Files: .FON
These files hold the standard OS/2 V2.0 bitmap fonts and are copied there by the OS/2 V2.0 install procedure.
Files: .PSF
PostScript font files are the new Type 1 Font files in internal-to-PM format which is designed (for efficiency) for the core fonts only (Times New, Courier and Helvetica).
Files: .AFM
These files hold the Adobe Font Metrics and are used by OS/2 PM ATM. Information such as character widths and kerning pairs are in this file.
Files: .PFB
These files hold the Printer Font Binary and are used by both OS/2 PM ATM and WIN-OS/2 ATM. These are the files that can be downloaded into printer storage.
Files: .PFM
These files hold the Printer Font Metrics and are used by the PostScript device driver to download fonts and by WIN-OS/2 ATM.
Files: .PFA
These files hold the Printer Font ASCII and are embedded by the PostScript device driver into the PostScript print job if you installed them as downloadable fonts.
For non-ATM file formats, such as the native formats for PCL, PPDS and 420X printers.
Figure "File Structure of Adobe Type Manager"