Comment by sarahj

xv6 is an amazing teaching OS - it is very simple to dive into and play around with. A while ago I wanted to explore some filesystem/permissions stuff and use xv6 to play with some concepts (see http://sarahjamielewis.com/posts/file-system-permissions-and... - still lots I want to play around with there when I find some time) - If you are at all interested in OS dev it is a great gateway.