pdp11/84 PMI memory: What is the problem with Q bus?

Jerry Weiss jsw at ieee.org
Fri Apr 24 11:50:01 CDT 2020

Sorry about the uNOTE confusion...  I was focused and just used the 
reference from the OEM version.  I was aware but had mentally excluded 
the older Microcomputer Products Group/Components Group version.

If you look at the Memory Comparison table in this OEM uNOTE, it only 
lists Block Mode for "JD/JE ONLY".  Hence my comment about it not being 
on the JB/JC.


On 4/24/20 11:23 AM, Noel Chiappa via cctalk wrote:
>      > From: Jerry Weiss
>      > uNOTE # 028 indicates that MSV-11 JB/JC (M8637-B/C) doesn't do block
>      > mode.
> I went and looked at uNOTE #28, after I found it (it's not in the initial set
> of uNOTEs, but in the second set - the so-called 'OEM uNOTEs"; note that the
> numbers were re-used between the two sets, so there are _two different_ uNOTE
> #28's).
> I couldn't find anything there about the JB/JC not doing block mode? All it
> says is they "can not be used in a Q-BUS system due to gate array
> incompatibilities".
> 	Noel

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