MicroVax II

Greg Stark stark at mit.edu
Sat Jul 30 11:09:53 CDT 2016

On Sat, Jul 30, 2016 at 2:38 AM, Mouse <mouse at rodents-montreal.org> wrote:

>> 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).

The Micro VAX II supports mop booting so you can boot NetBSD entirely
diskless with an NFS from a BSD or Linux NFS server just fine. This is
supported right up to current versions of NetBSD though I recommend
NetBSD 6.1.5. Later versions have bugs GCC which cause massive
headaches. Even the GCC in 6.1.5 is a bit buggy. I had to recompile
awk with -O0 or else various

I followed:


I forget where I diverged from it so if you run into any issues just
ask and I'll check what I did.

The hardest part was getting mopd on Linux to serve up the NetBSD boot
loader properly. The mopd for Linux didn't support ELF images and the
NetBSD boot loader isn't in mopd format in more recent versions of
NetBSD like it was in older versions. Now it's just ELF. But it's
finally working. If you use NetBSD to serve mopd this isn't an issue.
If you want to use Linux I can send you an mopd format copy of the
boot loader.

There are lots of advantages of booting diskless but my main
motivation was that older hard drives can be quite noisy. The
Vaxstation without a drive is fairly quiet, the only noise is the
power supply fan. Also they're moving parts that often fail and can be
quite small.

Having 20G of space for my root filesystem is quite handy too and now
I can easily take lvm snapshots, backups, etc so if this Vaxstation
dies I could perhaps find another and netboot it from the same root. I
should be able to boot simh from the same root too though I haven't
tried that. I'm not sure simh supports mopd so I might need to create
a boot device that remounts NFS over it.


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