Thanks to Andi Kleen for the idea, answering my questions, fixing my mistakes, filling content, etc. Philipp Rumpf for more spelling and clarity fixes, and some excellent non-obvious points. Werner Almesberger for giving me a great summary of disable_irq(), and Jes Sorensen and Andrea Arcangeli added caveats. Michael Elizabeth Chastain for checking and adding to the Configure section. Telsa Gwynne for teaching me DocBook.