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Newsgroup Newbie Question

Old 05-16-02, 07:42 PM
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Newsgroup Newbie Question

Hi, I'm new to newsgroups and I was wondering what's the purpose of the files that end in .p01, .p02 and etc for vcds. I tried downloading just the rar files once and the vcd still worked perfectly. Thanks
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Old 05-16-02, 08:35 PM
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http://www.disc-chord.com/smartpar/

SmartPAR is an application that handles files specified by version 1.0 of the parchive parity file format. These are files that have extensions like PAR, P01, P02, P03, etc. SmartPAR can create these files as well as recover data from them and SmartPAR makes it easy to use these files.

Parchive parity files (or par files for short) create redundant data that can be used later in case parts of the original data is lost or corrupted. Par files allow file level recovery of data. That is, out of a group of many files, if a limited number of files are lost or corrupted, they can be recovered.

This has multiple uses; for example, backing up or transferring a large file via zip disks. With a compression program like RAR or ACE, a large file can be compressed and divided into pieces that are small enough to fit on a zip disk. But if a single disk is lost or fails in some way, all the data is lost. In fact, if the chance that a single disk will fail is x (say 0.1%) and you have y disks (say 20), then the chance that you'll suffer data loss is on the order of xy (2%).

The addition of redundant data through par files decreases the chance that the data will be lost dramatically. In the above case, chance of data loss goes down from 1.98% to 0.12% with a single par file and 0.00015% with two par files. This is also applicable to situations where data is transmitted through email and usenet where data integrity of large files can be much lower. For example, if there is a 5% chance of loss per file and 65 files, odds of data loss is shown below
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Old 05-18-02, 10:29 PM
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As was stated above they are parity files for the smart par program. After you download a large .rar or .ace file you can run the .par file using smartpar.exe. Setup all .par attachements to auto execute using smartpar.exe and after you download a group of archived files all you have to do is click on the .par file in the bunch.

Smartpar will scan each file in sequence and respond with a 'complete' for a good file, 'corrupted' for a bad file, or 'missing' if you don't have one. Once the scan is complete, if you have enough p01-p0?? files to recover all the corrupted or missing ones you just go up to the drop down menu and hit 'recover files'. It saves alot of frustration if you just spent a few hours (or days) downloading a huge file.

If you do not have enough parity files to recover you need to jot down all the corrupted and missing files and go back on the newsgroup and see if you can find the reposts. Usually everyone gets the same corrupted files and someone has already requested the repost but if no one has then you can do that yourself. Just reply to one of the headers in the file asking for a repost of the ones you need.

-K
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Old 05-20-02, 01:01 AM
  #4  
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Cool, thanks for the help :-)
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