CMD uses emulator.exe to start the Android Simulator -- emulator-data image file name

CMD uses emulator.exe to start the Android Simulator -- emulator-data image file name

You can use emulator.exe to start the Android simulator in the command line:
-Emulator-avd (AVD name)
-Emulator-data (image file name)
The image files in the avd directory include:

File file type cache. img: VMS Alpha executableuserdata. img: VMS Alpha executableuserdata-qemu.img: data

Which image file is it?
Apparently cache. img is not, userdata-qemu.img is neither the data type nor, only userdata. img.

Actual Operation Verification
Input:
Emulator-data userdata
Or
Emulator-data userdata-qemu
Or
Emulator-data userdata-qemu.img
Result:
C: UsersAdministrator> ko: Cannot detemine type of userdata partition: no image files!

Input:
Emulator-data userdata. img
Result:

According to figure 2, the model is Nexus 5 API 21x86.