Request for Comments: updating RPMs using binary deltas.

[Charles R. Anderson]

On Thu, Jan 08, 2004 at 04:19:24PM -0500, Alan Cox wrote:
> Problem 2:  Where do you get the original package from ? The CD has been one
> suggestion but JBJ pointed out that you can assemble an approximation of
> the original package from the on disk data in most cases. The config files
> might be a little different but most of the content is basically the same.

This is part of the transactions/rollback support for rpm IIRC >= 4.2. 
When an up2date is performed and it is configured to save old files
(enableRollbacks=1), rpm will repackage the files from the filesystem
to an rpm package in /var/spool/repackage.

Would this be useful to create a binary delta from?  Of course, the
original files would have to have been unmodified, or this will fail. 
This might be acceptable as long as the update client was smart enough
to attempt a non-diff download of the full package if the patching
failed.