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Since about 1997, I've used the Rar format for my compressed archives, simply because it makes the files smaller than Zip (That is the point of compression, no?). Archives are typically 10-30% smaller, moreso if the archive contains a lot of similar text, because Rar uses a patented text compression algorithm (The same one, I believe, as Bzip1 did before it was removed for Bzip2 due to the patent).

Other compression tools have come and gone. The "Ace" format is okay, but on the occasion that it does make smaller files than Rar, they are 1-2% smaller at best, and its archives are frequently larger.

Bzip2, while much better than zip, was rarely able to compete with Rar.

Recently, I tried 7-Zip, a compression tool whose compression algorithm is based on LZ77 (Lempel-Ziv 1977) compression, the same thing Zip, Arj, and others are based on. Difference being that 7-Zip's LZ77 derivative is "optimized and enhanced." I wasn't really expecting much, especially when you consider the rather poor interface, the fact that it thus far only runs in Windows (or Unix with WINE if that counts), and the occasional flakiness of the compression tool itself.

I did one test. I compressed Dev-C++ along with about 20 C++ projects in a subdirectory. Uncompressed, the files are about 150MB.

Rar, using maximum compression, solid archiving, and no recovery record, was able to squeeze it down to an impressive 18MB. Quite the compression ratio.

Then I tried with 7-Zip, using LZMA compression on "Ultra" level, a 48MB dictionary size, solid archiving, and the 7z archive format. The compression took forever, working at a rate of about 100KB/sec on a Athlon64 3200+ laptop.

When it finished, however, the resulting file was no more than 13.9MB. :blink:. 7-Zip was able to best Rar's already outstanding compression by almost 30% (in this specific test). Not bad at all! I've never seen anything best Rar by more than a few %.

While the tools need some work, this compression algorithm is amazing. I'd recommend it to anybody who wants the smallest possible archives and doesn't necessarily need them compressed quickly.

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i went to 7-zip's website, and according to its main page and it says that pk-zip 2.5 has a much better compression. have u tested that 1 yet?

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i went to 7-zip's website, and according to its main page and it says that pk-zip 2.5 has a much better compression. have u tested that 1 yet?

You read that wrong, pkzip 2.50 is the worst one!

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Since about 1997, I've used the Rar format for my compressed archives, simply because it makes the files smaller than Zip (That is the point of compression, no?). Archives are typically 10-30% smaller, moreso if the archive contains a lot of similar text, because Rar uses a patented text compression algorithm (The same one, I believe, as Bzip1 did before it was removed for Bzip2 due to the patent).

Although rar makes smaller files, lately I find Zip a better choice since it is noticebly faster (subjectively up to 50% faster with large files) and its compressed files are only marginally bigger.

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But in this case plain Zip would be a much worse choice, since what Sivar is

describing depends on making a more compressed archive, which would

also probably be significantly slower to restore.

Sivar, have you tested speed on extracting files? I know that is not as

much of an issue for you, but it would make a good performance note.

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Since about 1997, I've used the Rar format for my compressed archives, simply because it makes the files smaller than Zip (That is the point of compression, no?). Archives are typically 10-30% smaller, moreso if the archive contains a lot of similar text, because Rar uses a patented text compression algorithm (The same one, I believe, as Bzip1 did before it was removed for Bzip2 due to the patent).

Although rar makes smaller files, lately I find Zip a better choice since it is noticebly faster (subjectively up to 50% faster with large files) and its compressed files are only marginally bigger.

There is NO situation in which WinZIP is in any way better than WinRAR (including speed). In fact, WinRAR is FASTER than WinZIP when working with .ZIP files. If you pick maximum RAR compression, yes it is slower, but it gets a better ratio. With the lower compression levels, it is still better compression than ZIP, and is faster.

BTW, yes 7-zip is impressive, and the default LZMA algorithm is general purpose. You can select PPMd in the 7z archives for text-optimized compression.

7z and UHarc get about the same compression ratios on most files, but UHarc gets an INSANE ratio on multimedia files if you enable UHarc multimedia compression. (bitmaps and sounds, not videos). UHarc is extremely slow even compared to 7z however, has a tendency to crap out while compressing large files, and has an absolute limit of 2GB per archive.

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But in this case plain Zip would be a much worse choice, since what Sivar is

describing depends on making a more compressed archive,  which would

also probably be significantly slower to restore. 

  Sivar, have you tested speed on extracting files?  I know that is not as

much of an issue for you, but it would make a good performance note.

WinRAR is disk limited when extracting files, even if you have a good RAID system. The CPU usage likely won't go over 20% unless you are using a PIII or slower.

