Create a root file system

Steps for creating a root file system:

1. Compile/install busybox and generate/bin,/sbin,/usr/bin,/usr/sbin directory

2. Use the cross-compilation tool chain to build/lib Directories

3. Close construction/etc directory

4. manually build the simplest/dev directory

5. create other empty directories

6. Configure the system to automatically generate the/proc directory

7. Use udev to build a complete/dev directory

8. Create a jffs2 image file for the root file system

Create a root file system