The best way to create a new grafinfo(DSP/4dsp) file is to copy an existing grafinfo file, then modify the lines in the header section to match your adapter(s). Select a grafinfo file for an adapter that is similar to yours and check the various procedures defined for each adapter mode to see if they will work for your adapter.
For example, check CLASS. Compare the new mode's video memory base address and address window to other mode descriptions in the grafinfo file. If the new video memory requirements match, use the existing CLASS statement. Otherwise, you must define a new class.
For a list of the procedures to check in grafinfo files, see grafinfo.
If the vendor_name or adapter_model strings do not match (case-insensitive) the Video Configuration Manager will not display your adapter during configuration.