Microsoft has been adamant in its claim that Windows 8 will be a universal experience across all devices, including both x86 and ARM based machines. So it comes as little surprise to learn that Microsoft is encouraging developers to both create a Metro version of their programs, as well as recompile them for ARM-based machines.
Windows 8 will be the first version of the operating system to run on devices with both x86 processors (PCs typically running Intel or AMD chips) and ARM chips (typically mobile machines, including most tablets), whereas previous versions of Windows had only supported x86. Unfortunately for developers, ARM devices will not support programs previously written for x86. Devs will have to recompile the programs in order for the programs to run on the new platform.
Both the ARM and x86 versions of Windows 8 will feature the Metro user interface as well as the traditional desktop mode. By deciphering Microsoft’s early terminology, it appears there will be two levels of program: Metro-style apps for the Metro tile-based UI and traditional programs for the desktop. Thus, devs may want to release three distinct version of their programs: an x86 version, ARM version, and a Metro app version.
For consumers, Metro apps will be only available for download through the Windows Store as Microsoft wants to keep things centralized and secure (similar to Apple, which will not allow users to install apps onto iOS device from outside the App Store). Developers and business users will be able to sideload them with no restrictions. These will be account-based, similar to the Android Market, and are licensed for up to five machines.
Traditional desktop apps will not be available for download directly through the Windows Store, but Microsoft may promote them and provide an external link to the developers’ sites for download, should the programs meet certain standards. Otherwise, desktop programs will retain the traditional distribution method.