Don’t know if you guys remember the tab sticker on the right hand side that made the discs re-writable. If the disc came without the notch you could cut one with a pair of scissors. There’s one in the first pic.
For reference my first ever pc was a 386sx25mhz. I think 2mb ram and a 40mb hard drive. I got it as a twelve year old for Xmas. I remember my parents coming home one day not long after and were mortified, because I’d taken it apart to “clean it” learned so much from PCs as a teen doing this sort of thing. Then got into making cheats for games by editing the hex code in saves using Xtree Gold. Great fun.