[OAI-implementers] Beginner questions

[Caroline Arms]

One of the advantages of OAI-PMH from the point of view of some data
providers is that they don't need to know exactly HOW their metadata is
being used.  However, I do check a few particular sites.

OAIster
  http://oaister.umdl.umich.edu/o/oaister/ 
and the UIUC Cultural Heritage Repository
  http://oai.grainger.uiuc.edu/oai/search

harvest the metadata records for digitized historical materials that the
Library of Congress (LC) makes available.  

A Sheet Music Consortium hosted at UCLA
  http://digital.library.ucla.edu/sheetmusic/
harvests LC's set of records for digitized sheet music.

These service providers all harvest and index the records and link
to the resource as mounted at LC.

The OAI protocol does not itself support the harvesting of the underlying
resources, and whether or not it is permitted will depend on the
repository.  LC has one arrangement with another institution that involves
harvesting the records and then use of the records to facilitate
harvesting of resources outside the protocol.

On possible uses for the ListIdentifiers request:  

1.  It can be used to count records, which can be useful in 
scheduling harvesting of the records themselves.

2.  I proves useful for LC as a data-provider for verifying batch
additions or set membership.

3.  I had always assumed that very selective harvesters might harvest a
set of records, filter the set in some way, and retain a list of
identifiers for the items in the subset.  This list could be used to
control re-harvesting.  Whether any current harvesters are doing this I
don't know.

    I hope that helps.

Caroline Arms                                              caar@loc.gov
Library of Congress

On Tue, 8 Apr 2003, Venugopal R Pally wrote:

> Thanks. This has made my questions cleared. could you
> please inform me how 'METADATA' and 'RESOURCE' are
> being used by harvestors or by any user ? Since we are
> getting records by ListRecords, GetRecord, how
> ListIdentifiers is used ? 
> Thanks,
> Venu.
> 
> --- Naomi Dushay <Naomi@cs.cornell.edu> wrote:
> > One of the ways we think about the two different
> > identifiers is this:
> > 
> > 
> > The DC identifier is an identifier for the RESOURCE.
> >  In fact, our rule
> > of thumb is that any information within the metadata
> > tag is about the
> > RESOURCE.
> > 
> > The OAI identifier is an identifier for METADATA for
> > the resource.  And
> > again, information in the header tag is about
> > METADATA for the RESOURCE.
> > We tend to think of the about tag as being about the
> > METADATA as well.
> > 
> > 
> > - Naomi Dushay
> > National Science Digital Library
> > _______________________________________________
> > OAI-implementers mailing list
> > OAI-implementers@oaisrv.nsdl.cornell.edu
> >
> http://oaisrv.nsdl.cornell.edu/mailman/listinfo/oai-implementers
> 
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