@governa I don't see why you would compare a kernel to an OS.

The kernel, Linux actually does have a minimal RAM requirement of at least 1 MiB to boot up, but you'll just get a panic() during boot and a not actually usable computer as a result.

I've noticed that GNU/Linux manages to work on CPU is out of order execution, with a framebuffer, 88MB of RAM and some swap, but the minimum amount I would really recommend would be 512MB of RAM - good luck getting computers with less than 4GB RAM nowadays even so.