No indicators or subfield codes; the data elements are positionally defined.
| Character Positions | |
| 00-04 - Record length | |
| 05 - Record status | |
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| 06 - Type of record | |
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| 07-08 - Undefined character positions | |
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| 09 - Character coding scheme | |
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| 10 - Indicator count | |
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| 11 - Subfield code length | |
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| 12-16 - Base address of data | |
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| 17 - Encoding level | |
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| 18 - Punctuation policy | |
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| 19 - Undefined | |
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| 20 - Length of the length-of-field portion | |
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| 21 - Length of the starting-character-position portion | |
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| 22 - Length of the implementation-defined portion | |
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| 23 - Undefined | |
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First field of an authority record. It is fixed in length at 24 character positions (00-23). The Leader consists of data elements that contain numbers or coded values that define the parameters for the processing of the record.
Character positions 20-23 comprise the Entry map for the Directory. They contain four one-character numbers that specify the structure of the entries in the Directory. More detailed information about the structure of the Leader is contained in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.
Computer-generated, five-character number equal to the length of the entire record, including itself and the record terminator. The number is right justified and unused positions contain zeros.
Relationship of the record to a file.
Used for file maintenance purposes.
Encoding level (Leader/17) of the record has been changed from o (Incomplete authority record) to n (Complete authority record).
Addition/change other than in the Encoding level code has been made to the record.
Used when neither code s nor code x is applicable, or when an organization chooses not to use code s or x.
Some level of manual intervention may be needed to effect the change in bibliographic records because the deleted heading may or may not be carried as a 4XX See From Tracing field in other authority records and a 682 field explaining the delete may be present in the record marked for deletion.
| Leader/05 | d | ||||||||
| 150 | ##$aFruit processing | ||||||||
| 682 | ##$iThis heading has been replaced by the heading$aFruit-Processing,$ia heading not distributed because it uses a freefloating subdivision controlled by a pattern heading. | ||||||||
Record is a newly input record.
Record content is obsolete, but the record has not been deleted from a file.
Record has been deleted from a file because the heading has been split into two or more headings, requiring a new authority record for each. The heading from the deleted record is included in each of the new authority records as a tracing in a 4XX See From Tracing field. This specialized delete value supports use of automated systems to carry out any necessary reviews, since when a heading is split, a computer cannot automatically replace the old heading in bibliographic records.
| Leader/05 | s | ||||||||
| 150 | ##$aBuddha and Buddhism | ||||||||
| Leader/05 | n | ||||||||
| 100 | 0#$aGautama Buddha | ||||||||
| 450 | ##$aBuddha and Buddhism | ||||||||
| Leader/05 | n | ||||||||
| 150 | ##$aBuddhism | ||||||||
| 450 | ##$aBuddha and Buddhism | ||||||||
Record has been deleted from a file and that a new authority record in which the heading from the deleted record appears as a 4XX See From Tracing field has been added to the file. (In a system where authority control is linked to the bibliographic file, a computer can effect the one-to-one replacement indicated by code x without manual intervention.)
| Leader/05 | x | ||||||||
| 150 | ##$aOleomargarine | ||||||||
| Leader/05 | n | ||||||||
| 150 | ##$aMargarine | ||||||||
| 450 | ##$aOleomargarine | ||||||||
Characteristics and definitions of the components of the record.
Content of the record constitutes an authority record. The specific kind of authority record is identified by the code in 008/09 (Kind of record).
Both are undefined; each contains a blank (#).
Coding scheme used affects the number of octets needed per character, the placement of non-spacing characters, and the use of escape sequences and may affect the character repertoire. Detailed information on the character sets used in MARC 21 records is contained in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.
Character coding in the record uses the 8-bit character sets described in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media. Non-default character sets used are identified in field 066.
Makes use of characters from the Universal Coded Character Set (UCS) (ISO 10646), or Unicode™, an industry subset.
Computer-generated number 2 that indicates the number of indicators occurring in each variable data field.
(An indicator character position contains a code which conveys information that interprets or supplements the data found in the field.) In MARC 21, two character positions at the beginning of each variable data field are reserved for indicators; therefore, the Indicator count is always 2.
Computer-generated number 2 that indicates the number of character positions used for each subfield code in a variable data field.
(Each data element in a variable data field is identified by a subfield code.) In MARC 21, a subfield code consists of a delimiter ( $) and a lowercase alphabetic or numeric data element identifier; therefore, the Subfield code count is always 2.
Computer-generated, five-character numeric string that specifies the first character position of the first variable control field in a record. The number is right justified and each unused position contains a zero.
Number is the base from which the starting character position of all the other fields in the record is addressed in the Directory. (The starting character position in the Directory entry for each field of the record is relative to the first character of the first variable control field rather than the beginning of the record.) The Base address of data is equal to the sum of the lengths of the Leader and the Directory, including the field terminator character at the end of the Directory.
Whether the authority record is complete.
A record, where complete or incomplete, that is being considered for modification after its initial creation is identified by code b (Record is being updated) in field 008/31 (Record update in process).
Record meets national-level record requirements for content and content designation.
Authority record is incomplete because it does not yet contain all the information needed for a complete record. The record may or may not meet the national-level record requirements.
One-character alphanumeric code that designates the punctuation policy followed in the headings and tracings fields.
Refers only to end of field and end of subfield punctuation, and not to internal punctuation.
No information is provided as to the punctuation practices followed in headings and tracings fields.
The headings and tracings fields do not contain punctuation.
The headings and tracings fields contain punctuation.
It is unknown whether the headings and tracings fields contain punctuation.
Undefined and contains a blank (#).
Always a 4.
Always a 5.
In MARC 21, a Directory entry does not contain an implementation-defined portion.
Always a 0.
Undefined; always contains a 0.
System-Generated Elements - The following Leader elements are usually system generated:
| 00-04 | Logical record length |
| 07-08 | Undefined character positions |
| 09 | Character coding scheme |
| 10 | Indicator count |
| 11 | Subfield code count |
| 12-16 | Base address of data |
| 20-23 | Entry map |
It is common for default values in other Leader elements to be generated automatically as well.
Capitalization - Alphabetic codes are input as lower case letters.