Parchive is a tool that helps data recovery of multi-part archives on Usenet.
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. We accomplished that goal. Our new goal with version 2.0 of the specification is to improve.
It extends the idea of version 1.0 and takes the recovery process beyond the file-level barrier. This allows for more effective protection with less recovery data, and removes some previous limitations on the number of recoverable parts. See Par1 compared to Par2 for a more detailed view of the differences.
Because this new approach doesn't benefit from like sized files, it drastically extends the potiental applications of PAR. Files such as video, music, and other data can remain in a usable format and still have recovery data associated with them.
The technology is based on a 'Reed-Solomon Code' implementation that allows for recovery of any 'X' real data-blocks for 'X' parity data-blocks present. (Data-blocks referring to files OR much smaller virtual slices of files).
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 data-blocks.