This is a tiny, fully working "bootloader" for x86 IBM-PC computers.
It prints text to the screen (and the code is doing that via some calls to subroutines.)
Writeup on original author's blog.
To see it in action, just run
bochs -f bochsrc.txt
which runs bochs with the correct config file.
In Ubuntu, you may want to install:
sudo apt install bochs-x
to run it correctly.