# Welcome to the UK List of TeX Frequently Asked Questions on the Web

## What is a DVI file?

A DVI file (that is, a file with the type or extension `.dvi`) is the main output file of “original” TeX; later TeX-like systems, such as PDFTeX may use other formats.

\xetex (released some time after PDFTeX) uses an “extended DVI format” (XDV) to send its output to its close-coupled DVI driver, xdvipdfmx.

‘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. The character encoding of a DVI file is determined by the document itself — see “what are encodings” for an explanation of encodings. 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 any 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). A partially complete “standard” for the way they should be processed may offer further enlightenment.

DVI processing standard
dviware/driv-standard (or browse the directory)
dvitype
systems/knuth/dist/texware/dvitype.web; catalogue entry