Online public access catalog
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An Online Public Access Catalog (often abbreviated as OPAC or simply Library Catalog) is an online database of materials held by a library or group of libraries. Users typically search a library catalog to locate books, videos, and audio recordings owned or licensed by a library.
Early online catalogs
Although a handful of experimental systems existed as early as the 1960s, the first large-scale online catalogs were developed at Ohio State University in 1975 and 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 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.
Throughout the 1980s, the number and sophistication of online catalogs grew. The first commercial systems appeared, and would by the end of the decade largely replace home-grown systems. Library catalogs began providing improved search mechanisms, such as basic keyword searching, as well as ancillary functions, such as the ability to place holds on items that had been checked-out.
At the same time, libraries began to develop applications to automate the purchase, cataloging, and circulation of books and other library materials. These applications, collectively known as an integrated library system (ILS) or library management system, often include a library catalog module as the public interface to the system's inventory. Most library catalogs, then, are closely tied to their underlying ILS system.
Stagnation and dissatisfaction
The 1990s saw a relative stagnation in the development of online catalogs. With the advent of the Web, library catalog interfaces gradually transitioned from terminals to web browsers, and would in time incorporate links to online resources, book covers, and other features aimed at improving the interface. The underlying search technology in most library catalog systems, however, did not advance much beyond that developed in the 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, yet more powerful, systems based on probablistic and vector-based queries.
As library users have grown more and more accustomed to these sites and search engines, they have become increasingly dissatisfied with the difficult and sometimes arcane search mechanisms of older library catalog systems. This has, in turn, lead to vocal criticisms of these systems within the library community itself, and in recent years to the development of newer (often termed 'next-generation') catalogs.
Next-generation catalogs
The newest generation of library catalog systems are distinguished from earlier OPACs by their use of more sophisticated search technologies, in particular faceted search, and features aimed at greater user interaction and participation with the system, including tagging, reviewing, and RSS feeds.
They are usually, although not always, independent of the integrated library system, with modules or 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 led by libraries themselves.
Union catalogs
Although library catalogs typically reflect the holdings of a single library, they can also contain the holdings of a group or consortium of libraries. These systems, known as union catalogs, are usually designed to aid the borrowing of books and other materials among the member institutions via interlibrary loan. The largest such union catalog is WorldCat, which includes the holdings of over 10,000 libraries worldwide.
Related systems
There are a number of systems that share much in common with library catalogs, but have traditionally been distinguished from them. Libraries utilize these systems to search for items not traditionally covered within a library catalog, specifically journal and newspaper articles and digitized materials.
These include bibliographic databases — such as Medline, ERIC, PsycINFO, and many others — which typically index journal articles and other research data. There are also a number of applications aimed at managing documents, photographs, and other digitized or born-digital multimedia items. Particularly in academic libraries, these systems (often known as digital library systems or institutional repository systems) assist with efforts to digitize archival materials or archive works created by faculty and students.
See also
References
- Antelman, Kristen, Emily Lynema, and Andrew K Pace, "Toward a Twenty-First Century Library Catalog," Information Technology & Libraries 25:3 (2006), pp. 128-139.
- Borgman, Christine, "Why are Online Catalogs Still Hard to Use?" Journal of the American Society for Information Science 47:7 (1996), pp. 493-503.