The WAIS implementation is still in use today resulting in over 50,000 users of Z39.50-1988 on the Internet, with an even greater number of users acquiring access via a suite of tools and services, for example, Gopher, World Wide Web, and America OnLine gateways. The Z39.50-1988 standard originally grew out of the library community as a search and retrieval protocol for bibliographic data. The design goals for the WAIS system required a more general information search and retrieval protocol. In addition, the new development activity taking place on the next generation WAIS systems is also presented. The WAIS client is a user- interface program that sends requests for information to local or remote servers.
Clients are available for most popular desktop environments.
The WAIS server is a program that services client requests, and is available on a variety of UNIX platforms. The server generally runs on a machine containing one or more information sources, or WAIS databases. The protocol, based on Z39.50, is used to communicate between WAIS clients and servers. Each operation is a two-step transaction made up of a request sent by the client to the server followed by a response sent by the server back to the client. A search request primarily contains information on what database to search and the corresponding query, where the query may contain a natural language question, a Boolean expression, and a set of documents for use in relevance feedback.