Machine Readable Cataloging, Automated Cataloging, Computerized Cataloging

1. MARC YOUR
WORDS!
P r e p a r e d B y :
J o l o V a n C l y d e S . A b a t a y o , R L
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MARC 21 is an implementation of the
American national
standard, Information Interchange
Format (ANSI Z39.2) and its
international counterpart, Format for
Information Exchange (ISO 2709).
INTRODUCTION
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3. INTRODUCTION
• These standards specify the requirements for a
generalized interchange format that will
accommodate data describing all forms of
materials susceptible to bibliographic description,
as well as related information such as authority,
classification, community information, and
holdings data.
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4. • The standards present a
generalized structure for
records, but do not
specify the content of
the record and do not,
in general, assign
meaning to tags,
indicators, or data
element identifiers.
• Specification of these
elements are provided by
particular implementations
of the standards.
• The following description
of the MARC 21 record
structure indicates the
specific choices made for
the MARC 21
implementation of the
standards.
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5. DEFINITIONS
Base address of data
• A data element in the leader which
specifies the first octet of the
first variable field in the record and
is equal to the sum of
the lengths of the leader and
the directory, including the field
terminator at the end of the
directory.
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Bibliographic level
A data element in the leader of
bibliographic records which
provides additional information
about the characteristics and
components of the record, and is
used in conjunction with the type
of record data element of the
leader.

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Blank (SP).
• ASCII character 20(hex)
(represented graphically in
MARC 21 documentation as
or #), which is used in
indicators and data elements
containing coded values (and
occurs in data content).
Generally, blank stands for
"undefined," but in some
instances it has been
assigned a meaning. ASCII
name is space.
Character.
• A member of a set of elements
used for organization, control, or
representation of data. In MARC
21 a character may be encoded
using one or more than
one octet, depending on the
character set. All ASCII characters
are encoded using one octet in
the ASCII encoding and the
Unicode UTF-8 encoding, thus a
character is equivalent in length
to an octet when an element's
values are restricted to ASCII.

7. Control field
• A variable field containing
information useful or required
for the processing of the record.
Control fields are
assigned tags beginning with two
zeroes. Control fields with fixed
length data elements are
restricted to ASCII graphics.
Content designation
• The codes and conventions
established explicitly by MARC
21 to identify and further
characterize the data elements
within a record and to support
the manipulation of that data.
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8. Data element
• A defined unit of information.
Data element identifier.
• A one-character code used to
identify individual data elements
within a variable field. The data
element may be any ASCII
lowercase alphabetic, numeric,
or graphic symbol except blank.
Control number
• An ASCII
graphic character string
uniquely associated with
a record by the organization
transmitting the record and
located in a specific variable
field.
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9. Delimiter
• ASCII control character 1F(hex)
(represented graphically in
MARC 21 documentation as or
$), which is combined with a
data element identifier to make
up the subfield code which
precedes each individual data
element within a variable field.
The ASCII name for the delimiter
is unit separator (US).
Data field
• A variable field containing
bibliographic or other data. Data
fields are assigned tags beginning
with characters other than two
zeroes. Data fields contain data in
any MARC 21 character set unless
a field-specific restriction applies.
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10. Encoding level
• A data element in the leader of
authority, bibliographic,
classification, and holdings
records which provides
information about the fullness of
the information and/or content
designation in the record.
Entry.
• A field within the directory which
gives the tag, length and starting
character position of a variable
field.
Directory
• An index to the location of
the variable fields (control
and data) within a record.
The directory consists
of entries.
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11. Field
• A defined character string that
may contain one or more data
elements.
Field terminator (FT)
• ASCII control character 1E(hex)
(represented graphically in
MARC 21 documentation as FT
or ^), which is used to terminate
the directory and each variable
field within a record. ASCII name
for the field terminator is record
separator (RS).
Entry map
• A data element in
the leader which specifies
the structure of
the entries in the directory.
Always set to 4500 in
MARC 21 records.
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12. Fixed field
• A field whose length does not
vary. The term is occasionally
used to refer to variable control
fields, especially those that
contain coded data such as fields
007 or 008.
Indicator.
• A data element associated with a
data field that supplies
additional information about the
field. An indicator may be any
ASCII lowercase alphabetic,
numeric, or blank. Indicators are
not used in control fields.
Fill character
• ASCII graphical vertical bar
( | )(7C(hex)), which fills a
required character position
and has the meaning "no
attempt has been made to
code".
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13. Leader
• A fixed field that occurs at the
beginning of each record and
provides information for the
processing of the record.
Length.
• A measure of the size of a data
element, field, or record and is
expressed in number of octets.
Logical record length.
• A data element in
the leader which contains the
length of the
entire record, including itself and
the record terminator.
Indicator count
• A data element in
the leader which contains the
number positions reserved
for indicators in each
variable data field. The indicator
count is always set to 2 in MARC
21 records.
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14. Record
• A collection of data elements
describing or identifying one or
more units treated as one logical
entity.
Record status
• A data element in
the leader which indicates the
relation of the record to a file
(e.g., new, updated, etc.).
Octet
• A string of 8 bits. In some
cases (e.g., ASCII) each
octet represents
a character; in other cases
(e.g., Unicode) multiple
octets may represent a
character.
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15. Starting character position
• The position, relative to the base
address of data, of the
first octet of the first character in
the variable field referenced by
the entry. The first character of
the first field following
the directory is numbered 0.
Subfield code
• The two-character combination
of a delimiter followed by a data
element identifier. Subfield codes
are not used in control fields.
Record terminator (RT)
• ASCII control character 1D(hex)
(represented graphically in MARC 21
documentation as RT or ), which is
used as the final character of
a record, following the field
terminator of the last data field.
ASCII name for the record terminator
is "group separator" (GS).
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16. Tag
• A three character string used to
identify or label an
associated variable field. The tag
may consist of ASCII numeric
characters (decimal integers 0-9)
and/or ASCII alphabetic
characters (uppercase or
lowercase, but not both).
Type of record.
• A data element in the leader that
with bibliographic level, specifies
the characteristics and defines
the components of the record.
Subfield code length
• A data element in
the leader which contains the
sum of the lengths of
the delimiter and the data
element identifier used in
the record. Always set to 2 in
MARC 21 records.
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17. Variable field
• A field whose length is
determined for each
occurrence by the length of
data comprising that
occurrence. There are two
types of variable fields control
fields and data fields.
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18. THANK YOU SO MUCH!
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