Parchive parity files

In July , Tobias Rieper and Stefan Wehlus proposed the Parity Volume Set specification, and with the assistance of other project members, version 1. Any of the recovery files can be used to rebuild a missing file from an incomplete download.

In January , Howard Fukada proposed that a new Par2 specification should be devised with the significant changes that data verification and repair should work on blocks of data rather than whole files, and that the algorithm should switch to using 16 bit numbers rather than the 8 bit numbers that PAR1 used.

Version 2. Peter Clements then went on to write the first two Par2 implementations, QuickPar and par2cmdline. Abandoned since , Paul Houle created phpar2 to supersede par2cmdline. Multipar uses par2j. Versions 1 and 2 of the file format are incompatible. However, many clients support both.

For Par1, the files f1 , f2 , Given all of the original files except for one for example, f2 , it is possible to create the missing f2 given all of the other original files and any one of the parity volumes.

Alternatively, it is possible to recreate two missing files from any two of the parity volumes and so forth. PAR2 , filename. PAR2 , etc. If an index file of a download states that 4 blocks are missing, the easiest way to repair the files would be by downloading filename. However, due to the redundancy, filename. PAR2 is also acceptable. There is also an index file filename. Par2 specification supports up to source blocks and up to recovery blocks. Input files are split into multiple equal-sized blocks so that recovery files do not need to be the size of the largest input file.

Directory support is included in the PAR2 specification, but most or all implementations do not support it. The Par3 specification was originally planned to be published as an enhancement over the Par2 specification. However, to date, it has remained closed source by specification owner Yutaka Sawada.

Anonymous Not logged in Create account Log in. Hand W iki. From HandWiki. Namespaces Page Discussion. Supports at least ". Supports at least English and Japanese. MacPAR deluxe A graphical client. PyPar2 A graphical frontend for par2cmdline. It is the reference implementation. From source code Use git to clone the source code. Bugs and questions for graphical client should be directed to that client's author. The Parchive developers are only responsible for the file format and the par2cmdline client.

Documentation for the par2cmdline client can be gotten by running "par2 --help" or "man par2" or "par2cmdline --help" and "man par2cmdline". Bugs in par2cmdline can be tracked on the Github project's issues page. Some help is available on the old website on Sourceforge.

Specification for Parchive files, version 2. Specification for Parchive files, version 1.