Adding and Removing Files

Upon creating a LogicalFile one needs to indicate which physical files are represented by this LogicalFile. This is done through the process of adding and removing File instances to a LogicalFile instance. Just like adding more space shuttle parts to your ebay shopping cart. But the difference is that in adding File instances to a LogicalFile the user and application programmer should execute caution and only add files that are byte-for-byte equivalent to any other files which are already present in the LogicalFile. For the ebay shopping cart, though, you can add whatever you want. If does not heed this caution, then the LogicalFile instance will end up being a headache instead of a help, as you'll have all your space shuttle parts mixed in with your autographed photos of Phillip Paley, monkey-boy Chaka in ``Land of the Lost.''