Current drive name

[Simon Lord]

This is a Mac OSX related question.

When I get the full path to my stack it returns something like this:

stack "/Applications/MetaCard/directory-navigation.mc"

My question is, how can I tell which *drive* the stack is on?  I 
have upwards of 5 drives (3 internal, 2 external).  My stack has 
it's own directory navigation system made for SGI's way back in 
the old days and it works fine under OSX as long as I don't try 
to go to the root directory.  As soon as I try I completely lose 
the path to the stack which not only needs the drive name now, 
but has to be precluded by the word "/Volumes".

The "Volumes" problem is easy, but I'd appreciate any tips on 
getting the name of the drive the stack or standalone is 
currently sitting on.

Sincerely,
Simon