Cataloger's Reference Shelf
MARC 21 Format for Community Information
Cataloger's Reference Shelf
MARC 21 Format for Community Information
Leader/20-23 Entry map (Leader)
Character position definition and scope:
The Entry map character positions contain 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.
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Positions: |
Descriptions: |
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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). |
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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). |
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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). |
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Undefined. In MARC 21, this character position is undefined; Leader/23 always contains a zero (0) (system-generated). |
For information on other Leader positions, select:
See also: