Interchange Standards

There are several emerging standards which have been developed to facilitate the interchange of data in a distributed environment. Such standards make it possible to perform seamless searches across several distributed resources, which have been implemented on different platforms. This capability could be used:

• in collaborative projects to make data from several organizations accessible in a single search
• within single organizations to make their data available to a wider audience that may be operating in other platforms and with other interfaces.

For examples of projects involving standards for distributed access, see Standards Research and Implementation Projects.

There are several standards that are relevant to museums:

Z39.50 (ANSI Z39.50)  Z39.50 is "a computer protocol that can be implemented on any platform, defines a standard way for two computers to communicate for the purpose of information retrieval. A Z39.50 implementation enables one interface to access multiple systems providing the end-user with nearly transparent access to other systems"1. Z39.50 is an ANSI standard, and has also been adopted as an ISO standard, ISO23950. Z39.50 is based on a client/server architecture. The client sends the search request to an information server, which performs the search on one or more databases that could be in remote locations, operating on different platforms, and with different user interfaces. A user could enter a search on a Z39.50 client, with the interface and search commands that they are accustomed to using. The server returns the results of the search to the client in the native format of the client. In this way, "Z39.50 provides a consistent view of information from a wide variety of sources, and it offers client implementors the capability to integrate information from a range of databases and servers"2. There are drawbacks to the use of Z39.50; it requires special software that needs to be installed, configured, and maintained, and cost can be prohibitive. In addition to the technology and cost factors, there are other limitations; although Z39.50 addresses requirements for search and retrieval, it does not address data exchange. These issues have yet to be solved. Z39.50 has not gained widespread acceptance; there are newer technologies such as RDF and XML that may be more effective. For further information on issues relating to Z39.50 applications, see http://www.collectionscanada.ca/9/1/p1-242-e.html. Z39.50 Profiles have been developed within the museum and library communities to tailor Z39.50 searches to museum or library data. Certain Z39.50 Profiles have been developed to identify the particular Z39.50 features needed to support search and retrieval of cultural heritage information. The following profiles have been developed for use in museums and libraries: CIMI Profile CIMI has developed a Z39.50 profile for cultural heritage data. This profile was developed and tested in CIMI's Project CHIO and in the European Aquarelle project. The current CIMI profile harmonizes the original CIMI profile used in Project CHIO with the profile developed for the Aquarelle project. The CIMI Profile is available in English only. Bath Profile The Bath Profile is an internationally recognized profile which is maintained by the National Library of Canada. It was developed to facilitate distributed access among library applications. Zthes Profile The Zthes Profile is used for navigating hierarchical thesauri using the Z39.50 Profile. Includes support for multilingual thesauri, and includes an XML DTD for interchange of thesauri. CHIN has completed a test implementation of Z39.50 in the Fishnet biodiversity project.

Open Archives Initiative (OAI)  The Open Archives Initiative originated as a way to enhance access to e-print archives, but it is content independent and therefore is more broadly relevant to enable access to a range of digital materials, including museum information. Much of the data produced and managed by museums is not available to Web search engines, as it is usually stored in databases. The OAI protocol is a potential means for museums to : make their data more accessible on the Internet more easily participate in distributed "portal" services re-purpose their collections management data. OAI defines a protocol both for metadata harvesting, and for exposing OAI-compliant metadata to be harvested. A museum that wanted to exchange data using the OAI protocol would create an OAI-compliant data repository by: "exposing" their data in XML according to a simple technical protocol. Dublin Core (unqualified) is the minimum interchange standard required by OAI; however, any other metadata set described by an XML DTD (such as the SPECTRUM XML DTD) can be used for more detailed description. configuring their Web server to handle OAI protocol requests. OAI is designed to be easy to implement, with low technical barriers. In comparison to Z39.50, it does not require special equipment, and is less expensive to implement, but its use is relatively untested, and there are still problems to be solved. OAI is currently in an experimentation period, with organizations such as the Consortium for the Interchange of Museum Information (CIMI) running testbed projects in order to assess whether it is a realistic and functional option for use by the museum community. CIMI has made generic code and documentation for creating repositories available to CIMI members for download. On June 14, 2002, The Open Archives Initiative released Version 2.0 of the Protocol as a stable specification. An XML Schema for unqualified DC has been developed for use with the OAI Protocol.

1 "Z39.50 Resource Page". Jan. 2002. Available online at www.niso.org/standards/resources/Z3950_Resources.html. Last accessed: June 27/06.

2 "What is Z39.50?" Available online at www.cni.org/pub/NISO/docs/Z39.50-brochure/50.brochure.part01.html.

Last accessed: June 27/06.