Kearney & Trecker Core memory, may be PDP8
pete at dunnington.plus.com
Wed Nov 12 05:16:49 CST 2014
FWIW I'm pretty sure these boards are for a PDP-8/A chassis. See below...
On 12/11/2014 07:13, Paul Anderson wrote:
> On Wed, Nov 12, 2014 at 1:09 AM, jwsmobile <jws at jwsss.com> wrote:
>> On 11/11/2014 9:12 PM, Jon Elson wrote:
>>> On 11/11/2014 09:18 PM, Johnny Billquist wrote:
>>>> On 2014-11-12 04:00, Jon Elson wrote:
>>>>> On 11/11/2014 07:33 PM, jwsmobile wrote:
>>>>>> I can't tell for sure, but this auction may be for PDP8
>>>>>> core board.
>>>> The fact that the board have four edge connectors and not six
>>>> totally excludes PDP-11.
Not necessarily, but it's extremely hard to imagine how it could
possibly be a Unibus board with four edge connectors on ABCD rather than
CDEF, and the only QBus chassis those boards would fit would be an H909
with a DDV11 backplane. So, I'd agree it's highly unlikely to be any
sort of -11.
I believe this system was based on a PDP-8/A because:
- the memory doesn't look /quite/ like my 11/34 core but does
look like 12-bit PDP-8/A memory;
- the seller has several other cards from what seem to be the
same system, or at least the same type, some of which have I/O
connectors just above where the EF fingers would be - as found
on some PDP-8/A boards, but not AFAIK on any others;
- the pattern of power/ground connections visible on the solder
side of some exactly match the Omnibus layout but not Unibus
- a friend has a similar CNC system, built in a PDP-8/A
chassis, with a papertape reader exactly the same as the one
in one of the seller's other auctions.
There's a picture of it here, taken at DEC Legacy 2011:
It's a long time since I looked inside that system, so I can't be sure
how many of its boards were custom items, or if they match the listings.
Unfortunately I can't go and look for a week or two :-(
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