[17.7] How do I determine the current drive letter or volume name?

These can be extracted from the pathname, which returns the absolute path to the current movie, including the drive or volume. Despite the different path formats of the Mac and PC, both coincidentally start with the item we want followed by a colon (eg, "C:\BLAH" or "matthew:Desktop Folder:Blah")

    on getDriveOrVol
      -- save off the old item delimiter so we can use our own
      set oldDelimit = the itemDelimiter
      set the itemDelimiter = ":"

      -- get what we want
      put item 1 of the pathName into driveOrVol

      -- restore the old item delimiter so everyone else can keep using it
      set the itemDelimiter = oldDelimit
      return driveOrVol
    end getDriveLetter