A real OS doesn’t limit what you can do with your hardware and it doesn’t charge you extra for doing what you want. GNU/Linux is a real OS. Just ask the hosting providers. On Netcraft’s list of 47, 1 uses F5-BIG-IP, 5 use *BSD, 5 have an unknown OS and only 4 use that other OS with the EULA from Hell. All the rest, 32, use GNU/Linux as they should.