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Date: Wed, 14 May 2003 14:07:38 +0100
To: Peter Pentchev <roam@ringlet.net>,
	Colin Percival <colin.percival@wadham.ox.ac.uk>
From: Colin Percival <colin.percival@wadham.ox.ac.uk>
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cc: FreeBSD Security <freebsd-security@freebsd.org>
Subject: Re: xdelta files for security patches
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At 12:06 14/05/2003 +0300, Peter Pentchev wrote:
>When I read this thread yesterday, I was going to suggest taking a look
>at the rsync code.  Still, it sounds like your code is much simpler than
>the rsync algorithm described at http://rsync.samba.org/tech_report/.
>This is probably a good thing :)

   Rsync solves a problem much harder than binary diffs -- rsync constructs 
half-blind binary diffs.  The old and new files are on different machines, 
so rsync uses a clever statistical sampling trick to locate large common 
sections which the two files share.  xdelta uses the same method, but when 
we have both files in the same place we can do much better by using a 
suffix sort.

Colin Percival