[dragonwriter]

> But then if floppies are diskettes, what's the non-'ette' disk referring to

Fixed disks (which were also quite large at the time.) Floppies were removable disks, like cassettes; disk + cassette = diskettes, also disk + dimunitive -ette = diskette.

[kgwgk]

Note that removable hard disks and hard disk cartridges were also a thing.