The Entry map contains four computer-generated, single-digit numeric characters that indicate the structure of each entry in the Directory.

Users typically do not have access to these Leader positions; the Entry map is automatically generated by the system.

National and minimal level record requirements for Leader/20-23 for all formats are Mandatory.




Length of the length-of-field portion.  A character that indicates how many character positions will be used in a Directory entry to store the length of a variable field.  In MARC 21, the length-of-field portion of each Directory entry is always 4 character positions in length; Leader/20 always contains a 4 (system-generated).


Length of the starting-character-position portion.  In MARC 21, the starting-character-position portion of each Directory entry is always 5 character positions in length; Leader/21 always contains a 5 (system-generated).


Length of the implementation-defined portion.  This character is produced by some automated systems and is only defined for that system.  In MARC 21, a Directory entry does not contain an implementation-defined portion; Leader/22 always contains a zero (0) (system-generated).


Undefined.  In MARC 21, this character position is undefined; Leader/23 always contains a zero (0) (system-generated).

For information about Leader/20-23 in a specific MARC format, select:

Leader/20-23 Entry map  (Authority)

Leader/20-23 Entry map  (Bibliographic)

Leader/20-23 Entry map  (Classification)

Leader/20-23 Entry map  (Community Information)

Leader/20-23 Entry map  (Holdings)

To return:

Use the key.