Here is my (draft) idea as to how to explore this further. The advantage of this approach is that it can work as a separate 3rd party add on software without any modification to the existing software. I have to confess I'm currently not very familiar with the inner workings of up2date, apt, yum etc, so maybe there are gotchas here I havn't thought about. A RPM repository proxy server runs on the local computer. This proxy server will be configured with the following information: * Location of locally stored RPMs (/var/spool/up2date, copies of install CDs etc) * Location of online RPM repositories * Location of RPM diff/delta reposities Yum/up2date/apt is configured to point to this local server as the repository. When the proxy server receives a request for a RPM, it checks the diff repository and obtains a list of diffs that apply to that RPM. It then checks the local cache to see what RPMs are available. If there is a suitable match, the downloads the diff, applies the patch, checks the integrity of the resulting RPM and passes the RPM back to the calling software (yum/up2date whatever). If no diff is found, it just downloads the RPM and passes it on directly. A copy of any new RPM (obtained by diff or by whole) is keep in a cache for possible use later. Obviously a separate project is to produce a tool that can automatically crunch a diff/delta repository out of a standard RPM repository. Any flaws in this idea? If not I'll consider taking it on. Joe.
