There are localized EMP attacks as well, that can target a specific location.

FACT, An EMP attack shall WIPE all the data stored on those BIOS chips etc that control devices. As ALL bits get restored to 0.

I suggest getting a custom made LEAD box, for that external storage solution connected to your PC.

If it's NOT surrounded by LEAD it shall be wiped.

If you're a full on survivalist, you'd do this for your CB radio and ANY other electronics that use Microchips. ;)