On Fri, 2011-04-15 at 22:33 -0700, JD wrote: > On 04/15/2011 09:04 PM, Andre Robatino wrote: > > http://cedarandthistle.wordpress.com/2009/11/06/on-binary-delta-algorithms/ > Read the article and parts of the thesis. > So, the final version of the algorithm > still remains with the University of Oxford?? > > I downloaded the bsdiff srpm for fc15 and built it. > > I then used it to diff > -rwxr-xr-x 1 root root 3699072 Feb 6 23:09 > /boot/vmlinuz-2.6.35.11-83.fc14.i686 > vs > -rwxr-xr-x 1 root root 3702144 Mar 31 15:26 > /boot/vmlinuz-2.6.35.12-88.fc14.i686 > and the resulting patch > -rw-r--r-- 1 root root 3554921 Apr 15 22:17 > vmlinux-2.6.35.11-83--2.6.35.12-88.patch > > So, you can see that the patch is almost the same size as the files diffed. > > Obviously, version 4.3-8 does not contain the unpublished optimizations > that Colin Percival mentions in his thesis. A couple of things: 1. vmlinuz is compressed and it's essentially useless to delta compressed files without uncompressing them first. 2. We use the program deltarpm to make deltas between rpms. Deltarpm uses a modified bsdiff algorithm as well as the add block enhancements mentioned in my blog post. Jonathan
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