1. 0 LocalRemote Procedure Call API…( J2EE, COM, WIN32, OLE, Single UNIX Speci- fication) XML RPC, SOAP (WSDL, UDDI) Data Access ODBC, JDBC, JDO XDI? Local APIs don’t have to worry about finding and binding to available interfaces across system boundaries. Most Procedure Calls provide Application Specific access to data.. e.g: getCalendarEntry(Date, Time) Most Procedure Calls provide Application Specific access to data.. e.g: getCalendarEntry(Date, Time) It appears that RPC over http has gained adoption largely because it can be deployed easily over existing infrastructure and configurations (you don’t need IT to be opening ports in corporate firewalls like you do with CORBA) Database engines provide controlled access to data schema and elements in a totally application agnostic way… enabling you to build ANY application (supported by the data) or mine the data for new value While these protocols can be used across system boundaries (very common in J2EE to use JDBC from an app server to a DB server) it generally only works in very tightly controlled environments and configurations for it not to become a security nightmare. None of these protocols natively deal with distributed data. XDI can provide the advantages of http based (SOAP based can even leverage existing XML routing hardware) transfer protocols while enabling Application Agnostic, Controlled, data access to remote distributed data sources. Author: Andy Dale, XDI.ORG

2. 1 XDI graph elements Resource Link Data Ref Backref Nodes Arcs XRI only Physical Logical Type Instance Version Data or XMLResource

3. 2 Authority delegation Resource Link Data Ref Backref Nodes Arcs XRI only Physical Logical Type Instance Version Data or XMLResource Delegation between Physical Authorities Delegation between Logical Authorities

4. 3 Graphing a link contract Physical Logical Type Instance Version Data or XMLResource !!1000 /(=A)/(=A*(=B)) *(=B) /(=B) /($contract) /personal /($v/1) *(=A/(+email)/personal/($v/3)) /(+email) /personal /($v/3) !!1001 /(=A)/(=A*(=B)) *(=B) /($contract) /personal /($v/1) *(=A/(+email)/personal/($v/3)) /(+email) /personal /($v/3)

5. 4 Author’s Path vs. Rights Path Physical Logical Type Instance Version Data or XMLResource !!1000 /(=A)/(=A*(=B)) *(=B) /(=B) /($contract) /personal /($v/1) *(=A/(+email)/personal/($v/3)) /(+email) /personal /($v/3) !!1001 /(=A)/(=A*(=B)) *(=B) /($contract) /personal /($v/1) *(=A/(+email)/personal/($v/3)) /(+email) /personal /($v/3) “Rights Path”“Author’s Path”