MARC 21 - Application To Information Material (Nov 09)

What is MARC?
- A MARC record is a Machine Readable Cataloguing record
- “Machine readable” is meant a record that a computer can read and interpret
- A cataloguing record is a bibliographic record, containing information on the catalog card.

MARC Record

A record includes the following information
- description of the item
- added entries
- subject headings
- call numbers

Why is MARC Necessary?

- Because computers cannot think or reason, they must be provided with guides that enable them to interpret the data which has been imputed into them.

- The MARC record contains directories or guideposts before each piece of bibliographic information to tell the cataloguer and the computer what type of data is to be found in a specific field.

Examples of Fields

- Author, title and subject are examples of the various field types. Because the length of names and titles are usually different, the best library software allows for unlimited field lengths and an unlimited number of fields.

MARC Term and Definitions

- To understand what is being talked about when MARC records are being discussed one needs to be acquainted with the following terms:

Fields -

• Bibliographical data is divided into a number of fields to facilitate retrieval: fields for authors, fields for titles and so on. The fields are further subdivided into one or more subfields. For example, the place of publication, the publisher’s name and the date of the publication are all included as part of the MARC field tagged “260”.

Tags -

• A tag is a three-digit number which precedes each field in a MARC record.
• The tag identifies the field and the kind of data that follows to the computer.
• Repeatable fields (those which can appear more than once in any given record) will be followed by an “R”. Non-repeatable fields (those which can appear no more than once in any given record) by an “NR”

Indicators -

• Two spaces follows each tag.
• One or both of these spaces may be used for indicators
• In some fields only the second space is used.
• Sometimes, only the first is used and sometimes both are assigned.
  Indicators acts as signals to the application software. They define how the software should treat the information within a specific field.

Subfields

• Most fields will contain several related pieces of data.
• Each type of data within a field is called a subfield and each subfield is preceded by a subfield code.
• For example, the physical description field defined by the 300 tag typically contains a subfield for the number of pages, one for physical details such as illustration, and a further subfield for dimension in centimeters

Subfields Codes

• Subfield codes are one lower-case letter preceded by a delimiter.
• Each subfield indicates what types of data follows it
• In the example below, the subfield codes are a for extent, b are for other physical details and c for dimensions.
  300 a240 p. :bill. ;c24 cm.

Delimeters

• With different kinds of keyboards, different keys are used to represent the delimiters. In some cases, a ($) is used, or () or a (\).

to be continued