Over the years, however, despite cooperation efforts, several versions of MARC emerged, e.g. UKMARC, INTERMARC and USMARC, whose paths diverged because of different national cataloguing practices and requirements. We had an extended family of more than 20 MARC formats. Differences in data content meant some extensive editing was needed before records could be exchanged.
One solution to incompatible data was to create an international MARC format - called UNIMARC - which would accept records created in any MARC format. Records in one MARC format would first be converted into UNIMARC, and then be converted into another MARC format, so that each national bibliographic agency would need to write only two programs - one to convert into UNIMARC and one to convert from UNIMARC - instead of having to write twenty programs for the conversion of each MARC format (e.g. INTERMARC to UKMARC, USMARC to UKMARC etc.).
In 1977, the IFLA (International Federation of Library Associations and Institutions) published UNIMARC: Universal MARC Format, followed by a second edition in 1980 and a UNIMARC Handbook in 1983. These publications focused primarily on the cataloguing of monographs and serials, while taking into account international efforts towards the standardization of bibliographic information reflected in the ISBDs (International Standard Bibliographic Descriptions).
In the mid-1980s, UNIMARC expanded to cover documents other than monographs and serials. A new UNIMARC Manual was produced in 1987, with an updated description of UNIMARC. By this time UNIMARC had been adopted by several bibliographic agencies as their in-house format.
Developments didn't stop there. A standard for authorities files was set up in 1991, as explained on the website of IFLA in 1998: "Previously agencies had entered an author's name into the bibliographic format as many times as there were documents associated with him or her. With the new system they created a single authoritative form of the name (with references) in the authorities file; the record control number for this name was the only item included in the bibliographic file. The user would still see the name in the bibliographic record, however, as the computer could import it from the authorities file at a convenient time. So in 1991 UNIMARC/Authorities was published."
In 1991 a Permanent UNIMARC Committee was also created to regularly monitor the development of UNIMARC. Users realized that continuous maintenance - and not just the occasional rewriting of manuals - was needed, to make sure all changes were compatible with what already existed.
On top of adopting UNIMARC as a common format, The British Library (using UKMARC), the Library of Congress (using USMARC) and the National Library of Canada (using CAN/MARC) worked on harmonizing their national MARC formats. A three-year program to achieve a common MARC format was agreed on by the three libraries in December 1995.
Other libraries began using SGML (Standard Generalized Markup Language) as a common format for both the bibliographic records and the hypertextual and multimedia documents linked to them. As most publishers were using SGML for book records, librarians and publishers began working on a convergence between MARC and SGML. The Library of Congress worked on a DTD (Definition of Type of Document, which defines its logical structure) for the USMARC format. A DTD for the UNIMARC format was developed by the European Union. Some European libraries chose SGML to encode their bibliographic data. In the Belgian Union Catalog, for example, the use of SGML allowed to add descriptive elements and to facilitate the production of an annual CD-ROM.
1984: COPYLEFT
[Overview]