iOS memory capacity

Is there a good reference somewhere for how iPhone/iPod/iPad manage memory, and how to find out how much program address space might be available on a given device? Is it a virtual system, where virtual address space can use the storage capacity that is free for adding songs, etc.? Are there any specs for how the different devices differ in this respect (if they do)?

Also - in a project, if there are many files, such as images, that are part of the project, but they only get looked up an开发者_Go百科d loaded a few at a time, does everything in the project use up available RAM, or only whatever is loaded and not released at any time?

Thanks.

Is there a good reference somewhere for how iPhone/iPod/iPad manage memory

Apple's Memory Management Guide.

how to find out how much program address space might be available on a given device

I wouldn't base any code on the available memory on a device.

Is it a virtual system

No.

Are there any specs for how the different devices differ in this respect

They differ in RAM size and other factors (CPU clock speed, GPU). The table here has some details.

if there are many files, such as images, that are part of the project, but they only get looked up and loaded a few at a time, does everything in the project use up available RAM, or only whatever is loaded and not released at any time

Only what is loaded into memory.