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Looking for memory for PDP 11/45

O

obsol33t

Member
Joined
Jul 6, 2017
Messages
43
Location
Ontario, Canada
I'm working on a restoration project of a PDP 11/45. It looks like it is missing the memory, so I'm looking for leads on where I can buy some.

Below is a list of the cards in the machine:

M8114 FRH
M8115 FRL
M8112 FRM
M8113 FXP
M8100 DAP
M8101 GRA
M8102 IRC
M8103 RAC
M8104 PDR
M8105 TMC
M8106 UBC
M8108 SSR
M8107 SAP
M8109 TIG

There are also some controller cards. The "silly sticker" shows a couple M8110 that are missing from the machine. I'll have to spend more time doing research, but there might be more required for memory, such as M8111.
 
It looks like you have the same complement of cards in your 11/45 that I have in mine :)!

Someone either pinched the core store out of mine, or added semiconductor UNIBUS memory into another chassis that I don’t have. I appear to have plenty of semiconductor UNIBUS memory - but it doesn’t fit in this chassis!

I have a UNIBONE that can simulate both I/O devices AND memory in the first instance. However, this was/is a retirement project - but work won’t let me retire yet :)!

Dave
 
Oh no, it sounds like it's going to be [nearly] impossible to find memory for our machines? :( I didn't know about UNIBONE, I'll have to look into it. But I'm still very interested in purchasing memory for my machine.

obsol33t
 
You can find here: http://retrocmp.com/projects/unibone

It can emulate memory, serial ports (DL11) and RL0x disks. Possibly more now?

It lives in a quad SPC slot.

I have just been looking at the latest Github image - seems to support RK05 and MSCP devices now also.

Dave
 
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That was fast :) !

That was the best way I thought of out of the problem - until I could find some cards...

As you get the source code, you can tweak the code. I would like to implement some other devices - but that's for sometime in the future...

I have a lot of controllers that came with my system - but absolutely no peripherals (unfortunately).

Dave
 
Uh oh... the email bounced. It looks like it could not connect to his email server. I'll have to look into it closer after work.

I've been collecting bits and pieces for years and have been assembling a complete system. I have a couple RK05 drives, platters, alignment disk, RK05 controller, PC05 high speed papertape drive & controller, TU10 tape drive & controller, TU60 dual cassette drive (no controller), three racks, almost complete set of pop panels, mastheads, DECwriter 2, etc. I'm now realizing that I am missing important components such as cables and memory. This year I'd like to get the machine up and running for the first time in probably decades. I also bought a PiDP 11 to play with.

Which controllers do you have?

obsol33t
 
That's a nice collection of peripherals you have there.

I will have to have a look in my notebook...

I have a TU56 tape drive and external controller that directly plugs into a UNIBUS slot. I have already built some RT11 software for it (using SIMH). All I am short of is a serial card and some memory (hence the UNIBONE).

Interestingly, I did have a serial card that came with the machine (all in separate cardboard boxes) - but it had a module number that I didn't recognise. It turns out that this card was out of a PDP-8... This is good news, because I have one of those now as well. Bizarrely, I have had 5 off 16KW OMNIBUS core store cards for this machine for years!

Dave
 
obsol33t said:
Uh oh... the email bounced. It looks like it could not connect to his email server. I'll have to look into it closer after work.
Click to expand...
You can also reach Joerg via the UNIBone (and QBone) Google group at unibone@googlegroups.com It's named after the UNIBone which came first but also covers the QBus version QBone as well. Most of the software for both is the same with just a couple compile time changes between the two boards.

As far as I know, Joerg is still the only source for a UNIBone. In North American you can get a QBone from the DECRomancer at https://decromancer.ooo/qbone/ I don't think they do the UNIBone yet.
 
Any Unibus memory could be added. My 11/45 has a small DD11-C backplane where the old core backplane once were located. In the DD11-C I have a third party 256k Unibus memory. But other boards should work fine. M7847 or M7891 for example. On the other hand Unibus is quite simple so building it yourself with a couple of SRAM chips and som glue logic should quite easy.
 
