DDI as a Communication Protocol

The development of the Data Documentation Initiative (DDI) has begun at an opportune time in the evolving life of the web. The inexpensive telecommunications infrastructure of the World Wide Web has witnessed an explosion of publishing and electronic services. Although the focus of the web up to this point has been electronic documents and e-commerce, the beginning of a revolution in data delivery is beginning. Currently, the web environment is made up of a host of standalone systems that do not communicate. Systems like the Survey Documentation and Analysis (SDA) system at UC Berkeley, the European NESSTAR/FASTER project, the Greta project at Minnesota, the DataWeb/FERRETT project being developed by the Centers for Disease Control and U.S. Census Bureau, the Virtual Data Archive effort at Harvard, and the Counting California Digital Library Initiative efforts all are using elements of the DDI to disseminate data. The DDI, begun as a way to electronically document archived data now has the potential to become a next generation Internet protocol for distributed data access in the same way the HTML has become the protocol for distributed Web document access.

Each of the systems listed are being developed separately and, although committed to the DDI standard, do not intercommunicate. The reasons are both political, due to the funding structure of the projects, and technical. We will outline some of the challenges and propose technical recommendations that are required to use the DDI as a means to communicate among the systems outlined above. The paper will focus on the proposed DDI enhancements for Aggregate Data as the basis of this inter-system protocol. It will outline some of the political and system elements needed by each of the systems involved to participate in a World Wide Data Network.