In my own internal narrative at least, my stance is BSD is UNIX moreso than not in that
the code may have changed, there may not even be a lick of AT&T in there (not true,
handful of files, SCO lawsuit, etc.), but it's still UNIX in design, much more than
say something like Linux could be considered. It's like if some architect inherited
the Empire State Building but was then told you can only do anything with it if you
replace everything.
In the end, it's still going to be different than taking a plot of land and deciding,
hey, I want to build something like the Empire State Building. In the former sense, you
can start to replace the windows, then the door, then the elevators, etc etc, over time,
you see a gradual transition of A into B, which leads to unmistakable vestiges since they
were actively being worked around and within in the replacement process.
With the latter, you instead have an external vision of what you want to present, and may
even be able to visibly present it better than the original since you are going ground up,
best practices can be employed, etc. However, there is a high likelihood that you strip
all the cladding and drywall away and the way the actual steel beams are arranged and the
load bearing supports and such are likely radically different because they didn't
have to be carefully created in a way to truss up the existing structure above them, they
just had to be able to support that outward appearance everyone wants.
Analogy over, that's just kinda how I think about that any time the question of
BSD's "UNIX-ness" comes up. Neither building in the above scenario would
be bad, they would just have different design goals informing how they work internally vs
externally. BSD wanted to be UNIX compatible for folks familiar with every level, Linux
just wanted to present a kernel that one could drop a UNIX-y userland on, but at least in
my understanding replicating internal behaviors, structuring, and practices of UNIX was
never a design goal/requirement.
- Matt G.
------- Original Message -------
On Thursday, January 19th, 2023 at 12:08 PM, Steve Nickolas <usotsuki(a)buric.co>
wrote:
Accidentally sent this only to the person I was
replying to.
I am getting some grief on Twitter too for
"omitting" FreeBSD. I
didn't, but the BSDs don't fit either definition of "Unix". The
pre-1993 one being "based on AT&T code" -- after all, BSD (4.4 Lite r2
was it? Before my time!) -- went to a lot of effort to eliminate AT&T
code.
From what I've seen it's very much a gradual transition; 4.3-Tahoe starts to
have the new code and UCB copyright notices with the predecessor of what we call
the "BSD License" appearing in some of the source files. Then with Reno, a
majority of the userland is open-sourced, and Net/2 is fairly complete. (Net/2
and 4.4BSD-Lite / Lite/2 were lacking a few things.) But even right up until
the end things were in a state of flux.
A few things weren't finished until much later by the FreeBSD, OpenBSD and
NetBSD people.
-uso.