Microsoft details Windows 8 for ARM devices

IDG News Service - Microsoft has released technical design details about the new version of Windows for devices that use ARM chips, outlining in a lengthy blog post different ways in which this OS, called WOA and still in the works, will be alike and different from existing versions of Windows.

WOA (Windows on ARM) will be based on the Windows 8 code base, itself still in development, and will replicate some familiar Windows design features, such as having a desktop interface component. In other ways, WOA will be uniquely crafted, such as requiring that devices running it use a system-on-a-chip design.

"WOA enables creativity in PC design that, in combination with newly architected features of the OS, will bring to customers new no-compromise experiences," wrote the post's author Steven Sinofsky, president of Windows and Windows Live Division.

"We created WOA to enable a new class of PC with unique capabilities and form factors, supported by a new set of partners that expand the ecosystem of which Windows is part," he wrote.

Microsoft expects WOA PCs, which will be based on hardware platforms from ARM licensees Nvidia, Qualcomm and Texas Instruments, to start shipping at the same time as Windows 8 PCs for the x86/64 processors from Intel and Advanced Micro Devices.

The Nvidia, Qualcomm and TI platforms will share what Sinofsky calls a "common" WOA foundation, running the same Windows OS binaries. Already, PC makers are involved with WOA to build devices like tablets as well as other devices that are lightweight, thin and require long battery life.

A big takeaway from Sinofsky's post is that Microsoft appears to be locking down the hardware specs for WOA devices, which has positive and negative implications, said IDC analyst Al Gillen.

The negative is that this reduces device makers' ability to differentiate their devices. "If [a device maker] wants to make a very unique Windows 8 ARM device, they can't necessarily add in new inputs and sensors that aren't supported by the OS," he said. "They can't go in and write extensions to the OS to make things happen unless they do it at the application level."

The positive is that this creates a larger ecosystem of devices that run the same version of the operating system, and applications have better portability, which ultimately outweighs the negative, he said.

"You have more standardization in the Windows market, which in turn creates a larger ecosystem, a larger, more addressable device market for software makers, and that's what Microsoft needs: a strong software ecosystem," Gillen said.

Like Windows 8 PCs for x86/64, WOA devices will be able to run Metro-style applications from the Windows Store created using the WinRT APIs (application programming interfaces). However, WOA PCs will not run, emulate or port existing x86/64 desktop applications.