> Debian isn't an operating system. Linux an operating system and is a small part of the Debian distribution.

No. Debian GNU/Linux is an operating system (specifically a variant of GNU/Linux). Linux is a kernel, not an operating system (I think only Linus tries to claim that a kernel is all that makes an operating system -- but I'd require at least libc and POSIX coreutils before you can begin to call something an operating system).