[Info-vax] DEC Multia (UDB) issues

[Hans Vlems]

On Aug 23, 1:26 pm, MG <marcog... at SPAMxs4all.nl> wrote:
> On 23-8-2011 12:39, Hans Vlems wrote:
>
> > Running VMS on a Multia is not that difficult, even I managed to make
> > it work. My Multia came with just 40 MB main memory IIRC and though
> > VMS will boot and run in that limited space it halted within half an
> > hour.
>
> Which version did you run, do you recall that?

VMS V7.3.

>
> I'm a bit surprised, to be honest, that VMS wouldn't be able to handle
> that.  Is it as simple that Alpha, being 64-bit, would ordinarily
> require more RAM?  Or were you performing complex calculations, heavily
> using DECwindows and therein based programs, perhaps?

The 40 MB came in four boards: two 12 MB boards and two 8 MB boards.
My conclusion after a
couple of sudden stops of VMS (and that doesn't happen too often,
right) was that either 40 MB was
not enough to run X-motif in or perhaps that one of the memory boards
was slowly going south.
Then I learnt that AlphaServer 1000A boards fit in a Multia and after
the memory upgrade the problems were over.
So the cause is still uncertain.
BTW a Multia is slow compared to an AlphaServer 300 4/266 system which
has about the same internals.

>
> I'm asking because most VAXen with even less memory will run just fine,
> I've noticed (like some of the IPv7.net nodes).

Correct but the memory requirements of 32 bit VMS and 64 bit VMS are
quite different. Furthermore Alpha/VMS has
functionality in it that just is not present in VAX/VMS. And VAX/VMS
started life on a VAX 11/780 where memory capacity
could be as low as 256 kB (entry level 128 kB perhaps!).

>
> > The memory was expanded to 256 MB with memory boards with a height that
> > only just fitted with the box closed. Well, you read about its cooling/
> > airflow issues so the memory was reduced to 4 x 32 MB boards. It shares
> > memory boards with the AlphaServer 1000A 5/xxx models.
>
> There's a mere 32 MB in mine.  I don't think I really want to use the
> system for anything else than a glorified DECterm (especially since my
> LK463 works fine on it) to connect to my I64 cluster.  32 MB should be
> fine for that, correct?

Very likely, my Multia ran the DCE desktop on the graphics console and
at the same time I ran an X-session on
a PC with Reflection installed. And Motif is possibly not the easiest
windows environment...
If you just run the old style DECwindows kit, like the one that runs
on top of VAX/VMS then 32 MB will work.
Though adding memory is cheap (eBay) and any upgrade from 32 MB will
be noticable.
>
> > This works well, though its built in 10 Mb/s ethernet adapter slows it
>
> Purely out of curiosity, since you brought this up: Are 100BASE-TX
> ethernet adapters, since there's one PCI slot, available/known to work
> in it?

I have never dared to try! The Multia has cooling issues and I didn't
want to install too much additional equipment in it.
I also have an AlphaServer 300 which outperforms the Multia, so once
VMS was installed I lost interest in the Multia.
My study in the attic is small, has no airco and is fairly warm from
april to september. So not an environment to keep a
Multia in for daily work (a Digital Server 5305 does just that now).
AFAIK there are no restrictions on what you can put on the Multia's
PCI bus. A DE500 interface ought to work and wouldn't
raise the inside temperature too much. YMMV.
>
>   - MG

Hans