Can my iPad app cause the device to reboot?

I have an iPad app that has a process for downloading lots of map files (a couple of gigs of data and 10s of thousands of files).

In my most recent test release, the device will sometimes reboot during the download process, (downloads can take a couple of hours).

When the app reboots, it does not leave a crash report. We have observed this behavior on both an iPad 1 and a开发者_如何学JAVAn iPad 2 running 4.3.3.

The only thing I can think of is we increased the max concurrent threads from 4 to 20 for doing these downloads.

Completely exhausting the system memory triggers a hard reboot of the device. This used to be more common in iPhone OS 2.0, running on the limited hardware of the initial iPhones and iPod touches. In recent OS versions, Apple has more rigidly enforced the hard kill of your application when it exceeds its memory ceiling, so it's become much harder to do this. Also, the devices have much more memory than they used to.

One way that you can sometimes do this is by loading many large textures or other graphical components that may not be immediately identified as memory used by your application. I've been able to cause a system reboot when loading a pile of data onto the GPU in a tight loop. You may be encountering something similar here.

I doubt that this is related to the number of active threads you have going, although they probably make it easier for you to dump a mess of data into memory before the system can kill your application.

As an aside, rather than having piles of threads, which consume resources, have you looked at using GCD or a queue-based framework like ASIHTTPRequest? These might be more efficient for your application, yet still provide the concurrency you need.

Your app is crashing most likely due to memory management. Since you are downloading several GB's of data, maybe you are running out of disk space? I am not sure why it would take your device several hours to reboot.

Try posting some code.

Have you debugged in Instruments? This will show you if allocations are rising and filling memory. If you are attempting to load these GBs into memory, then of course your going to experience a crash.

Also, have you looked at dispatch_apply instead of threads? GCD automatically distributes and increases/reduces the threads it uses based on load. This way you don't have to manage this yourself. It might be worth a shot.