Originally posted here by catch
Yes we can dance around what an exact definition of Linux is... the system Torvalds invented did not have the functionality of which you speak.
It didn't support USB, Firewire, or as far as I can recall, PS2, does that somehow make linux today no longer linux? Of course not. Why are you further detracting from the point by talking about history when the discussion is about NOW?

If you say that root can be removed from the security policy and your average person reading this gose out and gets any of the major flavors of Linux, will they be able to do that? Of course not...
No, you're right, they might have to LEARN. Again you are detracting from your very own point about security being an abstract. What can the operating system be MADE to do, not what can it do out of the box? The important point I have brought up is that Linux can be MADE to use the ACL and permissions systems of Trusted operating systems.

Linux being open source can be completely modified... so what then is the functional definition of Linux? I used the one I'd heard most frequently (the kernel as provided by kernel.org), you disagree with this, and I recognized your points as valid exceptions... I still contented that systems like SE Linux are the exception to Linux and not the rule, and therefore constitute individual systems and not Linux as a whole.
See, now you're defeating your own argument because your original point (which I agree with in spirit, if not in your implementation of) was about how secure an operating system can be MADE, not what its capabilities out of the box are. In that sense, with enough time and investment Linux could adhere to every DoD accepted security standard out there, because the source is freely available. Think of linux as more of the modeller's clay, rather than the pottery that is the end result, and maybe my point of view will come across clearer.
As far as I see it, Linux can be made to suit your needs, and a lot of distributors have gone out of their way to do so. If you are looking for "trusted"-style ACLs/permissions schemas, look to SELinux. You cannot define Linux as explicitly as you like since it is easily and readily changed, thus I would put forth that the security models of its various distributions might have to be tested individually and disparate from the "official" kernel from kernel.org.

No, it isn't productive, nor is it the path I wanted this to take. It was supposed to be an abtract about quantifying operating system security... not comparing and complaining about specific definitions of operating systems.
Then why argue non-abstract ideas in an abstract context? Presenting some to reinforce a point is a good idea, however if you are incorrect the original idea can be lost in the ensuing discussion of where and why you were incorrect in your initial statements.