[OSUNIX-dev] Yet another package format - Feedback wanted

[Joerg Schilling]

"C. Bergström" <cbergstrom at netsyncro.com> wrote:

> More details can be found here [1], but wanted to share some quick 
> numbers.. 
>
>  1.3M   /usr/portage/packages/app-editors/vim-7.2.021.oxe
>  1.5M   /usr/portage/packages/app-editors/vim-7.2.021.tbz2

Why is the *.oxe file smaller?
 
> time xar -xf /usr/portage/packages/app-editors/vim-7.2.021.oxe
> 0.15u 0.01s 0:00.18 88.8%

Why is this extract faster?

> time gtar -xf /usr/portage/packages/app-editors/vim-7.2.021.tbz2
> 0.24u 0.02s 0:00.26 100.0%
>
> # Someone correct me if I'm doing this wrong
> time /usr/bin/star -x -bz < 
> /usr/portage/packages/app-editors/vim-7.2.021.tbz2
> 0.24u 0.03s 0:00.35 77.1%

star should be the fastest in case you have similar constraints.....

star -xp -time < ../cdrtools-2.01.01.tar.bz2 -no-fsync
star: WARNING: Archive is 'bzip2' compressed, trying to use the -bz option.
star: 1021 blocks + 9728 bytes (total of 10464768 bytes = 10219.50k).
star: Total time 0.508sec (20076 kBytes/sec)
0.518r 0.480u 0.140s 124% 0M 0+0k 0st 0+0io 0pf+0w

gtar xjf - < ../cdrtools-2.01.01.tar.bz2
0.723r 0.490u 0.130s 88% 0M 0+0k 0st 0+0io 0pf+0w

Star defaults to a mode that grants you that everything could be unpacked
correctly to disk in case that the final star exit code is 0.
Other tar implementaions do not support this, so I swichted the secure
more off in the example above.


> I ran it more than once and overall it seemed pretty consistent.. So 
> what exactly is under the hood
> .tbz2 ==  bzip2 compressed data, block size = 900k + xpak tagged on 
> after EOF so that metadata can be easily extracted..
> .oxe == xar archive - version 1 + xz (lzma2) compressed and using xar's 
> built-in toc to store metadata (gzip)

What compression is lzma2 and which program supports it?

Jörg

-- 
 EMail:joerg at schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
       js at cs.tu-berlin.de                (uni)  
       joerg.schilling at fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
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