The bagging control system at my customers seafood factory still uses DOS, it controls the hardware through 2 serial ports, the hardware has been updated severa

The bagging control system at my customers seafood factory still uses DOS, it controls the hardware through 2 serial ports, the hardware has been updated several times since the 80's, There are no drivers or security, just base DOS formatted hard disk and autoexec.bat with a single exe program being called, I just clone the hard disk for them when its time for an update and keep the old PC around for backup. I've thought of reverse engineering the software but to tell the truth the program and the machine it controls were just built very well and so long as we have spare hardware it could go forever. Due to driver problems I'm not sure you could even build a system these days that would be guaranteed future proofed for 30+ years.