Microsoft's Xbox One home-entertainment console has three operating systems at its core, company officials said during the May 21 unveiling of the device.

Why three? Marc Whitten, Microsoft's chief production officer of its Interactive Entertainment Business, explained during the hour-long reveal event in Redmond, that there'd be an Xbox operating system, the kernel of Windows and a third operating system designed to handle switching, multitasking and control inside the Xbox One.

Microsoft officials told Wired.com back in April something similar. From the Wired story:

"The Xbox One simultaneously runs three separate operating systems. First comes the tiny Host OS, which boots the machine and then launches two other hard-partitioned systems: the Shared partition, an environment that runs any apps (Skype, Live TV, Netflix, etc.) and helps provide processing power for the Kinect sensor and its gesture and voice controls; and the Exclusive partition, which is where games run. Because of the way memory is apportioned in the Shared partition, you can switch between apps with little to no load times, and even snap them into another app or game to use both at the same time."

Before today's Xbox event, Windows SuperSite's Paul Thurrott had said the next Xbox was built on top of the Windows 8 core. If I were a betting woman, I'd guess the Shared partition described in the Wired piece is based on the Windows NT kernel.

The NT "core" is what's shared across Windows 8, Windows RT, Windows Server 2012 and Windows Phone 8. It includes a shared file system (NTFS), networking stack, security elements, graphics engine (DirectX), device driver framework and hardware abstraction layer (HAL).

Dave Cutler, the father of Windows NT, moved to the Xbox team from the Windows Azure team a couple of years ago. At the same time, Hoi Vo also moved from Azure to Xbox. Vo was the director of OS/hypervisor on Windows Azure. So maybe Ho and/or Cutler had something to do with the "host OS" mentioned in the Wired story? (Just a guess on my part, as Microsoft so far isn't commenting on the Xbox One OS guts beyond what I've mentioned above.)

Update: In an under-the-hood architecture panel following the Xbox One reveal, Boyd Multerer, Director of Development for Xbox, confirmed that the team started with Microsoft's Hyper-V hypervisor in building the Xbox One operating system. Multerer said the team stripped out all the general-purpose "goop" to create an OS that allowd two virtual machines to run in side-by-side partitions. One of the partitions runs apps; the other runs games.

"David Cutler built the hypervisor that does the switching back and forth," Multerer confirmed.

The new Xbox One interface looks quite similar to the Windows 8 and Windows Phone 8 one, with a tiled look and feel. It runs Internet Explorer and Skype, just like any Windows PC/device. Also like Windows 8, the Xbox One includes snapping support. Microsoft officials demonstrated during the Xbox reveal how users will be able to "snap" applications, movies and games allowing them to multitask.

Another Windows 8 similarity: Xbox One is optimized to work in different power states, depending on the game or application that's running. The console remains in a low-power state so that when a user says "Xbox On," it will be able to power up quickly. This sounds a lot like Connected Standby in Windows 8.

Microsoft officials also mentioned Windows Azure during today's Xbox One reveal. Xbox Live does not run on Windows Azure; it runs on its own servers in Microsoft's datacenters. When Xbox Live launched in 2002, Xbox Live required 500 servers. It now requires 15,000. By the time Xbox One launches this holiday season, Micorsoft officials said it will be running across 300,000 servers.

We do know that the Halo game team at Microsoft has used a new cloud-programming model, codenamed "Orleans," which was developed by Microsoft Research. And during today's Xbox One reveal, the Redmondians noted that users will be able to store their movies, music, games and saves "in the cloud," which I am assuming means on Windows Azure.

Update No. 2: In an Xbox One frequently asked questions (FAQ) document, Microsoft officials also noted that the cloud (again, no mention of Azure specifically) will also allow for automatic game updating, game enhancements and saved preferences. VentureBeat's Dean Takahashi has more from the under-the-hood panel on how the cloud also will enable offloading tasks and freeing up more local console resources.

The aforementioned Wired piece states defnitively that "Xbox One gives game developers the ability to access Microsoft’s Azure cloud computing platform." Microsoft officials didn't say that today during the Xbox reveal event. However, Microsoft didn't say anything about the developer story for Xbox One today, presumably because that is going to be a big part of the messaging at the company's Build 2013 conference at the end of June.

Even without knowing (yet) what Microsoft will say at Build, it's becoming clear the company is edging closer to having a true cross-Windows development strategy at long last -- and that Xbox One is one of the devices that will be part of it.