[tz] [PROPOSED PATCH 2/2] Use lz format for new tarball

Antonio Diaz Diaz antonio at gnu.org
Mon Aug 29 01:55:01 UTC 2016

Paul Eggert wrote:
> Oscar van Vlijmen asked for something convenient on MS-Windows; see
> <http://mm.icann.org/pipermail/tz/2016-August/023945.html>. What's the
> story on that? Why doesn't 7-Zip support lz format? Will 7-Zip support
> lz format any time soon? Surely it would be an easy thing to add.

It is indeed an easy thing to add, and it has been requested a couple 
times[1][2], but Igor Pavlov does not consider it a priority. Given that 
Igor is busy maintaining 7-Zip and is co-author of the xz format[3], it 
is difficult to tell when (or if) 7-Zip will support the lz format. But 
he already knows about the defects of xz, so I have hope that he may 
change his mind.

[1] http://sourceforge.net/p/sevenzip/discussion/45797/thread/9e6de893/
[2] http://sourceforge.net/p/sevenzip/discussion/45797/thread/32771d84/
[3] http://tukaani.org/xz/xz-file-format.txt

> I'd rather not use bzip2 format, since it doesn't compress the tz
> tarball nearly as well. bzip2 format is 11% larger than xz format. (lz
> format is 0.3% smaller.)

I haven't got a real tzdb tarball, but I have made an approximate one by 
combining tzcode2016f and tzdata2016f. The sizes of the resulting 
compressed files are not big, and the size difference between bzip2 and 
lzip is of about 32 kB, which is not a problem even for dial-up users.

-rw-r--r-- 1 1597440 2016-08-28 16:17 tzdb.tar
-rw-r--r-- 1  377682 2016-08-28 16:17 tzdb.tar.bz2
-rw-r--r-- 1  508373 2016-08-28 16:17 tzdb.tar.gz
-rw-r--r-- 1  346119 2016-08-28 16:17 tzdb.tar.lz
-rw-r--r-- 1  346928 2016-08-28 16:17 tzdb.tar.xz

If the lack of support in 7-Zip is an obstacle for the adoption of lzip, 
then I would consider bzip2 the second best choice; it decompresses 
safely on all platforms at the only cost of an unimportant increase in 
tarball size. IMO gzip is also fine. Xz is the only format that I 
consider should be avoided.

Best regards,

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