[Tutor] python environment

[Eric Abrahamsen]

I've been looking around for a good tutorial or background info on how  
the Python runtime environment works, and haven't quite found what I'm  
looking for. I started fooling with having different versions of  
modules available to difference processes on a single server, which  
led me to virtualenv, and then I realized I'm way in over my head. I'm  
sure I can make virtualenv work, but I won't understand what's  
happening.

Can anyone recommend any resources along these lines? Chapter 26 in  
the library reference is on Python Runtime Services – these are the  
models I want to understand, but I feel like what I need is one level  
_under_ these modules: I guess, how the python interpreter works as an  
os process, and how its environment differs from... the other  
environment?. The command line interpreter also has options like  
'ignore environment variables' and 'don't imply "import site" on  
initialization' – I just don't quite get it.

Thanks in advance for any and all enlightenment.

Eric