On May 20, 2008, at 3:45 AM, Reinier Lamers wrote: > In attacking bug #777, I noticed that when darcs creates a patch > bundle, it > tries to take an SHA-1 hash of al the bundle text. When you do a > "darcs put" > with a big repository, the bundle is too big to fit in your RAM, so > the > machine grinds to a swapping halt. Could something similar also > happen when > you do a pull?
Just so everyone knows, cryptographers long ago decided to sacrifice certain desirable properties when designing secure hash functions like SHA-1 in order to gain the "on-line" property -- that you can process the input incrementally and in one pass and with a very small fixed amount of state. So, there is nothing in the secure hash spec that prevents darcs from efficiently computing the secure hash of a bundle much bigger than your physical RAM, by processing it incrementally. Regards, Zooko _______________________________________________ darcs-users mailing list darcs-users@darcs.net http://lists.osuosl.org/mailman/listinfo/darcs-users
