Re: [Bug-tar] new/old extract problems with 6GB sparse file

[Paul Eggert]

Joerg Schilling <address@hidden> writes:

> Do you know what GNU tar would do in case it would be able to extract as 
> many data (~ 4 GB) from the archive as star does and did not stop at ~ 1.8 GB 
> already?

I don't fully understand your question, but it's hypothetical and I'm
not sure it's worth figuring it out.

> When storing sparse files, GNU tar violates general structuring rules for TAR
> archives, so anything may happen with a broken archive....

We're well aware that the old format for sparse files is horrible.  If
I could go back in time and speak to the folks that misdesigned it, I
would.  That being said, clearly the old format should suffice for
this test case, and it was a bug that GNU tar mishandled it (a bug
that is fixed in CVS, apparently).  I don't know what else useful can
be said about the matter of this particular bug.

I'll let Sergey address the issue of improving the new format.  To be
honest, I haven't been following it that closely.  We want something
that is upward compatible with POSIX, that interoperates reasonably
well with other implementations, that can support files of
practically-unlimited length, that responds well to corrupted
archives, and that has reasonable time- and space-efficiency.  These
are competing objectives to some extent, unfortunately.