"What Is This Wall Mounted Metal Thing That Was Seen In Hohensalzburg Fortress? There Were 3 Or 4 Rooms With One Of These Objects And None Had An Explanation"
Answer: "These are pretty much radiators that were filled with embers and/or hot stones when needed."
Cabbage sliced for making sauerkraut.
5¼"disks came with stickers to cover up the notch to make them read/only again.
So the thing in not for write-protecting; quite the opposite actually.
Second this. Notch = writable, no notch (stick some tape or the like over it), write protected. If you wanted to use the back side of a single sided disk you had to punch three holes in the plastic housing, the write protect notch and two that would line up with the hole that marked the start of the track. We usually made a cardboard model of a disk to guide the punches as it required a fair degree of precision.
Single-side floppies were far cheaper than dual side, but at least by the time I was on the scene the chances of a failure on the back side were very low. I would guess we lost more due to not being careful enough when punching the sync holes than were bad from the factory. (One jaw of your punch had to go inside the housing and the disk was easy to scratch.)
I think you mean seat covers not toilet paper