No, the ARIX "OS" and I refuse to call it an OS, is still sitting on top of a Linux kernel
Then you don't seem to understand what an OS *is*.
Linux is a Kernel that the OS is built upon, what people refer to as Linux as actually "GNU Linux" and that's the OS.
Or take the fact that you can actually compile Linux with a different kernel than the Linux Kernel, or BSD using Linux or Mach or one of several others.
