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Don't Use RAR

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Re: Don't Use RAR

#161

Post by anonu »

tropin wrote: post #23
anonu wrote: post #11

The sightly better file compression with rar is still interesting. But I suppose with today's compute when you think about the time vs space trade-off, time is more important. Space is cheap.

Is not just "slightly better" in some cases. An obvious one is repeated files. If RAR encounters a file ten times, it will compress once and store it and nine pointers. lzma and zstd guis i've tested will store ten compressed copies. It happens all the time in backups.

Handling multiple identical files is certainly desirable - but this is not the "core" compression algo. Its a cute optimization trick...

Re: Don't Use RAR

#163

Post by noAnswer »

rcfox wrote: post #113

One benefit of RAR is when dealing with multi-file archives, you don't need all of the files to be able to decompress one of them. You don't even need a complete file to be able to look inside! Yes, some of your files will be broken if you don't have the entire archive, but at least you can salvage some of your data. Or you can peek in to make sure you've got the right thing before committing to multi-gigabyte downlo…

Yes, it is pretty annoying if someone posts a .7z.001 file on usenet. You can't peek inside. You can't even see if it's password protected until you downloaded the whole thing.

Re: Don't Use RAR

#165

Post by kosasbest »

Interesting that the warez scene adopted RAR as the standard for packaging up pirated works. The alternatives like 7z save more bytes, yet RAR somehow became the winner. Anyone know why?

Re: Don't Use RAR

#166

Post by deelowe »

TheFreim wrote: post #111
useFAR wrote: post #98

Earlier quoted context omitted.

7z does not offer archive recovery. This has saved my archived data couple of times, which would be gone, if I was using 7z.

I'm not familiar with compression very much, what's the difference between what 7z does versus "archive recovery"? Thanks

Some compression formats are actually designed for data archival and compression. Rar is one such format. One of the early use cases was data archival onto long term storage mediums such as tape. As such, it has built in parity which means you can recover partially corrupted archives. It can also do things like split the archive up over many smaller files. Again, because this sort of thing was needed for backing up to tape, floppy, etc in the late 90s/early 2ks.

Re: Don't Use RAR

#167

Post by programmer_dude »

300bps wrote: post #152
Someone1234 wrote: post #97

Earlier quoted context omitted.

I'm not sure what you're talking about. The major tool promoted in the article is 7Zip which is not made by either Google or Facebook, costs $0, and doesn't contain ads or collect data. The two tools which are made by Google or Facebook are command line utilities which also don't contain ads.

7zip is just one of three applications mentioned in the article and the article says it’s much slower and seems to more recommend offerings from Facebook and Google. First off, 7-Zip achieves a better compression ratio, but it is much slower to compress than RAR. However, since 2013 Google's Brotli and since 2015 Facebook's Zstandard (Zstd) are two good options for file compression. I didn’t say either of them contai…

Google/Facebook aren't getting paid for these products. You are not supporting them by just using their compression tools.

Re: Don't Use RAR

#168

Post by Hello71 »

bombcar wrote: post #164

If you're using compression, and you have more than one core, you should consider trying pbzip2 - it's parallel http://compression.ca/pbzip2/ 7zip may also do something similar, but it may depend on the archive type it's creating.

bzip2 is almost always the worst option. it is significantly slower and results in larger output than xz, which is in turn slower and larger than 7zip (lzma2).

Re: Don't Use RAR

#170

Post by colonwqbang »

throwaway81523 wrote: post #10

The rar license prohibits writing a compatible compressor? What kind of nonsense is that? I clicked the license link and there is a scary looking anti-reverse-engineering clause, but 1) that sounds legally dubious given how the program is distributed; and 2) there is a FOSS decompressor, and studying that may be sufficient to write a compressor without examining the non-free official compressor. The article is right…

Once you have fully "re-created the RAR algorithm" you would not need to license the official one anymore. So it's OK, just uninstall RAR from your computer at that point :)
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