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Recoverable File Archiving with Free Software?
Viqsi asks: "Back in my Win32 days, I was a very frequent user of RAR archives. I've had them get hit by partial hardware failures and still be recoverable, so I've always liked them, but they're completely non-Free, and the mini-RMS in my brain tells me this could be a problem for long-term archival. The closest free equivalent I can find is .tar.bz2, and while bzip2 has some recovery ability, tar is (as far as I have ever been able to tell) incapable of recovering anything past the damaged point, which is unacceptable for my purposes. I've recently had to pick up a copy of RAR for Linux to dig into one of those old archives, so this question's come back up for me again, and I still haven't found anything. Does anyone know of a file archive type that can recover from this kind of damage?"
Par archives is just a scam popularized by cluless usnet abusers. Think about it, if those files really could reconstruct a corrupt rar archive, why not post only the smaller par files (pigeon hole principle comp.compression faq)? What they do is just add redundansy. They contain the first and last parts of the rar archive, as those are the most likely to dissapear or not propagate. Get youself double copies and you'll be far better off, diffrent brands cd's/dvd's are easy, a backup hd is cheaper in the long run. (you could score a point by giving good reasons for the extra importance of first/last-part, but it's still just adding redundancy, and you can only get as much redundancy as you add or the technique would be better used as compression in the first place). Sorry if this sounds a bit harsh, but you're not the only one being tricked by those par files.