Haystack

"The Ozone user interface is the sole client at this time. The Haystack server hosts a number of information stores, including an RDF store. Other stores are simply wrappers around other sources of information such as LDAP servers, IMAP servers, and Microsoft Outlook stores. All stores are federated by a single Federation Service, which is responsible for dispatching queries to and combining query results from several stores."

I'd like to download or at least somehow look at the Adenine language which sounds interesting:
"Adenine takes the p-code concept one step further by making the ontology explicit and extensible and by replacing byte codes with RDF. Instead of dealing with the syntactic issue of introducing byte codes for new instructions and semantics, Adenine takes advantage of RDF’s ability to extend the directed “object code” graph with new predicate types...Values in Adenine are represented as Java objects in the underlying system."

http://haystack.lcs.mit.edu/haystack

This was presented at the 2002 W3C conference:
http://www.ai.mit.edu/people/dquan/haystack_intro.htm