Posts Tagged ‘Structure’

Understanding the MARC Structure

Monday, March 16th, 2009

Underneath the MARC records that we all know and love is a somewhat cryptic structure that tells our systems how to read the record. Luckily, this structure rarely gets corrupted, but when it does, it’s good to have a basic understanding of how to read and understand a MARC Format.

The MARC format is a text based format, meaning you can open it with a text editor. It is probably a good idea to only open a few (or only one!) record in a text editor, because it’s very difficult to read otherwise.

Every MARC record starts with a leader, the leader gives your system information about the record, including how big it is and what type of a record it is. Next is what is called a directory. Just like a normal directory, it tells you what tags are in it, and where the data for each tag is located.

This is how a leader is defined for a Bibliographic Record:

Leader: 

Position | Description              | Explination
------------------------------------------
00-04 | Record Length               = This is how long the record is
05    | Record Status               = Is the record new, changed or deleted
06    | Type of record              = Authority, Book, Computer file, etc.
07    | Bibliographic level         = Monograph/Serial/etc.
08    | Type of control             = Archival or not
09    | Character coding scheme     = MARC8 or UTF8
10    | Indicator count             = # of indicators each tag has
11    | Subfield code count         = # of subfield codes that make up 1 subfield
12-16 | Base address of data        = The byte where actual record data begins
17    | Encoding level              = Level of encoding/cataloging
18    | Descriptive cataloging form = AACR2
19    | Multipart resource record level = # (blank)
20    | Length of the length-of-field = # of bytes to store how long each tag is
21    | Length of the starting-character-position = # of bytes to store where tag begins
22    | Length of the implementation-defined portion = Rarely used
23    | Undefined                   = Not used

Looking at a leader can be confusing, but it’s also the only way to find some problems.

Here is an example record, as it may appear on your screen:
001 __ 3180021
005 __ 20050216201852.0
008 __ 040805s2005    nyu      b    001 0 eng 
010 __ ▼a  2004018260
020 __ ▼a0415971675 (alk. paper)
035 __ ▼a(DLC)  2004018260
040 __ ▼aDLC▼cDLC▼dDLC▼dCaONFJC▼dOrLoB-B
043 __ ▼an-us—
050 00 ▼aPS374.H56▼bO73 2004
082 00 ▼a813/.5409358▼222
090 __ ▼aPS374.H56▼bO73 2005
100 1_ ▼aOrbán, Katalin.
245 10 ▼aEthical diversions :▼bthe post-holocaust narratives of Pynchon, Abish, DeLillo, and Spiegelman /▼cKatalin Orbán.
260 __ ▼aNew York :▼bRoutledge,▼c2005.
300 __ ▼aix, 209 p. ;▼c24 cm.
440 _0 ▼aLiterary criticism and cultural theory
504 __ ▼aIncludes bibliographical references (p. 193-205) and index.
505 00 ▼gCh. 1.▼t”Mauschwitz” : monsters, memory, and testimony — ▼gCh. 2.▼tFamiliarity and forgetfulness in Walter Abish’s fiction — ▼gCh. 3.▼tPinpricks on the Ars(e) Narrandi : liminality and oven-games in Gravity’s rainbow.
600 10 ▼aPynchon, Thomas▼xKnowledge▼xHolocaust, Jewish (1939-1945)
600 10 ▼aSpiegelman, Art▼xKnowledge▼xHolocaust, Jewish (1939-1945)
600 10 ▼aAbish, Walter▼xKnowledge▼xHolocaust, Jewish (1939-1945)
600 10 ▼aDeLillo, Don▼xKnowledge▼xHolocaust, Jewish (1939-1945)
650 _0 ▼aAmerican fiction▼y20th century▼xHistory and criticism.
650 _0 ▼aHolocaust, Jewish (1939-1945), in literature.
650 _0 ▼aJudaism and literature▼zUnited States▼xHistory▼y20th century.
650 _0 ▼aWorld War, 1939-1945▼zUnited States▼xLiterature and the war.
650 _0 ▼aEthics in literature.
650 _0 ▼aJews in literature.
852 0_ ▼bkr▼hPS374.H56▼iO73 2005
856 41 ▼3Table of contents▼uhttp://www.loc.gov/catdir/toc/ecip0421/2004018260.html
949 __ ▼aApproval▼b1628024-35▼c67.20▼d1▼i20027328▼jUSD▼tBook

Now, if we are to take a look at the actual MARC structure, it looks like this (when looking at an underlying MARC record, you may not be able to see all of the special characters like end of field and end of record marks, but they are there):

01872cam a2200397 a 450000100080000000500170000800800410002501000170006602000280008303500220011104000360013304300120016905000240018108200

210020509000240022610000210025024501180027126000340038930000250042344000430044850400640049150502240055560000620077960000

620084160000600090360000590096365000590102265000500108165000660113165000650119765000260126265000240128885200280131285600

