iOS has some copy-pasted BSD code, but is probably the mainstream operating system that feels the least like {Free,Open,Net,Dragonfly}BSD. These feel even more

iOS has some copy-pasted BSD code, but is probably the mainstream operating system that feels the least like {Free,Open,Net,Dragonfly}BSD. These feel even more "open-source" than Linux. Every one I have used installs the source code to the entire OS in /usr/src and make it very easy to change and recompile the system. On the BSDs I mentioned, if you don't understand how something works or you want to fix some bug, it's usually pretty easy to go find the source code, read it and learn how it works, and fix it. On most Linux-based OSs you would have to go figure out which random organization makes the component that has a bug (Linux project for the kernel, GNU for a lot of utilities, zillions of others for everything else), figure out how to download and build the source and install it into your distro (which is probably totally unsupported since your distro will expect to be using RPMs or DEBs rather than random stuff installed from tarballs...) This is the most salient feature of the modern pc BSDs to me. It's impossible to describe how different it feels to be truly in control of your system and understand/change it however you want.