Re: Bug in hfstar, GPL requirements

[Stepan Kasal]

Hello,

On Mon, Jun 30, 2003 at 12:25:37PM +0100, Tim Hewett wrote:
> I'm looking to report a bug I've found in hfstar. If you use
> the gzip or bzip2 compression options but send the output
> to stdout, i.e. "hfstar cfz - files > archive.tar", extra bytes get
> added to the end of the file compared to doing

OK, I've tried it with my tar-1.13.25 on GNU/Linux.

$ tar cf - src|bzip2 >x1
$ tar cjf - src >x2
$ ls -l x1 x2
-rw-rw-r--    1 kasal    kasal       98870 Jul  4 14:01 x1
-rw-rw-r--    1 kasal    kasal      102400 Jul  4 14:01 x2
$

The reason is that the output is reblocked after compression.
This is necessary if the result is written to a tape.
If you write to stdout, tar may not know where the output
goes to.

See also the node "Blocking Factor" in the tar info manual.

> Finally, I am currently using and distributing hfstar as part
> of my shareware application DV Backup (see
> http://www.coolatoola.com). In the credits section I am
> giving a link to the hfstar source and binary downloads
> page. I am not distributing the source itself. Is that
> satisfactory?

Unfortuantely not.  If you were asked to deliver the source by snail
mail on a physical media, you would have to do it (possibly for a fee,
but it would be annoing, anyway, if someone asks you for the source
twelwe years later, just for fun...where do I have it).
It's always easier to pack the source with the binary distribution.

See also The GPL FAQ, http://www.gnu.org/copyleft/gpl-faq.html, eg.
http://www.gnu.org/copyleft/gpl-faq.html#TOCDistributeWithSourceOnInternet

Hope this explains it,
        Stepan Kasal