System V Release Trivia (was BSD vs. System V,... )

[Peyton Yanchurak]

In article <687 at packard.UUCP>, shz at packard.UUCP (S. Zirin) writes:
> In article <687 at pyuxe.UUCP> pwy at pyuxe.UUCP writes:
> >Actually System V Release 2 Version 4 was the first paging release
> >for the 3B20 not the 3B2.  It came out in January of 1985.
> 
> Not True.
> 
> SVR2.1 V3 was the first paging release for the 3b20.  Some people
> called this SVR2.1.0 V3.
> 
> The second paging release for the 3b20 was called SVR2.1.1 V4 and supported 
> binary-only distributions (in addition to source).
> 
> The last swapping release for the 3b20 (to my knowledge) was SVR2.0.3 V3.
> 
> Seth Zirin
> att!packard!shz


The date on the Product Overview for System V Release 2.1.0
Version 3  for the 3B20 is October 1985.
It actually hit the street in December of 1985.  

System V Release 2 Version 4 for the 3B20 was Released
around January of 1985.  This was a provisional release
and was only distributed to people really needing paging.
I believe the date on the product overview was November 1984
( I have since discarded the documentation). You can read
a description of the paging algorithm in Release 2 Version 4
in the AT&T UNIX System Support and Update News (April 1985).
Also there was a paper given in the 1985 Summer USENIX
Conference by Robert S. Jung of UniSoft describing several
ports of the paging memory management system done from System
V Release 2 Version 4.
System V Release 2 Version 4, besides having demand paging
it also had advisory file and record locking and an improved
f77 compiler (it was functionally equivalent to
System V Release 2 Version 2 for the VAX11/780).

System V Release 2 Version 3 (which had support for new
hardware features - new tape and disk drives) was apparently
developed independently from Version 4 (conversely Version 4
was developed independently of Version 3).
Since neither release had the new features that were in the other,
there was a need to merge Version 3 and Version 4 since
the new features in each were mutually exclusive.
I believe that at one time there was some thought to
calling the merger of two releases Version 5, but instead
the merged release was called System V Release 2.1.0
Version 3.  The idea being that when the version number changed
it meant that new hardware peripherals were being supported.
In this way it is possible to put out a release just to support
new hardware by just incrementing the version number.
The base release number would stay the same, avoiding
the confusion of the paging relase being on Release 2 Version 2
for the VAX and Release 2 Version 4 on the 3B20.
In the new numbering scheme, for the release number,
the number on the left is the major feature
release number, the middle number is the minor feature release level,
and if there is a number on the right it stands for a maintenance
release level. 

				Peyton Yanchurak
				pyuxe!pwy