How iPad Multitasking Might Work
There has been much complaining on the web about how iPad doesn’t support multitasking, and little analysis of why Apple doesn’t allow it. Adam C. Engst wrote up a great analysis of the types of benefits that multitasking can provide and what technology is required to achieve those benefits.
I’d like to approach the question of multitasking from the user’s perspective and not from a technology standpoint. How would allowing third-party background processes impact the user experience?
Games Don’t Want Multitasking
Game consoles don’t allow third-party background processes, period. Even first-party background processes are limited. Xbox 360’s dashboard and PS3’s XMB is the interface to access system functionalities while playing a game. Both systems also reserve a small amount of memory and CPU to run system functionalities.
The reason why consoles take such extremes to limit multi-tasking is to give games consistent hardware performance. Games typically pushes the performance of the system to the limit. When a game updates at 60 frames per second, a small decrease in performance will drop the frame rate to 30, which is immediately noticeable by the player.
Now imagine a game developer writing games for the iPad. It would be impossible to squeeze every ounce of performance out of it if at any point a random third-party application can wreck your performance and turns your game from running smoothly to slowing to a crawl.
For this reason alone, I don’t think any iPad application should expect to be running in the background at all times.
Multitasking on iPad
Believe it or not, there exists an API that manages multitasking on the iPhone. It is called Audio Sessions. An application can claim exclusive access to hardware audio codecs and stop the iPod application from running in the background by setting the appropriate audio session category.
I think this could be a glimpse into how Apple will implement multitasking on the iPad. Apple can define a set of categories for multitasking and each application will set it’s category to the most appropriate one.
Here are some categories which I think might be usedful:
- Multitask Session Default – allow other application to run in the background with the current application. Quit the current application when the home screen is brought up.
- Multitask Session Background – allow other applications to run in the background and also wants to keep running when another application starts, maybe quit if an exclusive application starts.
- Multitask Session Background Resume – Same as background, except restart the application in the background when possible, i.e. after an exclusive application stops.
- Multitask Session Exclusive – Do not allow other applications to run in the background. Quit the current application when home screen is brought up.
By defining the multitasking behavior through the API, Apple will still have complete control over the user experience, without exposing the complicity of managing processes to the users.
The Apple Way
I am just conjecturing how Apple might add multitasking to the iPad. I don’t have any sources inside Apple. However I believe that Apple will provide the best possible user experience when using the iPad. If they determine that multitasking will decrease the overall user experience then they will not add it.
Like the Cut-and-Paste complaints of a few years ago, Apple will wait until it finds the best possible way of introducing a functionality before adding it. That is the Apple way.
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