As I mentioned earlier in this thread, application crashes are usually caused when application memory gets low enough that iPhone OS shuts down the running application to recover memory. Everything that is running on the device, including all operating system functions, must fit into application memory. Applications that are most prone to crashing are larger applications that push the limits of available memory. Virtual Families is much larger than Fish Tycoon and, depending upon what else is running on the device in the background, Virtual Families may be terminated by the OS due to low memory conditions, whereas Fish Tycoon will not be.
Application memory is not the same memory as the flash memory where applications, music, videos, etc. are stored (the 8 GB, 16 GB, 32 GB, etc. that you see displayed in Settings or iTunes). The only way to see how much application memory is available is to use a system monitoring application that provides such information about the device's status. 3rd generation iPhones (3GS) and iPod touch (released in September 2009) have 256 MB of application memory and have far fewer crashes than older devices. All previous generations have 128 MB of application memory.
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Barbara
Unicorn
Last Day of Work