[del4]

Originally Posted by makkonen

Here's the breakdown. In unix systems, the file system is all organized around root. That is:
/

So... at boot, HaRET loads the kernel (zImage) and the initial ramdisk (initrd.gz), which has a lightweight filesystem on it, into memory. This allows the booting of linux to proceed, without having to interact with the block devices (sd card, in this case), which are not yet initialized. After the kernel and initrd have booted the hardware, then it's time for the actual / (root) filesystem to be mounted. (If you were to mount rootfs.img, you would see a number of initialization scripts, as well as standard linux directories (proc, bin, lib, dev, etc), some with files in them, some empty.) The init script in the rootfs, in turn, loads data.img (the userdata) as a rewriteable partition under /data, and system.sqsh (the Android code) as a read-only partition under /system. Then it calls the Android initialization routine, and that cool nexus one boot animation starts. The end.

So, if we want to retain our information between android updates, e.g., mail settings, contacts, wallpaper selections, ..., we should keep from overwriting the data.img file or would this introduce problems, depending upon what's updated in the new kernel and/or modules?