20 May
2007
20 May
'07
11:04 a.m.
On 19/05/2007 11:46, Johnny Billquist wrote:
"Jerome H. Fine" <jhfinedp3k at
compsys.to> skrev:
Good catch! I didn't think of that one. Yes, you're right. In fact the
-JD and -JE don't even claim to be PMI memory, but just plain Q-bus
memory (according to the field guide). That's definitely not useful. You
need the -JB or -JC.
No, that's wrong. Both the Micronotes and the manual for the MSV11-J
are quite clear that they're all PMI memory, and that the difference is
that the ASICs in the early ones (the -JB and -JC) do not support
block-mode DMA (and imply that there may be other minor differences)
which mean that you should not use the early ones in a QBus. However,
the later ones work in both Unibus and QBus systems, as stated on page
1-3 of the MSV11-J manual. The 11/84 Technical Manual lists the
MSV11-JD and -JE as the memory for an 11/84 system.
This is also borne out by notes in the DECUServe archive, which also
notes that the -JB and -JC do actually work in a QBus system, but very
slowly with "fast" QBus DMA devices that want block-mode. The
microPDP-11 Maintenance Manual also lists them as PMI. The Field Guide
is wrong.
You can use any of them in an 11/84, but you should not use the -JB and
-JC in a QBus machine.
--
Pete Peter Turnbull
Network Manager
University of York
Rod
Smallwood wrote:
>Now that makes a lot more sense.
>
>So PMI memory choice is: (2 Max)
>
>MSV11-JD M8637-D 1 MB ECC PDP-11/84 or PDP-11/83
>MSV11-JE M8637-E 2 MB ECC PDP-11/84 or PDP-11/83
>
Jerome Fine replies:
I am not absolutely positive, BUT the probability is VERY
high that the above two PMI memory boards are ONLY for the
Qbus. I believe that you must use either the MSV11-JB or
the MSV11-JC within the PDP-11/84 system.