实用busybox制作的linux根文件系统，此系统最简单，实现了最基本的功能，可以当做学习参考，开发出自己的根文件系统，本系统是跑在9G20上的。-The production of practical busybox linux root file system, this system is the easiest, the most basic functions can be used as a reference, to develop their own root file sys