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DATE: December 9, 2015

NAME: Define Subfield $2 and Subfield $0 in Field 753 of the MARC 21 Bibliographic Format

SOURCE: Online Audiovisual Catalogers (OLAC), GAMECIP

SUMMARY: This paper proposes to add $2 (Source of term) and $0 (Authority record control number or standard number) to field 753 (System Details Access to Computer Files).  Subfield $2 will allow the vocabulary used for the terminology in subfields $a (Make and model of machine) and $c (Operating system) to be documented and the subfield $0 (Authority record control number or standard number) would allow the URI of the vocabulary term to be entered.

KEYWORDS: Field 753 (BD); System Details Access to Computer Files (BD); Controlled vocabularies (BD); Subfield $2, in field 753 (BD); Source of term (BD); Subfield $0, in field 753 (BD); Authority record control number or standard number (BD)


12/09/15 – Made available to the MARC community for discussion.

01/10/16 – Results of MARC Advisory Committee discussion: Converted to and approved as a proposal. When the discussion opened with recognition of general support for this paper, the OLAC representative suggested that MAC vote on this as a proposal. Subsequent discussion included a request to clarify that $2 could refer to the source of term for either the make/model of machine or the operating system.  With that agreed upon, the discussion paper was converted to a proposal by MAC and passed unanimously.

03/03/16 - Results of MARC Steering Group review - Agreed with the MAC decision to convert to and approve as a proposal.

Discussion Paper No. 2016-DP06: Define Subfield $2 and Subfield $0 in Field 753


The current definition of field 753 in the Bibliographic format is as follows:

In the Field Definition and Scope, field 753 is described as providing: 

Information on the technical aspects of a computer file and any accompanying material that may be used to select and arrange the record with other records in a printed index.

Used for the type of machine, operating system, and/or programming language. This kind of added entry is assigned according to various cataloging rules to give access to the bibliographic record which otherwise would not be possible and to facilitate the capability of selecting and arranging records for production of printed indexes.

Despite the mention of cataloging rules, no such rules are included in RDA nor in AACR2, where this information is generally entered in a system requirements note (field 538) with other free-text data.  However, from the field definition it is apparent that there has been a desire for some sort of organized access to hardware and software required to run an electronic resource.  While this has become less important for some electronic resources (e.g. texts, videos, etc.) it is still of importance to video games.  Video games historically have been issued in versions for particular gaming platforms (i.e. make and model of machine) or for particular operating systems in games versioned for PC.  Even downloadable games are intended for one or another gaming platform.  This information is crucial for users, who need to match an item to the gaming platform which they have available.  It is also important for library collection and preservation needs (e.g. weeding games for obsolete platforms, assessing hardware needs, etc.).   A controlled vocabulary for this field would make these tasks more efficient.  Libraries have often used this field for video game platforms over the years, but lacking a controlled vocabulary, the terms have been entered inconsistently, discouraging widespread use of the field.

GAMECIP (the GAme MEtadata and CItation Project, a multi-year IMLS-funded joint initiative between the UCSC Library, UCSC Computer Science, and Stanford University Library) is in the process of developing a controlled vocabulary for gaming platforms, available as open linked data (  The MARC Standards Office has assigned a source code for the vocabulary: gcipplatform.


Standardized terminology has been developed for many bibliographic data elements to allow for predictable retrieval. As a controlled vocabulary is being developed for video game platforms, field 753 is the ideal existing MARC field to take advantage of this controlled vocabulary.

The field needs an indication of the source of the vocabulary. This is particularly important because of the use of MARC 21 world-wide. Subfield $2 has been used in other fields for this purpose. Although some fields include a second indicator value 7 to inform the user that the source is recorded in subfield $2, the definition of the second indicator is not needed in this case since no other values would be defined.

