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[kitz]

Thanks for the suggestion, but it wont work as I dont have a copy of those mails on the PC to upload back to the server.   I didn't keep a copy thinking that I'd got it on my ipad.  If I had prior notification what iOS 9 would do with the mail, then I could have transferred them first back to the PC.

Its not too important because it was only personal stuff with friends.  It was more of an inconvenience that they changed something which worked for me.  Judging my others response to the changes there are others that also arent too happy with the change and also liked to keep copies on their ipad/iphones.
I'm far more astute with the site mail, which has backups of backups.

[kitz]

btw I meant to post this which may explain a lot.    However I had to mail it to the PC to be able to attach it.

Ive been watching the ram for about a week or so now.   System memory may start off lower circa 200 MB after a fresh boot, but after Ive attempted to open say safari it will soon creep up and it doesnt always go back down even if I properly close down the apps.   Apparently I cant do much about wired memory used either.   Ive quite often seen free memory at around 30MB which may explain why it will crash when I try to open an app, and now is pretty useless at some of the games I played.

It will also explain why its only problematic with the ipad2 and not say the Air2 which has 2GB of RAM.

Having researched further, it would appear its the system memory starting with iOS 8 which has caused the majority of problems for users of the ipad2.   For some reason I didnt really notice it with iOS8 and my problems only really started with iOS9.

I have cleared out all unwanted apps and frequently now do cold boots, but since a cold boot can take >5mins its not always practical to do this each time I want to switch between apps.

[sevenlayermuddle]

Food for thought, I think you might well be on to something.

I think I waffled on earlier about memory management, the assumption that Memory allocation won't ever fail, and how it depends (for handling of low memory) on a kind of 'semi-voluntary' co-operation by Apps.  If none of the Apps co-operate then the OS has to forcibly unload an App, in order to satisfy that assumption.  These are code-paths that, IMHO, app developers may not always necessarily test exhaustively.

I'd also go along with the theory that these issues began with iOS 8.  My reasons for saying that surround issues we've had with our iPad Mini 2 (64 bit cpu, retina display), which really shouldn't have been challenged by iOS 8.  But I'll not go into too much detail as it's not strictly on topic.

I'll see if I can dig any deeper, having a marginal advantage of access to some of the development and profiling tools...

[kitz]

I think I waffled on earlier about memory management

You did.. which is why I sought out an app to view available & memory in use.   

[sevenlayermuddle]

I think I waffled on earlier about memory management

You did.. which is why I sought out an app to view available & memory in use. 

To save me the bother of searching the App Store since I'm bone lazy at heart... what app is that, you used?

[kitz]

Sorry trying to check full name but damn ipad keeps crashing. 
Just waiting on a cold boot but I think from what I can see before it crashes is Memory and Disk Scanner Pro.


ETA - yes it is.  Author is Phan.   I've got the trial version v 1.0.3 which I think is time limited. 

[sevenlayermuddle]

No worries, I'll find it.

Another train of thought,  not synchronised with any particular iOS release but in the right sort of time frame, a change in the Objevtive C compiler was rolled out.   This relieved the programmer from the need to keep track of object allocation, and let the compiler do it.      I don't think I'm breaking any rules with this link, as it is publicly discoverable...

https://developer.apple.com/library/ios/releasenotes/ObjectiveC/RN-TransitioningToARC/Introduction/Introduction.html

Personally while I have not heard any serious criticism of arc, being the age that I am, I have always preferred to do things myself rather than trust it to a compiler.   

Edit:  makes no odds, but replaced link to MAC arc with link to iOS arc.

[kitz]

Thanks 7LM. 
It could possibly be that, or alternatively although I didnt seem to notice much difference with iOS8, there is no doubt that both ios8 and ios9 both use and need more RAM to operate.   Most of the complaints with the ipad 2 seem to started with ios8, it could be that ios9 just took that wee bit more which started to impact on what I used it for and why I suddenly started to notice the crashes?

-----
btw I edited my earlier post to give full details of the memory app

[sevenlayermuddle]

Kitz,

Inspired by that memory scanner app I have at last yet another suggestion, may I ask what are you using for wallpaper, on Home & Lock screens? 

