Re: Help identifying mystery Dataram VAX-11/750 (?) board

[Ethan Dicks via cctalk]

On Thu, Jul 16, 2020 at 5:11 PM Glen Slick via cctalk
 wrote:
> On Thu, Jul 16, 2020 at 1:42 PM Josh Dersch via cctalk
>  wrote:
> >
> > I think I may have answered my own question here; looks like it's for a VAX
> > 8000 series:
> >
> > https://www.wikiwand.com/en/VAX_8000
> > 
>
> Obviously now you need to pick up a VAX 8000 system.

One with an NMI bus, naturally.  The low-end 8000s are pure VAXBI (I
have an 8300).

I'm sad I had to abandon a VAX 8530 when Software Results closed down
in 1993.  It was a bit large for home use, and I was never going to
have 3-phase power for it.

AFAIK, it got left for our landlord to dispose/sell off.  We only paid
$5000 for it a year earlier (nobody wanted them in the early 90s) so
it's unlikely he found a quick buyer.

-ethan

Re: Help identifying mystery Dataram VAX-11/750 (?) board

[Antonio Carlini via cctalk]

On 16/07/2020 22:38, Josh Dersch via cctalk wrote:

On Thu, Jul 16, 2020 at 2:11 PM Glen Slick via cctalk 
wrote:



Obviously now you need to pick up a VAX 8000 system.


That does seem to be the most logical next step, yes :).

- Josh



I think I have a load board for one somewhere ... No idea how I got it, 
but if you end with with a VAX 8000 before I do, let me know and we can 
cut a deal :-)



Antonio

--
Antonio Carlini
anto...@acarlini.com

Re: Help identifying mystery Dataram VAX-11/750 (?) board

[Josh Dersch via cctalk]

On Thu, Jul 16, 2020 at 2:11 PM Glen Slick via cctalk 
wrote:

> On Thu, Jul 16, 2020 at 1:42 PM Josh Dersch via cctalk
>  wrote:
> >
> > I think I may have answered my own question here; looks like it's for a
> VAX
> > 8000 series:
> >
> > https://www.wikiwand.com/en/VAX_8000
> > <
> https://www.wikiwand.com/en/VAX_8000?fbclid=IwAR3QoE8s_7NE3ILHqMIuxGHJ4m_qR_TXn_J5jrczGVtbD8sPY8tWvhPjSzw
> >
> >
>
> Obviously now you need to pick up a VAX 8000 system.
>

That does seem to be the most logical next step, yes :).

- Josh

Re: Help identifying mystery Dataram VAX-11/750 (?) board

[Glen Slick via cctalk]

On Thu, Jul 16, 2020 at 1:42 PM Josh Dersch via cctalk
 wrote:
>
> I think I may have answered my own question here; looks like it's for a VAX
> 8000 series:
>
> https://www.wikiwand.com/en/VAX_8000
> 
>

Obviously now you need to pick up a VAX 8000 system.

Re: Help identifying mystery Dataram VAX-11/750 (?) board

[Ethan Dicks via cctalk]

On Thu, Jul 16, 2020 at 4:42 PM Josh Dersch via cctalk
 wrote:
> On Thu, Jul 16, 2020 at 1:34 PM Josh Dersch  wrote:
> > Picked up a board advertised as a "4mb memory board" for a VAX-11/750...
>
> I think I may have answered my own question here; looks like it's for a VAX
> 8000 series:

That makes more sense than a board that replaces the memory controller.

IIRC, the 11/750 has an architectural limit of 14MB of RAM, but that
might just be because of 8 memory slots (individual select lines), the
implementation of the L0016 memory controller, and that's what you can
hit with 2X 4MB boards + 6X 1MB boards.  I _think_ if you could have
gone to 16MB of RAM, DEC might have made a memory controller that
could control 3X 4MB boards + 4x 1MB boards or 4X 4MB boards, but they
did not.

I installed the extra memory line wire on the backplane of our 2MB
11/750 (and installed the L0011), but we never made that final jump
from L0011 -> L0016.  By the time that was available, we weren't going
to spend that kind of money on that machine.  It still has 8MB to this
day.

-ethan

Re: Help identifying mystery Dataram VAX-11/750 (?) board

[Josh Dersch via cctalk]

On Thu, Jul 16, 2020 at 1:34 PM Josh Dersch  wrote:

> Hi all --
>
> Picked up a board advertised as a "4mb memory board" for a VAX-11/750.
> It's made by Dataram and I'm unsure of the model number, based on photos of
> it.  I just noticed that rather than being a hex-height board that goes in
> the memory backplane, it looks like a board that goes in the main CMI
> backplane.  It also appears to have 16mb of ECC memory on it, rather than
> 4mb.
>
> My thought is either (1) it's not actually for an 11/750 (in which case
> I'm curious what it would go into), or (2) it completely replaces the
> memory controller and standard memory and gives you 16mb in the 750.  (Or
> it could be that it's something else entirely.)
>
> If anyone has any ideas or has a source of information, let me know.  I
> put up a few pictures here:
>
> http://yahozna.dyndns.org/scratch/dataram/
>
> Thanks as always,
> - Josh
>

I think I may have answered my own question here; looks like it's for a VAX
8000 series:

https://www.wikiwand.com/en/VAX_8000


- Josh

Help identifying mystery Dataram VAX-11/750 (?) board

[Josh Dersch via cctalk]

Hi all --

Picked up a board advertised as a "4mb memory board" for a VAX-11/750.
It's made by Dataram and I'm unsure of the model number, based on photos of
it.  I just noticed that rather than being a hex-height board that goes in
the memory backplane, it looks like a board that goes in the main CMI
backplane.  It also appears to have 16mb of ECC memory on it, rather than
4mb.

My thought is either (1) it's not actually for an 11/750 (in which case I'm
curious what it would go into), or (2) it completely replaces the memory
controller and standard memory and gives you 16mb in the 750.  (Or it could
be that it's something else entirely.)

If anyone has any ideas or has a source of information, let me know.  I put
up a few pictures here:

http://yahozna.dyndns.org/scratch/dataram/

Thanks as always,
- Josh