KT-24 and/or -11/24 backplane info

[tony duell]

> So I'm trying to work out how the PDP-11/24 memory works - in particular, how
> the memory slots in the backplane can also support SPC devices.
> 
> Chapter 5 of the -11/24 Technical Manual does not help - irritatingly! It
> spends a lot of time talking about the CPU's memory mapping (well documented
> elsewhere), and little on these blasted busses!

If it's anything like the 11/44 (which I have, and which also has 22 bit 
memory addressing), the memory bus is carried on the A and B 
connectors, the peripheral bus on the C,D,E,F connectors. 

-tony