Work in progress page incomplete.

PAR files come in 2 different versions.. par 1 files and par2's the way to tell which is used for a perticular set of files is the file name extension. Below is a selection of "par2" files par 1 files are easy spot also as the typical file extension for par1 files will be...

PAR, .P01, .P02, .P03, and so on (much shorter file names

Par 1 files are hardly used these days the reason for this is that par 1 files replace a missing or incomplete file so if you have 3 missing/incomplete files you will need 3 par1 files to repair them regardless of how much is missing par 1's are just a like for like swap of files. Par2 files on the other hand contain a certain amount of "recovery blocks" per par file this makes them far more user friendly as you may have 20 incomplete files that just have 2 blocks missing each. To recover/repair these 20 files all you would need is 40 recovery blocks so instead of needing 20 par files to fix the problem you would just need to grab maybe two par files that contained 20 blocks each or even 1 par file that contained 40 blocks. For this reason par 2 files are far more versitile (its even possible to repair a set of rars that are all incomplete with this method with a few par files)

Here is a typical bunch of par2 files, all you really need to pay attention to here is the part i have highlighted in green, the highlighted part shows the amount of recovery blocks each par file contains. Here we have 200 recovery blocks.

Here we have another set of files i have found.

Now if you have a quick add up off the incomplete parts (i.e 34 of 41=7 blocks needed) This set of rars has 120 missing blocks so lets see what pars we have...

This is the pars for those rar files the par files that are 41 blocks are large enough to replace whole files but as we have no full files missing from our rars we just need enough pars to recover the missing segments

248 recovery blocks

So as we need 120 blocks the best way to achieve this is to just download 3 of the "41" block par files giving us 123 recovery blocks. Easily enough for us to repair our files.

Now view my tutorial to see this put into practice.