> EM> Are there such architectural drawings? > > I made some rough ones a long time ago, and they're not really great, > but they're at > http://www.gnu.org/software/hurd-noframes/gords-hurd-and-linux.html. I think those pictures are good. Representing the kernel as a rather unhomogeneous ring round the outside instead of a homogeneous thing in the middle, which the work "kernel" suggests, is quite enlightening ...