Re: Compression Comparison

[Jim Meyering]

address@hidden (Bob Proulx) wrote:

> Jim Meyering wrote:
>> To reiterate, here are the sizes:
>>   coreutils-6.9.90.tar.gz    8.6 MB
>>   coreutils-6.9.90.tar.bz2   5.6 MB
>>   coreutils-6.9.90.tar.lzma  3.6 MB
>
> I am a hard sell.  It is impressive but not hugely.  The original size
> was 35M and so all of these already make large size reductions.  Let's
> look at the numbers.
>
>  36280320 coreutils-6.9.90.tar
>  12955108 coreutils-6.9.90.tar.Z
>   8996724 coreutils-6.9.90.tar.gz
>   5952780 coreutils-6.9.90.tar.bz2
>   3682634 coreutils-6.9.90.tar.lzma
>
> That yields[1]:
>
>   100% 36280320 coreutils-6.9.90.tar
>    64% 12955108 coreutils-6.9.90.tar.Z
>    75%  8996724 coreutils-6.9.90.tar.gz
>    83%  5952780 coreutils-6.9.90.tar.bz2
>    89%  3682634 coreutils-6.9.90.tar.lzma
>
> Let's see that more visually.  Here is a bar graph.
>
>   +----------+--------------------------------------------------+
>   | compress |================================                  |
>   | gzip     |=====================================             |
>   | bzip2    |=========================================         |
>   | lzma     |============================================      |
>   | true     |==================================================|
>   +----------+--------------------------------------------------+

Hi Bob,

I'm surprised you'd compare in such a pessimistic manner.
I look at it differently:

compare download time:
  going from gzip to lzma, I see a speed-up of 2.39
  going from bzip2 to lzma, I see a speed-up of 1.55

compare disk usage:
  going from gzip to lzma, I can store more than twice as much (2.39x) data
  going from bzip2 to lzma, I can store 55% more data