Bug 64633 - Support for file type PAR (RAR archive recovery)
Summary: Support for file type PAR (RAR archive recovery)
Status: RESOLVED INTENTIONAL
Alias: None
Product: ark
Classification: Applications
Component: general (show other bugs)
Version: unspecified
Platform: openSUSE Linux
: NOR wishlist
Target Milestone: ---
Assignee: Raphael Kubo da Costa
URL:
Keywords:
Depends on:
Blocks: 192630
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Reported: 2003-09-21 10:39 UTC by Thibaut Cousin
Modified: 2015-07-30 16:49 UTC (History)
2 users (show)

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Description Thibaut Cousin 2003-09-21 10:39:55 UTC
Version:           v2.1.9 (using KDE 3.1.3)
Installed from:    SuSE
Compiler:          gcc version 3.3 20030226 (prerelease) (SuSE Linux)
OS:          Linux (i686) release 2.4.20-4GB-athlon

Nowadays, one the biggest of RAR is in newsgroups. In that context, RAR alone can almost never extract files correctly, because of CRC errors (very common on news servers). In order to compensate for that, a secondary tool has been made, called PAR.

Could you think about adding PAR support in Ark?

If it may help:
- You can find PAR 1.1 in http://sourceforge.net/projects/parchive
- You can find a Perl-Tk GUI, called TkPAR, if you need to see how it works, in http://www.strangesoft.net/software.ss

I also packaged those apps for SuSE 8.2:
- PAR 1.1: ftp://ftp.gwdg.de/linux/misc/suser-tcousin/suse82/i586/RPMS.Thibaut/par-1.1-1.i586.rpm
- TkPAR: ftp://ftp.gwdg.de/linux/misc/suser-tcousin/suse82/i586/RPMS.Thibaut/tkpar-1.0-1.noarch.rpm

Thanks for your attention!
Comment 1 Thibaut Cousin 2003-11-05 00:51:45 UTC
As a sequel to my wish item, and again in the hope that it may help you, I've also packaged (and heavily tested) version 2 of the Par format, handled by Par2cmdline. That application also handles Par1 format. Its website is the same as Par 1.1 and my package is available here (for SuSE 9.0):

ftp://ftp.gwdg.de/pub/linux/misc/suser-tcousin/suse90/i586/RPMS.Thibaut/par2cmdline-0.3-1.i586.rpm

It should work with most RPM-based distros, as it's a very simple command line program.

Thanks for your attention!
Comment 2 Henrique Pinto 2003-11-09 02:29:43 UTC
I've visited PAR's website and read some things, but I'm still not really sure on what par really is.

Are PAR files distributed alongside original RAR files? If so, how can we detect what PAR file relates to what RAR archive?
Comment 3 Thibaut Cousin 2003-11-09 09:54:13 UTC
You get a set of Par files alongisde a set of other files, not only RAR files (but usually RAR files). The set of Par files starts with a "master Par file".

- For Par1 files, the master file has extension .par and the others have extension .p01, .p02, etc.
- For Par2 files, all the files have extension .par2 but the file name tells you which one is the master file. Example: the master file is called "mysetoffiles.par2" and the others "mysetoffiles.vol00+01.par2", "mysetoffiles.vol02+04.par2", etc.

The master Par file does not contain recovery information, but it contains the list of the files to repair (usually the list of all the RAR files). So it's usually much smaller than the other Par files (example: a few ko for the master  Par file, several Mo for the other Par files).

How to use it? It's the same for Par1 and Par2 files, as Par2Cmdline is compatible with both.

- The command "par2verify name_of_master_par_file" will detect all the Par files, see how much recovery information they contain, then check the integrity of the RAR files (it knows them because they are declared in it).
- The command "par2repair name_of_master_par_file" will first run a "verify" like above, and then, if possible (i.e. recovery information > damaged data), repair everything.

Of course the set of RAR files is fixed, it is declared precisely in the master Par file. But the number of Par files is a bit more loose. If I understood it correctly, each Par file has a number written in its header, so you can have only one Par file with a given number in a set. It means you can add Par files from several sources, as long as their numbers don't overlap. It's something you don't really care about, you let par2verify do all the work. If a Par file is not fit, it's ignored and that's it.

It's also possible to create Par files against a set of files with "par2create", but I've never used it.

In fact, all three commands "par2verify", "par2repair" and "par2create" are only hard links to the binary "par2". So if you prefer to use only the real binary, the commands are, respectively, "par2 v", "par2 r" and "par2 c".

I can provide you wih a set of Par/RAR files, if you like, as a test subject.

Thanks for your attention!
Comment 4 Raphael Kubo da Costa 2010-12-08 02:14:22 UTC
Changing the default assignee for currently open Ark bug reports to me.
Comment 5 Ragnar Thomsen 2015-07-30 16:49:57 UTC
PAR is some sort of data recovery and protection tool. Support for it is outside the scope of Ark. Closing this ancient bug.