Process-specific variables

Hello Pharoers,

I was trying to load a package apparently written for an earlier
version of Pharo (Ratpack, from
http://ss3.gemstone.com/ss/RatPack.html into Pharo 1.4).

There I got deprecation warnings about `environmentAt:put:` not being
supported for `Project`.

The way to go, according to the documentation, is to use
`ProcessSpecificVariable`.

My questions are:

- How do I use them?
- How to port older code to this new system?

http://stackoverflow.com/questions/13682917/what-are-process-specific-variables

Thanks in advance!

Sebastian