[TUHS] PG3 or Gen3.0?

[Clem Cole via TUHS]

below

On Fri, May 8, 2026 at 10:25 AM Larry McVoy <lm at mcvoy.com> wrote:

> On Thu, May 07, 2026 at 10:28:49PM -0400, Clem Cole wrote:
> > matrix against all the different favors from SVRx, BSDs, Ultrix, Tru64,
> > SunOS, Solaris, HPUX, AIX370/RS/PS2, DGUX ??? you get the idea.
>
> With the exception of AIX370/RS/PS2 and DGUX, BitKeeper ran on all of
> those and added Linux/370, SGI, MacOS, and all variants of Windows.
>
I know it did.  For many (most) programs and tool suites, frankly, POSIX
conformance was all that was needed.  But much larger programs, and often
had tentacles into OS things, such as Oracle, SAP, BAAN, and a slew of CAD
vendors, could not.  BTW: this only got worse with Linux clusters.  For
instance, Fluent (later purchased by ANSYS) had a test matrix of over 144
combinations to get a release out the door at one point.

>
> It sort of doesn't matter these days but the portability stuff in that
> source base is worth a look.
>
Actually, I've found it is now worse than it was during the proprietary
UNIX days, as you know, we have many of the "end-arounds" that traditional
UNIX had. Since the hardware is no longer "single sourced" from Sun, DEC, HP,
or whoever (in the old days, users really wouldn't mix the "supported"
hardware on production systems.  The largest end users are stuck with what
the ISV approved.  Then add things like security planes, and modern *IX
systems just have to deal with more issues. Users are in trouble even if
their application programs run on an Intel*64 or compatible processor
board, when the user adds hardware subsystems such as different kinds of
interconnects, or when they add other tools that step on each other (for
instance, different tool vendors bring their own MPI) or shared libraries.
 FWIW: I just ran into the shared library issue this week with macOS Tahoe
— some of Apple's binaries and dynamic libraries are compiled as arm64e
[which only Apple can certify — it part of the SIP system], so package
managers must use the traditional arm64; but try to mix certain programs
using exec that have shared libraries and SIP will fail.