I have several customers who have old equipment. Robots and machine tools built before a certain time have RS232 ports and that is their ONLY method of communication to the outside world. I had programmed this robot some time ago, and we had never backed it up. SO I tunneled around until I found an old Pentium computer that had Dos 6.0 on it, and a serial port. And I had to ressurect a bunch of brain cells that I haven’t used in a very long time, but I managed to accomplish a backup of the old girl.
This is why I can never completely switch to Mac, this is one of at least a dozen types of machinery that can ONLY communicate with PC’s. And there are literally hundreds of thousands of these robots/machines out there. And now, it’s limited to only PC’s that have serial ports, and slow clock speeds. So I have to keep a couple around just to that purpose. I ought to set them up and get them connected so I can move the files around. Pity nobody makes an RS232 to USB adapter.