According to the Anglo-American Cataloguing Rules (AACR2R), a catalogue is a list of materials in a collection. It contains bibliographic descriptions, created in accordance with known and presumably universal rules. A cataloguer obtains information to be used in a bibliographic description from a "chief source of information". With a printed book, this is primarily the the book's "title page" - both its recto (front) and its verso (back). With AACR2R, the units of the bibliographic description were designed with automation in mind from the outset. The units of the description translate directly into "fields" in a book's MAchine Readable Cataloguing (MARC) record (cf. ISO 2709).

For instance, the AACR2R rule 1.1 establishes the "title and statement of responsablity area" of an item's description. This information is eventually encoded in the "245 tag" of a MARC record. The author's name is encoded in a field identified with a numeric tag in the "1xx" range, and information about the publisher and place of publication will be encoded in a "260" tag. Here is a simplified example:
 

Note the "04" before the 245 tag. These are called the "indicator" positions, and in this case, they are being used to tell the indexing software to skip the word "The" and the following space, when indexing the title. The "$a", $b", etc. are called "subfield codes", and they are used to refine the basic tags further. Both tags and subfields can repeat within a record. This makes updating easier, and lends flexibility to the indexing process. For instance, you can index on specific subfield codes, or perform "global" updates more easily when subject terms become obsolete. Subject terms are arrived at "by warrant", based on the way people use terms in everyday language. For instance, the qualifier "Computer network", is no longer needed when we talk about the Internet, so this term could probably be deleted from the description given above.

Standard Generalized Markup Language

Standard Generalized Markup Language (SGML), (cf. ISO 8879), originally developed for the printing trade, has been proposed as an alternative to MARC. SGML has been considered for widespread application in Archives. For more information on SGML and libraries, see related entries in the BUBL Archive at the BUBL Information Service site, Strathclyde University. As well, you should be aware of project Gutenberg, and the Internet Public Library, and similar projects to digitize full-text documents.

Here are some actual MARC records as the computer sees them. Of course, users never see these records in this format - the tags are used to create friendly screens for users, and to define the terms which will be indexed by the system. Most library automation systems index data from the 1xx, 2xx, and 6xx fields - that is authors, titles, and subjects.

Sample MARC Records

00692cam 2200133 i 45 000010019000000080041000190500021000600820012000811100023000 93240002600116245035600142260003500498300002500533| 753002 92 //r844|760609s1844 enk 00000 eng |0 $aBX514 5$b.A4 1844| $a264/.03|20$aChurch of England.|10$aBook of c ommon prayer|04$aThe Book of common prayer and administratio n of the sacraments & other rites & ceremonies of the Church according to the use of the Church of England :$btogether w ith the Psalter or Psalms of David, pointed as they are to b e sung or said in the churches, and the form and manner of m aking, ordaining, and consecrating of bishops, priests, and deacons.|0 $aLondon :$bW. Pickering,$c1844.| $aca. 600 p. ; $c36 cm.|#

01046cam 2200241 i 4500001001800000008004100018 020002400059050002200083082001300105100003100118240002400149 245012300173250001100296260005000307300003600357500004300393 500023000436504003000666500002000696650002500716700003700741 700002600778| 77020468 //r83|780810r1978 nyua b 00110 eng | $a048623617X :$c$7.95|1 $aZ244.A2$bM93 1978| $a686.2/24|10$aMoxon, Joseph,$d1627-1700.|10$aMechanick exer cises|10$aMechanick exercises on the whole art of printing ( 1683-4) /$cby Joseph Moxon ; edited by Herbert Davis & Harry Carter.| $a2d ed.|0 $aNew York :$bDover Publications,$c197 8, c1962.| $alviii, 487 p. :$bill. ;$c24 cm.| $aFolded lea f attached to p. 3 of cover.| $aOriginally reprinted in 195 8 by Oxford University Press, London, from a copy of Mechani ck exercises, vol. II, 1683, in the Bodleian Library (Gibson 200). This ed. represents a reprint of the Oxford Universit y Press second ed.| $aBibliography: p. 409-444.| $aInclude s index.| 0$aPrinting, Practical.|10$aDavis, Herbert John,$d 1893-1967.|10$aCarter, Harry Graham.|#
 

Text Copyright © Christopher Brown-Syed 1995-2002. Disclaimers.