Sustainability of Digital Formats: Planning for Library of Congress Collections

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XML (Extensible Markup Language) 1.0

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name Extensible Markup Language (XML) 1.0
Description Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML (ISO 8879). See XML. Version 1.0 is a W3C Recommendation. As of March 2008, XML 1.0 is based on Unicode, Version 2.
Production phase Can be used as initial, middle, or final-state format.
Relationship to other formats
    Has later version XML_1_1, XML (Extensible Markup Language) 1.1
    Subtype of XML, Extensible Markup Language
    Contains Unicode, Version 2. Not described here. See Unicode 2.0.0 (July, 1996).

Local use Explanation of format description terms

LC experience or existing holdings See XML.
LC preference See XML.

Sustainability factors Explanation of format description terms

Disclosure Open standard. Developed by W3C (World Wide Web Consortium). See XML.
    Documentation Maintained by W3C []. As of March 2008, the latest edition is Extensible Markup Language (XML) 1.0 (Fourth Edition). See Notes below.
Adoption See XML.
    Licensing and patents None
Transparency See XML.
Self-documentation See XML.
External dependencies None
Technical protection considerations None

Quality and functionality factors Explanation of format description terms

Normal rendering See XML.
Integrity of document structure See XML.
Integrity of layout and display See XML.
Support for mathematics, formulae, etc. See XML.
Functionality beyond normal rendering See XML.

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension xml
Common practice for XML document instances is to use the .xml extension. The particular schema or DTD should be declared within the document. Some schemas specify the use of different file extensions.
Internet Media Type See related format.  See XML.
Magic numbers See related format.  See XML.

Notes Explanation of format description terms

History Several editions of the XML 1.0 specification have been published as W3C Recommendations. The underlying specification has not changed. The first edition of XML 1.0 became a W3C recommendation in February 1998. See The second edition, released in October 2000, incorporated the changes dictated by the first-edition errata. The third edition was released in February 2004. This integrated changes dictated by errata and also introduced markup on a significant portion of the prescriptions of the specification, clarifying when prescriptive keywords such as MUST, SHOULD and MAY are used in the formal sense defined in IETF RFC 2119. In the fourth edition, released in August 2006, this markup was modified to better match the intent of IETF RFC 2119 and to integrate changes dictated by errata.

XML 1.1, originally released in February 2004, updated XML 1.0 so that it no longer depends on a specific Unicode version: the latest version can always be used. It also adds checking of normalization, and follows the Unicode line ending rules more closely. Authors are encouraged to generate XML 1.0 documents if the added flexibility is not required. XML Parsers are expected to understand both XML 1.0 and XML 1.1.

Format specifications Explanation of format description terms

Useful references


Last Updated: 02/22/2017