This format was developed to simplify use of Type1-fonts in some software. It’s 8-bit and so it’s quickly processed by programs and it has a compact structure. PFB contains additional metadata. Besides the storage of system fonts, a good example of its use is its application in AutoCAD to create font files with compilation.
This was developed by the Adobe Company and contains data regarding the metric characteristics of Type 1 PostScript fonts. The AFM structure requires a control template that defines the look of every font symbol. It’s used primarily for UNIX.