Nuclear Data ND-812 info...

Bohdan Bodnar bbodnar1 at
Tue Jul 7 16:58:27 CDT 2009

I stumbled across this thread from a year ago.


I owned a BR2412 and designed and built a serial interface for it around
1981 or so.  There were plans for this machine, but grad school interfered
and when my home was flooded the computer hit the garbage.


The BR2412 used a gel-cel battery to back up DRAM in the event a power
failure occurs.  Simply turning the computer off didn't drop power to the
memory.  You are correct this was a Bunker-Ramo version of the ND812; the
BR2412 was used for factory automation.  The ND812's design was highly
motivated by the PDP-8 family - 133 ohms unidirectional busses, memory
banks, no stack (used a "jump and save" instruction with some additional
hardware to determine whether an indirect jump referenced a subroutine
return address or something like that).  The clock was 2 MHz 8-phase derived
from a 16 MHz crystal-controlled clock.  The entire motherboard was
wire-wrapped; although the motherboard looked kludgy, the cold-weld contacts
were extremely reliable and the rat's-nest of wiring reduced electromagnetic
effects.  The vast majority of the circuitry was based on Fairchild's 9000
and 9300 family of TTL SSI and MSI parts.


Nuclear Data tried to compete with NCR with this machine and failed
miserably.  Although ND could build excellent hardware, they apparently
never got the software side up to par.  


Thanks for the memories!







Bohdan Bodnar, PhD

Lemko Corporation

1700 East Golf Road, 7th Floor
Schaumburg, IL 60173

+1 847-240-1990 x238


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