Open Search Environments: The Free Alternative to Commercial Search Services.

Open search systems present a free and less restricted alternative to commercial search services. This paper explores the space of open search technology, looking in particular at lightweight search protocols and the issue of interoperability. A description of current protocols and formats for engineering open search applications is presented. The suitability of these technologies and issues around their adoption and operation are discussed. This open search approach is especially useful in applications involving the harvesting of resources and information integration. Principal among the technological solutions are OpenSearch, SRU, and OAI-PMH. OpenSearch and SRU realize a federated model to enable content providers and search clients communicate. Applications that use OpenSearch and SRU are presented. Connections are made with other pertinent technologies such as open-source search software and linking and syndication protocols. The deployment of these freely licensed open standards in web and digital library applications is now a genuine alternative to commercial and proprietary systems. [ABSTRACT FROM AUTHOR]