RDF/XML Description of Data
There is a wide variety of data in Gaia - descriptions of objects, services, users, event logs, security and other policies, etc. What is needed is a way
of managing all this data in a standard way. This is where XML and RDF come in.
XML defines a standard interoperable and extensible framework wherein all data can have structure and be validated.
RDF defines an object oriented mechanism for describing resources and for describing the relationships between resources.
In Gaia, we are using XML and RDF to describe all the different types of data. There are schemas that define the format of the XML and RDF
documents. These schemas describe the different types of objects, their properties and the relationships between the objects. We are also building a
repository for holding all XML/RDF documents. This repository would make it possible to store and retrieve specific documents, browse through different
documents, perform queries and perform a wide variety of other manipulations on these documents like convert them to HTML
Since Gaia is highly dynamic, there should exist ways to manage these documents in a changing environment. There are ways to change the schemas
(say, to add or delete object classes, modify properties, etc.). The changes in the schema should then be reflected in the various
XML/RDF documents that conform to the schema. We are currently looking at ways in which this dynamism
can be achieved.
This framework for describing all objects in Gaia has several advantages. It is possible to obtain descriptions of different objects for various tasks like
bootstrapping the objects. Queries can be performed on these descriptions. It is also useful in resource discovery through better search engines. It also
makes possible browsing object descriptions, policies and logs on the web or other interfaces.