Proposal that we now create two branches - 2_5 and head

Donovan Baarda abo at
Wed Jan 29 22:41:40 EST 2003

On Wed, 2003-01-29 at 18:22, Craig Barratt wrote:
> > I have several patches that I'm planning to check in soon (I'm waiting
> > to see if we have any post-release tweaking to and/or branching to do).
> > This list is off the top of my head, but I think it is complete:
> And I have several things I would like to work on and submit:
>  - Fix the MD4 block and file checksums to comply with the rfc
>    (currently MD4 is wrong for blocks of size 64*n, or files
>    longer than 512MB).

I'm interested in contributing to this effort too; I have helped fix and
optimise the md4sum implementation for librsync. Once the issue of
protocol backwards compatibility is resolved, this code could be dropped
as is into rsync (up to 20% speed increase over current implementation).

However, I also want to change to using the RSA implementation API, and
submit this code upstream to libmd (it has an optimised md5sum, but only
the RSA md4sum). That way all the projects that used the RSA
implementation could benefit from a more optimised md4sum (and can
contribute bug fixes etc).

>  - Adaptive first pass checksum lengths: use 3 or more bytes of the MD4
>    block checksum for big files (instead of 2).  This is to avoid almost
>    certain first pass failures on very large files.  (The block-size is
>    already adaptive, increasing up to 16K for large files.)
> But before I work on these I would like to make sure there is interest
> in including them.

IMHO adaptive checksum sizes is critical. People are starting to rsync
partition images and the maths shows rsync degenerates really badly as
file sizes get that big.

ABO: finger abo at for more info, including pgp key

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