[TUHS] PG3 or Gen3.0?

[Warner Losh via TUHS]

"USG mod level 3.33" might be the best moniker.

Unix Operating System Generic makes the most sense to me, since Bell
entities would take that and turn it into the specific OS for their switch,
billing system, etc. USG curated the research products into something that
people could use.

Warner


On Thu, May 7, 2026, 6:13 PM Thalia Archibald via TUHS <tuhs at tuhs.org>
wrote:

> Interestingly, Pirzada calls it “issue 1 of UNIX Operating System Generic
> PG-1C300”, never “Program Generic”.
>
> These are the Generic releases mentioned by Pirzada:
> - USG release 1.0 (15 December 1973)
> - PG-1C300 issue 1: USG release 2 mod level 2.24 (April 1974)
> - PG-1C300 issue 2: USG system at mod level 3.33 (January 1976)
> - PG-1C300 issue 3 (spring 1977)
>
> Additionally with the same number scheme:
> - PG-1C600: MERT Release 0 (November 1977)
>
> Thalia
>
> > On May 7, 2026, at 16:55, segaloco via TUHS <tuhs at tuhs.org> wrote:
> >
> > Received a question from Thalia Archibald concerning my use of the
> > nomenclature "PG3" vs Pirzada's "Gen3.0".  I pulled together the info
> > below, seems like it might be interesting to the broader audience:
> >
> > So it's a bit fuzzy when you get into the weeds. This document[1]
> > defines the acronym "PG" as such:
> >
> >> At the highest level in the document hierarchy is the
> >> Program Document (PG) Index that lists all of the documents
> >> associated with a program generic.  A single PG-level directory
> >> occupies the corresponding position in the file system hierarchy.
> >
> > So within their source control structure you would have directories:
> >
> > pg-1c300-01 (issue 1)
> > pg-1c300-02 (issue 2)
> >
> > And then under those the "PR" directories containing the individual
> > groupings of source files, other documents, etc.
> >
> > This isn't what I originally based my use of this acronym on though,
> > rather just Program Generic (PG).
> > Typically if I do see a shorter name,
> > the system is just referred to as a "Generic", proper noun. This was
> > common practice within AT&T and did not just apply to UNIX[2][3].
> > In fact, this first round of USG UNIX (before UNIX/TS and later) was
> > very "Bell-ish" compared to later efforts. The manuals were the only
> > ones rendered to Bell System standards in that they had the OSD headers
> > with document ID, issue, date, etc. rather than just the standard
> > manpage masthead. Several of the USG documents of the time look like
> > the same typesetting package used for 3ESS generic pidents for instance.
> >
> > As I was gathering some of this info, I keep seeing PG-1C300 used where
> > the system is referred to in short.  This actually makes sense given
> > AT&T's use of the "PG" prefix for a number of different projects.
> > For instance, MERT Release 0 is given as PG-1C600[4]. COSMOS, built
> > on UNIX by WECo for a frame system in telco offices[5], has
> > documentation given as PA-6P014, possibly implying a PG-6Pxxx prefix
> > for the underlying generic. Outside of UNIX, PG-3H903 is one of the
> > 3ESS generics[6].
> >
> > After compiling all of that info, I'm inclined to say that the
> > "canonical" names in increasing length are "PG-1C300", then "Generic",
> > then "Program Generic". I would think given Pirzada's being at AT&T
> > at the time though the "Gen3.0" etc. nomenclature would also be
> > acceptable, just maybe not "period".
> >
> > - Matt G.
> >
> > P.S. As always this is just my own research, I wasn't there so I'd
> > certainly get some second opinions if available.
> >
> > [1] -
> https://www.tuhs.org/Archive/Documentation/TechReports/USG_Library/1099_Program_Generic_Control_and_Documentation_on_UNIX.pdf
> > [2] -
> https://telecomarchive.s3.us-east-2.amazonaws.com/docs/bsp-archive/233/233-154-135_I1.pdf
> > [3] -
> https://telecomarchive.s3.us-east-2.amazonaws.com/docs/bsp-archive/234/234-090-161_I1.pdf
> > [4] -
> https://www.tuhs.org/Archive/Documentation/Manuals/MERT_Release_0/Pgs
> 01-02 Title Page.pdf
> > [5] -
> https://telecomarchive.s3.us-east-2.amazonaws.com/docs/bsp-archive/SPCS/PA-6P014_I3.pdf
> > [6] -
> https://telecomarchive.s3.us-east-2.amazonaws.com/docs/bsp-archive/SPCS/PG-3H903_I10.pdf
>
>
>