Because of special circumstances regarding MARC 21 variable control fields, special attention was focused on that area during the Format Integration discussions of 1983-1988. A new bibliographic data element, field 006 (Fixed-Length Data Elements--Additional Material Characteristics), was defined to solve the problem of the non-repeatability of field 008 (Fixed-Length Data Elements). A general model was adopted to indicate how repetitions of field 006 and a single field 008 would coexist in a record, especially in relation to the values in Leader character positions 06 (Type of record) and 07 (Bibliographic level). The relationship of field 007 (Physical Description Fixed Field) to fields 008 and 006 was also clarified.
Form of Material Level I (field 008) Books Computer files Maps Music Serials Visual materials Mixed materials
Seventeen positions in field 008 (positions 18-34) are defined differently in MARC 21 bibliographic records for each of the seven Level I forms of material. Field 008 does not carry any explicit flag identifying the definition of positions 18-34. Instead, the identification of the type of field 008 is dependent on the content of Leader/06 (Type of record) and,in the case of textual material (i.e., when Leader/06 contains value a), the content of Leader/07 (Bibliographic level). The combination of Leader/06 and Leader/07 values determine Level II form of material in MARC 21 bibliographic records. The relationships between Level I designations and Level II are as follows:
Form of Material Level II (Leader/06) Form of Material Level I (field 008) Language material (and any bibliographic Books level except serial or serial compon- ent part) Manuscript language material Books Language material (bibliographic level Serials is for a serial or serial component part only) Projected medium Visual Materials Kit Visual Materials Two-dimensional nonprojectable graphic Visual Materials Three-dimensional artifact or naturally Visual Materials occurring object Mixed material (often an archival Mixed materials collection) Printed music Music Manuscript music Music Nonmusical sound recording Music Musical sound recording Music Cartographic material Maps Manuscript cartographic material Maps Computer file Computer files
Since field 008 is not repeatable and is dependent on the content of Leader/06 and Leader/07 for its definition, only one occurrence of field 008 can be included in a MARC 21 record. Field 008 thus provides coded information about only one aspect of an item. Data concerning additional aspects of a bibliographic item are coded in repeating fields 006.
Field 006 contains the same elements as the part of field 008 that varies for different forms of material (i.e., character positions 18-34). There are seven different configurations of field 006 defined, one for each type of field 008. Since the configuration of field 006 is identified by the content of the first character position of the field, as many occurrences of field 006 may be included in a record as are needed. Most often this would be to record additional information about a non-textual serial or multimedia item.
It should be noted that a third level of material designation is found in MARC 21 bibliographic records in field 007 (Physical Description Fixed Field). The following forms of material are identified in this field:
Form of Material Level III (field 007) Map Computer file Globe Tactile material Projected graphic Microform Nonprojected graphic Motion picture Kit Notated music Remote-sensing image Sound recording Text Videorecording Unspecified
These categories are identified as ones for which information about special physical features need to be recorded. Field 007 is defined differently for each of the Level III forms and uses the first character position to identify the configuration. All types of field 007 may be used with any of the Level I forms, if needed.
In general, the 008 and 006 are regarded as containing "bibliographic" information about a work, while the 007 is regarded as carrying information about the "physical" characteristics of the item. This dichotomy does not hold for all character position definitions, however, and the line between bibliographic and physical is not always clear in some media.
If an item is basically textual: