OLAC Aggregator

[Steven Bird]

ANNOUNCING THE OLAC AGGREGATOR

OLACA, the OLAC Aggregator, is an OLAC data provider which contains the
metadata from all the other 20+ registered OLAC archives.  OLACA is not
intended for end-users but for service providers.

OLACA is built on top of the OLAC harvester, announced last month
[http://lists.linguistlist.org/cgi-bin/wa?A1=ind0205&L=olac-implementers].
The harvester contacts each OLAC archive nightly and downloads its metadata
records, storing them in a central MySQL database.  The OLAC Aggregator
provides an interface to this database that service providers can use.

Service providers offer search facilities and other services to end-users.
At present OLAC has two service providers:

- the main service provider on the LINGUIST site
  (http://www.linguistlist.org/olac/)

- the experimental service provider on the OLAC site
  mainly used for testing data providers
  (accessed through the OLAC homepage)

We hope other service providers will be set up, adding further value to the
content of OLAC archives.  The OLAC Aggregator simplifies the job of such
service providers, since they only have to go to a single location in order
to harvest all OLAC metadata.  Next week we expect to announce a new
service built on the OLAC Aggregator.

The BaseURL of the OLAC Aggregator is
  http://www.language-archives.org/cgi-bin/olaca.pl

This CGI program receives OAI protocol requests and returns XML documents.
The OAI Repository Explorer gives a convenient interface for humans to
interact with data providers.  Use the following link to try out the OLAC
Aggregator using the Repository Explorer:
  http://oai.dlib.vt.edu/~oai/cgi-bin/Explorer/oai1.1/testoai?archive=http://www.language-archives.org/cgi-bin/olaca.pl

In future we may add a special protocol verb to OLACA that allows
harvesters to retrieve only those records that match a particular
search pattern.

The OLAC Aggregator was developed by Haejoong Lee at the Linguistic Data
Consortium, and the work was funded by the National Science Foundation.
OLACA was inspired by OAIA, the OAI Aggregator, and uses the OAI Perl
library [oai-perl.sourceforge.net].  In case anyone wants to run their
own OLAC aggregator, the source code will soon be available from the tools
section of the OLAC site [http://www.language-archives.org/tools.html].

Steven Bird

--
Steven.Bird at ldc.upenn.edu  http://www.ldc.upenn.edu/sb
Assoc Director, LDC; Adj Assoc Prof, CIS & Linguistics
Linguistic Data Consortium, University of Pennsylvania
3615 Market St, Suite 200, Philadelphia, PA 19104-2608