== I object to Windows RT being listed as an operating system == 

 Windows RT or Windows Run Time is no more a complete operating system than Java Virtual Machine or Android's Davlik. I can run Android (Davlik) Apps on my PC or on my Mac. Although Window Managers (like Enlightenment) are the face of Linux they are not the operating system. Windows 8 and Windows RT are not binary compatible, indicating different operating systems. RT is a presentation interface running on top of Phone OS core whether CE or BREW etc. Wikipedia calls Linux an operating system because it has a bootable kernel and even without the Window Managers and presentation APIs boots to a usable command line. Still has shell. Windows 8 can also boot to a command line and Windows Server has Core Mode sans GUI. Still has Win32 subsystem. RT is a presentation API only; saying it is an operating system depreciates the term.