Online public access catalog

An Online Public Access Catalogue ( publicly available on-line catalog ), short OPAC is an online, now mostly on the Internet accessible library catalog. Since the 1980s, he began older types of library catalogs replace, today has almost every library has its own OPAC, which lists its stock of publications and makes searchable. The software that the OPAC is processed by librarians today is usually one of several components of an integrated library system.

Each OPAC has a database in which each existing in the respective library publication is saved as a digital catalog record. The librarians can edit the OPAC in the so-called online service catalog; library users is just another version, the online catalog available. This can be called up on the website of the library, where you will find a user interface through which you ( the author's name, publication date, keyword, etc.) can search for the constituents of the cataloging records. About the right keywords you come to this publication or group of publications.

In libraries that have not yet incorporated all their media in their OPAC, are for these stocks remain older catalog types in use. In the course of catalog enrichment the OPAC catalog entries are increasingly attached and full texts.

History

In the 1980s, the OPAC began the then common types of library catalogs, the card catalogs to displace, and today is the most authoritative and by far the most widely used catalog type. Initially, access was via a local network, with the proliferation of the Internet, more and more of these catalogs were available about this since the early 1990s. Initially, the Internet access was often a telnet interface or special clients. Since the World Wide Web has established itself in the mid- 1990s, OPACs are typically without the respective library must be visited with its own freely accessible websites searchable. Metasearch engines such as the Karlsruhe Virtual Catalog enable simultaneous search in many OPACs, while bibliographic databases such as WorldCat offer an OPAC interface, which relies on a common database of many libraries.