MEM11A questions

Guy Sotomayor ggs at
Mon Mar 7 16:18:39 CST 2016

> On Mar 7, 2016, at 2:06 PM, Mike Ross <tmfdmike at> wrote:
> On Tue, Mar 8, 2016 at 10:46 AM, Guy Sotomayor <ggs at> wrote:
>>> On Mar 7, 2016, at 1:27 PM, Mike Ross <tmfdmike at> wrote:
>>> On Tue, Mar 8, 2016 at 8:16 AM, Guy Sotomayor <ggs at> wrote:
>>>> Hi,
>>>> Over the weekend I was looking through some old CAD files and came across my
>>>> original design for the MEM11A.  It was an SPC board that contained only 128KW
>>>> of FRAM.
>>>> I’m wondering if there’s any interest in that board.  I do have to iterate on the design
>>>> a bit but I should be able to get something ready sooner than with my current board
>>>> design (plus I know it will fit in an SPC form factor because I’ve already done it).
>>>> What I’d like to know from folks is if there’s interest in that design?  Would there still
>>>> be interest in what I’m now calling UMF11 (Unibus Multi-Function)?
>>> Ummm enlighten us a little more about what exactly it could do and
>>> what machines it could be used in?
>> MEM11A?  It can be used in any PDP11 that has SPC slots and will provide 128KW
>> of non-volatile RAM.  I had originally gone down this road to provide memory for
>> memory challenged machines (most notably the 11/20) but could be used in any
>> Unibus PDP11.
> Ah ok so it's a universal RAM board that will add modern reliable
> Unibus memory to any -11 from the 11/20 on up?
> I'll have six please! Preferably tomorrow! (It was the 'multifunction'
> bit that confused me; I wondered if it was doing something else beyond
> memory)

OK, part of this is my own fault.  I started working on a board design (MEM11A) that
was only memory.  During one of the (several) re-designs it morphed into the multi-funciton
board that I’ve also been calling MEM11A.

To alleviate the confusion as I’m thinking of resurrecting the *original* MEM11A design
(just Unibus Memory), I’m renaming the more recent design (which I also called MEM11A)
to UMF11 (Unibus Multi-Function) which has in addition to memory, DL11s, RF11/RS11s,
etc to be able to support all of the peripherals (sans RK11) needed for Unix V1.

So to re-iterate, I’m looking at producing two products:
MEM11A which is just 128KW of memory in an SPC form factor
UMF11 which is 128KW of memory, 2 DL11s, RF11/RS11s, boot roms, etc.

The UMF11 has been taking so long because it has a micro-controller (J1) on it to perform
the configuration and emulation tasks.  It has no switches and only a few jumpers.  Every
thing else is configured through one of the serial ports.

I’ve finished the Verilog code for the UMF11 and am close to completing the simulation of
all of the individual blocks.  I still have some uCode work to do in terms of emulated
devices but now that all of the H/W interfaces are designed and coded, I can complete
that as well.  The remainder is doing the schematic capture, board layout and testing…lots
and lots of testing.  ;-)

The MEM11A is *much* simpler and the work I need to do on it is mainly to put the random
logic into a CPLD.  In that respect, the MEM11A is pretty hardwired compared to the UMF11.

TTFN - Guy

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