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Par 2.0

Old 06-06-03, 09:20 PM
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Par 2.0

I've just discovered this new version, PAR 2.0. After reading the differences between version 1.0 and 2.0, what a huge improvement over the previous version. There was at least 10 corrupted rar files and I was able to recover the whole rar set by downloading a large enough PAR2 file using QuickPar.

Here are the differences:
http://www.pbclements.co.uk/QuickPar/AboutPAR2.htm
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Old 06-06-03, 11:41 PM
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I've always been amazed by PAR technology - it's like magic. How can it reconstruct ANY missing file from a set?
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Old 06-07-03, 01:20 AM
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cool. Thanks for the info zuffy.
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Old 06-07-03, 02:17 AM
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Yeah - just ran into a PAR2 file yesterday and loved it. Worked out nicely.

http://www.slyck.com/ng.php?page=6

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Old 06-07-03, 02:46 AM
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par v2 uses an improved formula. instead of being file based it splits all the data into even blocks so that if a little section is missing or corrupt you can dl enough pars to fix that section instead of a par the size of the largest file.
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Old 06-07-03, 03:27 AM
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I am still in awe when it comes to pars.

Damn, but i still cannot believe that you can fix a .rar file .


Like RolloTomasi says it's like magic.
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Old 06-07-03, 02:57 PM
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It's not magic. In fact, it's a very straight-forward concept. The concept of parity is used in everything of any significance. It only makes sense that we use it for rars.

I remember back when the first PAR creation/recovery tool came out, it was painfully slow, so I wrote my own that was about twice as fast. It only took a couple of days. I was in the process of prettying it up for release when things like SmartPAR and FSRaid started coming out, and they were better than what I had done, so I just dropped it.

Anyway, it's pretty basic stuff. The concept of parity is simple, and the math isn't bad either; writing an application that can create and recover them FAST is the difficult part.

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