I just finished reading through Steven Sinofsky’s detailed post about ‘re-imagining’ & re-engineering Windows for ARM based ‘computers’. Great read if you’re looking for some highly technical details. As you might imagine, getting something as massive and complex as Windows to run on a whole new architecture is no easy task. Since Windows was designed to be flexible from the beginning, it was a little easier however. Still ARM based systems are a different design from traditional PC hardware, where most chips are integrated into one piece of silicon, and everything is designed to use minimal power, and hence lacks performance abilities. Microsoft built custom ARM based hardware in order to do large scale testing of their new software, which is pretty impressive.
One of the key things I made note of while reading Sinofsky’s article is that while Windows 8 on ARM (WOA from now on) was designed to be as much like Windows 8 on x86-32/64 ,however it is significantly different in a few very important ways. Regular software written for traditional Windows (NT/x86 based) systems will not run on WOA. It will need to be re-written/ported to use WinRT, a new AIP set for WOA. However software written for WOA will run on Windows 8 systems. Microsoft will provide versions of its key software such as Office 15, that will run on WOA systems. The next key difference is that WOA is designed to be integrated tightly with the hardware it will be sold with. You wont be able to buy a copy of Windows for WOA and install it as you like. You wont be able to install other OS software on the hardware like you can with traditional PC hardware. For software/OS/hardware-drivers/firmware, and security updates, WOA will be serviced exclusively from Windows Update. And finally, they only way to load applications on a WOA device will be through the Microsoft App Store. The App store will be available on x86-32/64 systems as well and the Microsoft App store will handle both types of binaries, simplifying things on the developers end. At first thought, I was actually surprised Microsoft wouldn’t try to integrate some form of backwards compatibility with traditional x86-32/64 software much like Apple did with Rosetta when they switched from PowerPC to Intel chips. But then I realized they are using it as an opportunity to create a new, clean, highly locked down environment where software has stricter requirements.
These key points that make Windows 8 x86-32/64 different from WOA also make Windows on ARM much like Apples iOS. A closed environment, tightly controlled, limited, and highly integrated. I really like the idea of a highly controlled environment in the sense that it creates a great product. In giving up some flexibility, you get a highly reliable and simple device, something Microsoft and its partners have struggled with over the last decade with their Tablet PC attempts. The downside comes from a poor branding setup. Windows 8 will now not just be Windows 8 x86-32, Windows 8 x86-64, but now include Windows on ARM. And I see end users being highly confused when they buy a WOA tablet only to find most of their familiar Windows software wont run (until the developer ports it). Apple stumbled into a nice approach where there is clear distinction between their desktop (OS/X) and mobile (iOS) operating systems. And after spending a few hours with Windows 8 on a desktop, I’m personally not a fan of them trying to push a touch based UI to a traditional moused based desktop experience. I don’t know how well trying to mix two very different user experiences into one will work. Again Apple is slowly bringing some effective touch based controls to their old school desktop software, but not forcing it on users the way Microsoft is. I personally think the two experiences should be separate and customized, along with the branding. I truly hope Microsoft will re-brand WOA to avoid user confusion (especially as the ‘Windows’ paradigm fades since apps will run almost exclusively in fullscreen in WOA). I think there is an effective way of doing it, while still utilizing the power behind the Windows brand.
