A markup language is a set of annotations to text that describe how it is to be structured, laid out, or formatted. Markup languages might be manuscript form (often marks among or alongside text describing required formatting or binding), or they might be markup codes used in computer typesetting and word-processing systems. The former are also commonly used to describe the required layout of papers, articles, standards, or books. The latter tend more to be used to instantiate a particular document and nowadays are not generally used directly by authors.

A well-known example of a markup language in use today in computing is HyperText Markup Language (HTML), one of the protocols of the World Wide Web. HTML is an instance of SGML and follows many of the markup conventions used in the publishing industry in the communication of printed work between authors, editors, and printers.

History

The term markup is derived from the traditional publishing practice of "marking up"' a manuscript, which involves using a markup language consisting of conventional symbolic printer's instructions in the margins and text of a paper manuscript. For centuries, this task was done primarily by skilled typographers known as "markup men" who marked up text to indicate what typeface, style, and size should be applied to each part, and then passed the manuscript to others for typesetting by hand. Markup was also commonly applied by editors, proofreaders, publishers, and graphic designers.

GenCode

The idea of using markup languages in computer text processing was probably first publicly presented by publishing executive William W. Tunnicliffe at a conference in 1967, although he preferred to call it "generic coding." 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. Book designer Stanley Rice published speculation along similar lines in the late 1960s. Brian Reid, in his 1980 dissertation at Carnegie Mellon University, developed the theory and a working implementation of descriptive markup in actual use.

However, IBM researcher Charles Goldfarb is more commonly seen today as the "father" of markup languages. Goldfarb hit upon the basic idea while working on a primitive document management system intended for law firms in 1969, and helped invent IBM GML later that same year. GML was first publicly disclosed in 1973.

In 1975, Goldfarb moved from Cambridge, Massachusetts to Silicon Valley and became a product planner at the IBM Almaden Research Center. There, he convinced IBM's executives to deploy GML commercially in 1978 as part of IBM's Document Composition Facility product, and it was widely used in business within a few years.

Development informally began in 1978Fact: date=March 2009 on what ultimately became the SGML standard, which was based on both GML and GenCode; Goldfarb eventually became chair of the SGML committee. SGML was first and released by ISO as the ISO 8879 standard in October 1986.