iPhone OS 4

Today Apple unveiled details of iPhone OS 4 at a special event on their home turf. They certainly didn't disappoint.

If Apple had not added some form of multi-tasking into version 4 of the iPhone OS, they would currently be facing one hell of a backlash from many groups of iPhone, iPod Touch and iPad users. Although several areas of the iPhone OS could be said to have started to show their age when compared to recent versions of Google's Android OS, the lack of any form of multi-tasking has been the vocal critic's primary weapon of choice against the iPhone and it's operating system for at least the last year.

Today though, Apple announced over 100 new features to be included in it's upcoming iPhone OS, and while some of these were expected, many were a welcome surprise. For a complete rundown, Gizmodo has a great article detailing all the new stuff. Here, I want to point out I think are the most interesting features, as well as briefly explore the possibilities that a few of them have opened up for developers:

1. Multi-Tasking

The way that Apple has implemented this is incredibly simple, but looks like it will work perfectly. A double-click of the home button brings up a list of running apps, enabling fast switching between them.

What I find most interesting here is that when asked how users would now 'quit' an app, Steve Jobs said that they effectively no longer have to - the OS takes care of background processing for an app if necessary (such as playing audio, location information or VOIP). If it doesn't need to use any background processes but does need to save the location the user was last viewing when they quit, the OS can now save the state of the app and return the user to exactly where they left off (games will obviously benefit here).

2. Folders

Long overdue - drag an app onto another app and a new folder containing both will be created. These will definitely be a welcome addition to my own cluttered iPhone. Being able to see the first 9 apps contained inside simply by looking at a folder's icon is also a nice touch.

3. Calendar & Photo-Library Access

Also long overdue, allowing developers access to a user's calendar and photo libraries lets developers build far more powerful applications. For example, due to limitations with OS 3, Photoframeplus is forced to import photos from the users photo gallery into the application itself, effectively copying a file. There really is no need for this and I'm glad Apple have finally allowed developers proper access to this kind of media. Being able to access calendar information will also be great for anyone wanting to build any kind of personalised calendar view into their apps.

4. iAds

This is a pretty big one as there is obviously a huge amouns of cash to be made through advertising on mobile devices, but interactive ads like the ones Apple demoed earlier really do have the potential to make the developers of popular free apps a nice chunk of change.

5. Extras

iBooks on the iPhone is also cool, especially considering that it will automatically sync bookmarks and last viewed pages with its bigger brother on the iPad. A unified inbox and being able to customize the wallpaper is also a welcome addition.  Overall I am thoroughly impressed that Apple was able to pull out all the stops today; people were expecting a lot, and it seems to me that Apple surpassed even the most ambitious geeks' wishlists. It will also be interesting to see how many more hidden features will be unveiled alongside new iPhone hardware later in the year. Roll on June!