Online catalogs

Online cataloging has greatly enhanced the usability of catalogs, thanks to the rise of MAchine Readable Cataloging = MARC standards in the 1960s. Rules governing the creation of catalog MARC records include not only formal cataloging rules like AACR2 but also special rules specific to MARC, available from the Library of Congress and also OCLC. MARC was originally used to automate the creation of physical catalog cards; Now the MARC computer files are accessed directly in the search process. OPACs have enhanced usability over traditional card formats because:

1. The online catalog does not need to be sorted statically; the user can choose author, title, keyword, or systematic order dynamically.
2. Most online catalogs offer a search facility for any word of the title; the goal of the grammatic word order (provide an entry on the word that most users would look for) is reached even better.
3. Many online catalogs allow links between several variants of an author name. So, authors can be found both under the original and the standardised name (if entered properly by the cataloguer).
4. The elimination of paper cards has made the information more accessible to many people with disabilities, such as the visually impaired, wheelchair bound, and those who suffer from mold allergies and attention deficits.