FORTH Boot Disk

The other day I was digging along in my mine, I came accross a dungeon and dealt with it as normal, but when I was looting the chests I found something interesting. I found what looks like a floppy disk, and it was called "FOURTH boot disk" and the words were in gold so it's a secret item you can't spawn in normally. I assume it goes to computercraft because it's a floppy disk, but I don't know what it does, and I don't want to try anything yet cuz I only have the fourth, does anyone know what these are?