[OAI-implementers] Friends and Neighbours scheme ... locating OAI repositories

Alan Kent ajk@mds.rmit.edu.au
Sat, 2 Mar 2002 20:25:57 +1100

Another mailing list I am on related to Z39.50 is talking about the
concept of "Friends and Neighbours". It may be a bit early for
OAI (not that many sites yet!), but the basic idea is that sites
keep track of what other sites they know of. That way, there does
not need to be a central registry as such. Theoretically someone
can write a crawler, start at one site, find out what other
sites it knows of, and work its way on from there.

This allows major institutions with a real commitment to OAI to
maintain a list of other sites under their juristiction, with links
off to other places where similar lists are kept.

One way this could be done in OAI for example is to define a new
XML schema for information on repositories. You then ask your first
site (you have to be given a starting point) what sites it knows of.
It will probably return itself (not mandatory for simple data provider
implementations), but it may return other sites it knows of.
The crawler can then go off and ask those sites what sites they know
of, and so on.

Two things are needed to achieve this:

(1) A definition of a new schema describing a OAI site. Probably only
    needs repository id, BaseURL, and protocol version. The Identify
    verb can be used on the site to get other information.

(2) One or more of the data provider software implementors to support
    more than one record syntax (ie, not only dublin core).
I am assuming that in OAI if you ask for data in a particular record
schema, you will only get records that were in that syntax.

It seemed a better way of getting an up to date list of sites compared
to the current ListFriends.pl XML document at the www.openarchives.org
site. It allows the OAI protocol to maintain lists of OAI sites
in a distributed way. Aggregators just aggregate OAI site records
like any other record they would aggregate.

I thought it was a cute idea.

Alan Kent (mailto:ajk@mds.rmit.edu.au, http://www.mds.rmit.edu.au)
Postal: Multimedia Database Systems, RMIT, GPO Box 2476V, Melbourne 3001.
Where: RMIT MDS, Bld 91, Level 3, 110 Victoria St, Carlton 3053, VIC Australia.
Phone: +61 3 9925 4114  Reception: +61 3 9925 4099  Fax: +61 3 9925 4098