Once I converted an MSDOS db that used a proprientry db format, and I used DbaseV to parse out the data . Took me 80 hours work as each record was variable in length and some empty fields had a marker and some did not. It was a nightmare!
MSDOS dbs :- DBASE, Clipper, FoxPro, RBase, Dease, all of these had a decent development environment so you could export data as CSV files. What is are the file extensions of the db files.