7801340949005601418318002120050216201852.0040805s2005    nyu      b    001 0 eng    a  2004018260  a0415971675 (alk. paper)  a(DLC)  2004018260  aDLCcDLCdDLCdCaONFJCdOrLoB-B  an-us—00aPS374.H56bO73 200400a813/.5409358222  aPS374.H56bO73 20051 aOrbán, Katalin.10aEthical diversions :bthe post-holocaust narratives of Pynchon, Abish, DeLillo, and Spiegelman /cKatalin Orbán.  aNew York :bRoutledge,c2005.  aix, 209 p. ;c24 cm. 0aLiterary criticism and cultural theory  aIncludes bibliographical references (p. 193-205) and index.00gCh. 1.t”Mauschwitz” : monsters, memory, and testimony — gCh. 2.tFamiliarity and forgetfulness in Walter Abish’s fiction — gCh. 3.tPinpricks on the Ars(e) Narrandi : liminality and oven-games in Gravity’s rainbow.10aPynchon, ThomasxKnowledgexHolocaust, Jewish (1939-1945)10aSpiegelman, ArtxKnowledgexHolocaust, Jewish (1939-1945)10aAbish, WalterxKnowledgexHolocaust, Jewish (1939-1945)10aDeLillo, DonxKnowledgexHolocaust, Jewish (1939-1945) 0aAmerican fictiony20th centuryxHistory and criticism. 0aHolocaust, Jewish (1939-1945), in literature. 0aJudaism and literaturezUnited StatesxHistoryy20th century. 0aWorld War, 1939-1945zUnited StatesxLiterature and the war. 0aEthics in literature. 0aJews in literature.0 bkrhPS374.H56iO73 2005413Table of contentsuhttp://www.loc.gov/catdir/toc/ecip0421/2004018260.html  aApprovalb1628024-35c67.20d1i20027328jUSDtBook

And here is a sample analysis of this record:

Leader: 

Position | Description              | Data
------------------------------------------
00-04 | Record Length               = 01872 : confirmend in a hex editor the record is this length
05    | Record Status               = c
06    | Type of record              = a
07    | Bibliographic level         = m
08    | Type of control             = # (blank)
09    | Character coding scheme     = a
10    | Indicator count             = 2
11    | Subfield code count         = 2
12-16 | Base address of data        = 00397 : confirmed in hex editor this is correct
17    | Encoding level              = # (blank)
18    | Descriptive cataloging form = a
19    | Multipart resource record level = # (blank)
20    | Length of the length-of-field portion = 4
21    | Length of the starting-character-position portion = 5
22    | Length of the implementation-defined portion = 0
23    | Undefined                   = 0
Directory: 

Tag | Field length | Starting character position
001 0008 00000
005 0017 00008
008 0041 00025
010 0017 00066
020 0028 00083
035 0022 00111
040 0036 00133
043 0012 00169
050 0024 00181
082 0021 00205
090 0024 00226
100 0021 00250
245 0118 00271
260 0034 00389
300 0025 00423
440 0043 00448
504 0064 00491
505 0224 00555
600 0062 00779
600 0062 00841
600 0060 00903
600 0059 00963
650 0059 01022
650 0050 01081
650 0066 01131
650 0065 01197
650 0026 01262
650 0024 01288
852 0028 01312
856 0078 01340
949 0056 01418| (56+1418 = 1474) 1474 = Ending field terminator below

Fields:
(For our convenience in readin the record we have replaced certain non-displayed fields with graphical representations)
| = field terminator (also used to terminate the directory)
$ = subfield code delimiter
^ = record terminator
_ = utf8 characters have been replaced by an undersore so the postions line up in a non-hex display

3180021|20050216201852.0|040805s2005    nyu      b    001 0 eng  |  $a  2004018260|  $a0415971675 (alk. paper)|  $a(DLC)  2004018260|  $aDLC$cDLC$dDLC$dCaONFJC$dOrLoB-B|  $an-us—|00$aPS374.H56$bO73 2004|00$a813/.5409358$222|  $aPS374.H56$bO73 2005|1 $aOrb__n, Katalin.|10$aEthical diversions :$bthe post-holocaust narratives of Pynchon, Abish, DeLillo, and Spiegelman /$cKatalin Orb__n.|  $aNew York :$bRoutledge,$c2005.|  $aix, 209 p. ;$c24 cm.| 0$aLiterary criticism and cultural theory|  $aIncludes bibliographical references (p. 193-205) and index.|00$gCh. 1.$t”Mauschwitz” : monsters, memory, and testimony — $gCh. 2.$tFamiliarity and forgetfulness in Walter Abish’s fiction — $gCh. 3.$tPinpricks on the Ars(e) Narrandi : liminality and oven-games in Gravity’s rainbow.|10$aPynchon, Thomas$xKnowledge$xHolocaust, Jewish (1939-1945)|10$aSpiegelman, Art$xKnowledge$xHolocaust, Jewish (1939-1945)|10$aAbish, Walter$xKnowledge$xHolocaust, Jewish (1939-1945)|10$aDeLillo, Don$xKnowledge$xHolocaust, Jewish (1939-1945)| 0$aAmerican fiction$y20th century$xHistory and criticism.| 0$aHolocaust, Jewish (1939-1945), in literature.| 0$aJudaism and literature$zUnited States$xHistory$y20th century.| 0$aWorld War, 1939-1945$zUnited States$xLiterature and the war.| 0$aEthics in literature.| 0$aJews in literature.|0 $bkr$hPS374.H56$iO73 2005|41$3Table of contents$uhttp://www.loc.gov/catdir/toc/ecip0421/2004018260.html|  $aApproval$b1628024-35$c67.20$d1$i20027328$jUSD$tBook|^

Ending field terminator    = 1474
Record terminator position = 1475

Summary
———————————
Ending field position = 1475
Base address of data  = 397

1475 + 397 = 1872 (Record Length)