[TUHS] Release Dates, Systems History - (was Did System V Really Prevent 5BSD?)

[segaloco via TUHS]

On Friday, January 2nd, 2026 at 16:18, Warner Losh via TUHS <tuhs at tuhs.org> wrote:

> On Fri, Jan 2, 2026 at 4:32 PM Mary Ann Horton via TUHS tuhs at tuhs.org
> 
> wrote:
> 
> > On 12/29/25 13:10, Clem Cole via TUHS wrote:
> > 
> > > - Initial Internal Release: Some sources indicate an initial release in
> > > 1980. This was likely a pre-commercial version known internally
> > > by names
> > > such as UNIX/TS 3.0.1 or UNIX Release 3.0.
> > > - Official Commercial Release: AT&T formally announced System III
> > > in
> > > late 1981, and it was first made publicly (commercially)
> > > available outside
> > > of the Bell System in 1982.
> > > My UNIX Release 3.0 manual is dated June 1980. It's from Dolotta,
> > > olsson, and Petruccelli, Lab 364. The Acknowledgements page describes it
> > > (the manual) as descended from V6, UNIX/TS 1.1, and PWB/UNIX 2.0. My
> > > understanding is that this eventually turned into System III.
> > > AT&T's UNIX System V had major releases starting with the initial System
> > > V 1983,
> > 
> > My UNIX Release 5.0 manual is dated June 1982. It was internal to Bell
> > Labs Division 452 (the computer centers). I understand this turned into
> > System V.
> 
> 
> 4.1BSD was July 1981
> 4.1aBSD was April 1982
> 4.1cBSD was Late 1982
> 
> This leaves us with Kirk's story lining up in two possible ways:
> 1. If the reason is System V, then the dates line up well to 4.1->5.0 plans
> 
> changing to 4.1->4.2.
> 
> 2. If the reason is Unix 5.0 plans that were hatched when 3.0 was released,
> then it does line up with the 4->5BSD plans vs 4BSD -> 4.1BSD actual.
> 
> 
> I'll see if I can get a peek at the dates of the printouts next time I'm at
> Kirk's
> house which would tell us for sure. He's quite sure the reason was AT&T.
> I see now that I didn't ask this detail... I'll follow up with him.
> 
> Warner

Bill Joy gives November 1980 as the distribution date of 4BSD, and then
April 1981 as the date of the initial 4.1BSD revision[1].  This is the
earliest date I can find given for anything named 4.1BSD.

- Matt G.

[1] - https://www.tuhs.org/cgi-bin/utree.pl?file=4.1cBSD/usr/man/man0/changes.4-81