[Toybox] crc64?

Rob Landley rob at landley.net
Sun Feb 4 19:35:14 PST 2018


On 02/04/2018 07:54 PM, Rob Landley wrote:
> But the largest distribution in the wild seems to be the "jones" one
> used by redis:
> 
> https://raw.githubusercontent.com/antirez/redis/88c1d9550d198fd7df426b19ea67e9c51c92a811/src/crc64.c
> 
> Those are also the only three listed here:
> 
> https://users.ece.cmu.edu/~koopman/crc/crc64.html

The "Jones" variant was introduced by this paper:

http://www0.cs.ucl.ac.uk/staff/D.Jones/crcnote.pdf

Meanwhile, the xz variant is from Appendix B of a 1992 publication the
European Computer Manufacturers Association put out about 48 track
magnetic tape cartriges, which seems to have been completely ignored
until xz picked it up.

http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-182.pdf

Looking for more analysis on why xz chose an appendix of a 25 year old
standard for magnetic tape storage, I found this:

http://www.nongnu.org/lzip/xz_inadequate.html

Which doesn't _directly_ address the issue but really doesn't give me
confidence in xz's design decisions.

(What _everybody_ seems to agree on is the ISO version is actively stupid.)

Anyway, happy to have more info from somebody with actual domain
expertise...

Rob



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