[TUHS] First Unix-like OSes not derived from AT&T code?

[Clem Cole]

in blue

On Mon, May 2, 2022 at 2:57 AM Ron Natalie <ron at ronnatalie.com> wrote:

> Back around 1989 our company was provided the AIX 370 and PS/2 source
> code.    This was a distinct code base from either of the RT UNIXes.
>
Correct -- AIX for the 370 ISA and 386 were compiled from the same code base



>   It was a pretty straight-forward UNIX kernel with what IBM termed the
> Transparent Computing Facility (derived from the UCLA locus stuff).
>
Not quite correct.

TCF was based on the ideas from the Locus Distributed OS.   But not the
same code.  The Locus Distributed OS was based on a research (V7) kernel
originally on 11/70s; although I believe UCLA added BSDism over time and
Vax support (I never saw that personally).  But more importantly, AIX and
TCF itself were also owned by IBM (*i.e.* it was a work for hire of LCC for
IBM).   Bruce Walker was the implementation lead for both (and one of
Jerry's grad students).

Locus TNC (which is what OpenSSI for Linux is based on[1]) - although the
website seems to be taken down sadly - it never was ported beyond Linux 2.6
kernel) is a completely new implementation yet.   I'm one of the architects
of the same.   We were 'firewalled' so Bruce and our peers could talk about
things, but I was never allowed to actually look at the IBM code base.  I
could >>use<< it to try things out.  After the IBM AIX contract ended,
Bruce and the old AIX team at LCC was then given full access to TNC source
trees which Locus owned the IP.

The big difference between the 3 was the Locus was its own OS, that
supported UNIX-like features.  Whereas TFC was built into a modified/custom
AIX kernel and special FS with ad hoc support for the different issues that
allow process migration.   One of the cool things as Ron pointed out was
the TCF allowed the mixing of binaries from Intel and IBM ISAs and the
kernel would use whatever processor it needed.   With the 3rd generation
TNC, the technology was split into 14 separate 'products' that used
structured interfaces in the kernel.  For instance, the process support was
encapsulated in what we called VPROC (similar to the multiple FS style
layers from Research and later Sun -* i.e.* the different VFS) and while it
worked better if you used the Locus supplied cluster file system (which
supported full Unix semantics), basic process migration within the
constraints that NFS placed, also worked (the HP implementation was based
on NFS, while DEC, Intel, and SRVR4 implementations used CFS).
My personal role was much of CFS and some of the utility functions like the
Cluster Management System (CMS).

In fact, a small demonstration of TNC was done with OS/2 to show that the
OS/2 process semantics and the UNIX process semantics could co-exist, but
it was never completed as IBM did not buy it.  However, some of the
technology landed in the Rochesters AS/400 OS in their Posix emulator which
Locus also had a hand in building.

One of my favorite demos was at a trade show that had a LAN; our folks
would bring a PS/2 with an empty hard disk and load a single floppy.  Boot
the kernel, and add it to the TCF cluster back at LCC.  The system
immediately was usable, although since the disk was not populated, all
binaries had to come across the LAN/WAN.  But the caching would start to
take over in the background and slowly populated a local copy of /bin,
/lib, and the like.  Very cool ...

Clem

[1] Sadly, when I checked this AM, the OpenSSI website seemed to be taken
down.  I d not believe OpenSSI was ever beyond Linux 2.6 kernel.  IMO: It
was a shame that the upstream Linux kernel team had been willing to take
the VPROC changes, it would have been a very interesting and
exciting system enhancement.   As Ron said, anyone that used TCF or TNC was
pretty much hooked. I'll have to do some more poking to find out what
happened.
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