Jeffrey J. Kosowsky wrote at about 19:19:54 -0500 on Sunday, January 23, 2011:
> I was testing some of my md5sum routines and I kept getting weird
> results on ARM-based computers.
>
> Specifically, the pool file md5sum numbers were different depending on
> whether I computed them under Fedora 12 on an x86 machine vs under
> Debian Lenny on an ARM-based computer.
>
> This obviously creates issues if you want to move your backup drive
> between different CPUs.
>
> I narrowed it down to Digest::MD5, by doing the following 1-liner:
> perl -e 'use Digest::MD5 qw(md5_hex);$file=testfile;
> $size=(stat($file))[7];$body=`cat $file`; print md5_hex($size,$body) . "\n";'
>
> This should be the same as:
> perl -e '$file=testfile; $size=(stat($file))[7];$body=`cat $file`; print
> $size, $body;' | md5sum
>
> For maybe 1% of files in my pool the ARM machine gave the wrong answer
> when using Digest::MD5
>
> So, something must be wacko in the perl implementation of Digest::MD5
> on ARM machines!
>
Well, what do you know, Perl 5.10.0 (at least in Debian but I think
upstream too) are broken on ARM processors.
Something about 32-bit alignment.
You need to upgrade to 5.10.1 -- and now I wasted a day on this...
And now I need to write code to fix my pool - YUCK!
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