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This part of the manual comes in two flavours: Non-Technical and Technical. Feel free to follow the advice given in the Non-Technical section without worrying about the technicalities. Or read on further for background information behind that advice.

  • All iPad and iPhone applications may suddenly close due to a lack of system resources.
  • Due to the design of the iPad Operating System, this is perfectly normal and acceptable behavior.
  • The only way to prevent this happening is to reboot the machine before running a complex application, which will free up any resources that previous applications you have run still hold.
  • Since this is clearly inconvenient, and often unecessary, we only advise a reboot if you start experiencing the problem of applications suddenly closing.

The iPad, like the iPhone, has a limited amount of RAM (as opposed to disk space). Unlike a Mac or PC it cannot swap memory out to disk, so when this RAM is used up then the only option for the iPad Operating System is to close down the unruly programs that are hogging RAM. Even when applications are closed, they remain in memory and continue to use resources until such time that the operating system feels it necessary to remove them.

The situation is made more tricky because there is no way to know how much RAM is free (in fact, there is no such concept in iPad memory management), and so no way to know how close one is to the point that the Operating System may shut us down. All we can do is to react to being told by the Operating System that we are using too much of the currently available resources, free up the resources that we don't desperately need, and potentially notify the user.

When third-party applications first appeared on the iPhone, many people assumed that if an application failed to start or closed unexpectedly then that represented a bug in the application. Although bugs can happen, in most cases an app closing prematurely is due to this lack-of-resource situation occurring, and is not only something that application designers cannot control, but also a perfectly normal function of iOS platform. Application designers spend a great deal of time ensuring that under normal conditions their application will not use up sufficient resources to be a problem for the Operating System, but 'out in the field' where users often run hundreds of apps and never turn their iPad off, resource usage can become an issue. It is the larger apps such as 3D games (or cutting-edge virtual pianos) that will experience it first.

Again, the advice is to store the song you are working on often (as you would on a desktop PC), and to reboot if you experience applications suddenly closing.
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