[TUHS] Mach for i386 / Mt Xinu or other

Clem Cole clemc at ccc.com
Mon Feb 20 07:19:56 AEST 2017


On Sun, Feb 19, 2017 at 1:20 AM, <jsteve at superglobalmegacorp.com> wrote:

> True, but It’s not 4.3 BSD …  I was hoping for something vintage of the
> era, just as Solaris 11 is SYSV, but it’s nothing like SYSVr2 on the VAX….
>
​Fair enough... the Mt Xinu version is pretty much the CMU version
unadorned.   Which mean that it is a 4.3BSD kernel, with the BSD based MMU
code ripped out and replaced with the CMU code, and the Mach interfaces
(ney RIG - Mach's and Accent's predecessor) messaging system spliced into
it; then the whole mess was built back up using a 4.3BSD user space (and on
top of the i386, an Intel developed boot system - which is a different
story I'll not repeat at this time - but thankfully was common to all the
UNIX systems of the day because Intel developed and make it available to
community at large).

The other option which I would suggest to look at is the OSF/1 mk for the
i386 (monolithic) about version 3x which as I said forked off the Alpha
line and a couple of other systems.   The i386 version of OSF/1 supports
the same chips (i386/i486/Pentium) at the CMU version, it also comes with
more HW device support (disk, tape, network, display *et al*),  than the
CMU/Mt Xinu version -- including most importantly SCSI support by
default, which is why is might be a little easier to work on today's HW and
VMs.   When I last used it, it lacked USB support; but that was being
worked on around the time I started doing other things so even that might
even be available today.

FWIW: OSF/1 also started with 4.3BSD userspace, but it had a lot of work
done to it to updating it - adding the Sys V commands that BSD lacked those
days and adding Sys V options to many commands.  * i.e.* its user space is
a tad more "complete" / "wider" than pure 4.3BSD and again makes it a
little easier to complete.

Note that the user space commands from the mk would become the basis for
Tru64, HP/UX and later versions of AIX.   And also the OSF/1 version will
have better Graphics, Motif and a much better GUI options all around that
Mt Xinu, which alone may be it easier to work.


As I also said elsewhere, the uK or Research Institute (RI) version is a
tad more fun to play with.   It's a real kernel architecture moving things
like file systems *et al* in user space.  But you can do do things like
start up multiple system interfaces.   LCC had their DOS/Win95 interface
was actually developed running instead of as a VM like it did for the basic
mk code, but in as "second server" but I do not think they ever sold it.
The other thing the RI never did, was the uk still has the pager and all
the networking code in the kernel, so the uk, is hardly 'micro' in size.

There is a OSF Version 4 and maybe even version 5 (I've forgotten, if some
one remembers - please correct me).  The OSF RI folks were trying to
rewrite it a bit in C++ as I recall, again this part of the UI vs OSF wars
of the day and Chorus has rewritten there version from Pascal to C++, and
IIRC the RI was trying to counter that.  I don't remember if that version
of the uk ever saw the light of day.




Anyway, no matter which is the 3 code streams you pick, Mt Xinu, OSF/1 mk
or uk one hardest problems for today will be that the compiler is of course
extremely old by today's standards, and you are probably going to run it
some walls in that area faster than you might think.   That said, if you
are willing to deal with the compiler as it comes, non of them should be
very high, or hard to get clear, but some are likely to take some work.

Have fun and good luck and let us know if you can get any of these running.

Clem
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