DEC MM15 core mem found

Johnny Billquist bqt at
Tue Dec 8 06:14:13 CST 2015

Careful. Some PDP-11 memory is also 18 bits wide... 16 bits plus two 
parity bits.


On 2015-12-08 13:03, Pontus Pihlgren wrote:
> I've seen a memory assembly from a PDP-15 and it looks very much like
> this. Also, if each connector pair corresponds to one bit it adds up to
> 18 which matches the word lenght of a PDP-15.
> Of course, PDP-1, -4 and -7 used 18 bit word lenght, but they were not
> made with flip-chips.
> PDP-9 is made with flipchips and is 18 bit. But I seeem to recall it's
> memory looks quite different.
> /P
> On Tue, Dec 08, 2015 at 11:58:07AM +0100, Jörg Hoppe wrote:
>> I help cleaning out a large repository of DEC parts.
>> There a quantity of DEC core module assemblies appeared.
>> According to PDF docs these must be PDP-15 MM15's, but no labels are on the
>> boards.
>> I show/offer some of them at
>> ,
>> under "core memory"
>> Can somebody confirm they are MM15's?
>> Are any PDP-15 running at all?
>> Thanks,
>> Joerg

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