Does anyone know any good resources for detailed (but introductory) information about any of the BSD kernels, the Linux kernel (2.6+), or the Darwin kernel? Any books on basic kernel design and concepts would be helpful as well. Printed resources are preferable to online ones (if I'm going to read technical documents and information for an hour or two every day for a few weeks, I'd much rather be able to do it on my couch, under a lamp, than staring at a screen until my neck cramps [that rhyme was unintentional]).
Thanks in advance!
--Patrick C.