Components of the Detailed Descriptions
A detailed description may consist of seven parts; content designator listing; character position or field definition and scope; guidelines for applying content designators; input conventions; related USMARC document/field; or other related documents; and content designator history.
The content designator listing area presents:
the name of the content designator and
the repeatability or non repeatability code (R or NR)
For the Leader and the variable control fields, the list gives the name of the character position and any defined codes. For the variable data fields, the list gives the name of the indicator positions and any defined values and the name of the subfield code and any defined codes. For all variable fields, the repeatability or non repeatability code at the field level specifies whether the field may be repeated in a holdings report. For variable data fields, the subfield repeatability code specifies whether the subfield code may be repeated within a field.
The character position or field definition and scope area describes the contents of the character position or field and gives other information, such as field repeatability in particular circumstances and the use of required lists or rules in formulating the data.
The guidelines for applying content designators area describes the content and scope of each code, indicator, or subfield code and gives other information, such as appropriateness for use and repeatability in certain circumstances. The coded values and subfield codes in this area are presented in alphabetical or numerical order. Examples showing the use of the content designator illustrate the application of specific USMARC content designators and immediately follow the description. In the examples, ,location identifier. may be used instead of an NUC symbol of the organization holding the item or from which it is available. No item identifier (fields 004 , 010-030 ) is shown in the examples although in separate holdings records such a link may be necessary to identify the related bibliographic title. No item identifier field is needed in embedded holdings statements.
The input conventions area provides general guidance for the application of the content designators and for such things as punctuation, spacing, and the use of the content designator in embedded holdings information.
The related USMARC field or document area provides references to related fields in the holdings format and in other documents, such as related fields in the USMARC Format for Bibliographic Data, or documents such as Symbols of American Libraries.
The content designator history area provides a record of significant content designator changes. The types of changes that may be included are:
newly defined content designators that impact on coding consistency within a file
redefined codes and values
changes in codes and values for consistency across USMARC specifications
changes i repeatability when it impacts on file consistency
restructuring
obsolete content designation
In the USMARC formats, a distinction is made between obsolete and deleted constant designators. An obsolete content designator is one that may have been used in USMARC records and that may continue to appear in records created prior to the date it was made obsolete. Obsolete content designators are not use in new records. An obsolete content designator is recorded in the content designator history area. A deleted content designator is not recorded in the content designator history area and will no longer appear anywhere in the USMARC documentation. A content designator that had been reserved in USMARC but had not been defined, or one that had been defined but is known with near certainty not to have been used, may be added from the format. A deleted content designator is available for redefinition in a format.
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