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Bibliographic record directory elements

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Find details about the elements of the bibliographic record directory.

The record directory consists of a series of fixed-length entries containing the tag, length, and starting character position of each control and variable field in the record. A field terminator ends the record directory. Each entry is 12 bytes.

The starting position is expressed as the byte offset from the first character following the record directory field terminator.

In OCLC-MARC Records, any element, value, field, subfield, etc., marked obsolete is no longer valid. Current records will not contain these invalid codes. However, records supplied from archives may contain obsolete MARC coding.

Ind = Indicator  |  SFC = Subfield code  |  R = Repeatable  |  NR = Nonrepeatable  |  Blank = Blank

Bytes 00-11

Byte Definition
00-02

Tag

  • Number of characters associated with the field
  • Always = 3 numeric characters
  • Right-justified with leading zeros
  • Values range from 001 to 999
03-06

Field Length

  • Number of characters in the field identified by the tag: indicators, subfield codes, data, and a field terminator
  • Always = 4 numeric characters
  • Right-justified with leading zeros
07-11

Starting Character Position

  • Starting character position of the variable field to which the entry corresponds
  • Relative to the Base address given in bytes 12—16 of the record leader
  • Always = 5 numeric characters
  • Right-justified with leading zeros

Examples:

Tag                          Field Length                         Starting Character Position

 001                          0013                                             00000

 008                         0041                                             00013

 050                         0011                                              00054