Library of Congress >> MARC >> Authority >> Leader

Leader (NR)


MARC 21 Authority
October 2002

Indicators and Subfield Codes
No indicators or subfield codes; the data elements are positionally defined.
Character Positions
00-04 - Record length

05 - Record status
a - Increase in encoding level
c - Corrected or revised
d - Deleted
n - New
o - Obsolete
s - Deleted; heading split into two or more headings
x - Deleted; heading replaced by another heading

06 - Type of record
z - Authority data

07-08 - Undefined character positions
# - Undefined

09 - Character coding scheme
# - MARC-8
a - UCS/Unicode

10 - Indicator count
2 - Number of character positions used for indicators

11 - Subfield code length
2 - Number of character positions used for a subfield code


12-16 - Base address of data

[number] - Length of Leader and Directory

17 - Encoding level
n - Complete authority record
o - Incomplete authority record

18-19 - Undefined character positions
# - Undefined

20 - Length of the length-of-field portion
4 - Number of characters in the length-of-field portion of a Directory entry

21 - Length of the starting-character-position portion
5 - Number of characters in the starting-character-position portion of a Directory entry

22 - Length of the implementation-defined portion
0 - Number of characters in the implementation-defined portion of a Directory entry

23 - Undefined
0 - Undefined


FIELD DEFINITION AND SCOPE

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.


GUIDELINES FOR APPLYING CONTENT DESIGNATORS

CHARACTER POSITIONS

00-04 - Record length
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.

05 - Record status
Relationship of the record to a file.
Used for file maintenance purposes.
a - Increase in encoding level
Encoding level (Leader/17) of the record has been changed from o (Incomplete authority record) to n (Complete authority record).
c - Corrected or revised
Addition/change other than in the Encoding level code has been made to the record.
d - Deleted
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.
n - New
Record is a newly input record.
o - Obsolete
Record content is obsolete, but the record has not been deleted from a file.
s - Deleted; heading split into two or more headings
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 ##$aBuddha and Buddhism
x - Deleted; heading replaced by another heading
Record has been deleted from a file and that a new authority record in which the heading from the deleted record appears as a 4XX See From Tracing field has been added to the file. (In a system where authority control is linked to the bibliographic file, a computer can effect the one-to-one replacement indicated by code x without manual intervention.)
Leader/05 x
150 ##$aOleomargarine
Leader/05 n
150 ##$aMargarine
450 ##$aOleomargarine

06 - Type of record
Characteristics and definitions of the components of the record.
z - Authority data
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).

07-08 - Undefined character positions
Both are undefined; each contains a blank (#).

09 - Character coding scheme
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.
# - MARC-8
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.
a - UCS/Unicode
Makes use of characters from the Universal Coded Character Set (UCS) (ISO 10646), or Unicode™, an industry subset.

10 - Indicator count
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.
2 - Number of character positions used for indicators

11 - Subfield code length
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.
2 - Number of character positions used for a subfield code

12-16 - Base address of data
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.
[number] - Length of Leader and Directory

17 - Encoding level
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).
n - Complete authority record
Record meets national-level record requirements for content and content designation.
o - Incomplete authority record
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.

18-19 - Undefined character positions
Both are undefined; each contains a blank (#).

20 - Length of the length-of-field portion
Always a 4.
4 - Number of characters in the length-of-field portion of a Directory entry

21 - Length of the starting-character-position portion
Always a 5.
5 - Number of characters in the starting-character-position portion of a Directory entry

22 - Length of the implementation-defined portion
In MARC 21, a Directory entry does not contain an implementation-defined portion.
Always a 0.
0 - Number of characters in the implementation-defined portion of a Directory entry

23 - Undefined
Undefined; always contains a 0.

INPUT CONVENTIONS

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.

CONTENT DESIGNATOR HISTORY

05 - Record status
d - Record deleted because heading is replaced by another heading [REDEFINED, 1983] [USMARC only]
d - Record deleted because heading is replaced by another heading [REDEFINED, 1997] [CAN/MARC only]
o - Obsolete [NEW, 2002]
x - Record deleted for reason not covered by other codes [REDEFINED, 1983] [USMARC only]
x - Record deleted (explanation may be present in field 682) [REDEFINED, 1997] [CAN/MARC only]

17 - Encoding level
0 - Full level [OBSOLETE, 1997] [CAN/MARC only]
1 - RECON record [OBSOLETE, 1997] [CAN/MARC only]
3 - Incomplete record [OBSOLETE, 1997] [CAN/MARC only]

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