You can read more about it on Wikipedia, but one thing I noted in the article is that it's "mature for widespread use" (referring to the PAR2 format), but is really being used? I'm reasonably technical, take great care with my backups, but even after spending some time reading about it, I'm still unclear on it's use. This might be a real life-saver for certain users/groups -- can we make some recommendations?
Anyway, I tried to put together a listing of my assumptions about it and open questions (below). For our purposes, I'm focusing on Multipar just because it appears to be in active use and development.
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Who would use this? (use cases)
- Backups - either long term or on on unreliable media (e.g. an older hard drive). Also see Midas' post on bit rot.
- Poor connections, or where re-sending data would be expensive or problematic .
- Unreliable file servers - specifically newsgroups, where PAR files were originally popularized.
Associated tools - if you're trying to copy a file that's been damaged and keeps giving an error message:
- Unstoppable Copier - https://www.portablefreeware.com/index.php?id=149
- Encopy - https://www.portablefreeware.com/index.php?id=1015
- Raw File Copier Pro - https://www.novirusthanks.org/products/ ... opier-pro/
Open questions
- Is there a cogent recommendation on redundancy? I'm assuming (in the case of Multipar) 100% redundancy is 100% reliable but is that reasonable? Can we recommend something based on your situation?
- A way to do command-line operations to batch add it to your file or files?
Did I miss anything? Is the wrong solution to the problem? Maybe there a better method than PAR.
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EDIT:
I realize this is a broad question so I'll also add a specific one: when I was drafting the entry, I wrote up "10% of the original for already safe methods, 50% for frequent failures", but is that accurate?