instability in Berkeley versus AT&T releases

[John Mashey]

> > > ...the S3 driver's backward compatibility with UNIX 2.0 is totally
> > > useless to anybody outside the former Bell System.
> > 
> > And since most real world UNICES are V7 derived, what does that say about
> > Bell?
> 
> It says that due to a mixture of technical and legal reasons they couldn't
> a) throw away the 2.0 compatibility in S3 replacing it with V7 compatibility
> or b) offer two versions of UNIX 3.0.1/S3.
I can't remember any legal reasons.  The technical reason was real simple:
remember that UNIX/TS -> PWB 2.0 -> SIII ->SV was a convergence process
to desperately try to get a UNIX that more people could agree
on and avoid having to make weird extensions; terminal driver was a notorious
area for such extensions; too many people doing non-research projects found
they needed other things.  Again, ANYONE WHO EXPECTS TO GET UPWARD-COMPATIBLE
RELEASES FROM SOMETHING LABELED RESEARCH does not understand research.  
Research versions of things and production, guaranteed-upward-compatible
things are different animals [not better or worse, just different].
> 
> As for your claim that "most real world UNICES are V7 derived", I don't
> believe it.  Period.  Most commercial vendors are offering S3 or S5-based
> systems.  Several 4.2 vendors are now offering 4.2BSDs that have some degree
> of S5 compatibility.  Some of them are even clever enough to offer 4.2
> functionality and S5 compatibility to the same programs as opposed to
> walling the two systems off in separate worlds.  I suspect this will happen
> more in the future.
I wish someone could quote numbers here; "most real world UNICES are V7 derived"
is certainly true, since XENIX, V and 4.2 are all V7-derived.  In the more
specific sense of "V7, rather than III", this is probably true [numbers,
somebody?] because I suspect there are a lot of V7-derived XENIX systems
still out there [by sheer numbers of CPUs].  By number of users, who knows?
> 
> I think enough has been said - more than enough, since most of the postings
> on this subject have been broadsides fired in religious wars rather than
> accurate discussions of the places where {V7,4.2BSD,S5} do well and where
> they do poorly.  If anybody else wants to wage holy war over why their
> favorite version of UNIX is the "only true UNIX", could they please move the
> discussion to net.flame or net.religion.software?
Yes!!  It is often more prudent to ask why a (dumb) decision was made than
to flame upon its stupidity; sometimes environments and tradeoffs are
different and you learn something.  Some of the "X is better than  Y"
arguments are really "[in my situation] X is better than Y [and I don't
have much experience with other kinds of situations] and therefore people
who use Y must be communist mutants from space [or worse!]
Here's a test case: how many people think UNIX is better than IBM's OS/MVS?
....
If you answered:
-What do you want to use it for?	10 points - good answer.
-What's MVS?	5 points for honesty.
-UNIX is better, of course - MVS is UGLYYYYY. - 0 points [because what you
get to do is a 10 Gigabyte database with required response times that
and needs a 3084.]  Don't laugh; I've known people who tried to put
projects like that on UNIX; not too many worked.

Much insight can come from tradeoff analysis; sometimes by looking at
differences we learn what the real general cases are and make progress
by synthesizing better mechanisms that cover more cases; little
progress is made in religious wars.
-- 
-john mashey
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