Jeffrey J. Kosowsky wrote at about 16:56:30 -0500 on Tuesday, February 8, 2011:
 > Jeffrey J. Kosowsky wrote at about 16:07:04 -0500 on Tuesday, February 8, 
 > 2011:
 >  > When I backup files on an arm (armel) architecture with rsync
 >  > checksums and then transfer the pool over to an x86 architecture, the
 >  > checksums no longer verify.
 >  > 
 >  > In other words checksums that verify properly on the armel platform,
 >  > don't verify when run on an x86 platform and vice-versa.
 >  > 
 >  > This is quite distressing since this means that one can't copy over
 >  > the pool from one architecture to another and expect it to work
 >  > properly without lots of checksum errors.
 >  > 
 >  > I have double checked this by writing my own routine which uses the
 >  > subroutines in File::RsyncP::digest to verify digests on both
 >  > platforms -- and the same file gives *different* results on the
 >  > different platforms.
 >  > 
 >  > I'm really at a loss to explain how and why this happens but it is not
 >  > a good bug ;)
 >  > 
 >  > I am not sure if this is related to the bug I mentioned last week in
 >  > perl 10.0 where md5sums are miscomputed on the arm platform.
 >  > 
 > 
 > Here is the bug report identifying the problem with Digest::MD5
 > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=289884
 > 
 > Apparently, it has to do with arm processors requiring
 > U32_ALIGNMENT_REQUIRED.
 > 

OK - here is some more info...
Looking through the source files for Digest::MD5 and Digest::MD4, they
both include code to take care of both big-vs.-little endian *and* u32
alignment.

It seems that perhaps this code is missing from md4c.c in
File::RsyncP::Digest.


I'm not sure how to fix the code, but I am guessing that the issue is
there.

I think this is an IMPORTANT bug since if I am following this right,
then many of the md4 rsync checksums end up being wrong on arm
architectures.

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