A year ago, Microsoft announced the development of a Windows 8 version designed to run only on chips based on ARM's SoC architecture--the platform of choice for tablets and other mobile products due to its ability to combine long battery life with power and performance. Since then, there's been much speculation about what Windows 8 on ARM (WoA) will and will not do.

Windows chief Steven Sinofsky put much of that speculation to rest this week with a blog post that provided the most details yet on the company's plans for WoA tablets and PCs. Here are some of the highlights.

1. Windows Desktop lives. Windows 8 is all about the built-for-touch Metro interface, but users will have the option of bringing up the familiar Windows Explorer desktop to get under the hood and access the Control Panel and other tools. "Availability of the desktop incurs no runtime overhead. It is just there should you want or need it," said Sinofsky.

2. Chipmakers confirmed. Microsoft has selected three silicon vendors to build ARM system-on-a-chip (SoC) packages for Windows 8 tablets. They are Qualcomm, Nvidia, and Texas Instruments.

3. Simultaneous shipping. Windows-on-ARM systems will ship at the same time as Windows 8 for x86 systems if all goes according to plan. Based on the timing of Microsoft's Feb. 29 Windows 8 Consumer Preview, that could be later this year.

[ Planning an upgrade to Windows 8? Here are some tips to keep in mind. Windows 8: What IT Needs To Consider. ]

4. Windows unboxed. Unlike other versions of Windows, WoA will not be sold as standalone, boxed software. It will be available only preinstalled on WoA tablets and PCs. Patches will be delivered through Windows Update. That's "just as you would expect from a consumer electronics device that relies on unique and integrated pairings of hardware and software," said Sinofsky.

5. Ditto for apps. Apps for WoA systems will be available only as preinstalled software, or through downloads from the Windows Store. Microsoft says it's taking a closed-loop approach to the WoA ecosystem to ensure quality and a consistent user experience. It's a page straight from Apple's App Store playbook.

6. Windows Store not ARM-exclusive. In addition to Metro-style WoA apps, consumers and businesses will also be able to purchase x86 apps from the Windows Store. "The Windows Store can carry, distribute, and service both the ARM and x86/64 implementations of apps (should there be native code in the app requiring two distributions)," Sinofsky said.

7. Office is key. Microsoft is pitching WoA tablets and ultralight PCs as Android and Apple alternatives that allow the full breadth of entertainment and media options, without sacrificing productivity. To that end, Office 15 is being built for WoA that offers touch, keyboard, and mouse input. "WoA will be a no-compromise product for people who want to have the full benefits of familiar Office productivity software and compatibility," said Sinofksy.

8. No Linux support. Sinofksy said ARM "technical restrictions" eliminate the possibility for users to run anything but Windows 8 preinstalled on their tablets. That means no dual-booting of Linux or other operating systems .WoA also will not support virtualization or emulation, so that route also is out.

Sinofksy said Microsoft will start distributing WoA test systems to developers about the same time that the Windows 8 Consumer Preview drops later this month. But don't get your hopes up. "These devices are already allocated and spoken for," said Sinofsky. Microsoft will likely unveil more Windows 8 plans at the World Mobile Congress, which runs from Feb. 27 to March 1 in Barcelona, Spain.

The Enterprise Connect conference program covers the full range of platforms, services, and applications that comprise modern communications and collaboration systems. It happens March 25-29 in Orlando, Fla. Find out more.