2 Feb
2001
2 Feb
'01
8:14 a.m.
I have an interesting question. Can this board be used as additional ram
in a PDP-11? If so, how might it be done?
I have a Qbus Memory board that must be from a uVAX II - M7609-AP
with 288 (I hope I counted correctly) memory chips
4256L-15 8726255
A 21-22422-42 R
with the standard male 50 pin header at the top to be connected to a uVAX
CPU.
If my arithmetic is normal, does this make it an 8 MByte memory?
Now, I am no hardware expect, in fact about all I can do with a soldering
iron is to plug it in and unplug it - before it gets too hot and I burn something.
But, is there any way that a regular PDP-11/73 could see this memory
and use it in some manner?
Otherwise...
I don't expect that anyone will want it, but if so, can I swap it for a regular
PDP-11 Qbus memory of 4 MBytes?
Sincerely yours,
Jerome Fine
2 Feb
2 Feb
8:38 a.m.
But, is there any way that a regular PDP-11/73 could
see this memory
and use it in some manner?
I really doubt it. It would probably be easier to build up a memory board
from scratch. Unless I'm mistaken the MicroVAX II
doesn't even talk to the
Q-Bus to access this board, it's all done via the
ribbon cable that connects
the RAM to the CPU.
OTOH, if I'm wrong, I wouldn't mind knowing about it, I've got at least a
couple of these boards around myself.
Otherwise...
I don't expect that anyone will want it, but if so, can I swap it for a regular
PDP-11 Qbus memory of 4 MBytes?
Good luck :^)
Zane
12:43 p.m.
healyzh(a)aracnet.com wrote:
But, is there
any way that a regular PDP-11/73 could see this memory
and use it in some manner?
I really doubt it. It would probably be easier to
build up a memory board
from scratch. Unless I'm mistaken the MicroVAX II doesn't even talk to the
Q-Bus to access this board, it's all done via the ribbon cable that connects
the RAM to the CPU. OTOH, if I'm wrong, I wouldn't mind knowing
about it, I've got at least a
couple of these boards around myself.
It would be amazing at that - a uVAX II memory board for a now no longer
available new computer (I hear that no more new VAXs are being sold whereas
it is still possible to buy a new PDP-11) being converted since there are so
many available for use as a RAM disk for the older PDP-11.
Otherwise...
I don't expect that anyone will want it, but if so, can I swap it for a regular
PDP-11 Qbus memory of 4 MBytes?
Good luck :^) 
1:19 p.m.
Jerome Fine replies:
I assumed that is the case since the uVAX II supports 16 MBytes while the
Qbus is only 22 bits which means the maximum is 4 MBytes. I was
Isn't the max memory in a MicroVAX II 13 MB? Mine has 1 MB
on the CPU board, an 8 MB board, and a 4 MB board and it is my
understanding that this is maxed out.
Jeff
--
Collector of Classic Microcomputers and Video Game Systems:
Home of the TRS-80 Model 2000 FAQ File
http://www.geocities.com/siliconvalley/lakes/6757
1:45 p.m.
Isn't the max memory in a MicroVAX II 13 MB?
Mine has 1 MB
on the CPU board, an 8 MB board, and a 4 MB board and it is my
understanding that this is maxed out.
The Max is 16MB, that's with two 8MB boards (or a 3rd Party 16MB board, at
least I think such a beast was made). When running a 16MB config, the 1MB
on the CPU board is ignored.
Zane
1:23 p.m.
It would be amazing at that - a uVAX II memory board
for a now no longer
available new computer (I hear that no more new VAXs are being sold whereas
it is still possible to buy a new PDP-11) being converted since there are so
many available for use as a RAM disk for the older PDP-11.
Actually you've got me thinking there. Considering that RAM is dirt cheap
these days. I'm wondering what it would take to build a RL02 drive that is
actually a RAM disk (of course you'd be able to fit several disks on one
stick of RAM), and what kind of performance you'd get. Off course I'm not a
hardware type, so I don't know how hard that would be.
Just thought that someone might have an old uVAX I
with a 4 MByte memory
and I could probably toss in a uVAX II CPU as well. I probably have a better
chance of winning a lottery.
Aren't the 4MB MicroVAX I boards the same as a 4MB MicroVAX II board? I've
never even seen a MicroVAX I, so I really don't have a clue on this.
Zane
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