7z archives extract at around 8MB/s on my 3500+. Uharc extraction is about 4MB/s on the same machine.

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7zip's only real advantage over rar/ace is it's ability to use a dictionary size above 4MB. Since it is patent and license encumbered, it is not something that would be even remotely worth my time to download. It also seems to exist for the sole purpose of annoying warez nntp users (which is hilarious IMHO!). What's so bad about gzip and bzip anyway?

Thank you for your time,

FranK Russo

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What's so bad about gzip and bzip anyway?

Their compression ratios SUCK by today's standards.

7z archives are often less than HALF the size of gzip archives of the same files.

And even creating zip archives it does about 4% smaller than gzip. It's not just the dictionary size.

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gzip is ancient and bzip seems slow for not too much in gains. what is patented about 7zip? isn't it gpl'd? if i were distributing something on a web site i would use 7z self-extractors just to save on bandwidth but winrar is fine for me locally.

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gzip is ancient and bzip seems slow for not too much in gains.  what is patented about 7zip?  isn't it gpl'd?  if i were distributing something on a web site i would use 7z self-extractors just to save on bandwidth but winrar is fine for me locally.

I figured you would be one to use vanilla Zip, because it is the most common format by far (similar to the use of MP3 over technically superior formats like Vorbis).

7-Zip is LGPL'd, but a proprietary license is offered "for those who can not use the GNU LGPL in their code." I don't know who that would be, unless someone can't stand to give credit for the algorithm.

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i use mp3s because everything works with them (hardware and software) and the quality on 192vbr is completely satisfying for me. different situation altogether, i don't know why you would compare the two. as for rar/zip i use rar for my own stuff and zip for anything i'm sending/hosting.

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One of my friends told me about 7-zip not too long ago and I thought I would give it a try. So to test it I added my Quake3 directory with winrar and with 7-zip using best compression. I just looked for the paper where I wrote down the results but I can't seem to find it - but the essence of the result was the following:

It took more than twice as much time to add with 7-zip.

Winrar was able to cut off around twice as much of the filesize as 7-zip.

So I was far from impressed. It might perform better with other types of data I don't know. But yeah I've always been happy with winrar - it always offers a pretty good compression and at a reasonable speed. And I must agree with glug - winrar is almost always better and faster than winzip. At least the last times I tried winzip - it's been quite a while now though.

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One of my friends told me about 7-zip not too long ago and I thought I would give it a try. So to test it I added my Quake3 directory with winrar and with 7-zip using best compression. I just looked for the paper where I wrote down the results but I can't seem to find it - but the essence of the result was the following:

It took more than twice as much time to add with 7-zip.

Winrar was able to cut off around twice as much of the filesize as 7-zip.

So I was far from impressed. It might perform better with other types of data I don't know. But yeah I've always been happy with winrar - it always offers a pretty good compression and at a reasonable speed. And I must agree with glug - winrar is almost always better and faster than winzip. At least the last times I tried winzip - it's been quite a while now though.

Winrar was able to cut off around twice as much of the filesize as 7-zip.

This is ABSOLUTLY not true.

Look on this http://www.overclockers.ru/news/newsitem.s...4&id=1074586553

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gzip is ancient and bzip seems slow for not too much in gains.  what is patented about 7zip?  isn't it gpl'd?  if i were distributing something on a web site i would use 7z self-extractors just to save on bandwidth but winrar is fine for me locally.

7zip is the algo for the origional bzip (bzip1) with a large dict size. Wasn't it some strange patent thing (like the unisys patent) that forced them to make bzip2? I assume with 7zip that the patent has recently expired. The other unfortunate thing about using a 48MB dict size is that you will have a heck of a time uncompressing it on a a 32MB box.

Just because it is gpl'd, doesn't mean it is unencumbered. Take XVID for example. It is GPL'd, but encumbered bt the MPEG-LA's patents. So, basically, we're screwed untill Theora becomes stable or the MPEG-LA's patents expire (whichever comes first). I wonder what the story is with the BBC's codec?

Thank you for your time,

Frank Russo

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well i still encode using xvid because autogk rules and even if some weird patent thing happens they can't take away the software i already have

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well i still encode using xvid because autogk rules and even if some weird patent thing happens they can't take away the software i already have

Same here. It would just be nice to have an unencumbered compressor, even if the compression/quality was a little less. Like FLAC vs. APE. By no means am I saying "don't use xvid". I am saying, make an effort to find a free alternative. It's like when I buy tires, I "make an effort" to buy American. If the quality is the same, and the price difference is small, I go for it.

Frank

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