EAD Application Guidelines for Version 1.0

Appendix F: Glossary

Attribute: Named properties of an element that may carry different values depending upon the context in which they occur. Attributes modify the meaning of the elements to which they apply. Examples of some EAD attributes include STATUS, LEVEL, and TYPE. Several attributes are available to effect character rendering, such as RENDER. Most EAD attributes are optional.

Authoring Software: Computer programs that assist in inserting, reading, and editing SGML tags. Sophisticated authoring software also can enforce the rules of a DTD. See also Parser.

Cascading Style Sheets (CSS): A style language that can control the appearance of HTML and XML documents by defining display features such as font types, color and size, as well as text formatting features such as indentions, margins, and tabular presentation. See also Stylesheet.

Case Sensitivity: A characteristic of computer software that considers the case of alphabetic characters to be significant. For example, a case sensitive search engine would not retrieve the character string "Encoding" if the search was entered as "encoding". In XML, tags are case-sensitive, and so all EAD tag names must be entered in lower case.

CDATA: See Character Data (CDATA).

Character Data (CDATA): Characters that appear in a part of an SGML document in which text is not parsed and markup is not recognized. This includes the values of an attribute whose content has been defined in a DTD as being character data, or the contents of a marked CDATA section of a document-one that has been delimited and identified as character data. CDATA is useful when it is desirable to pass data to an application without having to deal with the character set issues that would be introduced by parsing, such as when computer code is included within the text of a document. The XML specification uses the expression "character data" in a more general and slightly different way than SGML when it states that "All text that is not markup constitutes the character data of the document." See also Parsable Character Data (PCDATA).

Computing Platform: The type of computer hardware and software (the operating system and applications) being used, e.g., DOS/Windows, Macintosh, UNIX.

Content Model: In SGML, defines the structure of and types of elements and subelements contained within a DTD.

Convention: An agreed-upon usage, for example, of a term.

Default Values: Values that are supplied automatically by the system if the encoder of the finding aid does not specify an alternative value.

Document Element: The highest-level element in a DTD. In EAD, <ead> is the document element. (The term "root element" is sometimes used to refer to the document element, but this is incorrect SGML usage.)

Document Instance: See Instance.

Document Style Semantics and Specification Language (DSSSL): A language for preparing stylesheets that may be used to specify the formatting of SGML documents or transform them into other formats. An international standard (ISO/IEC 10179:1996). See also Stylesheet.

Document Type Declaration: Provides technical information to SGML authoring and publishing software about how the DTD and encoded document will use SGML.

Document Type Definition (DTD): The formal specifications and definitions of the structural elements and markup to be used in encoding specific types of documents in SGML.

DSSSL: See Document Style Semantics and Specification Language (DSSSL).

EAD Instance: See Instance.

Editing Software: See Authoring Software.

Element: A component of the structure defined by a Document Type Definition, identified in a document instance by descriptive markup, usually a start-tag <...> and an end-tag </...>.

Element Name: The full descriptive name given to each SGML element, e.g. Date of the Unit. See also Tag Name.

Empty Element: An element that contains neither PCDATA nor other elements.

Entity: An SGML convention that allows an encoder to specify in a Document Type Definition or in the Declaration Subset of an SGML instance an abbreviated name that serves as a substitute in the instance for something else, such as a block of boilerplate text, another document, or an image file.

Extensible Markup Language (XML): A simplified subset of SGML designed so that generic SGML might be served, received, and processed on the World Wide Web in the same way as HTML. XML retains the sophisticated data structuring and validation of SGML, while eliminating many of the options that complicate the development of SGML viewers.

Extensible Style Language (XSL): A language for expressing stylesheets which may be used to transform XML documents into other formats or to display XML documents in XML-capable browsers. See also Stylesheet.

Formal Public Identifier (FPI): A text string that serves as a structured citation to an SGML object such as an entity, a DTD, or an element. An FPI includes the name of its owner, the class of objects to which the associated item belongs (e.g., DTD, entity), an arbitrary description of the object, its language, and, optionally, its version. Public identifiers contrast with system identifiers that identify an SGML object by citing a system-specific characteristic, such as a URL or a file name that physically locates the object in a file storage system.

Formatting Elements: Generic elements that affect a document's appearance, such as Paragraph <p>, Emphasis (which carries the RENDER attribute for specifying display characteristics such as boldface or italics) <emph>, and Line Break <lb>.

Header: A set of SGML elements, such as the EAD Header <eadheader>, which record documentation (or "metadata") about the text itself and its encoding. May also refer to text encoded to appear at the top of each page of a document. Do not confuse with the EAD element Heading <head>, which is used to supply a heading for a block of text.

HTML: See HyperText Markup Language (HTML).

Hyperlink: Linking elements that provide nonlinear ways to move around and between digital documents, or to link to related objects such as image or audio files. See also Linking Elements.

HyperText Markup Language (HTML): An SGML-derived markup language used to create documents for World Wide Web applications. HTML encoding effects principally layout and visual representation, not intellectual or hierarchical aspects of document structure, such as those in EAD.

Instance: The text and tags (excluding the DTD and related files) of an individual SGML-encoded document, such as a single EAD-encoded finding aid. See also SGML Document.

International Standards Organization (ISO): The preeminent international standards-setting body, made up of representatives from countries worldwide, that oversees the development and ratification of many telecommunications and information-related standards.

Internet: A global "network of networks" originally developed by the U.S. Department of Defense and used predominantly for academic and research activities. Today it is also used for commerce, entertainment, and social and community interaction, much of which takes place on the World Wide Web, a service that is delivered via the Internet.

Legacy Data: Finding aids created prior to implementation of EAD. Such finding aids often must be restructured to some degree in order to fit within EAD's hierarchical structure and set of data elements.

