How to open ClockworkMod's .tar.a archives? To open the TAR archive on my PC, I have to rename the .tar.a to .tar, otherwise my archive manager will say "Archive type unsupported" or similar.

Why do they do that, and how to open these archives in a proper way?
It does this in order to break up large .tar files into chunks of 1000000000 bytes (or 1 GB):

-rwxrwx--- root     sdcard_r          0 2014-03-19 14:31 data.ext4.tar
-rwxrwx--- root     sdcard_r 1000000000 2014-03-19 14:33 data.ext4.tar.a
-rwxrwx--- root     sdcard_r 1000000000 2014-03-19 14:36 data.ext4.tar.b
-rwxrwx--- root     sdcard_r 1000000000 2014-03-19 14:38 data.ext4.tar.c
-rwxrwx--- root     sdcard_r  135127040 2014-03-19 14:38 data.ext4.tar.d


Even if the resulting file is under the 1000000000-byte split limit, the .a file will still be generated:

-rwxrwx--- root     sdcard_r         0 2014-03-19 14:29 system.ext4.tar
-rwxrwx--- root     sdcard_r 484504064 2014-03-19 14:30 system.ext4.tar.a


You can combine these split files back together using the following syntax:

On Windows: copy /b finelame* filename E.g. copy /b data.ext4.tar* data.ext4.tar
On Linux: cat filename* &gt; filename E.g. cat data.ext4.tar* &gt; data.ext4.tar