DIF RFC Final Recommendation

Frank,

Attached is the report of our technical working group that conducted a review of the Global Change Master Directory (GCMD) Directory Interchange Format (DIF). We recommend that DIF continue to be used and maintained as a catalog standard while recognizing that it is not a substitute for more complete inventory metadata.

In reviewing the usefulness of the DIF as a NASA standard we had very interesting feedback that you can find on our review site: http://www.esdswg.com/spg/rfc/esds-rfc-012/rfc-12-survey-responses

Some weaknesses and limitations were expressed. Though some data centers do use DIF as a internal catalog, many respondents stated that the standard is less useful for a data center internal catalog for several reasons. Most importantly, the DIF was never intended to be a data file inventory standard, rather it was conceived as a first-tier catalog search to enable users to identify resources. Most NASA data collections require more detailed or specialized metadata than is covered by the DIF. Also the GCMD DIF is a unique implementation that, while compatible with the ISO and FGDC standards, does not completely cover the requirements for some data collections or data centers. For this reason, some respondents expressed that use of DIF was in addition to and even superfluous of other metadata documentation.

Even so, from these 15 community responses, the TWG concluded that the DIF is a useful standard, especially for its primary purpose that is to register data collections as a catalog and to exchange such catalogs. This is especially true in light of years of successful use in NASA's internationally recognized Global Change Master Directory registry.

-Richard Ullman SPG Chair