Our home had carpet on the first floor, which is concrete slab, that we ripped up to hopefully restore to its former glory. However, about half of the floor has old laminate vinyl that's sealed down with tar, and the other half seems to be topped with some sort of white textured paint-looking stuff. It's also a bit discolored in places, but we can't tell if that's from the carpet padding that was laid down, or maybe an additional layer of something that's underneath the white paint-looking stuff.
As additional info, all that was between this material and the carpet was a layer of carpet padding and tack strip looked like this. The last image was where we tried to put some paint thinner (which we mistakenly got instead of paint remover) and scrubbed it for a bit.