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Hows does WINRAR get so much more Compression that ZIP ?

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Hows does WINRAR get so much more Compression that ZIP ?

Old 11-09-01, 11:36 PM
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Hows does WINRAR get so much more Compression that ZIP ?

is Winrar the best compression tool around ?

it's awesome!

u download a 200meg file and it uncompresses to 700 meg !
Old 11-09-01, 11:57 PM
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that's only 3.5 to 1 compression. I've had winzip do 10 to 1
(try zipping a wav file)
anyway, it isn't the program so much as the data
for example, if the data only uses 6 out of the 8 bits in a byte (every byte is always 00xxxxxx) then every 4 bytes of uncompressed data can be stored in 3 bytes. This is just one way of compressing stuff
Old 11-10-01, 12:10 AM
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I thought .ace was the best?
Old 11-10-01, 03:08 AM
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I haven't read much on the subject lately, but I don't think lossless data compression technology has improved significantly since the 70's. That is, there shouldn't be much difference between .zip, .rar, .ace, and whatever else is out there.

One may be slightly better than others with one or more different types of data, but for the most part I think it's fair to say that they're all roughtly equivalent in terms of their overall ability to reduce file sizes.

I think Des, that if you were to take that same 700 MB data set and compress it with .zip or .ace, you'll find that they'll also be able to reduce it about 200 MB. As Mr. Hunt says, compression ratio is more a factor data type than compression program.
Old 11-10-01, 03:41 AM
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You know what cracks me up? When people zip single file mpgs up, and get like 3 kbs more compression.
Old 11-10-01, 09:11 AM
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rar is most definitly the best compression program around

and this program to create par files, just made it a ton better
www.wehlus.de/mirror

an example of how par files work...
you create a archive or rar files.. 35 files, 15mb each..
then you use this program to creare par files.. it will make 3 or 4 par files, 15mb each..

you include the par files with the rar files.. then if by chance, someone misses a rar file, or a one of the rar files are currupt..

you can use those 3 par files (along with the mirror program), to recreate any one of the 35 rar files..
Old 11-10-01, 09:21 AM
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Originally posted by twikoff

rar is most definitly the best compression program around
I've heard from most people that .ace is a little better. I assume it really comes down to the speed of the algorithm versus the compression ratio, and for that I've definitely had the best luck with ace.

This mirror program is interesting, I'll have to give it a shot.
Old 11-10-01, 09:51 AM
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Originally posted by Aghama

I've heard from most people that .ace is a little better. I assume it really comes down to the speed of the algorithm versus the compression ratio, and for that I've definitely had the best luck with ace.
there are still a few people out there that use ace.. but in my experience, the majority seems to be rar, and has been for at least the past 5 or 6 years..

although, overall, zip is probably the most used format.. but thats because its the only one that the masses know about.
Old 11-10-01, 09:59 AM
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Originally posted by twikoff

there are still a few people out there that use ace.. but in my experience, the majority seems to be rar, and has been for at least the past 5 or 6 years..
It's a matter of momentum. Everybody uses mp3's, even though there are several better algorithms out there; that's not going to change any time soon.

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