooth 2.1 support and more.

A statement I received on May 4 from a Microsoft spokesperson when I asked (for the umpteenth time about this) didn't confirm Bloch's post. Here's the statement, which is vague enough to be open to a variety of interpretations:

“Windows Phone 7 is based on the Windows Embedded CE kernel – the next generation of the Windows Embedded CE platform will be Windows Embedded Compact 7 when released, and the current version is Windows Embedded CE 6.0 R3. Although Windows Phone 7 was built on the Windows Embedded CE kernel at its core, the Windows Phone team has incorporated innovative features and functionality on top of the platform to develop an OS specifically designed to meet the needs of mobile phone manufacturers.”

I asked again whether this meant Windows Phone OS 7.0 was built on top of the Embedded CE 7.0 platorm -- or whether this meant Windows Phone 7 version 1 devices were built on the CE 6.0 R3 ("Cashmere") core and a later version of Windows Phone 7 devices would be based on the Windows Embedded Compact 7.0 operating system. I was told Microsoft is not willing to discuss version numbers at this time. I also asked how Microsoft would be substituting the Windows CE 7.0 kernel for the Windows CE 6.0 R3 one (i.e., would some kind of firmware update be required), but got no response.

Or maybe the core of Windows Phone OS 7.0 is a hybrid of CE 6.0 R3 and 7.0? (The same way the Silverlight platform for Windows Phone 7.0 devices is a hybrid of Silverlight 3 and 4?) No word.

Update: My annoying persistent questioning paid off (a little). The updated statement from the spokesperson: "As (Embedded Compact) 6.0 is in market, the phone is based on the current version." But  all my other questions -- re: how and when Microsoft will update its Windows Phone 7 devices to Compact 7.0 remain.

Back to Menlo. I don't have any kind of timeframe as to when or if any of the Menlo operating system work from Microsoft Research may show up in mobile phones/devices. But remember: Menlo isn't even an incubation project at this point (at least as far as I know), so it could be a while...