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The RAR file format is somewhat new to me and I'm trying to understand why people are switching to it over the "zip" file format. What's so special about RAR's?

My initial assertion is that it's a poor choice for an archive format since native extraction programs do not come bundled with every OS.

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Seriously, it's only a certain special group of people who are truly using the RAR format like there's no tomorrow. –  caliban Sep 8 '09 at 18:21
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It's undoubtably better than .zip - using that because windows ships with it (I know most linuxes have great outofthebox archiving, and I assume OS X does too) is like jumping in lava because the man eating sharks did it. –  Phoshi Sep 8 '09 at 18:27
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LOL @ 'certain special group of people' –  Molly7244 Sep 8 '09 at 20:36
    
I remember the good old days, when some people would use ZIP, and some people would use LZH, and some people would use ARC, and some people would use ZOO... –  John Fouhy Sep 9 '09 at 1:23
    
In my opinion if you're not using Zip, (which i just don't like), your best bet is to use Rar files. –  RCIX Sep 9 '09 at 3:53

12 Answers 12

up vote 19 down vote accepted

RAR can store file system attributes of NTFS (like streams, full acl permissions, modification/access/etc time, not sure about linux attributes as I prefer tar archives there) and thus makes it a nice complete backup tool with decent compression ability. ZIP can store none of these except plain old simple DOS attributes (read-only, hidden, system).

Additionally RAR supports solid archiving (one compression dictionary for all files) which improves compression ratio if having a lot of small files in the archive. There are also data redundancy and error correction techniques which can be used to fix broken archives (eg broken by transmission errors or bad sectors).

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Solid archiving can be achieved with ZIP, too. Just first zip all your files and directories into an intermediate zip file without compression. Then compress that single intermediate zip file to the final zip file. –  Mike L. Feb 22 '12 at 8:42

Zip compression has the ability to break into parts for quite a long time already, so I don't think people are choosing RAR because of that.

RAR does have better compression, but only slightly, and if that is the winning advantage, everybody will be flocking to 7z instead.

IMO, the real reasons why I think RAR is the dominant format now among (coughs-ahems) certain users, are because of a few perceptions:

  1. You are a n00b if you use ZIP, and if you use 7z you are too hardcore.
  2. It identifies the n00bs when they start questioning how to "un-zip" the files, or what program to use for those "silly RAR files".
  3. WinRAR has a better interface with customizable icons, etc. Oooh shiny!
  4. You have to pay for WinRAR, and true coughs-ahems users will have a copy somewhere - it's like an exclusive club of sorts, and WinRAR is the membership card.

Welcome to the club, mate.

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WinRAR DOES have a better interface, though - especially the draggy stuff. Lovely <3 –  Phoshi Sep 8 '09 at 18:29
    
Don't forget about .ACE. Only the truly l33t users use that for compression. –  Anthony Giorgio Sep 8 '09 at 18:34
    
ACE users are like the Davy Jones of the pi... well the seas I guess. They've been around forever, they are usually ancient, they trawled the far seas of Usenet before, and they are one heckuva bunch of swashbucklers. –  caliban Sep 8 '09 at 19:21
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I must say... The shell integration of WinRAR has been unmatched by any other compression software I've tried. –  Breakthrough Sep 8 '09 at 22:40
    
I would argue that the hardcore use .tar.gz files personally :) Although, for my own use I use 7z it's got the convenience of zip, and the Free (as in speech) nature of tar.gz –  salmonmoose Sep 9 '09 at 0:38

I wouldn't say a lot of people are switching to it.

One of the early advantages were that you could split a .rar file into several files so users could download each one seperately, or you could put each one on a floppy disk or CD. RAR also has some better compression than .zip, but I wouldn't call it anything spectacular. I tend to use 7zip for better compression.

One of the common reasons I'll use it is for sending EXE's through e-mail (as i'm a developer). Gmail and Outlook will block .zip's containing executables as potential viruses, and will allow .rar files.

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That's kinda discriminatory of outlook. Rar files can contain viruses just as well. People just haven't thought of doing it yet. –  KdgDev Sep 8 '09 at 18:14
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Right, and as a developer, it ends up being a major annoyance in both Outlook and Gmail's parts that I'm 100% prevented from using .zip's for transferring legit executables. Zip is more convenient just because I know all the major OS's have baked-in support. –  Will Eddins Sep 8 '09 at 18:18
    
Gmail started blocking .RAR'd executables if I recall correctly... I just change the extension to .xyz and then send 'er! –  Breakthrough Sep 8 '09 at 22:40

One big advantage, outside of the users of cough certain classes of users cough, is that ZIP files have traditionally had size limitations -- notably no more than 4GB for the entire archive, and no more than 4GB for any given (uncompressed) file. This issue is resolved with later versions of the format, but you'll still see Windows display error messages when you try to create large archives, even if you're simply trying to compress gigabytes of plain text (which result in tiny files, comparatively).

