iOS 6 App Development: Device Limitations of iPhone and iPad
Along with all the great features of the iPhone and iPad, they also have some limitations. The key to successful app development — and to not making yourself too crazy — is to understand those limitations, live and program within them, and even learn to love them. (It can be done. Honest.) These constraints help you understand the kinds of applications that are right for this device.
Often, it’s likely that if you can’t do something (easily, anyway) because of device limitations, maybe you shouldn’t.
The iPad evolved from the iPhone and iPod touch, and you need to consider related limitations, as well as a few things left out. So learn to live with and embrace some facts of iPad life:
Users have fat fingers. You may think that the iPad’s larger display makes that relatively easy to deal with, but keep in mind that you may want to design a multiuser app for the iPad that takes into account multiple fingers. (Anyone for a nice game of Touch Hockey?)
Memory and battery power are limited. This limitation may or may not be a decisive factor, depending on what kind of app you want to create, but smaller apps generally perform better.
You can use only one app at a time. Although users can switch from one app to another instantly, and apps can continue where a user left off, only one application actually runs at a given time, with some apps capable of running in the background to serve notifications or play music.