The Xinu Approach Second Edition. Avoiding the typical black box approach found in other operating system textbooks, this bestselling book explains how to build an operating system from the ground up. It removes the mystery from operating system design and consolidates the body of material into a systematic discipline. The text presents a hierarchical design paradigm that organizes major operating system components in an orderly, understandable manner. This second edition has been completely rewritten with updated code throughout and examples for two low-cost experimenter boards.