The program takes a semi-algorithmic specification of a font, and produces a bitmap font (whose properties are defined by a set of parameters of the target device), and a set metrics for use by TeX.

The bitmap output may be converted into a format directly usable by a device driver, etc., by the tools provided in the parallel mfware distribution. (Third parties have developed tools to convert the bitmap output to outline fonts.)

The distribution includes the source of Knuth’s Metafont book; this source is there to read, as an example of writing TeX — it should not be processed without Knuth’s direct permission.