* Shlomi Fish <shlo...@gmail.com> [2010-11-19 19:55]:
> here is a report on compressing Graph-Easy-0.70.tar with various
> compression methods:
>
> {{{
> shlomif:~/progs/perl/cpan/Graph/Easy/trunk/Graph-Easy/TEMP$ ls -l
> total 3420
> -rw-r--r-- 1 shlomif shlomif 2160640 Nov 14 22:20 Graph-Easy-0.70.tar
> -rw-r--r-- 1 shlomif shlomif 329197 Nov 5 12:24 Graph-Easy-0.70.tar.bz2
> -rw-r--r-- 1 shlomif shlomif 416916 Nov 14 22:23 Graph-Easy-0.70.tar.gz
> -rw-r--r-- 1 shlomif shlomif 270796 Nov 14 22:21 Graph-Easy-0.70.tar.lrz
> -rw-r--r-- 1 shlomif shlomif 312844 Nov 5 12:24 Graph-Easy-0.70.tar.xz
> }}}
>
> As one can see, there are significant savings in size (and
> bandwidth) by switching to .bz2 and .xz.
Where does one see that? I see some savings, but not significant
ones. You drop from 2 MB to 400 kb by using gzip, then a further
100 to 150 kb by using more unusual compression programs. Just
going to http://search.cpan.org/dist/Graph-Easy/ will pull down
more data than you just saved.
The initial savings is worthwhile, but the additional gains?
The era of 28.8 modems is long past. (And even in areas where
internet connectivity is bad, bandwidth is not the limiting
factor. You go from cell phone with data plan to satellite
internet to CD-ROMs delivered by truck: the scarce resource
becomes latency, not the bandwidth at any one instant.)
Gzip has 100% installed base. Even bzip2 does way worse; it has
100% installed base if you are looking at Linux and the 386BSD
family, but is way less commonplace elsewhere, esp. Windows. And
the other tools are only just making inroads on Linux. How long
until they’re as widespread as bzip2? How long until bzip2 is as
widespread as gzip?
How large is the total CPAN archive – 10 GB? Re-compressing all
of it now would yield a benefit of what, 3 GB? 4? Even 5 maybe?
As Dave said, it fits on a thumb drive already. And we’re not
even talking about re-compressing here, just about future support
for new distributions.
It’s gonna be a lot of work to iron out the entire tool chain to
support the newer formats; then it will take a lot of time until
the work trickles out far enough that people could start relying
on it.
For quite piddly gains, in absolute numbers.
I really don’t see the point. Gzip is Good Enough.
Regards,
--
Aristotle Pagaltzis // <http://plasmasturm.org/>
