I'd guess that "adapter" is device which tells if bootblock of the floppy is being written. I've made similar device as DIY project loong ago. It beeped and flashed led every time bootblock was written, intentionally or for example by a bootblock virus. So it only helps with bootblock viruses, which are common when using Amiga with floppies, but no help for more recent file based viruses on harddisks. And it doesn't stop virus for writing.. so damage is made for custom bootblock programs etc already.
