MicroVax II

Mouse mouse at Rodents-Montreal.ORG
Fri Jul 29 20:38:14 CDT 2016

> I just got a MicroVax II in the BA123 world box chassis.  I has a
> TK50, RX50, RXDQ2, but no DEQNA.  I'd like to get it running an OS.

> The DU disks don't work, but I have a couple of Qbus SCSI controllers
> that might come in handy.

Ooh, those are (my impression!) substantially rarer than DEQNAs.  (I
know _I_'d cheerfully swap a DEQNA for Qbus SCSI.)

> What OS's can I use with this hardware?  NetBSD?

Yes.  Recent (and some not-so-recent) versions are broken, in that they
can't self-host; as far as I know nobody knows exactly what's wrong.
My impression (as someone who hasn't tried it, but who has seen it
discussed on port-vax) is that something breaks somewhere in the
compiler when running native.

You may also find recent(ish) versions are too resource-hungry; the
MicroVAX-II can't have more than 16M RAM, which is pretty tiny by
modern NetBSD's standards (pretty much ever since they relegated most
ports to second-class, er, sorry, "organic" status).

Fortunately, older NetBSD is still available; I think it's even
available from netbsd.org.  I don't have any VAXen up at the moment
(I'm more constrained than historically usual about how many computers
I have live or almost-live), or I'd offer to build you a tarball; I can
do that anyway, but I won't be in a position to test whether it
actually works, that it may be suboptimal.

> Are versions of VMS available?

I imagine so, but I don't actually know, since I haven't gone looking
for any.  (I have fond memories of my VMS days, but as long as it
remains closed-source, I'm not running it.)

> How do you get an OS onto this system?

Same way you would any other system.  In your case, I see four options:
tapes, floppies (I think the RX50 is a floppy drive?), netboot (if you
can find a network for the thing), and putting the disk on another
machine and plopping the install on it there.  Personally, I'd be
installing NetBSD, and I'd probably dig out a spare DEQNA, netboot,
then install onto local disk from the netbooted system.  In extremis, I
might download a grappling-hook program via memory binary deposit
commands, then ship stuff over the console serial line.  This would
work, but would be slow; I think the fastest the console serial can run
is 19200, or maybe 38400.

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