Out of disk space error when trying to write to frame buffer

I’m using this command:

cat /dev/urandom >/dev/fb0

I tried it with both root and sudo and even then I’m shown that there is no disk space left.

I’m using Fedora 29. I’ve checked the disk space, there is plenty of disk space on both home and root.

I found the above code on the answer here: Is it possible to access to the framebuffer in order to put a pixel on the screen from the command line?