Understanding of Android system partitions

About partition understanding: An EMC physical storage chip in a mobile phone or other device is divided into partitions such as boot, system, recovery, userdata, cache, misc, sdcard, etc. by the linux partition, and there may be other partitions, but these partitions are generally Yes, they are more commonly used; these partitions are mounted to each directory, for example, the userdata partition is mounted to the /data directory, the system partition is mounted to the /system directory, and the sdcard partition is mounted to /sdcard directory; so far, it has nothing to do with the Android system, but the Android system is burned into the EMC, which is to burn each program image in the Android system to each partition, for example, system.img is burned In the /system directory, userdata.img is burned into the /data directory, so I always understand that the /data directory is the directory of the Android system, which has no effect on development, but it is not, but the /data directory contains the Android system. The userdata.img image data is just the image data, and other program images can also be installed, but the installation looks professional and clear at a glance; in addition, it should be understood that the sdcard partition is a storage space allocated by EMC to interact with users, and users can store them arbitrarily. Pictures, music, videos and other files belong to the internal sdcard, and it is not a physical storage chip in the true sense; generally, the pluggable TF card belongs to the external sdcard, and there will be another partition to correspond, which may be / sdcard2 or /sdcard/sd is different from /sdcard anyway; AutoNavi can only traverse the offline data of all external storage spaces. If you need to copy the embedded offline data, you can only separate it from the EMC and store it offline. Data, and the attribute of this partition must be the attribute of external storage, otherwise it cannot be traversed. The offline data of Gaode map is a requirement encountered in my project, which has nothing to do with the previous partition understanding.