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The idea is excellent (I've lost files to bitrot before), but what is the advantage here over using "Parchives" [1]? There is widespread cross-platform software

by kardos 11y ago

The idea is excellent (I've lost files to bitrot before), but what is the advantage here over using "Parchives" [1]? There is widespread cross-platform software available for "par2" format. [1] https://en.wikipedia.org/wiki/Parchive https://en.wikipedia.org/wiki/Parchive

deleted 11y ago
[deleted]
Tomte 11y ago
I tried to use it with my backup folder and the Windows tool I used (not sure which) dies from too many files. I gave up after that.
chongli 11y ago
Par (at least version 1) uses Reed-Solomon codes. It says right there in the article you linked. Par1 used Reed-Solomon error correction to create new recovery files.
- kardos 11y ago
  Right, par2 does as well [1]. My question is: what advantage does the freeze/melt thing have? It looks to me that freeze/melt produces a larger file that contains the recovery blocks, while par2 stores the recovery blocks in a second file (or files). If the recovery bits are stored at the end of the freeze/melt file then you can still use your frozen file as long as your program doesn't barf on extra data at the end, while the par2 approach doesn't have that limitation. [1] http://parchive.sourceforge.net/docs/specifications/parity-volume-spec/article-spec.html http://parchive.sourceforge.net/docs/specifications/parity-v...
  - chongli 11y ago
    The freeze/melt tool is meant for solving one particular problem: sector errors on block devices such as hard drives, floppies, and CDs. Par, on the other hand, was designed for posting to Usenet binary groups where files are split into many small chunks and the loss of some chunks was so common as to be expected.
ashmud 11y ago
Multithreaded (Intel TBB) version of par2cmdline (archive.org link): http://web.archive.org/web/20150607135928/http://chuchusoft.com/par2_tbb/index.html http://web.archive.org/web/20150607135928/http://chuchusoft.... (Apologies for not directly answering the question.)

by kardos 11y ago

deleted 11y ago

[deleted]

Tomte 11y ago

I tried to use it with my backup folder and the Windows tool I used (not sure which) dies from too many files. I gave up after that.

chongli 11y ago

Par (at least version 1) uses Reed-Solomon codes. It says right there in the article you linked. Par1 used Reed-Solomon error correction to create new recovery files.

kardos 11y ago
Right, par2 does as well [1]. My question is: what advantage does the freeze/melt thing have? It looks to me that freeze/melt produces a larger file that contains the recovery blocks, while par2 stores the recovery blocks in a second file (or files). If the recovery bits are stored at the end of the freeze/melt file then you can still use your frozen file as long as your program doesn't barf on extra data at the end, while the par2 approach doesn't have that limitation. [1] http://parchive.sourceforge.net/docs/specifications/parity-volume-spec/article-spec.html http://parchive.sourceforge.net/docs/specifications/parity-v...
- chongli 11y ago
  The freeze/melt tool is meant for solving one particular problem: sector errors on block devices such as hard drives, floppies, and CDs. Par, on the other hand, was designed for posting to Usenet binary groups where files are split into many small chunks and the loss of some chunks was so common as to be expected.

ashmud 11y ago

Multithreaded (Intel TBB) version of par2cmdline (archive.org link): http://web.archive.org/web/20150607135928/http://chuchusoft.com/par2_tbb/index.html http://web.archive.org/web/20150607135928/http://chuchusoft.... (Apologies for not directly answering the question.)