Question: I was reading about magical Chinese drives. How would this be done? The post talks about a ‘looped mode’ and comments suggest having a different controller to lie to the OS.

I went and bought one of these devices, tried it and it worked as advertized (overwriting data when it was full), although when I formatted it, it started showing its ‘true’ capacity.

How is this achieved?

Answer: FAT32 has a master table with free space. You can hexedit that master table to show any amount of free space. I’ve had a floppy disc sized 3.7 GB for ages now.