Printer font metric files are a Microsoft Windows standard. They are encountered frequently in archives that contain Type 1 fonts. Unfortunately, these archives occasionally fail to include AFM files, which are more standard outside of the Windows community. Even more unfortunately, PFM files do not contain all of the information that is in an AFM file. However, the PFM2AFM program can construct a partial AFM file. I believe that the PFM file format is described in a Microsoft technical note; however, I have never seen it. Unless you use Microsoft Windows, PFM files are likely to be useless. If you need PFM files, the MS-DOS program Refont can create them from AFM files.