Most of the Arduino’s lines drive the floppy interface, so the five-button control comes to a single ADC pin via a resistor ladder. He freely admits that it’s not a perfect cycle-exact ...

For many of us the passing of the floppy disk is unlamented ... The interface for a floppy drive might have required some complexity back in the days of 8-bit microcomputers, but even for today ...

Each floppy disk is divided ... And, because floppy drives don't contain their own controllers, they're far easier to manipulate with third-party boards and tools like the Arduino.