> Additionally, iOS only supports a subset of UNIX.
Of course. It only needs what the applications supposed to run on it need. The same is true about my car entertainment system - it probably doesn't have many tty's and doesn't really need more than one filesystem. Same, BTW, applies to Android - it's a Linux, but it's not really a desktop OS.
> How many iOS apps have your ever shipped?
Does it have any relevance to knowing the difference between an OS and a GUI?
Additionally, iOS only supports a subset of UNIX.
Finally it is impossible to ship an iOS application only using the POSIX subset exposed in OS.
How many iOS apps have your ever shipped?