Hello Peter
FAT 16 was a file system used by Microsoft on OS up until windows me,after that they used FAT32.
Some older pc,s have 2 serial ports although these days most modern pc utilise usb. You can buy a usb to seria port splitter (RS232).
Win XP vista do not use msdos as such although they give an interface that looks like it.
Probably best way forward is to find an old laptop/ pc on win98 and hopefully with 2 serial ports
Regards
Les