Twenty years of UDC. Changes after the year 2000

Abstract

Since the beginning of the twentieth century Universal Decimal Classification (UDC) has become the predominant classification system employed at every level of the Hungarian library network. The most recent Hungarian edition of the schema, containing the material of the UDC version released in 2000, was published in 2005. The last thirty years have seen a continuous, co-ordinated and scientifically based revision of the system. The explicit purpose of the modifications was, aside from following the accelerated changes in science and other knowledge areas, to render it easier to automate the schema's grammar and vocabulary. Although the results of the first period of refactoring appear in the aforementioned Hungarian edition, many further changes have been published in the last twenty years. Since the National Széchényi Library joined the UDC Consortium and the preparation of the new Hungarian online edition began, it has become particularly pertinent to review the recent changes of UDC.