Diff-debs

[Ulrik Mikaelsson]

Interesting point, no doubt about it. Even more, some packages consist
of relatively large binares, support for binary deltas could fit well
in this picture as well.

As I see it, this could be one of the things that could give Ubuntu an
upper hand, and something the other distros have not. (Albeit not for
long) Also, it would fit well in the picture of Ubuntu being for
_everyone_ even those not equipped with good internet connectivity. (I
doubt it's likely to get a fibre-wire in Ghana, probably even low-end
DSL is something to dream about.)

As another side-note I think I've seen Micrsoft does/will be doing this.

Regards
/ Ulrik

2006/1/13, Jonathan Carter <jonathan at ubuntu.com>:
> Hi Ubuntu devel list
>
> I want to know how plausable this is.
>
> I was thinking this morning about getting the download sizes smaller for
> .deb files (there are probably entire teams of people working on this,
> so this might just be a millionth monkey thing), and I've wondered why
> there aren't a deb format that contains diff's between one release and
> another, let me ellaborate.
>
> On the deb server, you have deb-dif files, which would be files that
> contain the diffs to the files in the package between one release of
> Ubuntu and another. At the client side, you have a line in APT similar
> that starts with deb-dif that points to the deb server, then a user
> could just apt-get deb-dif-upgrade to download the differences between
> the previous release and the current release. dpkg could even build a
> package from existing files and the diff files so you would still end up
> with the exact same .deb file in /var/cache/apt/packages. deb-dif could
> use md5sums which is already there to check if a local file has changed,
> and whether it needs to fetch that single file off a mirror containing
> the file.
>
> You could probably do it with unstable versions too, but it will
> probably require lots of diskspace, unless you have some kind of
> checkpoint system.
>
> So, is there any big practical or other reason why this is not possible,
> I haven't been able to think of one on my own so far.
>
> -Jonathan
>
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