[Lzip-bug] Tarlz 0.13 released

[Antonio Diaz Diaz]

I am pleased to announce the release of tarlz 0.13.

Tarlz is a massively parallel (multi-threaded) combined implementation 
of the tar archiver and the lzip compressor. Tarlz creates, lists and 
extracts archives in a simplified posix pax format compressed with lzip, 
keeping the alignment between tar members and lzip members. This method 
adds an indexed lzip layer on top of the tar archive, making it possible 
to decode the archive safely in parallel. The resulting multimember 
tar.lz archive is fully backward compatible with standard tar tools like 
GNU tar, which treat it like any other tar.lz archive. Tarlz can append 
files to the end of such compressed archives.

Tarlz can create tar archives with five levels of compression 
granularity; per file, per block (default), per directory, appendable 
solid, and solid.

Of course, compressing each file (or each directory) individually can't 
achieve a compression ratio as high as compressing solidly the whole tar 
archive, but it has the following advantages:

   * The resulting multimember tar.lz archive can be decompressed in
     parallel, 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, the option '--keep-damaged' can be
     used to recover as much data as possible from each damaged member,
     and lziprecover can be used to recover some 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.

Note that the posix pax format has a serious flaw. The metadata stored 
in pax extended records are not protected by any kind of check sequence. 
Because of this, tarlz protects the extended records with a CRC in a way 
compatible with standard tar tools.

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/

The sha256sum is:
3fe238913147625e535490108a05e5d5fc6f3a254490b16f0a97e47fd4f85cea 
tarlz-0.13.tar.lz


Changes in version 0.13:

  * Skipping of unreadable files during multi-threaded archive creation 
with per-file compression has been fixed. Tarlz did produce empty lzip 
members, and sometines left the last files out of the archive.

  * Multi-threaded listing of tar.lz archives containing empty lzip 
members has been fixed. It listed members out of order and sometimes hung.

  * When creating an archive, negative modification times are now 
stored as cero (1970-01-01 00:00:00 UTC). Negative times are not portable.


Please send bug reports and suggestions to address@hidden


Regards,
Antonio Diaz, tarlz author and maintainer.
Self-determination is a right, not a crime. Free Catalan political 
prisoners.
--
If you care about long-term archiving, please help me replace xz with 
lzip. See http://www.nongnu.org/lzip/lzip_benchmark.html#xz1
http://www.nongnu.org/lzip/manual/lzip_manual.html#Quality-assurance and
http://www.nongnu.org/lzip/xz_inadequate.html Thanks.