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Terminology… M

Manual Review

Manual Review is a visual examination of authority controlled headings in your bibliographic records. MARS 2.0 Manual Review is performed by experienced MARS 2.0 staff librarians and library technicians, and results in a catalog of records with fewer errors and inconsistencies than machine processing alone can provide. (mpg)


MARC is an acronym, used in the field of library science that stands for MAchine-Readable Cataloging. The MARC standards consist of the MARC formats, which are standards for the representation and communication of bibliographic and related information in machine-readable form, and related documentation. It defines a bibliographic data format that was developed by Henriette Avram at the Library of Congress beginning in the 1960s. It provides the protocol by which computers exchange, use, and interpret bibliographic information. Its data elements make up the foundation of most library catalogs used today. (wp)

MARC 8 format

MARC-8 is based on ISO 2022 and allows the use of Hebrew, Cyrillic, Arabic, Greek, and East Asian scripts. (wp)

MARC-21 Field Conversions

During the automated authority control process there are several areas of the bibliographic record that require more complex changing to the tag or subfield. A number of MARC Update conversions are more complex than simply changing a field tag or subfield code to the current value. Some fields, such as the 007, often need to be added to a record. The special MARC field conversion and additions currently provided are: (mpg)

  • Add missing format data
  • Add missing subfield data
  • Complex field conversions

MARC 21 Format

MARC 21 is a result of the combination of the United States and Canadian MARC formats (USMARC and CAN/MARC). MARC21 is based on the ANSI standard Z39.2, which allows users of different software products to communicate with each other and to exchange data.[4] MARC 21 was designed to redefine the original MARC record format for the 21st century and to make it more accessible to the international community. MARC 21 has formats for the following five types of data: Bibliographic Format, Authority Format, Holdings Format, Community Format, and Classification Data Format.[5] Currently MARC 21 has been implemented successfully by The British Library, the European Institutions and the major library institutions in the United States, and Canada. MARC 21 allows the use of two character sets, either MARC-8 or Unicode encoded as UTF-8. (wp)

MARC delimiter

A character or sequence of characters found in a MARC record marking the beginning or end of a unit of data. Field delimiters separate data fields. Record delimiters separate groups of fields. All records contain the following standard MARC delimiters: (wp, mpg) see also subfield delimiter

  • Record terminators (ACSII 1d16)
  • Field terminators (ASCII 1E16)
  • Subfield delimiters (ASCII 1f16)

MARC Organizational Code

Specific code created for the MARC record to represent an organization. The code can be found in the 040 Tag of the Authority Record. It is used when ever an organization modifies the MARC record. For Backstage it is UtOrBLW. MARC code for or the name of the organization(s) that created the original bibliographic record, assigned MARC content designation and transcribed the record into machine-readable form, or modified (except for the addition of holdings symbols) an existing MARC record. These data and the code in 008/39 (Cataloging source) specify the parties responsible for the bibliographic record. See Appendix I: Organization Code Sources for a listing of sources used in MARC 21 records. (m21)


Often referred to as a MARC Field, a MARC tag is a string of data prefaced by a three digit number. It represents a unique part of the bibliographic record. For example, all 100 tags are the personal name of the author of a works. There are 999 possible MARC tags, many of which have been established by the library of congress as fields in the various MARC formats. (ac)


MARS is an acronym for MARC Record Service (MARS). It is automated authority control software originally created by WLN (Western Library Network) in 1989. In 2004 Backstage Library Works partnered with OCLC for the purchase of the OCLC MARS Authority Control services. The MARS software, databases, client files, profiles, and other MARS components were successfully transferred to Backstage Library Work’s care over a six month period, including several months of parallel processing on both OCLC and BSLW systems. In 2008 Backstage Library Works enhanced the software making it compatible with new technology. The current version of the software is called MARS 2.0. (mpg)

MARS Master Authority File

MARS 2.0 maintains a Master Authority File for each institution that has been supported by any of the MARS 2.0 Authority Control services. A library’s MARS 2.0 Master Authority File can actually consist of a number of separate authority files, based on the profile options selected by the library: (mpg)

  • National-level authority records (separate files for LC, MeSH, NLC, etc.)
  • Locally generated records that conflict with LC practices, but are required for your catalog
  • Locally generated records to be replaced by national-level records
  • National-level authority records with local tags & subfields to be merged with updates in national records
  • MARS 2.0 unmatched heading records for all bibliographic headings that did not fully match a national-level authority record during the MARS 2.0 Authority Control processing of your bibliographic records

MARS Authority Control Profiles

A quick reference or set of instructions the automated authority control client fills out to determine how they would like the MARS 2.0 software to process their data. There are six steps/profiles in all that cover the following. (mpg)

  • Step 1 Database
  • Step 2 Cleanup
  • Step 3 Matching
  • Step 4 Output
  • Step 5 Reports
  • Step 6 Ongoing

MARS stamp

The text MARS can be added in a subfield $a in a field you specify, for example a 945 field. MARS 2.0 programs can stamp each bibliographic record with one or all of the following identifiers or only stamp those bibliographic records that were changed during the MARS 2.0 process. (MPG)

040 $d "UtOrBLW

MARS Stamp

Leader byte 23 "M"

Update/Add 005 Field with date and time stamp

Other that library specifies.

Medical Headings

see MeSH


see Local Authority Field Merge

MeSH National Library of Medicine Authority File

Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed article database and by NLM’s catalog of book holdings. MeSH can be browsed and downloaded free of charge on the Internet. The yearly printed version was discontinued in 2007. (wp) The current MeSH authority file contains just over 580,000 authority records for descriptors, qualifiers, and descriptor/qualifier combinations. Over 300,000 new and updated authority records are issued by NLM in the MeSH annual update. (mpg)


Metadata (meta data) is "data about data", of any sort in any media. An item of metadata may describe an individual datum, or content item, or a collection of data including multiple content items and hierarchical levels, for example a database schema. Metadata provides context for data. Metadata is used to facilitate the understanding, characteristics, and management usage of data. (wp)

Model Heading

See Pattern heading. (lchspa)

Multiple matches

On occasion multiple matches occur when the normalized version of the heading matches two or more national authority records. When this happens the MARS 2.0 software will not replace the bib heading with any of the matches. The program cannot know which one to take over the others and so the bib heading remains unchanged. The multiple potential authority matches will be reported to the user in an optional report R10 - Heading Matches Established Headings in Multiple Authority Records. (mpg)