One big Windows world. It's coming, but when and how?

For months, rumors have been circulating that Microsoft was poised to make its "Windows Everywhere" world a reality. But that reality is still a ways off, in spite of comments by Microsoft execs this week at the company's Worldwide Partner Conference about a unified ecosystem across phones, PCs and TVs.

Here's the quote from Microsoft Windows Phone President Andy Lees from his partner-show keynote this week that has many buzzing:

"One of the key important things here, though, is the change that's yet to happen, but it's about to happen, and that is the bringing together of these devices into a unified ecosystem, because at the core of the device itself it's possible to be common across phones, PCs, and TVs, and even other things, because the price drops dramatically. Then it will be a single ecosystem. We won't have an ecosystem for PCs, and an ecosystem for phones, one for tablets. They'll all come together. And just look at the opportunity here."

In Microsoft lingo, "ecosystem" is a broad-brush term that can mean anything from the development environment, to its distribution channels. Was Lees making a vague reference to the idea of a shared app-store across phones, PCs and gaming consoles -- something that could possibly launch as soon as next year when Windows 8 launches? Or was he actually talking about a unified operating system development platform -- a goal which is a lot harder to achieve and make take years?

First things first: When Microsoft currently describes a gadget or system as being a "Windows" device, it doesn't necessarily mean that it is running the Windows PC operating system.

Windows Phone, for example, runs an operating system which is, at its core, Windows Embedded Compact, with a layer of Microsoft customization on top. Set-top boxes run Windows Embedded Compact, too, not Windows. Some of the Windows tablets and slates on the market -- and still coming to market  --also are running Windows Compact Embedded. Windows Azure, Microsoft's cloud operating system, has its roots in Windows Server, but has been architected from the ground up to be customized for datacenters. Xbox runs a highly customized operating system that includes elements of the old Windows NT operating system.

Because Microsoft has managed to port Windows to the ARM processor -- something it will make available on ARM-based tablets and clamshell devices with Windows 8 -- it is now technically feasible that Microsoft could make Windows the operating system that powers its Windows Phones. To date, the Softies haven't done this because while Windows Embedded Compact worked on ARM, Windows did not. But as of Windows 8, the "real" Windows will be able to run on the ARM/System on a Chip architectures.

Just because something can be done, doesn't necessarily mean it will be done. I've been asking around as to whether Microsoft will be redoing its Windows Phone 8 operating system to use the same Windows 8 as will be on PCs and tablets. After all, both Windows 8 and Windows Phone OS 8 (codenamed Apollo) are expected to be out and available to consumers in 2012. I hear this isn't likely. In fact, it's highly unlikely, my contacts say. That means the big harmonic Windows convergence probably isn't happening until Windows Phone OS 9 (2013?), at best.

The biggest question mark in this "one big Windows world" scenario is on the apps front. Even if Microsoft can't/won't have the same Windows operating system on phones, PCs and TVs, does that mean the same apps can't run across all of these devices? In other words, would the Angry Birds game on Windows Phone automatically work on a Windows 8 tablet and on your Xbox? The "write once, run anywhere" goal -- is it possible when the underlying operating systems are different -- even though their user interfaces look very much alike?

Some developers with whom I've spoken think the differences between the platforms are relatively trivial, since Windows Embedded Compact is a subset of Windows. At one point, Microsoft was talking about plans to make its Silverlight browser plug-in available everywhere -- on phones, PCs, set-top boxes and Xbox. (The Silverlight on Mediaroom and Silverlight on set-top plans -- codenamed Taos and Santa Fe --may or may not still be alive). But in recent months, that talk has waned.

Other developers think that new apps that are written in HTML5/JavaScript will be able to run on any Microsoft platform that has an HTML5 browser built in, and that HTML5/JavaScript will enable Microsoft, its partners and its customers to gloss over underlying Windows-level differences.

I'm interested in hearing from developers as to what you're hoping/expecting here. Do you care whether Microsoft actually makes all of its platforms run the same Windows core? Or does an HTML5 browser running on all platforms go far enough in terms of enabling Microsoft to create its promised unified ecosystem?

Update: The Windows Embedded team at Microsoft wants it known that they aren't going away, regardless of all this one-Windows talk. A spokesperson sent the following statement, for the record:

“Support for ARM architecture on Windows 8 creates new opportunities to bring the full power of Windows to a range of devices. Windows Embedded has a long history of delivering platforms and technologies for the ARM architecture and we are excited to continue our work in that field. We will also continue our collaboration with Windows to shape Microsoft's future, but we have no additional news to share at this time.”

(And no, that doesn't mean anything contrary to what I've said Microsoft's ultimate plan to put Windows on phones, from what I hear.)