和 sicp 一样，这个也是必读的，后续的读书笔记都会放在这里，长期更新。
controller VS adapter
THe distiction between the two(controller and adapter) is mainly one of packaging. Controllers are chip sets in the device itself or on the system's main printed circuit borard(often called the motherboard). An adapter is a card that plugs into a slot on the motherboard. Regardless, the purpose of each is to transfter information back and forth between the I/O bus and an I/O device.
caller-saved / callee-saved register 两个策略
