XZ embedded bug unpacking linux-3.8.tar.xz

[John Spencer]

On 03/01/2013 10:16 PM, Matias A. Fonzo wrote:
> El Fri, 1 Mar 2013 21:50:44 +0100
> Denys Vlasenko<vda.linux at googlemail.com>  escribió:
>> On Fri, Mar 1, 2013 at 9:41 PM, Matias A. Fonzo<selk at dragora.org>
>> wrote:
>>>> What percentage of bbox users would want to produce .lzip files?
>>>
>>> How to know it?
>>
>>
>>>
>>>> It isn't a widely used format.
>>>
>>> With this thought (nothing personal), what chances have the good
>>> alternatives out there?.
>>>
>>> (xz is not more popular (or widely used) than gzip or bzip2).
>>
>> LZMA-based compressors give a better, and slower, compression
>> than bzip2. It is not unexpected that with faster processors,
>> we reached the point when people can use it without excessive
>> time penalty.
>>
>> Kernel is released in .xz tarballs (in addition to .bz2).
>> Distributions are using xz-compressed .rpms.
>
> I prefer to download tarballs in bzip2 format, (if there's no other
> option between xz or bzip2). At least, bzip2 provides a recovery
> tool. ;-)
>

xz (and also lzip) have 2 major advantages over bzip2
1) better compression (about 15-40%)
2) much better decompression speed (about 3-4x faster)

when you build stuff in qemu, like mips or arm, especially the speedup 
makes a huge difference.
for example unbz2'ing the kernel tarball takes nearly 2 hours in qemu 
mips (which has a very slow emulation).
otoh the 30 minutes it takes with xz are much nicer.