I recall something different than what others had suggested. When the US government issued requests for proposals, they weren't permitted to specify products by name. In particular, if you wanted something that wasn't Microsoft, you couldn't actually specify that it be Unix.

So POSIX was born partially as a way of letting it be known you wanted a Unix variant rather than something else.

Certainly porting was an issue. I did work for a software shop in the late 80s and early 90s that produced graphics software, and porting between Unix systems was relatively easy, compared to, say, moving the software to Apollo's DomainIX, a sort of Unix-like version of Apollo Domain. With Unix systems and this software, the biggest issue was fonts, as the software needed to be able to calculate the extent, that is, the bounding box, for text that was to be displayed.

Strangely enough, the other big issue was time.

Rik


On Tue, Aug 6, 2024 at 6:29 AM Peter Weinberger (温博格) via TUHS <tuhs@tuhs.org> wrote:
and the folks from PARC wanted a more RPC-based open OS, according to
my not-yet-fully-retrieved memories.

On Tue, Aug 6, 2024 at 2:40 AM <arnold@skeeve.com> wrote:
>
> segaloco via TUHS <tuhs@tuhs.org> wrote:
>
> > Another way to put it would be as a chicken and egg, which came first, ...
> > ..., or the ongoing need for UNIX standardization finding sponsorship
> > by the working groups, IEEE, etc.?
>
> This.
>
> Try to understand what things were like at the time. There were
> a ton of competing Unix systems, all different:
>
> - IBM: AIX on the mainframe and PS/2, which were different from
>   AIX on the RT/PC and later RS/6000 (workstations).
>
> - DEC: Ultrix on minicomputers and microvaxen, and later on MIPS
>   based workstations
>
> - Data General: DG/UX on their minicomputers.
>
> - Pyramid: A BSD/System V hybrid RISC minicomputer
>
> - Sun: Workstations, 680x0 based and later SPARC based, and servers.
>   Initially BSD based, later SVR4 based.
>
> - Workstations from HP, Tektronix, NBI, others I've probably forgotten,
>   3B2 and 3B1/Unix PC from AT&T... The list goes on and on and on.
>
> Things split roughly along BSD/System V lines, but code wasn't portable.
> Did you use bcopy() or memcpy()? index() or strchr()? There was lots
> of mixing and matching happening, too.
>
> There was a crying need for a standard. The mess is what begot GNU
> Autoconf, which made a difference at the time. Having the ANSI C standard
> also helped.
>
> HTH,
>
> Arnold