From the homepage:
The original idea behind this project was to provide a tool to apply the data-recovery capability concepts of RAID-like systems to the posting and recovery of multi-part archives on Usenet.
Parchive can be used to add recovery records to e.g. a DVD. How to do this is described on Mike West's blog. Basically, you will create PAR files using the command:
par2create -s262144 -r10 [NameOfParFile.par2] [FilesToRead]
You can then later recover broken files using