ETDs are intimately connected with libraries. The first key automation of libraries, launched in the 1980s, involved computerization of the card catalogs. Online Public Access Catalogs (OPACs) were developed, and supported search through records describing library holdings.
Many library catalogs have their holdings encoded according to the MARC (machine readable cataloging) standard. Managed by the US Library of Congress, the MARC standard in the USA has been applied in many other contexts, leading to broader standards like UNIMARC. The latest standard as of 2001 is MARC 21.
VTLS, Inc. (http://www.vtls.com), is one company that sells software (e.g., their Virtual system, which works with MARC) and services to support catalog search and other related library requirements. OPACs in many cases have evolved into sophisticated digital libraries, and can be used to help manage ETD collections. Indeed, ETDs at most universities can be found by searching in the local catalog system, as long as one can distinguish this genre or type of work from other holdings (e.g., books, journals, maps).
VTLS has volunteered equipment, software, staff, and services to help NDLTD. From http://www.vtls.com/ndltd one can gain access to a system affording search and browse support to the union catalog of all ETDs that can be harvested using the mechanisms supported in the Open Archives Initiative.
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