Likely just full height, not double height. What has become the normal height for a 5.25" drive is half height. I've seen plenty of full height 5.25" hard drives, but I don't think I've seen double height (would take 4 bays in a modern computer case, if modern computer cases had 4 bays)
I was going to say "my current desktop has 4 CD-capable bays", but I checked and it's actually only 3 bays followed by unused space (and then 2.5" and 3.5" bays below that).
Even if you didn't have that 3.5" drive for your computer, perhaps you can take solace in the fact that you understand intuitively why the disks were called "floppy"!
Mmmm...back when your computer had a smell. You mentioned that hard drive and the memories of computer aroma flashes in my snoot. I had a friend that would seal up his Nintendo to trap the aroma.
I was jealous of my friend's Mac w/ a 720 KB disk drive and 30 MB hard drive (although his system cost probably cost 6x what my PC cost).