[plt-scheme] Version incompatibilities in PLaneT packages

Sam Tobin-Hochstadt wrote:

>I'd like to point out that there are other solutions besides what planet
>adopted and DLL Hell.  For example, as Carl suggested in his first
>message, the system could keep separate copies of the library for each
>package that required it.  
>
The problem with that approach is that a library might work with a 
resource that it can't have two of no matter how many different copies 
of it exist. For instance you could make a library that kept a flat file 
database somewhere; if two copies of your library are running at all 
they'll step on each other's toes, and there's nothing planet can do 
about that no matter what it does short of creating two completely 
separate sandboxes. Extra copies of the library won't help.

Programs like that were actually the very first motivating example for 
adding this check at all.

-jacob