Windows 8: The Facts about ARM, Metro, and the Blue Stack

Information
2012-Feb-15 | Tags: analysisdevelopmentlearnmetro

Windows on ARMMany eyes will be focused on Barcelona on February 29, 2012 when Microsoft releases the Windows 8 Consumer Preview or what many are calling the beta version of the new platform. You’ve probably heard quite a bit about the Metro interface. It has design roots in Zune, Windows Media Center, and Windows Phone. It presents content-rich tiles and is designed to focus on a touch-first experience.


Metro provides a unique experience and involves a specific set of tools and technologies. When you read that Internet Explorer 10 doesn’t support plug-ins, you aren’t getting the full story because it’s really only the Metro version that has this restriction.

Of course, we’ve just learned about the experience for Windows 8 on ARM machines. Probably the most revealing quote for me was this one:

“WOA will not support any type of virtualization or emulation approach, and will not enable existing x86/64 applications to be ported or run.”

There’s quite a bit that can be read into that statement, so let’s break it down for a second. Here’s what I understand:

1. Regular Desktop Applications will NOT run on ARM Machines

I never imagined this would be the case because ARM is simply a different architecture. Fundamentally, the instructions used by the CPU at the lower level are different instructions than the ones on x86 and x64 machines. Microsoft bridged the gap between x86 and x64 somewhat by introducing an emulation layer called WOW64 (Windows on Windows 64-Bit) that enables 32-bit (x86) code to run in the x64 environment. I speculated that a possibility might be that Microsoft would create a similar engine for ARM but that is clearly not the case. So all of those programs compiled to x86 and x64 simply won’t work.

It is possible that some applications may make it over. Microsoft was clear, for example, that they will provide special versions of Microsoft Office 15. This appears to be part of the “blue stack” or desktop mode for ARM, which raises some interesting questions. If I were to try to draw the architecture of the Windows 8 stack based on the latest announcement, it would look something like this. Keep in mind this is a typical “stack” diagram that is not a true architecture and there are some obvious issues (for example, Win32 technically extends beneath the Metro stack but I’ve kept it out to keep it simple). Here’s what I am picturing:


Facebook Twitter RSS E-Mail

Windows on ARM - Windows RT