OPAC

An online public access catalog (OPAC) is an online database held by a library or group of libraries. Users search a library catalog to locate books and other materials available at a library. The first large-scale online catalogs were developed at Ohio State University in 1975 and at the Dallas Public Library in 1978. These and other early online catalog systems tended to closely reflect the card catalogs that they were intended to replace. Using a dedicated terminal or telnet client, users could search a handful of pre-coordinate indexes and browse the resulting display in much the same way they had previously navigated the card catalog.

The 1990s saw a relative stagnation in the development of online catalogs. Although the earlier character-based interfaces were replaced with ones for the Web, both the design and the underlying search technology of most systems did not advance much beyond that developed in the late 1980s.At the same time, organizations outside of libraries began developing more sophisticated information retrieval systems. Web search engines like Google and popular e-commerce websites such as Amazon.com provided simpler to use systems that could provide relevancy ranked search results using probabilistic and vector-based queries. Prior to the widespread use of the Internet, the online catalog was often the first information retrieval system library users ever encountered. Now accustomed to web search engines, newer generations of library users have grown increasingly dissatisfied with the complex search mechanisms of older online catalog systems.

The newest generation of library catalog systems are distinguished from earlier OPACs by their use of more sophisticated search technologies, including relevancy ranking and faceted search, as well as features aimed at greater user interaction and participation with the system, including tagging and reviews.These newer systems are almost always independent of the library's integrated library system (ILS), instead providing drivers that allow for the synchronization of data between the two systems. While older online catalog systems were almost exclusively built by ILS vendors, libraries are increasingly turning to next generation catalog systems built by enterprise search companies and open source projects, often led by libraries themselves. The costs associated with these new systems, however, have slowed their adoption, particularly at smaller institutions. An example of a next generation OPAC system is included in the Libramatic software package.

http://www.eosintl.com/modules/opac/