strange number corruption on pdp11/34

[Rick Murphy]

At 07:34 PM 1/27/2015, Jacob Ritorto wrote:
>Johnny, I just took the defaults,

 >BUS ADDRESS (O)  0 ?

What Johnny said. The prompt says "(O)", not "(0)" - the letter O for 
Octal. The zero after that isn't a default, it simply means that the 
value hasn't been set.

There is no default. Or at least no sane one. Zero in this case means 
that it's writing to memory address zero for CSR. The diagnostic should 
reject that, but diagnostics are notoriously user unfriendly.
         -Rick