The text-producing systems LaTeX and TeX produce DVI files from files written by the user. Those files used to be (and, to a moderate extent, still are) post-processed by a tool called dvips, which converted those DVI files into PostScript files, which are understood by many printers.Some older versions of dvips with embedded bitmapped fonts, which represented letters and symbols as pictures at a fixed resolution (for instance, at 300 dpi).