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comp.compression Frequently Asked Questions (part 1/3)
Section - [5] What is the best general purpose compression program?

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The answer is: it depends. (You did not expect a definitive answer,
did you?)

It depends whether you favor speed, compression ratio, a standard and
widely used archive format, the number of features, etc...  Just as
for text editors, personal taste plays an important role. compress has
4 options, arj 2.30 has about 130 options; different people like
different programs. *Please* do not start or continue flame wars on
such matters of taste.

Several benchmarks of MSDOS archivers are available:
- ftp://ftp.simtel.net/pub/simtelnet/msdos/arcers/actest*.zip
  and http://www.geocities.com/SiliconValley/Park/4264/act.html
  by Jeff Gilchrist <jeffg@cips.ca>
- ftp://garbo.uwasa.fi/pc/arcers/
  by Jonathan Burt <jonathan@jaburt.demon.co.uk>

Please do not post your own benchmarks made on your own files that
nobody else can access. If you think that you must absolutely post yet
another benchmark, make sure that your test files are available by
anonymous ftp.

Since all other benchmarks are for MSDOS only, here is one mainly for
Unix, on a 33Mhz Compaq 386.  All programs have been run on Unix SVR4,
except pkzip and arj which only run on MSDOS.

The programs compared here were chosen because they are the most
popular or because they run on Unix and source is available.  For ftp
information, see above. Three programs (hpack, comp-2 and ha) have
been added because they achieve better compression (at the expense of
speed) and one program (lzrw3-a) has been added because it favors
speed at the expense of compression:

- comp-2 is in ftp://ftp.coast.net/pub/Coast/disk2/msdos/ddjmag/
  (inner zip file nelson.zip),
- hpack is in ftp://garbo.uwasa.fi/unix/arcers/
- ha 0.98 is in ftp://garbo.uwasa.fi/pc/arcers/
- lzrw3-a is in http://wwwvms.utexas.edu/~cbloom/src/lzrw.zip

The 14 files used in the comparison are from the standard Calgary
Text Compression Corpus, available in
ftp://ftp.cpsc.ucalgary.ca/pub/projects/text.compression.corpus/

The whole corpus includes 18 files, but the 4 files paper[3-6] are
generally omitted in benchmarks. It contains several kinds of file
(ascii, binary, image, etc...) but has a bias towards large files.
You may well get different ratings on the typical mix of files that
you use daily, so keep in mind that the comparisons given below are
only indicative.

The programs are ordered by decreasing total compressed size. For a
fair comparison between archivers and other programs, this size is
only the size of the compressed data, not the archive size.

The programs were run on an idle machine, so the elapsed time
is significant and can be used to compare Unix and MSDOS programs.

[Note: These benchmarks are now *very* old. I have to do them again
on more recent hardware with the latest programs. For recent results
on MSDOS, check http://www.geocities.com/SiliconValley/Park/4264/act.html ]

       size     lzrw3a   compress    lharc    yabba     pkzip    freeze 
version:                   4.0       1.02      1.0       1.10     2.3.5
options:                                    -m300000                    
       ------    -----    ------    ------    ------    ------   ------
bib    111261    49040     46528     46502     40456     41354    41515 
book1  768771   416131    332056    369479    306813    350560   344793 
book2  610856   274371    250759    252540    229851    232589   230861 
geo    102400    84214     77777     70955     76695     76172    68626 
news   377109   191291    182121    166048    168287    157326   155783 
obj1    21504    12647     14048     10748     13859     10546    10453 
obj2   246814   108040    128659     90848    114323     90130    85500 
paper1  53161    24522     25077     21748     22453     20041    20021 
paper2  82199    39479     36161     35275     32733     32867    32693 
pic    513216   111000     62215     61394     65377     63805    53291 
progc   39611    17919     19143     15399     17064     14164    14143 
progl   71646    24358     27148     18760     23512     17255    17064 
progp   49379    16801     19209     12792     16617     11877    11686 
trans   93695    30292     38240     28092     31300     23135    22861 
    3,141,622  1,400,105 1,259,141 1,200,580 1,159,340 1,141,821 1,109,290
real             0m35s     0m59s     5m03s     2m40s              5m27s
user             0m25s     0m29s     4m29s     1m46s              4m58s
sys              0m05s     0m10s     0m07s     0m18s              0m08s
MSDOS:                                                   1m39s
                        

         zoo       lha       arj      pkzip    zip      hpack   comp-2    ha
        2.10    1.0(Unix)   2.30      2.04g    1.9      0.75a            0.98
         ah    2.13(MSDOS)   -jm       -ex      -6                        a2
       ------    ------    ------    ------  -------   ------   ------  ------
bib     40742     40740     36090    35126    34950    35619    29840   26927
book1  339076    339074    318382   312490   312619   306876   237380  235733
book2  228444    228442    210521   206513   206306   208486   174085  163535
geo     68576     68574     69209    68706    68418    58976    64590   59356
news   155086    155084    146855   144545   144395   141608   128047  123335
obj1    10312     10310     10333    10306    10295    10572    10819    9799
obj2    84983     84981     82052    81132    81336    80806    85465   80381
paper1  19678     19676     18710    18531    18525    18607    16895   15675
paper2  32098     32096     30034    29568    29674    29825    25453   23956
pic     52223     52221     53578    52409    55051    51778    55461   51639
progc   13943     13941     13408    13341    13238    13475    12896   11795
progl   16916     16914     16408    16122    16175    16586    17354   15298
progp   11509     11507     11308    11200    11182    11647    11668   10498
trans   22580     22578     20046    19462    18879    20506    21023   17927
    1,096,166 1,096,138 1,036,934 1,019,451 1,021,043 1,005,367 890,976 845,854
real    4m07s     6m03s                        1m49s   1h22m17s  27m05s
user    3m47s     4m23s                        1m43s   1h20m46s  19m27s
sys     0m04s     0m08s                        0m02s      0m12s   2m03s
MSDOS:            1m49s     2m41s     1m43s                              14m43s

Notes:

- the compressed data for 'zoo ah' is always two bytes longer than for
  lha. This is simply because both programs are derived from the same
  source (ar002, written by Haruhiko Okumura, available by ftp in
  ftp://ftp.simtel.net/pub/simtelnet/msdos/arcers/ar002.zip).

- hpack 0.75a gives slightly different results on SunOS. (To be checked
  with latest version of hpack).

- the MSDOS versions are all optimized with assembler code and were run
  on a RAM disk. So it is not surprising that they often go faster than
  their Unix equivalent.

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Top Document: comp.compression Frequently Asked Questions (part 1/3)
Previous Document: [4] What is an archiver?
Next Document: [7] Which books should I read?

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Last Update March 27 2014 @ 02:11 PM