I once had a computer with a SATA HDD, floppy dive, CD and DVD burners and a front mounted, internal USB connected multi card reader.
On a clean OS reinstall it allocated the floppy as A, card reader as C, HDD as D and burners as E and F.
As most software wants to install to C, and some not giving a choice, I had to unplug the card reader and start all over again.
