Lions Commentary on 6ed Unix — the source code, annotated. This was one of the few ways of learning how Unix worked (Back In The Day), and it’s still an interesting glimpse at how to build a “simple” operating system. Note line 2238’s famous comment.
Interactive Introduction to Quantum Computing — This is part one of a two-part series for those who want to learn a little about quantum computing, but lack the mathematics and quantum physics background required by many of the introductions out there. It covers some of the basics of quantum computing, such as qubits, state phases, and quantum interference. Part 2 goes on to look at quantum search.