[TUHS] AOS and IBM/RT [Re: Amdahl UTS, AIX/370, AIX/ESA

Brad Spencer brad at anduin.eldar.org
Thu Nov 21 23:07:00 AEST 2019

Dan Cross <crossd at gmail.com> writes:

> On Thu, Nov 21, 2019, 1:33 AM Al Kossow <aek at bitsavers.org> wrote:
>> On 11/5/19 11:59 PM, SPC wrote:
>> >
>> >
>> > Is it AOS stuff saved and available (including source code)
>> > un some place on the Internet?
>> It was, and may still be in the afs heirarchy
>> I'm not going to say where, or how complete what was there is
>> I also seem to remember it still sat on top of an AIX microkernel
>> and didn't go down to bare metal.
> No, that's not true. AOS was basically 4.3BSD Tahoe plus NFS and it ran on
> bare RT hardware. There was source code available to universities, though
> as I recall some bits related to memory management were missing and
> distributed as object files. I gathered, at the time, this was due to some
> obscure intellectual property reasons. People later tried to Port e.g.
> 4.4BSD to aging RT hardware and found it challenging because the memory
> subsystem was so different.
> But anyway, there was no hypervisor involved.
>         - Dan C.

For a brief time a long time ago, I used a 4.3BSD based Mt. Xinu, MACH
microkernel, OS on the IBM-RT as an alternative to AOS.  Ran well
enough, but was disk and memory constrained.  We had source to much of
the system (or perhaps all of it, don't remember), but I seem to recall
that compiling it was a big pain.  Something like you had to use a
specific compiler (perhaps referred to as High C??  hc command perhaps)
to compile some of the source.  gcc had a backend for the ROMP
processor, but it had a hard time making usable binaries.  I think that
some variation of pcc was the usual compiler.  I remember it being
pretty stock 4.3BSD with NFS and minus YP/NIS.  We used them mostly as X
terminal workstations.

Brad Spencer - brad at anduin.eldar.org - KC8VKS - http://anduin.eldar.org

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