Volume 3 of the Operating System Design Book Series is in the production stage. A few things here and there and it will be available.

I just wanted to put a shout out to Dean's water level over at hack-a-week. I have made something quite similar to this and used it a few times in the past. It is a very simple concept which makes it very interesting and enjoyable to use and watch other people use. The little things in life are the most enjoyable things. Thanks Dean.