URIs and Persistence: How long is forever?

Henry S. Thompson
School of Informatics
University of Edinburgh
W3C Technical Architecture Group
Markup Technology Ltd.
5 April 2007

1. Acknowledgements

2. URIs unpacked

3. More about syntax

4. More about resources

5. More about identification

6. What about web pages?

7. Resources vs. representations

8. A digression about media types and encodings

9. Multiple representations

10. Information resources

11. The Network Effect

12. Architecture of the World Wide Web

13. Grandmother observations about the Web

14. More from Grandma Webarch

15. More on terminology and technology

16. Connection with "persistent indentifiers"

17. Lookup plus hierarchy

18. (Parenthesis on distributed, secure and human-readable)

19. Parenthesis on versioning and extensibility

20. Just what is the problem?

21. myRIs and http: URIs compared

22. Standardised

myRI goal
myRIs should be susceptible to standardization within administrative units.
http: response
This is largely a management issue, not a technical one. Whatever invariants are in view can as well be enforced on (sub-parts of) http:-served resource collections as on those identified via myRIs.

23. Protocol Independence

myRI goal
Access to resources identified by myRIs should not be dependent on any particular protocol.
http: response
http: URIs are no more protocol-dependent than any other identification mechanism.

24. Location Independence

myRI goal
myRIs should not be locations.
http: response
http: URIs are not locations.

25. Structured names

myRI goal
myRIs should provide for structuring resource identifiers with shareable tags
http: response
The query component of http: URIs supports non-hierarchical structured naming.

26. Uniform access to metadata

myRI goal
myRIs should provide for consistent access to metadata about a resource as well as to representations of that resource.
http: response
Naming conventions or response headers can provide this already

27. Flexible Authority

myRI goal
myRIs require different approaches to identifying namespace authorities, in some cases simpler and in others richer than that provided by hierarchical domain names administered by IANA and resolved via DNS.
http: response
http: URIs can encode arbitrarily complex (or simple) namespace authority expressions.

28. Persistence

myRI goal
The relation between myRIs and the information resource they identify should persist indefinitely.
http: response
http: URIs support persistence as well as it is in-practice possible to do so.

29. Some folk wisdom

30. Conclusions