Reason for asking is that the iOS springboard process (handles the home screen) appears to be one of the biggest consumers of memory, other than the current foreground process.  And it seems to be affected by the wallpaper, to a greater extent than you might think.  By simply covering the camera with my hand and taking a photo, I get a nice black image that compresses well.  Setting that as wallpaper on both home & lock screens, it seems to 'save' me about 15MB, compared to the system-provided 'still' I had been using.  When setting a new wallpaper you can choose to enable/disable perspective zoom, seems to make no odds, but disabling it won't hurt.

I don't know why the 'saving' is so much.   Maybe I'm doing something dumb in my measurements, but it seems to be repeatable.  If you previously had a more exotic high res photo, it's worth a try in case you save even more?  If it seems to be helping you could even try something more methodical, creating a pure black image with editing tools rather than just covering the lens and taking a photo!

Other comments are, regarding the one and only game that I have installed... it has fairly crude graphics and  WOW, it's eating 160MB!   That compares to a game of my own, that renders in fully textured 3D graphics, and sits in 25MB.  I won't name either game as I don't want to be seen to be criticising it, or claiming one-upmanship.  There may be very good reasons for its footprint, that are not apparent to me.  Or it may be that the fact that author chose to use a commercial 'games engine' whereas I brewed my own.  All the same, 160MB does seem a lot. 

I also agree that, when the system returns to idle after all Apps closed, the amount of free memory does not always (but sometimes) seem to recover to the start of day figure.  I have yet to come up with any theories as to what's really going on in that respect, or whether there's anything that could be done to influence it.  But I'll keep thinking.   

[sevenlayermuddle]

On second thoughts, disregard above suggestion re wallpaper.  It is no longer producing repeatable results, may just have been a side-effect of stepping though the various menus.

One other thing I've thought of that may help....  could you play the memory management system to your advantage?    Prior to opening an App you want to actually use, launch another one - one that eats lots of RAM - and then close it again.  Only after it has closed, open your next App - the one you want to use.    My theory is that the greedy App will cause a low memory situation, but get it 'over and done with'.  After that, I suspect the memory scanner will show more free memory, and the next App might, just might, have an easier time getting all its resources allocated.   

Above strategy would not be a valid 'fix', far too much hassle, but if it proved any worth as a temporary avoidance then who knows, other ideas may come to light?

I can PM you if you like with the details of the Game I've been using, which seems to have a big-ish footprint,  to test the above trick.  I'd prefer not to have it identified on forum, lest my previous comments may be taken as unfair criticism.  It's actually a very good App and a lot of fun, and free.

[kitz]

@ 7LM - appreciate you looking at this.

Had time to look at ARC and from first impressions it looks like it could in some respects be similar to Java's garbage collector for memory, except a wee bit more complicated and not entirely automatic as it has a bit more control?

may I ask what are you using for wallpaper, on Home & Lock screens?

See attached for my current settings.  The image definitely isnt a high res image, it's taken from a (larger) photo I specifically cropped to use as the home screen. File size of the .jpg is just 232KB.

By simply covering the camera with my hand and taking a photo, I get a nice black image that compresses well.

Ive just tried this on a freshly booted system.
Using my original image: System memory 183 MB
Using the black image: System memory 202 MB  (WTH!) 

Hang on sorted perhaps.   I think perhaps it may be the fact that I'd opened "Settings" to change the image causes the increase and doesnt perhaps release all memory.
Another fresh boot show system memory back at 182.28 MB with the black image, but putting the photo of Zac back will increase it to 191 MB.    The more apps (or settings) that I open just increases the system memory.   This can be replicated.   The image of Zac only seems to use a fraction of a MB more.

Other comments are, regarding the one and only game that I have installed... it has fairly crude graphics and  WOW, it's eating 160MB!

 

Yes I agree this will be the issue and why the game now will crash.  Unfortunately I have no way of knowing how much memory the game is taking as I only have the trial version and I cant have both the game and the memory scanner running at the same time.   The game was animated with lots of moving individuals and graphics weren't of the crude type.  I can well believe that it requires more than 30-40MB to run, which at times is all the free memory I have if Ive say been using safari to browse beforehand. 

I also agree that, when the system returns to idle after all Apps closed, the amount of free memory does not always (but sometimes) seem to recover to the start of day figure.

