Jill Foster on X.500/WAIS BOF

Jill Foster
See minutes , IETF , the rest of Jill's report

This was really a companion BOF to the "Living Documents" BOF which had seen a wide ranging discussion on networked information retrieval. In contrast this BOF was more structured and started with presentations on the various applications. There is a need to have some sort of Universal Document Identifier that could be used by the various applications.


John Curran provided a short description of WAIS. (Unfortunately no one from "Thinking Machines" was able to attend the IETF). However John had a reasonably good knowledge and experience of the application (NNSC have a WAIS interface to the RFCs).
       _______________             _______________     _______________
      |               |           |               |   |               |
      |               |           |               |   | Files of      |
      |               |           |   WAIS        |   | Information   |
      |   Client      | --->----- |   Server      |   | (e.g. RFCs)   |
      |               |           |               |   |               |
      |               |           |               |   |               |
      |_______________|           |_______________|   |_______________|
The WAIS Server has an inverted index of all the words in a document which is pre-built. (This does not make sense for non-text files of course). It also holds other information about the document (size etc). A client will formulate a query on behalf of the user and send it to the WAIS Server which will search the index and retrieve and return the document using the same protocol (Z39.50). Use of a pre-built index makes this very fast.

One WAIS Server may have multiple sources (and multiple indexes). There are various WAIS Servers in existence, but there is currently no way of querying which Server is responsible for which source. The possibility of putting WAIS descriptor files on a Server or in an X.500 directory was discussed.

Differences: Z39.50/WAIS:

OSI-DS 22:

Wengiyk Yeong presented his draft RFC on representing a public archive in the directory. He also described a project using this. A file can be found using the directory and then automatically retrieved using the specified access method.

World Wide Web:

Tim Berners-Lee gave a talk on the World Wide Web. This project has been funded to provide a service to the world wide community of high energy physicists. It is a hypertext system. The philosophy behind it is that a user should be able to point and click on an item name or a word within a document and the associated document would be retrieved from wherever in the world and presented to the user in an appropriate format - without the user having to be aware of where the document is located or what the access method is. These details are hidden in the hypertext links. There were server programs for many information servers, gateways to WAIS, Archie and gopher and client programs for various user machines.

The overlap between WWW, WAIS, Archie, Prospero was indicated and the need for a UDI by all of these was discussed. Each application (apart from WAIS) uses a "handle" for a file which can be prefixed by something appropriate. WAIS currently can only have "WAIS" as the prefix. There is a need for it to be more flexible.

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Steve Kille discussed this paper "Representing the Real World in an X.500 Directory".

A Listing Service may be used to group like information items together for example to provide a Yellow Pages Service.

Services such as Archie could be considered to be Listing Services. One imagines an information Universe in which Information Brokers provide different subject based (say) views via their listing service. One would then need to locate the various listing services (using a mechanism such as a directory?)
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UK British Library Project:

Paul Barker described a project, sponsored by the BL, to represent grey literature (unpublished research papers) in the Directory. The project is thought to be unlikely to succeed - but one of the aims is to demonstrate whether or not it is possible. They will take the (UK) MARC records and model these within X.500. They might also consider trying to provide a listing service so that the documents might be retrieved more readily by subject area.


Cliff Neuman described Prospero. It follows a file system (rather than hypertext) model. It is built on UDP. It has the notion of a Directory which contains links to other objects (other directories or files). It returns the link to the information object and then automatically retrieves the file by another mechanism by the appropriate access method (Archie, WAIS, nntp, WWW - soon!, NFS, ftp etc.) It has linked very successfully with archie. Cliff stated that he expected to be able to use X.500 to translate between the document ID and how to get the document.

With Prospero the user has his own view of the global information base (or has a view built for him). Cliff thought there should be multiple name spaces - but the difficulty would be that these would need representing near the top of the directory tree. With multiple user chosen views - this would be difficult to manage. Also two users might refer to an object by different handles which would be relative to their individual name spaces - difficult when passing references (say in a mail message) from one person to the other.

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System 33

Larry Masinter talked about a project at XeroxParc. There was the concept of a
32 byte number (is a content ID)
FILE Location (6 part)
Protocol; Host; Path; piece; format; timeout
(normal "Catlogue" information: name, Author, Document, etc)
There is format negotiation when a document is retrieved.

Also considered Access Control. ACL is part of description. The Server exploits multiple protocols for Search and retrieve.

There is a problem with dealing with different types of document:

It is difficult to normalise the attributes of a general document.

Summing up

Tim Berners-Lee summed up by saying that all applications described had a need for a Unique Doc ID and for a name service for this. The UDI needed to be resolvable. (This is not the same as USDN - content ID - described earlier). There should be a WG on details of UDI (but this needs a better name) and a separate one for USDN (and the need for a single resolver for these). Chris Weider agreed to co-author a document on the issues.

I suggested that it might be useful to try just doing this. That is to have a pilot-project to try putting UDI's in the directory for a set of files and to have the gopher, Prospero, archie, and Prospero people try to utilise these.