[Mageia-dev] Proposal: Updating released versions (long post)

Marc Paré marc at marcpare.com
Sat Oct 9 06:37:15 CEST 2010

Le 2010-10-08 23:45, andré a écrit :
> Frank Griffin a écrit :
>> Marc Paré wrote:
>>> Thanks. So this thread is to see if there were a possibility to
>>> programme a more efficient roll-back option so that it would be more
>>> "aware" of the previous "dependencies" needs for the previous version.
>>> Having "double dependencies" is not so much of a problem, it is the
>>> rollback to a previous version where the dependency confusion may
>>> occur, and, ONLY, if an upgraded type of "dependency" thread had been
>>> installed. (Sorry I may have used the wrong terms in the last sentence).
>> Well, sort of. It's not an issue of efficiency, but of convenience and
>> just making it possible to do without resorting to manual use of the rpm
>> command.
>> The rpm command "knows" that a new version replacing the old version
>> supplies the same things that the old one did, so it will quietly allow
>> the upgrade. It will also do what we need, i.e. go the other way and
>> replace a newer version with an older one if you use the --oldpackage
>> keyword. We just need urpmi to support its use
> One thing that could facilitate this process, if the computer has a lot
> of free disk space, is to rename the files being removed (copying the
> configuration files), instead of erasing them. Although they will
> probably have to be erased eventually, since no computer has unlimited
> disk space. Keeping them long enough that a roll-back is no longer
> probable could be workable.
> Then a roll-back could be done very quickly, since the files are already
> on disk, and presumably reliably. Of course, if new data has been
> entered, and the format has been changed, this could be problematic.
> Note that configuration files that have been changed from the
> installation default are often already saved. (Generally ".old" is
> appended to the configuration file name, sometimes ".new" to the new
> configuration file.)
> This of course adds the maintenance task of removing the old files at
> some point - it could be done automatically according to some criteria,
> or the user could have to do it manually, perhaps after being prompted
> about it.
> (This rollback capability occurs with Microsoft products. The saved
> files are only removed manually, on user initiative, which partly
> explains the bloated size of a Microsoft installation over time.)
> If renaming-instead-of-deleting is implemented, perhaps a "do not keep
> old program files (useful if limited disk space)" checkbox option would
> be useful for computers with less free disk space.
> Of course how much disk space is usable to save old programs on a
> computer depends on the disk space usage for other purposes over time.
> my 2 cents :)
> - André (andre999)

Not sure about this process. Instead of making it easier for a user, 
this would now make it more difficult to do and add another layer of 
knowledge for the new user. It would have to be a little more seamless 
than this.

If there were a way at setup to establish the amount of remaining disk 
space at installation time, and if there were enough space to allow 
rollbacks without compromising the installation, then I guess the 
rollback could then be activated. The user could then be advised at this 
point that this was activated. If there was not enought disk space, a 
message could warn the user that software rollbacks would not be 
possible for lack lack of diskspace.

I guess then, in the MCC, if a user used the Backports and installed 
backported software, the rollback amount of diskspace could also be 
monitored at this level with perhaps an option to delete old programs 
that are now working well in their updated form.

I guess this would take a bit of coding. But at least the use of 
Backports would make a little more sense with a rollback option in case 
an updated software installation did not work out.


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