On 04/15/2011 10:58 PM, Jonathan Dieter wrote:
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Obviously, version 4.3-8 does not contain the unpublished optimizations that Colin Percival mentions in his thesis.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
So, deltarpm actually uses the enhanced (i.e. modified) algorithm that Colin Percival mentions in his thesis, or is it from a different author?
I