unix & real time -- is a rewritten UNIX still UNIX?

[Dave Martindale]

> How much UNIX can you hack up and still call it UNIX?   An interesting
> question, but not the central point I want to make.
> 
> UNIX can do anything if you just rewrite this or that.  The same
> applies to any piece of software -- if you rewrite it, it can do
> anything.

UNIX means different things to different people.  To old-time UNIX hackers,
UNIX is any operating sytem which started out from the Bell code and still
has somewhat the same flavour to it.  (When was the last time you saw
an unmodified UNIX kernel on any site with source and a guru, anyway?)
Certainly most of these modified kernels were closer to the original
UNIX than they were to RSX or CPM or whatever, so why not still call them
UNIX?  So, to this group, UNIX is a set of ideas more than any specific
piece of code.

Of course, when people ask "can UNIX do real time?", they probably mean
a version of unix they can buy off someone's shelf, and don't have to
modify themselves - a different definition entirely.

Maybe we should start referring to the "UNIX family of operating systems"?