Microsoft Deputy General Counsel David Heiner told Mozilla it won’t permit other browsers for two reasons, Anderson said: ARM processors, which power virtually all iOS, Android, and Windows Phone smartphones and tablets today, are different from the x86 chips that power PCs. The chips have new requirements for security and power management, and Microsoft is the only one who can meet those needs. Windows RT — the version of Windows 8 geared for ARM devices — “isn’t Windows anymore.” Anderson scoffs at the arguments. “I’m not aware that Microsoft is the exclusive and sole proprietor of technology capable of working in the ARM environment…. It’s a different architecture, but it’s not the first time we’ve had an OS that works on a different architecture,” he said of the first point.