Introduction and need help bringing some pdp11's back

Chris Zach cz at alembic.crystel.com
Tue Oct 29 20:38:45 CDT 2019


Oh the 9058 is the "Q Bus" card with the 50 pin breakout to 34 pin and 
20 pin lines for the various drives. That's not the RQDX3, and I don't 
need that since I have the BA23 with a bulkhead connector.

And yes, I do remember nothing could be after a RQDX1 or 2 so they had 
to be in the last unused slot on the box with a grant card needed if the 
slot above and to the right was open. They do use DMA/NPG.

Off to look up the jumper settings and see if this RQDX3 is configured 
properly....

CZ

On 10/29/2019 9:34 PM, Nigel Johnson via cctalk wrote:
> 
> On 29/10/2019 20:37, Chris Zach via cctalk wrote:
>> The M9058 can plug in to any general slot in Qbus for power and does not
>>> past interrupt or DMA grant.  Bottom/end of the bus is fine.
>>
>> Interesting, I didn't realize the RQDX series boards didn't use 
>> interrupts or DMA. Does the CPU just poll them endlessly?
>>
> RQDX1 and 2 did not pass them but used them. (Maybe not NPG)  I believe 
> the RQDX3 did, however.
> 
> Nigel
> 
> 
> 
> Nigel Johnson
> 
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