[Lzip-bug] Tarlz 0.4 released

[Antonio Diaz Diaz]

I am pleased to announce the release of tarlz 0.4.

Tarlz is a small and simple implementation of the tar archiver. By 
default tarlz creates, lists and extracts archives in the 'ustar' format 
compressed with lzip on a per file basis. Tarlz can append files to the 
end of such compressed archives.

Each tar member is compressed in its own lzip member, as well as the 
end-of-file blocks. This same method works for any tar format (gnu, 
ustar, posix) and is fully backward compatible with standard tar tools 
like GNU tar, which treat the resulting multimember tar.lz archive like 
any other tar.lz archive.

Tarlz can create tar archives with four levels of compression 
granularity; per file, per directory, appendable solid, and solid.

Tarlz is intended as a showcase project for the maintainers of real tar 
programs to evaluate the format and perhaps implement it in their tools.

The diagram below shows the correspondence between tar members (formed 
by a header plus optional data) in the tar archive and lzip members in 
the resulting multimember tar.lz archive:

tar
+========+======+========+======+========+======+========+
| header | data | header | data | header | data |   eof  |
+========+======+========+======+========+======+========+

tar.lz
+===============+===============+===============+========+
|     member    |     member    |     member    | member |
+===============+===============+===============+========+

Of course, compressing each file (or each directory) individually is 
less efficient than compressing the whole tar archive, but it has the 
following advantages:

  * The resulting multimember tar.lz archive can be decompressed in 
parallel with plzip, multiplying the decompression speed.

  * New members can be appended to the archive (by removing the eof 
member) just like to an uncompressed tar archive.

  * It is a safe posix-style backup format. In case of corruption, 
tarlz can extract all the undamaged members from the tar.lz archive, 
skipping over the damaged members, just like the standard (uncompressed) 
tar. Moreover, lziprecover can be used to recover at least part of the 
contents of the damaged members.

  * A multimember tar.lz archive is usually smaller than the 
corresponding solidly compressed tar.gz archive, except when 
individually compressing files smaller than about 32 KiB.


The homepage is at http://www.nongnu.org/lzip/tarlz.html

An online manual for tarlz can be found at 
http://www.nongnu.org/lzip/manual/tarlz_manual.html

The sources can be downloaded from
http://download.savannah.gnu.org/releases/lzip/tarlz/tarlz-0.4.tar.lz

The sha256sum is:
7ad1d8e44098af241560afabaa3417b7f529e4b1d5eb95b26af79f22db912cc2 
tarlz-0.4.tar.lz


Changes in version 0.4:

  * Some missing #includes have been fixed.

  * Files are now opened in binary mode on OS2.


Please send bug reports and suggestions to address@hidden


Regards,
Antonio Diaz, tarlz author and maintainer.

--
If you are distributing software in xz format, please consider using 
lzip instead. See http://www.nongnu.org/lzip/lzip_benchmark.html#xz1 and 
http://www.nongnu.org/lzip/xz_inadequate.html