It was formally defined as such by the Internet Engineering Task Force ( IETF ) with the mid-1993 publication of the first proposal for an HTML specification: " Hypertext Markup Language ( HTML )" Internet-Draft by Berners-Lee and Dan Connolly, which included an SGML Document Type Definition to define the grammar.

In the 1970s, Tunnicliffe led the development of a standard called GenCode for the publishing industry and later was the first chair of the International Organization for Standardization committee that created SGML, the first standard descriptive markup language.

SGML, which was based on both GML and GenCode, was developed by Goldfarb in 1974.

SGML was promulgated as an International Standard by International Organization for Standardization, ISO 8879, in 1986.

For example, SGML made end tags ( or start-tags, or even both ) optional in certain contexts, because it was thought that markup would be done manually by overworked support staff who would appreciate saving keystrokes.

Steven DeRose argues that HTML's use of descriptive markup ( and SGML in particular ) was a major factor in the success of the Web, because of the flexibility and extensibility that it enabled ( other factors include the notion of URLs and the free distribution of browsers ).

The main purpose of XML was to simplify SGML by focusing on a particular problem — documents on the Internet.

XML adoption was helped because every XML document can be written in such a way that it is also an SGML document, and existing SGML users and software could switch to XML fairly easily.

* Original SGML, which was accepted in October 1986, followed by a minor Technical Corrigendum.

** SGML was reworked in 1998 into XML, a successful profile of SGML.

As a document markup language, SGML was originally designed to enable the sharing of machine-readable large-project documents in government, law, and industry.

SGML also was extensively applied by the military, and the aerospace, technical reference, and industrial publishing industries.

Tag-validity was introduced in SGML ( ENR + WWW ) to support XML which allows documents with no DOCTYPE declaration but which can be parsed without a grammar or documents which have a DOCTYPE declaration that makes no XML Infoset contributions to the document.

SGML validity commentary, especially commentary that was made before 1997 or that is unaware of SGML ( ENR + WWW ), covers type-validity only.

Inspired by the WAIS project on full text databases and emerging SGML projects Z39. 50 version 2 or Z39. 50: 1992 was released.

DocBook originally started out as an SGML application, but an equivalent XML application was developed and has now replaced the SGML one for most uses.

Since DocBook was built originally as an application of SGML, the DTD was the only available schema language.

With the appearance of XML as an alternative to SGML, XML's associated stylesheet language XSL was also widely and rapidly adopted, from around 1999.

OASIS was first formed as SGML Open in 1993 as a trade association of SGML tool vendors to cooperatively promote the adoption of SGML through mainly educational activities, though some amount of technical activity was also pursued including an update of the CALS Table Model specification and specifications for fragment interchange and entity management.

He is known for designing and implementing the REXX programming language ( published in IBM Systems Journal in 1984 ) and the NetRexx programming language ( 1996 – 1997 ), his work on color perception and image processing ( 1982 – 1985 ), the STET folding editor ( 1977 ), the LEXX live parsing editor ( 1985, possibly the first editor with color highlighting ) for the Oxford English Dictionary, electronic publishing, SGML applications, PMGlobe, the IBM Jargon file ( IBMJARG ) through 1990, Java-related languages, the Acorn System 1 simulator,

The project was the first SGML / XML project for the House and Senate and paved the way for the drafting of legislation in XML in both chambers.

In 1974, he designed SGML and subsequently wrote the first SGML parser, ARCSGML.

The first version of the IAFD was brought on-line in 1995 by the programming efforts of Heretic who used the project as a training ground for SGML programming which he was learning in college.

A DTD is associated with an XML or SGML document by means of a Document Type Declaration.

Note that any valid SGML or XML document that references an external subset in its DTD, or whose body contains references to parsed external entities declared in its DTD ( including those declared within its internal subset ), may only be partially parsed but cannot be fully validated by validating SGML or XML parsers in their standalone mode ( this means that these validating parsers will not attempt to retrieve these external entities, and their replacement text will not be accessible ).

( Notations declared in the DTD are also referencing external entities, but these unparsed entities are not needed for the validation of documents in the standalone mode of these parsers: the validation of all external entities referenced by notations is left to the application using the SGML or XML parser ).

SGML allows for public identifiers to be mapped to system identifiers in catalogs that are optionally made available to the URI resolvers used by document parsing software.

Notations are also completely opaque for XML and SGML parsers, so they are not differentiated by the type of the external entity that they may reference ( for these parsers they just have a unique name associated to a public identifier ( an FPI ) and / or a system identifier ( a URI )).

Some applications ( but not XML or SGML parsers themselves ) also allow referencing notations indirectly by naming them in the < tt >" URN: name "</ tt > value of a standard CDATA attribute, everywhere a URI can be specified.

Note also that even in validating SGML or XML 1. 0 or XML 1. 1 parsers, the external entities referenced by an FPI and / or URI in declared notations are not retrieved automatically by the parsers themselves.

Except for the hyperlink tag, these were strongly influenced by SGMLguid, an in-house SGML based documentation format at CERN.

Many of the text elements are found in the 1988 ISO technical report TR 9537 Techniques for using SGML, which in turn covers the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS ( Compatible Time-Sharing System ) operating system: these formatting commands were derived from the commands used by typesetters to manually format documents.

One of the most noticeable differences between HTML and XHTML is the rule that all tags must be closed: empty HTML tags such as < code >< nowiki ></ nowiki ></ code > must either be closed with a regular end-tag, or replaced by a special form: < code >< nowiki > < nowiki >/></ nowiki ></ code > ( the space before the '< code >< nowiki >/</ nowiki ></ code >' on the end tag is optional, but frequently used because it enables some pre-XML Web browsers, and SGML parsers, to accept the tag ).

SGML is part of a trio of enabling ISO standards for electronic documents developed by ISO / IEC JTC1 / SC34 ( ISO / IEC Joint Technical Committee 1, Subcommittee 34 – Document description and processing languages ):

SGML is supported by various technical reports, in particular

A type-valid SGML document is defined by the standard as

DTDs persist in applications which need special publishing characters such as the XML and HTML Character Entity References, which were derived from the larger sets defined as part of the ISO SGML standard effort.

HTML 4 is an SGML application conforming to ISO 8879 – SGML.

The Standard Generalized Markup Language ( ISO 8879: 1986 SGML ) is an ISO-standard technology for defining generalized markup languages for documents.

SGML is an ISO standard: " ISO 8879: 1986 Information processing — Text and office systems — Standard Generalized Markup Language ( SGML )", of which there are three versions:

* SGML ( ISO 8879 )— generalized markup language

* ISO / IEC TR 9573 – Information processing – SGML support facilities – Techniques for using SGML

In this case, the XML counterpart would be the specific empty tag, equivalent to the SGML NET-enabling start-tag, introduced in the TC2 ( International Standard ISO 8879: 1986, Technical Corrigendum 2, November 1999 ).

* ISO 9069: 1988 – Information processing – SGML support facilities – SGML Document Interchange Format ( SDIF )

* ISO / IEC 9070: 1991 – Information technology – SGML support facilities – Registration procedures for public text owner identifiers

He has also contributed to and / or edited numerous computing standards, including ISO ( SGML, COBOL, C, C ++), BSI ( SGML, C ), ANSI ( REXX ), IETF ( HTTP 1. 0 / RFC 1945 ), W3C ( XML Schema ), ECMA ( ECMAScript, C #, CLI ), and IEEE ( 754 decimal floating-point ).

* ISO / IEC 9070 -- Information technology -- SGML support facilities -- Registration procedures for public text owner identifiers.