Is use_7z worth it? (was: Re: [57743] trunk/dports/graphics/ImageMagick/Portfile)

[Ryan Schmidt]

On Sep 16, 2009, at 01:53, Anders F Björklund wrote:

> Ryan Schmidt wrote:
>
>>> 	Is using 7z for downloads really worth the extra compile, etc.
>>> time for the decompressor required, and the (presumably) longer
>>> decompression time?
>>
>> IMHO, definitely, which is why the use_7z option was added to  
>> MacPorts base. Processors in today's computers are extremely fast,  
>> so the decompression time is practically nothing. All ports should  
>> switch to 7z or similar highly-compressed alternatives to gz and  
>> bz2 if available. lzma and xz are good choices too, though MacPorts  
>> doesn't yet have a use_xz option. The lzma, xz and 7z formats can  
>> all use the lzma compression algorithm.
>
> Using .7z isn't a good option in the same way that using .zip isn't  
> optimal.

In what way is .zip not optimal? It is the built-in compression method  
offered by the Mac OS X Finder, so at least somebody at Apple thought  
it was a good choice for something. And software distributed as .zip  
archives works perfectly fine in MacPorts. It's not optimal in that  
the compression isn't very good, but in that way it would be  
completely unlike .7z, which can use lzma compression which is very  
good.


> If you want the LZMA compression, it would be better to  
> use .tar.lzma instead ? Even better is to use LZMA2 in form  
> of .tar.xz, when that has been added/released*.
>
> * XZ Utils is still in beta (thus port "xz-devel"), see http://tukaani.org/xz/
>
>> The p7zip 9.04 bz2 distfile is 3.6 MB. This plus the size of the  
>> ImageMagick 6.5.6-1 7z distfile (5.7 MB) is only slightly larger  
>> than the size of the ImageMagick 6.5.6-1 bz2 distfile (8.6 MB). So  
>> if the user did not already have p7zip, then it will take a little  
>> longer this one time, but for every subsequent update, it's a win.
>
> Using xz instead of bz2 is a good alternative, since it makes  
> smaller files and is faster to decompress (it takes longer to  
> compress, but that's server-side/once).  It does *not* replace gz  
> however, as there are lots of cases where gzip is "good enough" (and  
> faster).
>
> But I don't think you should use the .7z format, use compressed .tar  
> instead.

If you have a disagreement with the fundamental nature of the 7z  
format then that's something you should take up with its developers.

The ImageMagick developers have chosen to distribute their software in  
many different formats. In decreasing order of size, they  
are: .zip, .tar.gz, .tar.bz2, .tar.xz, and .7z. I chose .7z because it  
is the smallest. I don't see a problem with this.