[Mageia-discuss] Suggestions for the ISO

andre999 andr55 at laposte.net
Sun Nov 7 00:54:52 CET 2010

Olivier Thauvin a écrit :
> * andre999 (andr55 at laposte.net) wrote:
>> Luca Berra a écrit :
>>> On Wed, Nov 03, 2010 at 08:16:22PM +0100, Olivier Thauvin wrote:
>>>> * andre999 (andr55 at laposte.net) wrote:
>>>>> Donald Stewart a écrit :
>>>>>> On 1 November 2010 10:24, Marc Paré<marc at marcpare.com>   wrote:
>>>>>>> Le 2010-11-01 06:00, Philippe DIDIER a écrit :
>>>>>> Using delta rpms would reduce the size of the updates, or has my lack
>>>>>> of understanding of delta roms got in the way?
>>>>> Delta rpms, relative to the latest distro release, are long overdue.
>>>>> (And not only in the Mandriva world.  Also for Mozilla, OpenOffice,
>>>>> etc.)
>>>>> Note that for much commercial software, updates are normally delta.
>>>>> Such updates are often erroneously called patches.
>>>>> This may be partly a limitation of rpm packages, or more the
>>>>> programs  that install/update such packages.  If so, it should be a
>>>>> priority to  correct this lack.
>>>> The problem of delta rpm is the work need to generated alls delta and
>>>> the space need on mirrors to host everything.
>>>> We must provide delta for each version to the next one:
>>>> - main foo-1
>>>> - upd  foo-2 D: 1->2
>>>>        foo-3 D: 2->3 and 1->3 ?
>>>>        foo-4 D: 3->4 and 1->4, 2->4 ?
>>>> etc...
>>>> What if delta 1->4 is bigger than the package itself ? and for 2->4 ?
>>> As nanar points out delta rpm is a bad design
>>> a working concept would have been basing all deltas on a specific rpm
>>> (i.e. the one in */release) and bundling entire files. in this case a
>>> patch will grow at most as the original rpm, and you don't care about
>>> keeping incremental diffs.
>>> L.
>> Which is exactly what I was proposing.
>> Delta by file relative to the official distro release.
> So to update from -1 to -3 I'll download around 300KB but to upgrade
> from -2 to -3 I'll download the full rpm so maybe around 20MB (in the
> case the rpm is 20MB) ?
No no no no no !
If from -1 to -3 is 300K, then upgrading from -2 to -3 would still be 300K.

Of course, this raises the point that the names of the original files in 
-1 will have to be retained after updates, as well as the names of files 
replacing them, in order to make the additional updates.  (And remove 
any interim updates subsequently replaced.)
This could be facilitated by making the names of the replacement files 
in delta updates the original file name + a suffix corresponding to the 
delta update.

Downloading the full rpm would only be need if one wanted to install a 
package not yet installed.  And of course the latest delta update, if any.
Of course, if full updates are retained, then one only downloads the 
full update, as it will be a full rpm.

> It's a proposal like others...
> I am not sure people having slow connections will enjoy this.
They will, as long as the proposal is well understood.
And adequately explained, of course :)

- André

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