Parity Archive Volume Set
The idea behind this project is 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. With a parity archive, this tool, and all but one part of a multi-part set you can recover the missing part.
The key to this mission is a clean file format specification which provides all the necessary capabilities for programs to easily verify and regenerate single missing parts out of a set of archives. We might just be able to make binary posting and downloading on Usenet a little easier. That's a pretty cool goal!
par2 is complete rewrite of parchive with much additional advantages. Read all about them on this page: http://www.pbclements.co.uk/QuickPar/AboutPAR2.htm