Simple example
Make a directory called “top” in Unix. Create a file RAW in the directory.
Make a script (an “analysis module”) to which we pass the top directory. The module knows to look for a file called “RAW”.
If the RAW file is there, it does its thing (some analysis with RAW), otherwise returns error.
The module can work with any directory containing a “RAW” file; it’s oblivious to other entries.
It cannot work with a directory without the RAW entry. The example on the right could be suitable for another module, but not for our script.