Which one is good: RAR, ZIP, 7z, TAR?

erwin1978

Golden Member
Jun 22, 2001
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I'm looking to securely compress my files and back it up to an online storage. Which format do you use that's proven to be reliable and secure?

Windows 7 has a built-in zip software but I am leery of it. I've used it to decompress a bios file which seemingly went OK until I actually tried to update my motherboard bios. The motherboard complained the bios file was incompatible. I then used Winzip to decompress the same file and my motherboard accepted the bios file. How do you explain that? Somehow Windows zip tool modified the bios file so it wasn't one-to-one.
 

RampantAndroid

Diamond Member
Jun 27, 2004
6,591
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The zip function built into windows has never cause me problems.

RAR has decent compression, as does 7z I think...but the 7zip tool isn't paid like the tool from rarlabs. How secure does it need to be?
 

lxskllr

No Lifer
Nov 30, 2004
59,104
9,538
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I use .7z on Windows because it's a libre format. I've never had archives corrupt though, not that I'm aware of anyway. I guess the way to check would be to get the md5sum or similar of an image, compress it, then decompress it, and see if you get the same thing.
 

skriefal

Golden Member
Apr 10, 2000
1,424
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TAR is an archive format only; it doesn't compress. But it can be combined with a compression algorithm such as GZip or BZip2, yielding files with a .tar.gz extension (or .tgz) or .tar.bz2. It's used mostly on Linux and other Unix variants.

Seems that your question is more about what compression software package to use, and less about which compression format to use. Most of the software packages will support multiple file formats. For Windows software I like WinRAR or 7-Zip.
 

VirtualLarry

No Lifer
Aug 25, 2001
56,570
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I'm looking to securely compress my files and back it up to an online storage. Which format do you use that's proven to be reliable and secure?

Windows 7 has a built-in zip software but I am leery of it. I've used it to decompress a bios file which seemingly went OK until I actually tried to update my motherboard bios. The motherboard complained the bios file was incompatible. I then used Winzip to decompress the same file and my motherboard accepted the bios file. How do you explain that? Somehow Windows zip tool modified the bios file so it wasn't one-to-one.

Barring a giant bug in the Windows unzip utility, I would say that your hardware is unstable. I would start diagnostics on it. Are you overclocked?
 

zebrax2

Senior member
Nov 18, 2007
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I think RAR has support for recovery records which should help case your archive get corrupted.
 

BirdDad

Golden Member
Nov 25, 2004
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Use RAR with PAR2 that way even if some of your files get corrupted you can still recover them.
 

maxi007

Banned
Sep 8, 2014
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i use RAR , compression is fast and more . and best part you can extract data from corrupted archives
 

ninaholic37

Golden Member
Apr 13, 2012
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The motherboard complained the bios file was incompatible. I then used Winzip to decompress the same file and my motherboard accepted the bios file. How do you explain that? Somehow Windows zip tool modified the bios file so it wasn't one-to-one.
I've seen the Windows zip tool complain that a file had an error during the decompression process a few times, even though the file opened just fine (and was not corrupt) in WinZip, WinRAR and 7-Zip. As your experiment also showed, I don't think the problem is how it compresses files but how it extracts them. It seems to only happen with small files (usually under 1KB) for some reason, and the bug only started with the Windows 7 version (I think).
 

bbhaag

Diamond Member
Jul 2, 2011
7,097
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I use Winrar on my machine. Mainly use it as a way to compress family photos. It works good but 7zip and Peazip would work just as well and don't have a nag screen.

I don't create Par2 files because its a local account. If I was uploading it to the cloud were the archive might be spread over thousands of miles and then transferred to multiple data centers I might consider using them.
 

lamedude

Golden Member
Jan 14, 2011
1,214
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I've seen the Windows zip tool complain that a file had an error during the decompression process a few times, even though the file opened just fine (and was not corrupt) in WinZip, WinRAR and 7-Zip.
My guess is the zip was compressed with something other than deflate.
 

smakme7757

Golden Member
Nov 20, 2010
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I use RAR - Latest version.

