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When will Ubuntu include delta updates?
In the old days, you downloaded or installed packages from a CD, and then a year later you got the new version of your distribution. The .deb system made sense.
Nowadays, there's a security hole patched every 3 days in one of the big monolithic packages (mozilla, libreoffice, the kernel, etc) where a patch probably changes on average <1% of the files but it requires to download the whole collection of .deb files in their entirety every time. If you look at the bandwidth used to actual payload ratio used for say a year of regular updates, it must be like 1:100.
Is there a replacement available or in development that downloads packages at the file level to avoid redownloading all the files that haven't changed, and ideally using diffs for files that have (e.g. rsync based). Integrity can be ensured by downloading a signature file for the .deb and then checking that the diff-update has reconstituted it correctly.
Edit: My concern is not so much download speed but the global bandwidth wastage it causes. Given estimates of 12 million users known to Canonical, if we conservatively assume 100MB of monthly bandwidth wastage per user per month, that's 1200 TB of wasted bandwidth per month. At Amazon web services prices, that's $125K/month, so about a million dollars or two a year. Add to that people who inadvertently pay high charges on restricted bandwidth or mobile connections (I've had the odd 10 euros surcharge myself), and other Debian-based distributions without delta updates, and it could reach 10+ million dollars. Not the end of the world on a global level, but still resources which could be better used.
