Some of us Microsoft watchers have heard and blogged about a rumored Microsoft mobile device known as "Andromeda."

But Andromeda isn't just hardware. It's also the codename for the software that will power not just Microsoft's Andromeda device, but Windows 10 itself, going forward, I believe.

Windows Central and MSPoweruser.com have both done good posts earlier this year outlining AndromedaOS, which Windows Central says may be an offshoot of Windows Core OS. Over the past few months, I've also been hearing bits and pieces about AndromedaOS from my own sources.

It's worth noting AndromedaOS is not a Microsoft Research project. It isn't Microsoft's attempt to create a new operating system without any roots in Windows, as was "Midori" -- an operating system that Microsoft worked on for years as a skunkworks project and then dropped.

AndromedaOS, instead, is going to be the guts of Windows 10 as it moves ahead, according to my sources.

Even though Microsoft officials have continued to claim publicly that Windows 10 is the same across different device types, it isn't. Microsoft was able to build a common Windows 10 Core, known internally as OneCore, that works across phones, tablets, laptops and PCs, IoT devices and the HoloLens. But, as Windows Central notes, the rest of the Windows 10 operating system that sits on each of these platforms isn't the same; it includes pieces that are specific to the device types.

AndromedaOS is a new implementation of Windows 10 that sits on top of OneCore, my contacts say. This OS is both a reference OS for Microsoft OEM partners' Windows 10 devices in the future, as well as the codename for the OS inside Microsoft's Andromeda mobile device.

I've also heard from some of contacts use a car analogy to describe how Microsoft thinks about this. There's a "Chassis" -- like the frame of a car -- that is the base for every Windows 10 SKU in the future. And different bodies can be added/built on top of this common chassis.

Windows 10, up until this point, still takes a lot of its cues from its predecessors: Windows XP, Windows 7 and Windows 8.X. Microsoft has been working for years to untangle the dependencies and rewriting the subsystems inside Windows. The AndromedaOS is the culmination of this result, sources say.

AndromedaOS is likely an expansion of what Microsoft's doing with the CShell, or Composable Shell, that's meant to unify Windows 10 elements like Start, window management, the Activity Center and Settings across different Windows form factors.

Microsoft is currently believed to be planning to roll out the new AndromedaOS platform first on the Microsoft Andromeda mobile device (which is unlikely to arrive before 2018) and then later for other form factors like desktops.

Unsurprisingly, Microsoft is not commenting on anything to do with Andromeda hardware or software.