Since the OAI is still very much in its infancy, there are not many implementations in existence. Virginia Tech was very much at the forefront of implementing OAI compliance, with the W3C Repository and CSTC being amongst the earliest projects. When comparing implementation notes, we discovered that the specifications could easily be read in different ways, as the two implementations had subtle differences. As one solution to this problem, the Repository Explorer was built to serve as a compliance test.
This program allows a person to browse through any archive which is supposedly compliant with the OAI, using only the protocol defined in the specifications. All aspects of the protocol can be tested, and the results of queries are checked for strict compliance with the expected syntax. The results are then parsed to present the user with a browsable interface.
To allow for maximum portability, the software is written in the form of a C++ CGI script which interrogates the archive, parses results and passes them on to the user. Thus users of the software need only access the central website instead of installing a client.
The project has been completed except for a few unresolved issues in the protocol, in which case the most popular interpretation has been adopted. As these issues are resolved, the Explorer is being updated to reflect the most current specifications.