My OS class at the University of Wisconsin used xv6. I love and hate that little operating system. My professor had actually taken the time to logically split all the source files into folders for their given purpose. When I found the original source and the flat structure, I died a little inside. There was no way I would be able to recreate a folder structure that would also successfully build with make. I tried and gave up in short order.
I rebuilt it into a folder structure when I was younger trying to teach myself operating systems. It wasn’t that difficult if you’re familiar with make.
