The emulator provides a default user-data disk image. At startup, the emulator creates the default image as a copy of the system user-data image (user-data.img), described above. The emulator stores the new image with the files of the active AVD.
from:http://androidappdocs.appspot.com/guide/developing/tools/emulator.html
1)What does the default images mean?(userdata.img?)
2)What does the system user-data image mean?(userdata-qemu.img?)