# Could someone explain iPad low memory plist?



## winwintoo (Nov 9, 2004)

I've been having trouble with Procreate crashing. Someone suggested I look at the low memory plist. Sure enough it was a low memory problem.

Looking at the attached plist, I'm tempted to draw some possibly erroneous conclusions.

When we talk about iPad RAM, what is it called? I looked at the specs for the new iPad and didn't see any mention of how much memory there is. Storage yes, but active memory no.

In this plist, I see how many "pages" each process is using. Do we refer to the amount of memory as "pages" now?

In many of the plist, I see apps "jettisoned". Does this mean the app has been tossed out but the icon stays on the task bar (what do you call that?) Is that why I leave an image open in procreate, go do something in another app and when I come back to procreate, the image is closed?

What does it mean "throttled pages"


----------



## Chealion (Jan 16, 2001)

The iPad does still have RAM (512MB on the 1 and 2, 1GB on the 3) - this has been verified by teardowns. It along with the CPU speed tends to be a spec that Apple doesn't feel is worth promoting. (Becomes just a feature checklist comparison that ignores the tradeoff of having too much RAM or too power hungry of a CPU for the battery)

Pages refers to a chunk of memory. In OS X and iOS' case; 4 KB. http://en.wikipedia.org/wiki/Page_(computer_memory)

Jettisoned memory has to do with the virtual memory system and multitasking: when an app is sent to the background it's memory is marked as suspended and can be reclaimed (jettisoned) if necessary. Unlike a computer there is no space used for swap on an iOS device, so instead of being written to disk it's thrown out. When this happens is when you can see an app having to reload data or reopen images. For example: On iOS, Safari's tab thumbnails and the contents of the tabs gets thrown out when a low memory usage event occurs causing them to need to be reloaded/regenerated the next time you have Safari open (1).

As for throttled pages, I'm not entirely certain. I don't see anything in the Developer docs expressly stating what this is; I'm guessing it's memory thrown away since the last restart.

1 - I'm not sure if the tab thumbnails are still solely stored in RAM, I think the images may be cached now as of iOS 5 or 6. After upgrading to my iPhone 4 from a 3G it doesn't happen enough to me to notice.


----------



## winwintoo (Nov 9, 2004)

Thank you so much, Chealion. Just the explanation I was looking for.


----------



## winwintoo (Nov 9, 2004)

So I decided to clean out apps I don't use and moved some stuff to Dropbox. 

And then I looked at the logs again. Attached is one log. Whenever I see "panic" and "kernel" that close together, I start to PANIC!

Any ideas? Does this mean my iPad is in trouble?


----------

