22 Mar
2014
22 Mar
'14
6:02 p.m.
From: Philipp Hachtmann: Saturday, March 22, 2014 3:55 PM
If I am understanding the configuration guide at
http://www.bitsavers.org/pdf/dec/pdp8/omnibus/EK-0PDP8-SP-001_PDP-8_Family_…
correctly, the maximal configuration consists of an 8/E with it's two
internal Omnibus backplanes, cabled to a BA8-C cabinet containing
another Omnibus backplane. That seems to give 60 slots, with 51
slots left over once you count the CPU, front panel, and backplane
interconnects.
Interestingly, the configuration with two 8/E boxes does not seem
to be allowed. Perhaps 80 slots was just too much?
In this thread
several people with relatively large Omnibus machine
configurations have self-identified.
What means relatively large Omnibus
configurations? My test machine here has
two backplanes, nearly full with different stuff. No expansion. Nobody denies that the perfect drivers would probably
work better in
configurations near the maximum. But that should be something like three to
four boxes with two backplanes each, filled with cards... And not to forget a
many feet long cable between them...
Apparently Omnibus systems with more than 2 boxes were not
guaranteed to work. I'm not sure what lengths the BC80C cable
assembly came in.
Vince