[TUHS] System IV

[arnold at skeeve.com]

One other thing that was cool was that the doc defined UNIX as "an
operating system for the DEC PDP-11, DEC Vax, and the IBM System/370".  :-)

arnold at skeeve.com wrote:

> Warner Losh <imp at bsdimp.com> wrote:
>
> > So I've seen a number of places that talk about Unix TS 3.0 -> 4.0 -> 5.0
> > progression and how System III was released and System V was released and
> > System IV was internal only.
> >
> > What I've not seen is the "why" part of this. Why was it internal only?
> >
> > Warner
>
> I did some contract programming at Southern Bell (one of the operating
> companies) for a while, starting in the summer of 1982.  We used
> USG Unix 4.0 on a PDP-11/70. There were also vaxen.
>
> It was no longer being called PWB by then. In fact, I think that PWB
> was V6 based and an ancestor of System III.  
>
> System III had been released to the world.  When I asked why AT&T
> hadn't released Unix 4.0, I was told that the policy was to release
> one version behind what was being run internally.
>
> After the Bell System break up (1/1/1984), AT&T decided to just
> release what was current, thus the jump to System V, with "System IV"
> never having gotten outside the Bell System.
>
> When I was doing the contract work, although we were on Unix 4.0,
> we used documentation from Unix 3.0; they didn't bother reprinting /
> updating the manuals since the primary changes were apparently
> performance improvements in the kernel. (For example, they moved
> to hash tables for many things instead of simple linked lists.)
>
> I still have the reference manual and the photocopies I made of all
> the other documentation. :-)
>
> There was also a screen editor, named 'se' (NOT related to the Georgia
> Tech 'se' editor) which they'd managed to shoehorn onto the '11.
> It was kinda cool. I used both it and 'ed'. vi was also available but
> I found the modal stuff weird and didn't end up learning it until a year
> or two later. :-)
>
> Hope this is of interest.
>
> Arnold