[TUHS] Bitsavers' RT/PC, AIX, AOS, etc. recent additions

Kevin Bowling kevin.bowling at kev009.com
Tue Feb 18 23:01:49 AEST 2020

Thanks for clarifying.  I will reassert that the three pieces of systems
software I mentioned (VRM, AIX2, AOS) are not Mach in any way I know
about.  AOS may have some generic cross pollination, it’d be whatever was
going on at CSRG also for non-RT (4.2-4.3?) BSD platforms at the time of
checkout. Kirk or Warner may be able to elucidate if provided the date and
some reference material from AOS or I can do some original research.

Most distinctly and important:  VRM is not in any way Mach, it was its own
bespoke microkernel.  The microkernel would have been the most “Mach” part
of Mach research, so this makes the VRM concept even more unique and
enjoyable to me being so different and ambitious.  Therefore I don’t think
it is particularly correct to say any of VRM, AIX, AOS software is Mach
without its ukernel.

What you linked is a very late port (late 1990s) of a hybrid of 4.3 and 4.4
BSD (late meaning in the time when Net, Free, and Open had long taken over
from CSRG BSD).  I will quote a Twitter communication I had with Miod
Vallat in the past:
“Also it's not really 4.4. It's a mix of 4.3BSD-Reno plus the 4.4 VFS layer
and new system calls. It still uses the 4.3, pre-Mach, VM system, hence no

What Miod means by “pre-Mach” above: 4.4 BSD adopted the kernel memory
subsystem of Mach into the existing BSD monolithic kernel. Not any of the
ukernel or things like Mach IPC.

Not trying to be overly pedantic with you just trying to keep the records
straight since these machines are one of my keen interests and I welcome
new information on them.


On Tue, Feb 18, 2020 at 5:30 AM Jason Stevens <
jsteve at superglobalmegacorp.com> wrote:

> Oh sure!
> I'm having to use my phone...
> It's the combined sources here:
> http://bitsavers.trailing-edge.com/bits/IBM/RT/rt_bsd44/
> doc  mk
> jsteve at localhost:~/rt_bsd4/src/sys/.local/mach2.4$ pwd
> /home/jsteve/rt_bsd4/src/sys/.local/mach2.4
> jsteve at localhost:~/rt_bsd4/src/sys/.local/mach2.4/mk/conf$ cat vers*
> 69
> 5
> 1
> X
> So 5.1x edit 69
> jsteve at localhost:~/rt_bsd4/src/sys/.local/mach2.4/mk$ more CHANGELOG
>  17-May-88 David Golub (dbg) at Carnegie-Mellon University
>  XM21:
>         David Black completely rewrote the accurate timing code
>         (which is now implemented on all machines) and the priority
>         and scheduling algorithms. The system now correctly reports
>         cpu_usage per thread.
> The all file has this before i386 was added.
> So it's an older v2 than what is on the CSRG CD, but not as old as the VAX
> '86 stuff.
> It seems to be March 11 1989, although that could be when this was either
> archived or ported..  I guess they didn't exactly sync to a public kernel
> tree all that often.
> On Tue, Feb 18, 2020 at 4:05 PM +0800, "Kevin Bowling" <
> kevin.bowling at kev009.com> wrote:
> I’m asking exactly where the Mach is in the linked archive. VRM, AIX or
>> AOS? Can you support this with a reference for my own documentation
>> On Tue, Feb 18, 2020 at 1:02 AM Jason Stevens <
>> jsteve at superglobalmegacorp.com> wrote:
>>> It's the CMU micro kernel.  The hybrid "2.6" lived on in NeXTSTEP, and
>>> OPENSTEP, with various upgrades to bring it up to OS X.
>>> The RT as I understand it was a research machine, hence the BSD ports,
>>> and Mach port.
>>> What is interesting the more I dig around is that there was ROMP
>>> coprocoessor cards, and an OS/2 and DOS monitor program to let you boot BSD
>>> on the card.  Peripheral IO was done on the x86 side.
>>> If RT's are rare, I can't imagine how impossible it would be to get one
>>> of those cards!
>>> The BSD assembler and linker source is in the archives too, no doubt
>>> it'll help someone make a RT emulator.
>>> Get Outlook for Android <https://aka.ms/ghei36>
>>> On Tue, Feb 18, 2020 at 12:54 PM +0800, "Kevin Bowling" <
>>> kevin.bowling at kev009.com> wrote:
>>> Can you clarify what is Mach in this archive if I have a gap in my
>>>> knowledge? I didn’t know the VRM had any direct relationship to Mach
>>>> Regards,
>>>> Kevin
>>>> On Mon, Feb 17, 2020 at 9:43 PM Jason Stevens <
>>>> jsteve at superglobalmegacorp.com> wrote:
>>>>> Interesting stuff!  And another version of Mach is buried in there.
>>>>> So the 4 csrg cd set may have updates to the romp support as it's an
>>>>> older version of the 5.1 kernel from 89...  Not that think there is any
>>>>> Mach romp users.
>>>>> Get Outlook for Android <https://aka.ms/ghei36>
>>>>> ------------------------------
>>>>> *From:* TUHS <tuhs-bounces at minnie.tuhs.org> on behalf of Charles H
>>>>> Sauer <sauer at technologists.com>
>>>>> *Sent:* Tuesday, February 18, 2020, 5:51 a.m.
>>>>> *To:* TUHS
>>>>> *Subject:* [TUHS] Bitsavers' RT/PC, AIX, AOS, etc. recent additions
>>>>> The Bitsavers' RSS feed (
>>>>> http://user.xmission.com/~legalize/vintage/bitsavers-bits.xml) seemed
>>>>> to me to be dominated by RT, AIX, AOS (BSD for RT), etc. stuff in the last
>>>>> week or so. I've only sampled a few items, but discovered a few things that
>>>>> I should have known (or knew and forgot?) while I was at IBM.
>>>>> http://www.bitsavers.org/pdf/ibm/pc/rt/ -- voice: +1.512.784.7526
>>>>> e-mail: sauer at technologists.com fax: +1.512.346.5240 Web: https://technologists.com/sauer/
>>>>> Facebook/Google/Skype/Twitter
>>>>> <https://technologists.com/sauer/Facebook/Google/Skype/Twitter>:
>>>>> CharlesHSauer
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