What is a DVI file?

A DVI file (that is, a file with the type or extension .dvi) is TeX’s main output file, when we use “original” TeX (later TeX systems, such as PDFTeX — see PDFTeX may use other formats).

‘DVI’ is supposed to be an acronym for DeVice-Independent, meaning that the file can be processed for printing or viewing on most kinds of typographic output device or display. The DVI file may be processed by a DVI driver to produce further output designed specifically for a particular printer, or it may be used by a previewer for display on a computer screen. DVI files use an internal coding designed for TeX; 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).

dvitype
systems/knuth/dist/texware/dvitype.web

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=dvi