00-02 - Tag
Computer-generated index to the location of the variable control and data fields within a record. The Directory immediately follows the Leader at character position 24 and consists of a series of fixed-length (12 character positions) entries that give the tag, length, and starting character position of each variable field.
Field length and Starting character position portions of the Directory are defined by Leader/20-23 (Entry map) as being 4 and 5 characters in length, respectively. Because a field tag is always 3 characters, the length of the Tag portion of the Directory is not specified in the Entry map.
More detailed information about the structure of the Directory entries is contained in the MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.
|Tag||Field length||Starting character position|
Library of Congress >> MARC >> Community Information >> Directory(03/17/2008)