I use iTunes on my Mac (OS X 10.6) but I wonder what's up with it's update. I really want know Why iTunes updates get released so fast and why everytime the entire iTunes has to be updated instead of patched.
P.S: I have limited bandwidth with my internet then the size of update was important for me.
The reason why they release patches so often, iTunes is the app where all their management of iPhone and iPad occurs, which means they often need to update it to add support for new iPhone/iPad/iPod touch models, and to support new features in those products. The fact that it is also where they handle a lot of their DRM (which they may have contractual obligations to update in some instances) probably is part of the reason as well.
The fundamental issue with delta patches is that they are more complex, and have higher support costs for the vendor. A full updater can run against any version of the app that is installed, a delta patcher most be made against specific version. A full updater will work regardless of whether the app has been modified (user hacking the binary to do something, tweaking the artwork, etc), a delta updater will fail against a modified app.
Given the extra work involved in preparing a delta patch, and the increased chance that it won't work, they tend to only be used in very specific cases. Apple tends to create delta updates for software updates, but they only create a delta against the most recent released version of the OS, rather than making dozens of versions that work with every release they make the one that will get most people, and then for everyone else they do a combo update that is a full updater that also incorporates every previous software update as well.
For smaller things like iTunes, they don't tend to bother with delta updates at all due to the increased workload, support, the increased number of versions that exist, and the fact that iTunes is fairly small in the scheme of things (it is smaller than an OS update, or an iPhone/iPad firmware).
I use iTunes on my mac (OS X 10.6) but I wonder what's up with it's update. I realy want know Why Itunes updates get released so fast and why everytime the entire Itunes has to be updated instead of patched.
It probably is patched. There are more then a few files that go along with iTunes, there are other applications and shared processes that must be updated as well.
Applications are updated on an as-needed basis. You probably don't have to update right this minute, it's simply saying an update is available, and you would be better off if you updated. This could fix any number of issues, from performance, stability, or misc "bugs" that were found. You can see the (abbreviated) changelog if you want to know exactly what this update is supposed to do.
Contrary to the other answer, it is not how Apple "bundles" applications. The "bundle" is simply a folder that finder interprets as an application. Applications can (and are often) "patched" by modifying files withing these .app folders. The entire application does not need to be replaced every time. Otherwise every Adobe update would take days do download.
Please note that the following answer is valid for any application (Apple-specific or 3rd party).
It's the way Apple bundles all applications. In fact every *.app is a bundle (think - folder). You can open it in finder (right click -> Show Package Contents) or cd to it in terminal. That's why any app is not patched like on windows systems where files of one program is scattered all over the file system, but sort of "replaced" as a whole.
