VAX 11/750

Mattis Lind mattislind at
Wed Feb 24 09:02:29 CST 2021

Den ons 24 feb. 2021 kl 04:57 skrev Ethan Dicks via cctalk <
cctalk at>:

> On Tue, Feb 23, 2021 at 9:53 PM Chris Zach via cctalk
> <cctalk at> wrote:
> > Wow, I've always wanted an 11/750. Not sure why, the small box size is
> > impressive and all that.
> I started on an 11/750 in 1984.  They are fantastic little machines.
> If you only have 3-4 users on them, they are quite peppy.
> > However it doesn't look like that one has a MASSBUS adapter so I will
> have to pass...
> The module map indicates an SI 9400 interface (CMI card to an SI 9xxx
> SMD disk box) and an L0007, which is an RH750 MASSBUS adapter.  Those
> slots appear to be populated with _something_ in the photo.  There
> _might_ be a MASSBUS connector at the lower-right of the I/O bulkhead.
> The CPU area seems to show an FP750 Floating Point accelerator
> installed in slot 1.
> It also appears there are a couple of cards in the memory area in
> slots 6 and 8.  What I don't know, since I didn't have one, is how you
> load up a machine with an L0022 14MB memory controller, but it's
> _possible_ we are looking at 4x 1MB + 2x 4MB (full boat).

Looking at the pictures it seems that the two boards to the left in the
memory backlane are NOT M7199 4 Meg boards. Those boards seem to be more
like standard full size 11/750 boards but the connectors of those are very
different so they would not fit. I just wonder if someone put spare boards
there? It may be so that they are not pushed in fully and latched properly?
It is impossible to read the ID of the board but they sure look like L0008
microcode boards to me.

There are two boards in the CMI bus slots, one seems to be a third party
something and the other might as well be the L0007 MBA. It is likely since
it has three gate arrays in the correct area as is visible from the picture.

My 11/750 has six M8750 and two M7199 and the L0022 controller. I don't
know if three M7199 and two M8750 config is possible as well.


> Cheers,
> -ethan

More information about the cctalk mailing list