嵌入式系统固件揭秘（英文版）

An embedded system is just a computer buried inside some other product. Surprisingly, you can know a great deal about programming and computing and still get lost in the arcane world of embedded systems. In the world of embedded systems programming, countless details — both hardware- and software-related — make the development process seem like a path that few have traveled and even fewer have survived. How do software, hardware, and firmware differ? How in the world does a 100,000-line program end up inside a device smaller than my fingernail? What is flash memory and why do I need a cache? What is the difference between a task and a process? Do I need to worry about reentrancy? As we progress through Embedded Systems Firmware Demystified, you will come to see that these questions are not as complex as they first appear. Embedded systems programming spans a wide range of activities from building programmable logic at the most concrete end to writing a UNIX™ process at the most abstract end. Bracketed by these poles, the industry has exploded in the last 20 years. In the late seventies, assemblers were considered luxuries. A typical embedded system used less than 64Kb of system memory (bits, not bytes!).