[jclulow]

tar streams don't have an index at all, actually, they're just a series of header blocks and data blocks. Some backup software built on top may include a catalog of some kind inside the tar stream itself, of course, and may choose to do so as the last entry.

[ahoka]

IIRC, the original TAR format was just writing the 'struct stat' from sys/stat.h, followed by the file contents for each file.