[Info-vax] What is a "real" Unix ?

[Scott Dorsey]

Simon Clubley  <clubley at remove_me.eisner.decus.org-Earth.UFP> wrote:
>
>In that case, what is a "real" Unix ?

Strictly speaking, it's anything licensed under the AT&T Unix source code
license.

>Is it something that implements a set of user-visible APIs and certain
>behaviour within its kernel (fork() semantics for example) ?
>
>Is it something that came from a specific source code base and hence
>nothing else can never be called Unix no matter how compatible that other
>something is ?

As every piece of code in the code base used to say, Unix is a trademark
of AT&T Bell Labs.

>If BSD is a Unix, then is System V also a Unix ?

Now that's an interesting question.  4.2BSD is Unix, because it incorporates
code from AT&T v7.  It comes with both an AT&T and a Berkeley license.

But the latest version of OpenBSD no longer has any AT&T code in it, so
strictly speaking it's not really Unix.

>If System V is a Unix, then why can't something else that also implements
>the same APIs and kernel behaviour also be a Unix ?
>
>Or is Linux really a Unix after all (in every way that matters) and what's
>really going on here is just some out-of-touch BSD Unix elitism ?

I think that philosophically Linux started out with the Unix philosophy but
is rather quickly drifting away from it now.  There's a lot of giant 
monolithic stuff in Linux, from gnome2 to systemd, which is somewhat
contrary to the original Unix philosophy.  Linux has succumbed to the urge
to put everything possible into the kernel and this is very non-Ritchie.
--scott
-- 
"C'est un Nagra. C'est suisse, et tres, tres precis."