Why I am happy to dump gzip for xz

[Jim Meyering]

Russ Allbery wrote:
> Warren Young <address@hidden> writes:
>
>> I went through both the .Z -> .gz and .gz -> .bz2 transitions.  I recall
>> a longer overlap period where major archive sites had everything in both
>> the new and previous forms.
>
> At least in my corner of the software world, no .gz -> .bz2 transition
> never happened.  I see occasional use of .bz2, but it's a definite
> minority.
>
>> I don't much care if .gz goes away now, as .Z did before it.  I'd like
>> to see a .bz2 option for everything I have to manually untar for at
>> least another few years.
>
> .Z went away because of annoying software patent issues at the time, which
> was the compelling case for gzip.
>
> Personally, I fail to see a similar compelling case for xz.  It's a much

If you were more intimately familiar with gzip's code,
you would have switched long ago ;-)

> more complex but nicer and more powerful compression algorithm, sure.  But
> there doesn't seem to be any horribly important reason to use it for
> typical open source software distributions where the data size is quite
> small, as opposed to, say, scientific data sets where the savings could be
> substantial.
>
> I'm planning on looking at it seriously for log compression, where I want
> to squeeze GBs (or more) of data into smaller disk, but so far for my own
> projects I haven't seen any reason to move off of xz.  My typical
> free software distribution is on the order of 200KB to 2MB, at which point
> any savings from xz is purely noise and the disruption of switching to
> something new that not everyone has readily available seems overriding.

The few people who do not have xz are in that position because they are
using old or unusual systems, which means they are already maintaining
and building packages on that system.  Thus they can build xz from source.

> It's fine with me for Autoconf to do whatever the Autoconf maintainers
> feel like doing; part of the fun of free software is doing things the way
> that you want to do them whether or not other people agree with the logic
> of your case.  :)  Or just because it's fun.  I use Debian and have xz and
> an appropriate GNU tar readily available and it's all the same to me.  But
> I'm fairly unconvinced by the larger argument that free software
> developers should move to xz and away from gzip.

Why I am happy to dump gzip for xz:
  - xz compresses much better
  - xz decompresses more quickly
  - xz's format is well-designed and extensible
  - xz's code base is robust and well-implemented (yes, I've audited it)
  - gzip's code is a mess, and has even had recent CVEs and data-loss bugs,
      which means we are doing users a favor by encouraging them to stop
      using their vulnerable/defective gzip programs.
      As gzip maintainer, I can attest that the code is far from ideal,
      both on a robustness scale and on the maintainability front.

>From an aesthetic standpoint, there is no comparison between
the code of the two projects, nor between the size of their outputs.