This page is for the TeX output file. For the video format see HDMI.
A DVI file (that is, a file with the type or extension .dvi) is TeX’s main output file, using TeX in its broadest sense to include LaTeX, etc. ‘DVI’ is supposed to be an acronym for DeVice-Independent, meaning that the file can be printed on most kinds of typographic output device.
DVI files use TeX’s internal coding; a TeX input file should produce the same DVI file regardless of which implementation of TeX is used to produce it. A DVI file contains all the information that is needed for printing or previewing except for the actual bitmaps or outlines of fonts, and possibly material to be introduced by means of special commands. The canonical reference for the structure of a DVI file is the source of Knuth’s program dvitype (whose original purpose, as its name implies, was to view the content of a DVI file).
TeX is a typesetting system written by Donald E. Knuth, who says in the Preface to his book on TeX (see books about TeX) that it is “intended for the creation of beautiful books — and especially for books that contain a lot of mathematics”. The input file for TeX usually has a .TeX extension.
Knuth is Emeritus Professor of the Art of Computer Programming at Stanford University in California, USA. Knuth developed the first version of TeX in 1978 to deal with revisions to his series “the Art of Computer Programming”. The idea proved popular and Knuth produced a second version (in 1982) which is the basis of what is in use today.
Knuth developed a system of ‘literate programming’ to write TeX, and he provides the literate (WEB) source of TeX free of charge, together with tools for processing the web source into something that can be compiled and something that can be printed; there’s never any mystery about what TeX does. Furthermore, the WEB system provides mechanisms to port TeX to new operating systems and computers; and in order that one may have some confidence in the ports, Knuth supplied a test by means of which one may judge the fidelity of a TeX system. TeX and its documents are therefore highly portable.
TeX is a macro processor, and offers its users a powerful programming capability. For this reason, TeX on its own is a pretty difficult beast to deal with, so Knuth provided a package of macros for use with TeX called Plain TeX; Plain TeX is effectively the minimum set of macros one can usefully employ with TeX, together with some demonstration versions of higher-level commands (the latter are better regarded as models than used as-is). When people say they’re “programming in TeX”, they usually mean they’re programming in Plain TeX.
See also LaTeX#TeX
LaTeX is a TeX macro package, originally written by Leslie Lamport, that provides a document processing system. LaTeX allows markup to describe the structure of a document, so that the user need not think about presentation. By using document classes and add-on packages, the same document can be produced in a variety of different layouts.
Both LaTeX and TeX (pronounced 'lay-tech' and 'tech' respectively) are typesetting languages that are compiled to produce PostScript or PDF output. TeX is the original language, and LaTeX is a suite of macro add-ons that have become the defacto "standard", and both are oriented primarily towards typesetting of mathematics into print. Any academic journal in mathematics or the physical science with many equations will not only accept articles written in LaTex, but will usually provide style files which will automatically typeset the document into the exact style specifications required by that journal with no additional work by the author other than including that style file.