256bit AES when you encrypt and can create recovery records.
 

maxi007

Banned
Sep 8, 2014
190
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^^ yeah exactly ,you can open maximum no of extesions with this , even if i used tosee some hidden files in my explorer
 

ninaholic37

Golden Member
Apr 13, 2012
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My guess is the zip was compressed with something other than deflate.
Interesting. When I go to the library (they have Windows 7 there) I will test out some zips I believe were problematic and either try to verify if they're using deflate, recompress them in Windows and see if it makes a difference, and/or post them. I have Dos PKZIP also but just checked it for fun and it's at v2.5 (not v1.x).
 

Mike64

Platinum Member
Apr 22, 2011
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It probably wouldn't help in this case, since I assume you were dealing with a single file, but I've found that WinRAR is better for recovering at least some files out of a corrupt archive, whereas 7zip just fails completely if any part of the archive is corrupt. WinRAR also has more detailed error reporting which is useful if you're dealing with a multipart archive. If only one of the parts is bad, WinRAR tells you which part is bad, 7zip doesn't.
 

user1193526

Junior Member
Sep 21, 2014
17
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0
erwin1978 to answer your question.

If you want reliable, you do not compress files.
If you want secure, you do not upload to a cloud.

For those who do not know. PAR can be thought of like Software Raid. It has its purpose. IMO it just does not have a purpose regarding backups. You have to create a significantly large PAR file for it to compidently serve as a backup. For data of value i simply create a "1 to 1" (1:1) uncompressed backup. Or if need be for significant space savings for certain data types, compress the file individually.

personally i find 7-zip usually gives higher compression ratio than winrar... when I am looking to compress.
 

erwin1978

Golden Member
Jun 22, 2001
1,654
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Yes, I was thinking that it's safer to backup files uncompressed. In the event of an unrecoverable bad sector on storage drive at least only data contained in that bad sector is lost as opposed to one giant compressed archive where a single bit error could render an archive file unreadable.

Have you guys tried the password remover for rar files that's been spreading around? The only reason I want to archive my files is to password protect it and upload it online for storage.

Why is it only a small number of websites provide the checksum on files you download on their website? I would think it's critical that everyone does a checksum validation when downloading bios files or and ISO of Windows for instance.
 

Insert_Nickname

Diamond Member
May 6, 2012
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Why is it only a small number of websites provide the checksum on files you download on their website? I would think it's critical that everyone does a checksum validation when downloading bios files or and ISO of Windows for instance.

Yeah, that's annoying. A quick and dirty "fix" to verify the download is to download 1 or 2 additional copies, if their checksum matches, there is a good chance they're good.

Its doesn't help with establishing if the files are legitimate though. ():)
 

jkauff

Senior member
Oct 4, 2012
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I don't know how large your files are, but most consumer cloud services have an individual file size limit for uploading. WinRAR can split large files or file sets into multiple RAR archives that can be reassembled easily. If you have things like 15GB movie files and a 1GB upload limit, this can be very useful.
 

John Connor

Lifer
Nov 30, 2012
22,757
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If I wanted to store stuff in the cloud I would use the 7z SFX archive feature and encrypt along with file names. Never had a corrupt file yet.
 

ninaholic37

Golden Member
Apr 13, 2012
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I've seen the Windows zip tool complain that a file had an error during the decompression process a few times, even though the file opened just fine (and was not corrupt) in WinZip, WinRAR and 7-Zip. As your experiment also showed, I don't think the problem is how it compresses files but how it extracts them. It seems to only happen with small files (usually under 1KB) for some reason, and the bug only started with the Windows 7 version (I think).
I just found one that causes this problem right now:

http://www.belowe.com/insan.zip

This is the error Windows 7 gives when I try to extract it:

wjds13.jpg


Pretty sure that MAPHEAD.TI (242 bytes) is not corrupt. Anyone else get this using the Windows 7 default zip extractor?
 

Mushkins

Golden Member
Feb 11, 2013
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I just found one that causes this problem right now:

http://www.belowe.com/insan.zip

This is the error Windows 7 gives when I try to extract it:

wjds13.jpg


Pretty sure that MAPHEAD.TI (242 bytes) is not corrupt. Anyone else get this using the Windows 7 default zip extractor?

I normally get this sort of thing in the opposite direction. For example I download a ZIP, and try to extract with 7zip and it says the files are all corrupt, but using the built-in windows extractor they're 100% fine.

I think it's just inconsistencies in the implementation of the "ZIP" compression algorithm. If what program zipped it is inconsistent with what is unzipping it, it throws a hissy fit.

I've never run into this with any other archive type.