[Lzip-bug] Tarlz 0.16 released

[Antonio Diaz Diaz]

I am pleased to announce the release of tarlz 0.16.

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 and safer variant of the POSIX pax format 
compressed with lzip, keeping the alignment between tar members and lzip 
members. 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.

Keeping the alignment between tar members and lzip members has two 
advantages. It adds an indexed lzip layer on top of the tar archive, making 
it possible to decode the archive safely in parallel. It also minimizes the 
amount of data lost in case of corruption. Compressing a tar archive with 
plzip may even double the amount of files lost for each lzip member damaged 
because it does not keep the members aligned.

Tarlz can create tar archives with five levels of compression granularity; 
per file (--no-solid), per block (--bsolid, default), per directory 
(--dsolid), appendable solid (--asolid), and solid (--solid). It can also 
create uncompressed tar archives.

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), and unwanted members can be deleted from the archive.
     Just like 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:
f384ad51e5f3b060639c0b94ee9c71ed1c7e32e2733e2a07fdc06ac65aeddf5f 
tarlz-0.16.tar.lz


Changes in version 0.16:

  * 'chown' and 'chmod' are now called in the right order on extracion to 
preserve the S_ISUID and S_ISGID bits of executable files.

  * The return value of '--delete' when failing to delete a tar member not 
individually compressed has been fixed. It returned 0, but should be 2.

  * The header <sys/sysmacros.h> is now #included unconditionally.

  * The new chapter 'Portable character set' has been added to the manual.


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.