MARCsystemet

MARCsystemet refers to the MARC (Machine-Readable Cataloging) system used by libraries to encode bibliographic and related data for machine processing and exchange. It originated in the 1960s as a joint effort of the Library of Congress and participating libraries to automate catalogs and enable interlibrary sharing. A MARC record is designed for machine readability and comprises a leader, a directory, and a set of variable fields. Each field carries a three-digit tag, two indicators, and one or more subfields, identified by codes such as $a, $t, or $b, to represent elements like title, author, publication data, subject headings, language, and holdings.

Different MARC formats exist, most notably MARC Bibliographic for general cataloging, MARC Authority for access points and authority data, and MARC Holdings for holdings information. The MARC 21 standard is the dominant version in North America and many other regions, with local variants and adaptations.

Data exchange between libraries relies on MARC records, often transmitted via library networks or harvested via protocols such as OAI-PMH and encoded in MARCXML for web interoperability. MARC records can be indexed and searched by integrated library systems, enabling discovery and linking of records across catalogs. In recent years, MARC has faced competition from newer approaches such as BIBFRAME, which expresses bibliographic data as linked data and aims to improve web interoperability, while MARC remains widely used for legacy catalogs and ongoing data exchange.

Summary: MARCsystemet has been foundational in library automation, providing a structured, machine-readable framework for describing and linking library resources, even as the field evolves toward more semantic web‑compatible models.