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Directory (NR)

MARC 21 Community Information
January 2000

Indicators and Subfield Codes
Has no indicators or subfield codes; the data elements are positionally defined.
Character Positions

00-02 - Tag
03-06 - Field length
07-11 - Starting character position


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.



00-02 - Tag
Three ASCII numeric or ASCII alphabetic characters (uppercase or lowercase, but not both) that identify an associated variable field.
03-06 - Field length
Four ASCII numeric characters that specify the length of the variable field to which the entry corresponds. This length includes the indicators, subfield codes, data, and the field terminator associated with the field. A Field length number of less than four digits is right justified and unused positions contain zeros.
07-11 - Starting character position
Five ASCII numeric characters that specify the starting character position of the variable field relative to the Base address of data (Leader/12-16) of the record. A Starting character position number of less than five digits is right justified and unused positions contain zeros.


  Tag Field length Starting character position
Entry 1 001 0013 00000
Entry 2 003 0004 00013
Entry 3 005 0017 00017
Entry 4 008 0016 00034
Entry 5 040 0013 00050


System-Generated Elements - Each Directory entry is system generated.

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