Directory
Character Position Definition and Scope:
The Directory consists of a series of fixed-length entries, with one entry for each variable field (control or data) present in a separate holdings record. Each Directory entry is 12 character positions in length and contains three portions: the field tag, the field length, and the starting character position. The Directory immediately follows the Leader at the beginning of the record and is located at character position 24. The Field length and Starting character 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 USMARC Specifications for Record Structure, Character Sets, Tapes.
Description of a Directory Entry:
00-02 Tag
03-06 Field length
07-11 Starting character position
Input Conventions:
System-Generated Elements:
Each Directory entry is system generated.
Embedded Holdings Information:
When holdings information is embedded in a related USMARC bibliographic record, the Directory entries for the holdings fields are part of the Directory of the bibliographic record.
Related USMARC Document or Field:
USMARC Specifications for Record Structure, Character Sets, Tapes
See also:
USMARC Holdings Formats: Contents
