The following writeup is a more formal specification for multiprocess 
GDB. It incorporates feedback from recent discussion, the results of my 
experimentation with a prototype, and bits from the HPD draft standard. 
Although there is a lot here, I wanted to lay out some longer-term 
direction so as to clarify how the immediate work fits into the big 
picture - the last section delimits what the first version will actually 
do, which is not much more than what I was able to get working in a 
couple weeks of prototyping (read: we have reason to believe it's 
implementable :-) ).

Stan