This implementation of IFile interface can be used to make Volante as an main-memory database. It should be used when cacheSizeInBytes is set to 0. In this case all pages are cached in memory and NullFile is used just as a stub. NullFile should be used only when data is transient i.e. it will not be saved between database sessions. If you need an in-memory database that provides data persistency, you should use normal file and infinite page pool size.