DEC 11/45 build - advice sought, parts requested possibly.

Jay West jwest at classiccmp.org
Fri Jul 8 11:02:12 CDT 2005


Ok, so I have a working processor, and a basement full of peripherals. I'm 
not sure which way to go with the rest of the build. I'm not really up on 
DEC stuff I admit, so maybe others here can offer me some advice as to what 
is the best way to proceed.

Background:
My 11/45 (11/45-CA actually) has the KB11-A processor, no FP. It's the older 
style with the power distribution board on the back wall of the cpu cabinet 
rather than on top. However, it's also got the newer 861A power control in 
the bottom rather than the dual 860's in the top. There is the two H742A's 
as well. I have one system unit installed - MF-11L in which is installed 8K 
of core. In the cpu backplane there are three unibus slots which I believe 
will take three quad? (C-F) boards. A&B in two of those slots are used for 
the unibus A to unibus B jumper, and A&B of the last slot is the connector 
to A&B of the MF-11L. The MF-11L has a 9312 in the last A&B slot. The SPC? 
boards currently installed are two DL11's and a M7228. The ONLY board in 
slot one is a 930C terminator in A&B. I have no MMU, so slot 13 is empty and 
slot 14 has the M8116.

Separately, I have a lot of peripherals to choose from. Scads of RL02's, 
DSD440, LincTape II, RX01's, RX02's, RA81's, etc. I also have a BA11-KU with 
a DD11-DK backplane in it.

Problem:
The unibus space on the cpu backplane is quite limited. At the VERY least I 
have to keep one of the DL11's there, so that leaves me with two more unibus 
slots for peripherals. I *THINK* that that standard controller for an RX02 
or RL02 takes all 6 rows (Hex cards?). However, the DSD440 controller only 
takes slots C-F (quad?). The linctape II controller also only takes C-F. So, 
I think I could have a reasonable system by putting the DSD440 controller, 
LincTape controller, and a DL11 and be done with it. However, I then am 
limited to using core memory in the MF11. At the very best, I can get... 
what... 32K in a MF11? I think I can get the additional core boards. But 
correct me if I'm wrong but isn't sticking with core (max 32K) going to make 
my operating system choices extremely limited? I'm guessing I can't run RSTS 
or Unix on it with that kinda memory. vtserver I think requires a full load 
of 128KW. On top of it all, the DSD440 takes most of the rack depth, as does 
an RL02, so I've been advised against mounting anything above the /45 except 
maybe the linctape.

Possible solutions:
1) I just got a M7891 (64KW) off Ebay. I could yank out the MF-11L system 
unit, yank out the DD11-DK from the spare BA11, and install the DD11 in the 
cpu cabinet. I'd use the unibus memory M7891, ditch the core, and have a 
fair number of slots left over in the DD11. However, there's problems with 
this approach. I'd still be mounting stuff above the /45 (DSD440 & Linctape 
at the least), and maybe an RL02. In other words, this would fix the memory 
and unibus slot availability, but I believe I'd still be restricting the 
airflow/cooling too much :\ Plus I'd need to find some of those rare Mate & 
Lock connectors to get the DD11 into the /45 cabinet and do some power 
harness building. I guess I might need one or more regulators for this 
approach as well. Then I'd have to find/buy a KT11-C to USE the M7891 I 
think.... I'm probably talking about unobtanium stuff aren't I :|

2) Take another H960 rack, bolt it to the 11/45 rack, and install the entire 
extra BA11 in there. Now it's a dual bay system, but I could use core still 
if I wanted, and I think also use the M7891 in the BA11. Then I'd have room 
in the 2nd rack for the peripherals. However, I'd really like to keep this 
in a single bay rack :\

I'm sure there's other solutions. Can someone advise me on what is likely to 
be the best route to go? I don't want this to be a really huge /45 setup. 
I'd like to run RT11 v5 with TSX+ on it. Temporarily, I'd also like to try 
loading up RSTS and some form of Unix. Thoughts anyone?

Jay West 




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