The Directory Interchange Format (DIF) content metadata is a specific set of attributes for describing Earth science data at the collection level. From its inception in the late 1980’s as a way to document and exchange information on scientific data to its implementation in NASA's Global Change Master Directory (GCMD), the DIF has evolved to serve the user community in the discovery, access and use of Earth science and related data. GCMD metadata records are now maintained in the Common Metadata Repository (CMR), and the DIF is one of several supported formats for submitting metadata to CMR.
The DIF, the ECHO metadata model, and the ISO 19115 standards for science metadata formed the basis for NASA's Unified Metadata Model (UMM) used by CMR.