The subfield could be defined as follows:

$2 - Source of term
Contains a MARC code that identifies the source of the term used to record the term for the make and model of machine or operating system. The source of the MARC code is the Subject Heading and Term Source Code List that is maintained by the Library of Congress.

Initially a code would be defined at least for the GAMECIP platform vocabulary when a code is available. Additional codes could be added as needed if other vocabularies are developed.


753 ## $a Nintendo Wii $2 gcipplatform

Subfield $2 could be associated with either subfield $a (Make and model of machine) or $c (Operating system).  If there were a controlled vocabulary for programming languages, there is no reason that $2 could not be used for the code for that vocabulary.  However, $2 is not repeatable in other fields and presumably would not be repeatable in this field.  This could lead to ambiguity if a single field 753 included more than one other subfield.  The GAMECIP platform vocabulary includes both hardware platform names and operating systems, but the OLAC Best Practices for Cataloging Video Games using AACR2 and MARC 21 suggests that for PC platforms, only give subfield $c (Operating system) and do not use subfield $a, since modern operating systems work on many makes and models of PC.   The Best Practices also suggest using a separate 753 field for each hardware platform and operating system which is applicable to the resource being cataloged.  Therefore, according to these guidelines, there will be only one subfield in any given 753 field to which the $2 would be applicable; therefore in the immediate future we do not anticipate any ambiguity in the use of $2.

Subfield $0 contains the system control number of the related authority record. The control number or identifier is preceded by the appropriate MARC Organization code (for a related authority record) or the Standard Identifier source code (for a standard identifier scheme), enclosed in parentheses. See MARC Code List for Organizations for a listing of organization codes. Subfield $0 is repeatable for different control numbers or identifiers.

The MARC list of standard identifier source codes also makes provision for recording URIs in subfield $0. The following examples demonstrate the coding of a URI in relation to an LCSH heading and an RDA vocabulary value:

650 #0 $a Courtship $v Fiction $0 (uri)

344 ## $a analog $0 (uri)

Adding subfield $0 to field 753 would allow the same functionality in this field.


The following example sets illustrate the use of subfield $2 as a means of recording Source of the term for the make and model of machine or operating system and subfield $0 as a means of recording URIs for controlled terms which relate the make and model of machine and operating system.  Either one or the other or both fields could be used but both are illustrated in these examples.

Example 1

753 ## $a Sony PlayStation 4  $0 (uri)   $2 gcipplatform

Example 2:  Compatible with two gaming platforms

753  ## $a Nintendo Game Boy Advance  $0 (uri)   $2 gcipplatform

753 ## $a Nintendo DS  $0 (uri) $2 gcipplatform

Example 3: PC/MAC game compatible with multiple operating systems

753  ## $c Microsoft Windows XP  $0 (uri) $2 gcipplatform

753 ## $c Microsoft Windows Vista  $0 (uri) $2 gcipplatform

753  ## $c Microsoft Windows 7  $0 (uri) $2 gcipplatform

753 ## $c Microsoft Windows 8  $0 (uri) $2 gcipplatform

753 ## $c Apple Mac OS X 10.8  $0 (uri) $2 gcipplatform

753  ## $c Apple Mac OS X 10.9  $0 (uri) $2 gcipplatform


As yet BIBFRAME has no explicit element corresponding to MARC field 753.  Assuming one is developed or borrowed from another schema, it would be desirable to indicate the source of the vocabulary.  The inclusion of an identifier in $0 is highly desirable for BIBFRAME when converting MARC data. 


5.1. Is the definition of subfield $2 (Source of term) in field 753 a desirable solution to document the vocabulary used for the terminology used in the field's subfield $a (Make and model of machine) and $c (Operating system)?

5.2. Is defining subfield $0 (Authority record control number or standard number) in field 753 a desirable solution for recording the URI of the vocabulary term being recorded? We are aware that not all questions on the handling of URIs in $0 have been settled; we would assume that whatever practices for $0 are decided for other fields, the same practices would apply to this field.

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