https://hackaday.com/2020/07/16/a-lowly-8-bit-micro-busts-copy-protection-from-the-16-bit-era/

Also, a pretty thorough/informative write-up... Dude uses a video-controller to generate a serial data stream to be written to disk. 

For some reason this reminds me of my trick in avr-lvds-lcd, which uses PWM to generate serial data packets to drive pixels on an lvds/fpd-link LCD.

I guess for FloppyBird the main takeaway is the nanosecond-positioning of flux-reversals.

Though I also dig how this hack is kinda like the exact opposite of FloppyBird; he uses a display controller to write to a floppy disk, FloppyBird uses a floppy disk to control a display.