Top Document: comp.compression Frequently Asked Questions (part 1/3)
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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