4 ms·

I remember par2 from usenet, seems like similar/same concept http://www.quickpar.org.uk/ http://www.quickpar.org.uk/ and something i've been wondering about for

I remember par2 from usenet, seems like similar/same concept http://www.quickpar.org.uk/ http://www.quickpar.org.uk/ and something i've been wondering about for a while for storage; glad to see it being implemented at such a scale! makes good sense. Though I would be curious how corruption/rebuild plays out over time. Also impressive how they shaved off all that extra power requirements and built-in expected unreliability. And really, utility is pretty darn reliable anyway, mixed with non-customer facing storage. Good move.

whyoh 11y ago
QuickPar hasn't been updated in a long time. Check out MultiPar for an actively developed alternative. (And of course there are other programs that handle PAR2 files as well.)
- acqq 11y ago
  Par, Par2, Par3, MultiPar, QuickPar and formats explained at: http://en.wikipedia.org/wiki/Parchive http://en.wikipedia.org/wiki/Parchive
fla 11y ago
Reed–Solomon error correction is one of these things that still feels like black magic to me.
- qrmn 11y ago
  They're not even the most arcane. Consider reading up on rapid tornado (Raptor) codes, other fountain codes, Goppa codes… there are whole families of error-correcting codes with different sets of tradeoffs. And the decoding can be enlightening, too: the Viterbi algorithm and its progeny can be surprisingly useful. Then blow your mind even further by looking up the principles of the McEliece cryptosystem (but don't use it as originally specified - modern developments have weakened and refined it a lot). I warn you: this is one of those down-the-rabbit-hole subjects that has a deliciously large amount of literature to soak up, you could find yourselves with bookshelves full of it. (An alarming number of patents, too, for the unwary.)
  - fla 11y ago
    Stop killing my productivity ! :)
zurn 11y ago
It's implemented a bit more widely still in storage: it (or close relatives) is used in all current disk and tape drives.
jl6 11y ago
Check out zfec - dead easy to add erasure coding to your backup scripts. My cold storage files look something like Archive.tar.gz.gpg.split.fec. Although I don't split across too many failure domains, it still protects against isolated bitrot.

whyoh 11y ago

QuickPar hasn't been updated in a long time. Check out MultiPar for an actively developed alternative. (And of course there are other programs that handle PAR2 files as well.)

acqq 11y ago
Par, Par2, Par3, MultiPar, QuickPar and formats explained at: http://en.wikipedia.org/wiki/Parchive http://en.wikipedia.org/wiki/Parchive

fla 11y ago

Reed–Solomon error correction is one of these things that still feels like black magic to me.

qrmn 11y ago
They're not even the most arcane. Consider reading up on rapid tornado (Raptor) codes, other fountain codes, Goppa codes… there are whole families of error-correcting codes with different sets of tradeoffs. And the decoding can be enlightening, too: the Viterbi algorithm and its progeny can be surprisingly useful. Then blow your mind even further by looking up the principles of the McEliece cryptosystem (but don't use it as originally specified - modern developments have weakened and refined it a lot). I warn you: this is one of those down-the-rabbit-hole subjects that has a deliciously large amount of literature to soak up, you could find yourselves with bookshelves full of it. (An alarming number of patents, too, for the unwary.)
- fla 11y ago
  Stop killing my productivity ! :)

zurn 11y ago

It's implemented a bit more widely still in storage: it (or close relatives) is used in all current disk and tape drives.

jl6 11y ago

Check out zfec - dead easy to add erasure coding to your backup scripts. My cold storage files look something like Archive.tar.gz.gpg.split.fec. Although I don't split across too many failure domains, it still protects against isolated bitrot.