Thank you everyone for the helpful tips. I managed to get through to Joerg using the contact page of his website and placed an order for a UniBone. It looks like that will be helpful for more than just dealing with my missing memory issue.
 
I have the following Unibus board available

M7819 8 Port EIA Aync Board
M7847 16K x 18 Bit Memory

DM me if either of these is of any interest to you.
 
Can anyone please help me find the model numbers of alternative memory cards that will work in my PDP 11/45? I'm still interested in original DEC cards for this machine. According to the "silly sticker" on my 11/45, it had two M8110 cards (memory control for MOS memory).

The processor handbook says:
Тһе CPU can control up to two independent Solid State Memory controllers, each of which can have from one to four 4K word increments of MOS memory (16K words) per controller, or one 4K word increment of Bipolar memory per controller. Each controller can handle MOS or Bipolar memory but not a mixture of the two. The user can therefore have a total of 32K of MOS, or 8K of Bipolar, or 16K of MOS and 4K of Bipolar.
Click to expand...
Since my machine originally had two M8110 memory control for MOS memory cards, I suspect it had somewhere between five to eight 4K word MOS memory cards.
 
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Can I ask what power supply modules you have fitted and what configuration is written on your chassis please.

Dave
 
I am using a third party 256k unibus memory in my 11/45. All the fast mem cards are missing in mine as well. But using any unibus memory board works just fine. Possibly not as fast.
 
daver2 said:
Can I ask what power supply modules you have fitted and what configuration is written on your chassis please.

Dave
Click to expand...
It has H754 (x1) and H744 (x4) power supply modules.

Regarding your second question, I think you are asking what is written on what I'm told is called the "silly sticker":

M8114 FRH fraction high order data path module
M8115 FRL fraction low order data path module
M8112 FRM floating point ROM control module
M8113 FXP floating point exponent data paths module
M8100 DAP data path module
M8101 GRA general register address module
M8102 IRC instruction register control module
M8103 RAC ROM address control module
M8104 PDR processor data and UNIBUS registers module
M8105 TMC timing and miscellaneous control module
M8106 UBC UNIBUS control module (Replaced by M8119)
M8108 SSR segmentation status register module
M8107 SAP segmentation address paths module
M8109 TIG timing generator module

Missing:
M8110 memory control for MOS memory (missing two)

I also have controllers for RK05 (I have two drives), PC05 (I have one drive) and TU10 (I have one drive) which are not installed.
 
MattisLind said:
I am using a third party 256k unibus memory in my 11/45. All the fast mem cards are missing in mine as well. But using any unibus memory board works just fine. Possibly not as fast.
Click to expand...
When you have time, can you please tell me the make and model of all memory related components you have? For example, if I just buy memory I suspect it won't work without a "memory control" as well. I'm hoping to find some on vcfed marketplace or eBay.
 
You don’t need memory control for unibus memory. It is built into the memory module.

Those memory control boards are needed if you want to install the fastmem bipolar or mos memory arrays. You better skip those. They consume a lot of power and give very little memory.

You can have 256 k memory directly on the unibus. That is how my machine is configured.

I am quite far away from my machine currently but in a couple of weeks I can give you answer.
 
obsol33t said:
It has H754 (x1) and H744 (x4) power supply modules.
Click to expand...
It appears that either you don't have the correct set of regulator modules, or you have a typo in your list. Assuming that you have two H742 power supplies installed then there should be an H745 in slot E. Recommend that you study http://www.bitsavers.org/www.comput...45 and PDP-1150 System Maintenance Manual.pdf, particularly Figure 1-3a on page 20, to determine how your 11/45 compares to a standard configuration (including regulator placement in the various H742 slots - see section 1.1.2.3). With installed floating point (modules in slots 2-5) additional regulators are required which appear to have been stripped from your configuration.

Notable is that you don't have any of the regulators required to support core memory.
 
You beat me to that one. That's why I asked the question about the power supply unit - it gives us a clue about what was fitted and (more importantly) what can be fitted.

I will have a look in my 11/45 notebook when I have had breakfast (but my wife may have a few chores for me to do as well...).

Dave
 
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