Several traditional PC makers – who also make Android tablets – have confirmed that they will make ARM tablets running Windows, but there are also persistent rumours that Nokia and other phone makers will also create Windows tablets.
Sinofsky didn't confirm any manufacturers but he did tell us WOA will "be supported by a new set of partners that expand the overall ecosystem". That could just be QUALCOMM, NVidia and Ti of course; the companies that are making the different ARM platforms.
The Windows 8 Consumer Preview is only for x86 PCs. That's not because WOA is behind the x86 version; it's because there isn't any WOA hardware. "These WOA PCs are all still under development, they're still being made. But our collective goal is that PC makers will ship them the same time as PCs that are shipped for Windows 8 on x86 and 64."
Developers and peripheral makers will get to see WOA first, on prototype hardware. "Over the next weeks and months following the Consumer Preview, a limited number of test PCs are going to be made available to developer and hardware partners in a closed, invitation-only program." Don't get excited: "They're already spoken for," Sinofsky warned us. And don't feel left out.
WINDOWS 8 ON ARM: From the original demos - the desktop
"There are no actual PCs yet. These are the PCs much like the ones we've been showing in demos. They are hardware prototypes. They're running all the same guts, just as debug boards. They're not the form factors that consumers will see, they don't have the industrial design. They're not thin and light. They have no battery sometimes!"
WOA PCs: only for WOA
"All the PC manufacturers are obviously super-hard at work on building these brand new devices that from the ground up are designed to be great - and exclusively for WOA," Sinofsky emphasized.
That means you can't take a WOA tablet and install Linux on it, and you can't put WOA on an existing ARM tablet. "It is not this level playing field across ARM devices," he pointed out to TechRadar; "Each one is unique. It's why you don't install Android on your iPhone."
Microsoft has done a lot of work to rebuild Windows for ARM and that's specifically for the hardware WOA PC makers are choosing.
"All of this is going to lead to a new generation of integrated end-to-end products. Hardware, firmware, the WOA software; it's all built from the ground up to work together, with a new level of collaboration between Microsoft, the ARM licensees, PC makers and developers of components and peripherals.
The work was across a really broad array of subsystems in Windows; some of them have been re-architected for low power and new kinds of devices, others are brand new support for things that haven't been there before."
But the way Microsoft is supporting ARM is also going to make life a lot easier for tablet manufacturers who've had to do a great deal of integration work putting Android onto their ARM tablets. Despite the range of hardware, there's only one version of WOA, because the Windows Hardware Abstraction Layer takes care of differences, and that could conceivably put tablet prices down.
"These PCs that we're building together are built on the hardware platforms from NVidia, QUALCOMM and Ti but they all share a common WOA OS foundation. The neat thing is all of them are running the same Windows binary," Sinofsky told us enthusiastically.
"It's a different approach that we've taken where we're working across different ARM hardware but the same Windows binaries are on each of them. We actually added more features to the HAL to work across different ARM buses, as we call them. What we're doing working across multiple ARM platforms is unprecedented."
Best of Windows, best of ARM
This is the 'best of both worlds' approach that we've predicted Microsoft would take with ARM and Windows 8. It's a tablet with tablet apps (although we expect to see slider and ultraportable form factors too and Sinofsky repeatedly said 'PC' rather than 'tablet'). But it's also a PC with the power of Windows and Office – just without many of the disadvantages.
If you want the whole of both worlds (good and bad), cross your fingers for the work Intel is doing to create low power SoC PCs. "We're doing a lot of work with Intel on this release too," Sinofsky reminded us.
"Especially when we talk about a lot of the power saving features, remember that Intel is making their System on a Chip stuff as well and everything we're talking about applies to those Intel chips." That would give you an ultra-low power system that gets the always-on Connected Standby feature and could run all your old Windows apps too, although those apps could weigh the system down and don't get all the advantages of WinRT.
The question is how many people want that 'belt and braces' approach and that's more Intel's problem than Microsoft's. With Windows on ARM, Microsoft is betting that the tablet market is going to be big, especially for tablets with long battery life and the advantages of a PC – like running Office.