MARC 21 Concise Classification: Leader and Directory
This is an ARCHIVED VERSION of the 2000 electronic
edition of the MARC 21 Concise Formats. Please see www.loc.gov/marc/concise/
for the most up-to-date version of the electronic MARC 21 Concise Formats.
A fixed field that comprises the first 24 character positions
(00-23) of each record and provides information for the
processing of the record.
Character Positions
- 00-04 - Record length
The computer-generated, five-character numeric string
that specifies the length of the entire record. The number
is right justified and each unused position contains a
zero.
- 05 - Record status
A one-character code that indicates the relation of the
record to a file.
- a - Increase in encoding level
- c - Corrected or revised
- d - Deleted
- n - New
- 06 - Type of record
A code that indicates the characteristics of and defines
the components of the record.
- 07-08 - Undefined character positions
Each contains a blank (#)
- 09 - Character coding scheme
- # - MARC 8
- a - UCS/Unicode
- 10 - Indicator count
The computer-generated number 2 that indicates the number
of character positions used for indicators in a variable
data field.
- 11 - Subfield code length
The computer-generated number 2 that indicates the number
of character positions used for each subfield code in a
variable data field.
- 12-16 - Base address of data
The computer-generated, five-character numeric string
that indicates 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.
- 17 - Encoding level
A one-character code that indicates whether the
record is complete.
- n - Complete classification
record
- o - Incomplete classification
record
- 18-19 - Undefined character
positions
Each contains a blank (#)
- 20-23 - Entry map
Four computer-generated, single-digit numeric characters
that indicate the structure of each entry in the
Directory.
- 20 - Length of the length-of-field
portion
Contains a 4
- 21 - Length of the
starting-character-position portion
Contains a 5
- 22 - Length of the implementation-defined
portion
contains a 0
- 23 - Undefined
Contains a 0
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A 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.
Character Positions
- 00-02 - Tag
Three numeric or alphabetic (uppercase or lowercase, but
not both)
characters that identify an associated field.
- 03-06 - Field length
Four numeric characters that indicate the length of the
field,
including indicators, subfield codes, data, and the field
terminator. The
number is right justified and each unused position contains a
zero.
- 07-11 - Starting character position
Five numeric characters that indicate the starting
character position
of the field relative to the Base address of data (Leader/12-16)
of the
record. The number is right justified and each unused position
contains a zero.
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