Safari 5.0.5 update is available
along with a system security update ...

Also an Xcode update for those that use it. Curiously it was telling me I couldn't install the update as I had used a different account to purchase it, even though I only have one Apple account...

What's in the XCode update?

According to the download page...

- Updated to support iOS 4.3.2
- Fixed a bug in the iOS Simulator when running OpenGL ES apps
- Fixed a bug handling some Core Data mapping models
- Fixed a bug in LLVM compiler 2.0 that could cause apps to crash on iOS devices
- Additional bug fixes and stability improvements

4GB download just for that lot

If you have the app store version does it just download a patch, or does that also require a full download?

I've got the app store version and that was the 4GB download...

Jon

I would have thought it would be a patch, but that doesn't seem to be how the App Store works...

Apple never patches apps, it always replaces the whole package.

In fact it never really patches anything — even OS X updates are a bundle of complete files.

It does make sense though. They can ensure that everything works together.

Well, there is a difference between that and what they do with Xcode, which would be the equivalent of giving you a whole new copy of Mac OS X every time! They do really need to figure out some sort of update management with this thing. I appreciate you'll still end up with a lot of files being updated (dev environments, can't really not) but there's no way the update touches every single file in the whole system.

Jon

But surely you can ensure everything works together as much if you supply the patch (ie. the diff between the installed version and the current version)?

Lets not forget that Apple sometimes don't think about the most space efficient way of doing things. IIRC when Time Machine was launched, any changed files would be re-backed up, it didn't just back up the changes, this made backing up virtual machine disks really cumbersome.

Yes but what if people do not install everything there could then be problems if the update it is using is not the correct one.

Well if the new version is X.3, say, with X.2 being the current version, any user who has X.1 has the X.2 upgrade applied first, and the X.3 upgrade applied on top of that. The App Store knows what versions are installed, so this should be trivial. A more efficient solution would be to diff the diffs first, which is the standard way of doing such things in most VCSs, so files/lines/blobs that are updated by both X.2 and X.3 only have the changes applied from X.3 plus the changes from X.2 that aren't replaced by X.3.