Hi
When preserving something you go for the best example you can find.
Even so in this case there was no choice involved. I want to keep as
original as I can a a PDP-11 from the era when I was working with them.
Speed is not an issue and a slower (but working)DEC KDJ11 board would
satisfy my criteria for originality.
All of your points are well made. One is very important the KDJ11-EB has
its memory on the CPU board. Are you saying some models of the KDJ11 do
not have their memory on the CPU board? Is it a case of unpopulated
sockets and add memory or is it no sockets and no memory?
Reading from the factory label the 11/94 was confgured thus
Slot 1 M8981 (Now sadly empty)
Slot 2 M7914
Slot 3 Empty
Slot 4 M8191 KTJ11-B
Slot 5 M7547 TUK50-BB
Slot 6 Empty
Slot 7 Empty
Slot 8 Empty
Slot 9 M9302 & M9713
So excluding the expensive options can anybody say exactly which board I
need. Full module and DEC code to me please. For example only say
M8980-AA KDJ11-BB
I must get a list of the KDJ11 boards. Iv'e seen one somewhere.
Rod
-----Original Message-----
From: cctech-bounces at
classiccmp.org
[mailto:cctech-bounces at
classiccmp.org] On Behalf Of Jerome H. Fine
Sent: 14 May 2007 03:16
To: On-Topic and Off-Topic Posts
Subject: Re: The Last of The Line
Patrick Finnegan wrote:
On Sunday 13
May 2007 06:28, Rod Smallwood wrote:
Hi All
Now for my dilemma. Before checking the cost of a KDJ11-EB you are
advised to make sure pacemaker batteries are fully charged and any
blood pressue medication has been taken. Take it from me the prices
are so high they need to join the astronaut corps!
..which is probably why your systems were missing the CPU boards when
yo got them...
I would like to get at least one of these historic
systems running
again. Suggestions please!!
It'd be a lot less expensive to turn it into an 11/84, the CPU for that
(some models of KDJ11-B) should be much less expensive,
then just add
memory. :)
Jerome Fine replies:
Your suggestion might not be possible. I once had the box and boards
for an 11/94. I really can't remember, but there might not have been
any slots for the memory.
In any case, I am extremely curious. What goal(s) will you achieve? Do
you want to run software faster? Is your only goal to have the fastest
PDP-11 that DEC ever produced? Note that a number of other companies
produced much faster PDP-11 CPU boards. Note that I very much
appreciate that from a hardware point of view your goal is extremely
gratifying - probably even more than my software goals. I am just
curious what your goals are.
One of my goals when I run using PDP-11 software is to run as fast as
possible. At present I run at about
15 times a PDP-11/93. Very shortly, I hope to be upgrading my hardware
and be able to run at 100 times a PDP-11/93 along with the availability
of having an extra GigaByte of spare memory for data that may also allow
a co-processor to perform CPU intensive calculations.
About 20 years ago, I was using a PDP-11/23+ on a system with 4 MB of
memory which included a co-processor that used the same memory as the
PDP-11/23+.
Any finally, although my experience is with an 11/93 on the Qbus, I
found that there is very little difference between an 11/93 and an 11/83
as far as CPU speed is concerned. That would also be likely to apply to
the difference between an 11/94 and an 11/84. Basically, I suggest that
the only difference in speed is due to the clock rate of 20 MHz on the
11/93 board and the
18 MHz clock rate (or crystal if you prefer) on the
11/83 board. Otherwise, the PMI memory on the 11/83 is probably about
as fast as the on board memory on the 11/93.
As for the actual CPU, almost all M8190 quad CPU boards or KDJ11-Bx
(maybe all) allow the use of PMI memory which is the primary reason the
11/83 is faster than the 11/73. The other reason is the 18 MHz clock
rate on the 11/83 as opposed to the 15 MHz clock rate on the 11/73. So
if anyone has a M8190 CPU with non-PMI memory and can find some PMI
memory, then as long as there are ABCD slots available for all of the
memory and CPU boards, the system will run much faster with PMI memory.
Sincerely yours,
Jerome Fine
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