XML Registries

A registry is a means to discover and retrieve documents, templates, and software (i.e., objects and resources) over the Internet. An XML registry/repository serves as a central location for XML objects and related resources. Registered objects may include: XML tags (elements), enumerated value lists, XML schemas, XML schema components, XML datatypes, XML namespaces, XML documents, trading partner agreements, UML models, and administrative documents (submittal and approval documentation).

It is believed that the full benefits of XML will be achieved only if organizations use the same data element definitions and those definitions are available for "partners" to discover and retrieve. This applies not only to the business world but also to the domains of science, engineering, and education/public outreach, which are of particular concern to NASA. Agency mission, engineering, and administrative applications will all benefit from the XML vocabularies, schemas, and other pertinent information stored in the XML Registry.

XML registry development is a relatively new field. It is important to survey existing registries and available tools as part of the process of identifying a solution for the Agency. The XML Working Group of the Federal CIO Council (XMLWG) has created a committee to consider development of federal government XML registries. Both the Department of Defense and the National Institute of Standards and Technology registries have been considered to be prototypes for a government-wide registry. At this time, an analysis of alternatives for managing XML resources in federal agencies is under development. See http://xml.gov/registries.asp for a partial list of existing registries.

NASA XML Registry

NASA has entered into an agreement with the Department of Defense (DOD) to use the XML registry created by the Defense Information Systems Agency (DISA; http://diides.ncr.disa.mil/xmlreg/user/index.cfm). As NASA gains experience in its use, the Agency will decide whether or not to continue using the DISA XML registry depending upon how well it meets the Agency's requirements, including those for security.

The NASA XML registry will eventually become the authoritative source for generation and reuse of XML metadata components for the Agency's XML programs. By using information stored in the registry, the Agency will gain improved interoperability among Agency software systems that use XML natively or via gateways, and will better support Agency initiatives.