Linking Elements: Elements that enable the creation of hypertext links within an SGML instance or from SGML instances to other digital objects. See also Hyperlink.

Markup Language: A formal way of annotating a document or collection of digital data in order to indicate the structure of the document or datafile and the contents of its data elements. This markup also serves to provide a computer with information about how to process and display marked-up documents.

Metalanguage: A set of rules that formally describes the syntax of a markup scheme. SGML is an example of a metalanguage, or in other words, it is a set of rules for establishing markup languages.

Multimedia: Digital materials, documents, or products, such as World Wide Web pages or CD-ROMs, that utilize any combination of text, numeric data, still and moving images, animation, sound, and graphics.

Nesting: The way in which SGML subelements may be contained within other elements to create a multilevel document. See also Recursion.

Paragraph: The basic unit of text within an SGML document.

Parent Element: An element that may contain other elements, referred to as subelements of the parent element. See also Subelement.

Parser: A computer program that checks any encoded document that begins with an SGML declaration to determine whether the SGML tagging being used by the document conforms with the tagging allowed by the DTD that has been declared. Sometimes referred to as a conforming or validating SGML parser. In XML, applications that provide this functionality are referred to as XML validators.

Parsable Character Data (PCDATA): Characters that appear in a part of an SGML document in which text is parsed and markup is recognized and which, having been parsed, are determined not to be markup. In virtually all cases, the text of an encoded finding aid consists of PCDATA. See also Character Data (CDATA).

PCDATA: See Parsable Character Data (PCDATA).

Perl: An interpreted programming language that is supported on many computer platforms and that commonly is used for developing special scripts for manipulating text for World Wide Web applications.

Plain Text: Text encoded in the ASCII format. As such, it is software independent and can be imported, read, and exported by virtually every software application.

Platform: See Computing Platform.

Prolog: The document prolog precedes the markup of an SGML instance and consists of the SGML declaration, (optional for SGML), an XML declaration (required if the instance is encoded in XML), and the document type (DOCTYPE) declaration, which may contain a DTD represented by a formal public identifier, or by a system identifier, or both.

Public Identifier: See Formal Public Identifier (FPI).

Recursion: Recursion refers to SGML elements that may contain one or more instances of themselves. See also Nesting.

Render: To reproduce or display encoded data in a specified manner.

Root Element: See Document Element.

Script: A program written in an interpreted programming language such as Perl. Also a term for a macro or batch file, in which a list of commands can be executed without user interaction.

SGML Declaration: A formal, standardized set of constructs that informs a computer as to which character set, delimiters and SGML features are being used in an SGML instance.

SGML Document: A sequence of data and markup characters that contains an optional SGML declaration, followed by the DTD that is being used, followed by an encoded document instance that conforms to the specifications of that DTD. See also Instance.

Standard Generalized Markup Language (SGML): An ISO standard (ISO 8879), first used by the publishing industry, for defining, specifying, and creating digital documents that can be delivered, displayed, linked, and manipulated in a system-independent manner.

Stylesheet: An ASCII text document that is attached to an SGML or XML encoded document and that contains instructions to specify the formatting and display of the encoded document, or to transform it into another format. See also Cascading Style Sheets (CSS); Document Style Semantics and Specification Language (DSSSL); Extensible Style Language (XSL).

Subelement: An element that is available within one or more other elements. In EAD, every element except the document element <ead> is a subelement of one or more parent elements. See also Parent Element.

System identifier: A character string that identifies an SGML object by citing a system-specific characteristic, such as a URL or a file name that physically locates the object in a file storage system.

Tag Name: A short, informal, mnemonic name used for an SGML element. An element's tag name appears within angle brackets to specify the start-tag and end-tag. For example, <unitdate> is the tag name for the element Date of the Unit. See also Element Name.

Template: A preestablished layout model using word processing or SGML authoring software that ensures that data entered into it will adhere to a consistent format and content scheme.

Text Encoding Initiative (TEI): An international cooperative effort to develop generic guidelines for a standard encoding scheme for scholarly texts.

Uniform Resource Identifier (URI): A string, structured according to the syntax of Internet Engineering Task Force RFC 2396, that identifies a resource on the Internet such as a file, a downloadable document, or an image. There are two classes of URIs: those that identify by specifying location (Uniform Resource Locators) and those that do so by naming the resource (Uniform Resource Names), such as purls (persistent URLs). See also Uniform Resource Locator.

Uniform Resource Locator (URL): A string, structured according to the syntax of Internet Engineering Task Force RFC 1738, that specifies the location of a resource on the Internet such as a file, an image or a downloadable document. A URL includes the type of naming scheme employed (http, ftp, telnet, news, file, etc.), a separating colon, the location of the host, and a path to the resource. URLs may be either absolute (containing the entire address of the resource) or relative (containing only a part of the address). Partial addresses may be used as long as the processing agent is able to resolve the full locations based on their context. Relative URLs enable terseness in documentation and the dynamic generation of links; they also minimize referential problems that may occur when hierarchical naming systems or file locations are modified.

Wrapper Element: An element designed only as a container for other elements. Wrapper elements may have attributes but must contain one or more subelements in order to include text.

XLink (XML Linking Language): Specifies constructs that may be inserted into XML resources to describe links between objects. XLink uses XML syntax to create structures that can describe the simple unidirectional hyperlinks of HTML as well as more sophisticated multidirectional links.

XML: See Extensible Markup Language (XML).

XML Linking Language: See XLink (XML Linking Language).

XSL: See Extensible Style Language (XSL).

Table of Contents
Home Page Preface Acknowledgments How to Use
This Manual
Setting EAD
in Context
Creating Finding
Aids in EAD
Authoring EAD
Publishing EAD
EAD Linking

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Copyright Society of American Archivists, 1999.
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