RAR does not have that limitation.

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Aha, I always thought the 4GB was a FAT32 limitation. Good links! –  Arjan Sep 8 '09 at 21:32

After downloading a file (that might have been split into many smaller parts), missing or damaged parts can be recovered by using parity files (PAR files, often in the form of parchives).

The parity file mechanism itself is not at all limited to RAR files. But the ability to split RAR files into smaller parts, combined with the availability of software for RAR/PAR, may have made RAR a popular format for huge downloads, like in newsgroups.

According to Wikipedia version 3 RAR no longer needs such files, as it has its own recovery files. (But I feel this still is not a good reason to use that proprietary format.)

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The ability to break a compressed file apart into multiple files.

Back in the day when people use to distribute files with ultra low bandwidth, RAR took off because it could break down a compressed archive into manageable portions that could be downloaded one at a time without worrying about needing to wait forever to get one file that could fail hours into the download and need to be restarted.

It also let you break up these archives into sizes that made things easy to backup such as 3.5 floppies or CDs etc.

Lastly, the compression on RAR is slightly better than zip I think as well and early on I think it had better ways of protecting the data within the archive.

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ZIP has supporting breaking files up for who-knows-how-long. (I recall multi-part ZIPs way back in the days of floppy disks and 14.4Kbps modems being considered "lightning fast.") –  John Rudy Sep 8 '09 at 21:17

Winrar has a better interface, and I believe for a while, it was easier to rar things when you were going to transfer it between OS than it was to zip. I don't think winzip was supported on linux machines until recently. I think winrar was built to originally be universal or platform independent.

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My experience on Linux has been the opposite: free zip tools have always been easy to find, but rar ones are usually encumbered in some way. –  legoscia Sep 8 '09 at 20:02
    
There was never really a problem with any of them. –  Ludwig Weinzierl Sep 8 '09 at 20:57

I don't think that rar is catching on very much, it always had a niche in some circles but that's all.

And you don't need to use winrar to unpack either, 7zip takes care of most format if you are a windows user. (so there is no magic haxxor club either).

My personal guess of formats popularity would be something more like this:

  1. zip
  2. tar (sometimes with zip compression)
  3. rar
  4. 7z

But if someone has some kind of numbers that could prove me right (or wrong) that would be great, so we can put some facts into this question.

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tar with zip compression? Surely you mean gzip/bzip2? I don't think I've ever seen an archive.tar.zip. –  Ryan Thompson Jan 28 '10 at 22:37

rant on

Just what I love, downloading a torrent and finding out it's a bunch of rar's that have to be put back together, then extracted. Gaaaah!!!

Missing the point with a torrent.

And I bet a bzip2'd tar file is smaller (for max compression, sticking the files together and then compressing them always beats compressing one at a time, and sticking that together).

And if your are rysncing, there is a lot to be said for gzip with the -rsyncable flag

/rant

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probably files that were originally from newsnet or some file share service with a space limit. –  Journeyman Geek Mar 22 '11 at 7:29

I have a suspicion that RAR files are more resistant to damage. For instance you can tack a RAR file to the back of a jpg, and both the jpg, and RAR remain readable. Frequently I've had ZIP files become corrupt and not let me get anything out, with RARs I've been able to extract at least some of the data.

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.RAR is better than .ZIP for a couple of reasons. The disadvantage of not being bundled with an OS is a small one in this case, since it is pretty static and bland support at best.

Why it is technically better, .RAR makes much smaller archives in about the same amount of time. It also supports solid archives and take advantage of a lot of small files. This is a huge plus for .rar, it can seriously compress a ton of small files by making them a single big file first, making real use of redundancies between the files. And it was said, .RAR compresses better overall anyway.

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I'm amazed that no one mentioned the decompression speed.

As far as I know, WinRAR offers best balance between compression speed, resulting size and decompression speed (2-3x faster than 7z decompression last I tried but it's a while ago). If LZMA2 has made 7zip decompression faster than winrar then props to 7zip guys. Otherwise I recommend sticking with WinRAR. The Unrar source is available.

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