Saturday, March 8, 2014
Additional information on use of $b in fields 336-338
Library of Congress has begun supplying $b codes for the equivalent terms in $a of fields 336 (Content type), 337 (Media type), and 338 (Carrier type). This is the most efficient manner to start populating a subfield that LC initially chose not to apply. This will allow LC records to conform more to records produced outside of LC (e.g., OCLC generally adds the codes in $b in new records). It will be supplied automatically if cataloger are using the macro or the RDA templates in Voyager—staff are not expected to manually add $b to fields in existing records that lack the subfield.
[Source : Library of Congress]