Messages in this thread | | | Date | Thu, 16 Oct 2003 18:49:06 -0700 (PDT) | From | Davide Libenzi <> | Subject | Re: Transparent compression in the FS |
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On Thu, 16 Oct 2003 jlnance@unity.ncsu.edu wrote:
> On Thu, Oct 16, 2003 at 04:04:48PM -0700, jw schultz wrote: > > > > The idea of this sort of block level hashing to allow > > sharing of identical blocks seems attractive but i wouldn't > > trust any design that did not accept as given that there > > would be false positives. > > But at the same time we rely on TCP/IP which uses a hash (checksum) > to detect back packets. It seems to work well in practice even > though the hash is weak and the network corrupts a lot of packets. > > Lots of machines dont have ECC ram and seem to work reasonably well. > > It seems like these two are a lot more likely to bit you than hash > collisions in MD5. But Ill have to go read the paper to see what > Im missing.
The TCP/ECC thingies are different since the probability of false negatives is the combined probability that 1) the data is wrong 2) the hash collides. In case of a hash-indexing algo the probability of coliding hashes is "raw".
- Davide
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