lê a partição e copiá-lo bit bit para algum arquivo?
Does it read the partition and copy it bit by bit to some file?
A backup of any partition works by simply copying an image of it to a file. This is accomplished by using the simple command
dd if=<path to device eg. sdcard (/dev/block)> of=<path to file to backup to>.
The resulting file is (as already written) an image of the original partition which can be explored as a drive on any OS, which features mounting an image to a drive (primarily any linux distro).