[Mageia-discuss] Suggestions for the ISO

Mon Nov 8 04:48:27 CET 2010

Renaud MICHEL a écrit :
+> On dimanche 07 novembre 2010 at 22:33, Luca Berra wrote :
+>    
+>>> you must include all intermediate updates packages to create the delta.
+>>>        
+>> you just have to keep track of package 1 and n-1, not all of them
+>>      
+> No, because a roll back of a file can happen on any update. If a file is
+> changed in release n-2 and rolled back in n-1, if you only consider packages
+> 1 n-1 and n you miss the roll back for the people who updated to n-2 but
+> missed the update to n-1.
+> So the system that will create the deltas must have access to every update
+> published since the release, or at least maintain a list of all the files
+> that changed in any update. And not only changes in the files themselves,
+> but also to their meta-informations, like ownership and mode, and other rpm-
+> related meta-informations like %doc or %config.
+>    
+
+You would have to keep the current version of all contained files that 
+changed since the release version, even if reverted to the state of the 
+release package.
+As well, in the spec file, you would have to keep meta info on all the 
+files that changed, including the files that were replaced, for each update.
+This since some users might go from update -2 to update -5, for example.
+
+If a user were to revert to a previous update, in most cases they would 
+require either a full update or the release package + the delta update.  
+This of course occurs much less frequently.
+Note that if the user installed from ISO, they would likely have the 
+release package readily available.
+
+It might be possible to avoid including some meta info, by analysing 
+which versions of the contained files are more recent, but because there 
+are differing ways of representing versions, this is probably not advisable.
+
+Since the spec file will normally be much smaller than the content to be 
+installed, this should not be significant overhead in terms of space.
+
+Note that a full update would include all files of the release, and in 
+the spec file, the meta info of the new versions of these files.
+
+If much content is changed, it might be advisable to produce a full update.
+
+- André
+