Re: compressor
Le jeudi 23 août 2012 à 14:26 -0600, Bob Proulx a écrit :
> Jon Dowland wrote:
> > Bob Proulx wrote:
> > > Jon Dowland wrote:
> > > > linux-3.6-rc2.tar.bz2 78M
> > > > linux-3.6-rc2.tar.gz 99M
> > > > linux-3.6-rc2.tar.xz 65M
> > > linux-3.6-rc2.tar.lz 66M
> > >
> > > I think lzip is worthy enough that it should have a mention too. It
> > > has gotten less attention than xz and that is sad since it is a nice
> > > free software tool. I recompressed that file using lzip for this
> > > comparison.
> >
> > Thanks for the data (mashed/reformatted into quote above). I copied the
> > listings from the kernel.org archives, so the choice of compression types
> > was theirs (although I hadn't heard of lzip, thanks!)
>
> There is a problem with the mashing and reformatting. It makes lzip
> appear to be 66M against xz being 65M and so xz is better, right? But
> wait the above says that gz is 99M. But ls says 100M. So the listed
> sizes are not 100% correct. So 66M is true if 100M is true. But it
> seems that something was truncating down to 99M and so perhaps that
> 65M is actually 66M? In which case xz and lz were actually the same
> for that sample. Or perhaps if they count 65M as true for xy then
> perhaps it should be 65M for lz too?
>
> I think you see the problem. I don't really know from the above data
> whether xz or lz is the same or worse or better.
>
> I didn't go and download the linux-3.6-rc2.tar.xz file to see what
> size it actually should be listed as. I probably should have. But I
> didn't have the time.
>
> It would be better to look at the long byte counts for this type of
> comparison.
>
> Bob
Even if you are perfectly right, I wouldn't look at the long byte count.
A MB today is downloaded in 1s with most internet connection and if you
take linux-2.6 archive or your whole / partition archive, you might see
that lz/xz performs worse/better that xz/lz considering file size.
>From my point of view, I see two programs performing almost equally well
on a big bunch of ascii files on this hardware.
So the next question would be "which one is faster?" and even before
that, I would wonder "Are these programs available on my cluster?"
But once again you are perfectly right to ask for more precision, I just
say that there are high chances that you won't be able to conclude
anything.
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