I think you mean 'how'? Koha uses MARC for the description of bibliographic records. Whether it is MARC21 or Unimarc is determined by the user during the Web install, and the choice is recorded in the system preference Cataloging/marcflavour . This then determines the field definitions in the Default framework of the Cataloguing module. The translation between the marc fields and the attributes of the MySQL tables is controlled by the 'koha to marc mapping' tables accessed on the Administration menu. The full marc definition of each bibliographic record is stored in MySQL in the biblioitems table, at biblioitems.marcxml. Hope that gets you started. Bob Birchall CALYX _____ From: koha-devel-bounces@lists.koha.org [mailto:koha-devel-bounces@lists.koha.org] On Behalf Of Musab Alghzawi Sent: Monday, 1 March 2010 10:58 PM To: koha-devel@lists.koha.org Subject: [Koha-devel] Question About MARC21 in koha Hello all, I just wanted to know who Koha uses MARC21 exactly. I mean where is it installed in Koha, how to develop and maintain the formats of MARC21 in Koha. Thanks, Musab No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.436 / Virus Database: 271.1.1/2752 - Release Date: 03/17/10 07:33:00