Testing that verifies the program under test stores data files in the correct directories and that it reserves sufficient space to prevent unexpected termination resulting from lack of space. This is external storage as opposed to internal storage.
Some applications work a little or more on the data entered (especially memo type, bitmap type etc) by the user before storing it in the database. In doing so, some s/w systems spoil the data entered. The same thing happens when retrieving such data from the database. If it is not stored properly, it can’t be retrieved properly either.