The universe is full of magical things, patiently waiting for our wits to grow sharper.-E. Phillpotts The machine does not isolate the man from the great problems of nature but plunges him more deeply
into them.-Antoine de Saint-Exupéry
Digital hardware systems can be viewed from many alternative perspectives, including Boolean logic, logic gates, and behavioral specifications. For most of this book, the most primitive abstraction we use is the logic gate. In this appendix, we peek beneath the sheets to get some idea of how logic gates are actually implemented by more primitive electrical components.