In my pursuit of ios memory management last week I read something somewhere that ios will retain previously closed apps in memory for 'x' period for faster next time opening - even if the app has been properly closed.   It will eventually release it and although there was no mention of timescale, I get the impression from my own observations of memory in use that we are perhaps talking hours.   

This could explain why system after a cold boot could start at just under 200MB, then say if you open safari to do some surfing and even if you close the browser properly, you dont immediately go back to what it was.   Then open say YouTube and system memory goes up again..  and before you know it I only have 30-40MB free and the next app I try to open will crash.   I saw several mentions that RAM is an issue with the older ipads.   
 

[kitz]

ETA
Just seen your latest post

Warning - while you were typing a new reply has been posted. You may wish to review your post.

I had started working my way through your suggestions already..... and was typing the results as I tried each test, so wasnt aware that you'd done another post until I hit 'send'.     But I thought you'd want to see the results of what I'd tried so I left the post as was.

[kitz]

One other thing I've thought of that may help....  could you play the memory management system to your advantage?    Prior to opening an App you want to actually use, launch another one - one that eats lots of RAM - and then close it again.  Only after it has closed, open your next App - the one you want to use.    My theory is that the greedy App will cause a low memory situation, but get it 'over and done with'.  After that, I suspect the memory scanner will show more free memory, and the next App might, just might, have an easier time getting all its resources allocated.   

Above strategy would not be a valid 'fix', far too much hassle, but if it proved any worth as a temporary avoidance then who knows, other ideas may come to light?

I think we are on the same lines of thinking, but also note that I read something last week (dont recall where now sorry) about how the system will still use some memory despite proper closure of apps and its why memory does creep up over time...  but open it the next day and you are back down to 200MBish.

I think I mentioned it is possible for me to open the game after a fresh boot and it will play for a while, and depending on what actions I do, will work for a while before it crashes.  I think I also mentioned I'd been playing it for a few years,  so was high ranking and therefore would have far more animated objects than a player who started from new.. and therefore likely be needing more RAM. 

If I've been using another app before opening the game, then it will crash upon game start and wont open at all... which is why I have to do a full boot to be able to open it.


-----
ETA

Although I talk about a game, it doesnt necessarily need to be the game which causes the crash.   Viewing a webpage that has a high video/animation content will also cause the ipad to crash.   

[kitz]

I just tried to refind the post I read last week about ios memory management.   I cant find the post now where someone on a forum explained it in simplified terms, but it looks like here may be a good place to start.

https://developer.apple.com/library/ios/documentation/Performance/Conceptual/ManagingMemory/Articles/AboutMemory.html

The info towards the bottom is interesting..  starting from here

In iOS, the kernel does not write pages out to a backing store. When the amount of free memory dips below the computed threshold, the kernel flushes pages that are inactive and unmodified and may also ask the running application to free up memory directly.

The symptoms described are what I am seeing, sometimes just the app in use will crash, but at other times it will cause a full system crash and I have to wait several minutes whilst it goes through the black screen process.

I'm not an expert in this area, but I am strongly beginning to suspect that the ipad2 simply does not have sufficient memory to be able to adequately run what started with iOS8 if they also use some apps which require a fair bit of running memory.   The fact that system memory frequently goes up to 300MB and wired memory also needs about 100MB, then it leaves very little to run other apps.

After performing the tests earlier with the wallpaper and a fresh boot, the only things I have had open are settings and the memory scanner.  My Active memory is currently 104.97MB.   Although that gives me 99 MB of free memory to play with, over time that 200MB system memory will increase to 300MB leaving me with practically nothing to open any new apps.

The only solution would be to routinely cold boot to clear system memory back down to 200MB. 
I can understand now why so many people with ipad2s and iphone4's would go back to ios 7 if they could.

[sevenlayermuddle]

Sounds like I wasted your time, sorry.   One thing worth explaining is, it shouldn't necessarily be a problem in iOS, launching an App that needs, say, 150MB when only 20MB is free.

When an App is in background it might take a pragmatic approach to memory usage, freeing up most resources but hanging onto to anything that would be time-consuming to reconstruct,  on the basis that the user may bring it back to foreground again.  This is one reason that 'free' memory, as displayed by that Scanner App, might become amazingly low.   Even when in foreground, Apps sometimes face a choice... do they keep (say) some big image data in memory even though it's not strictly needed on the screen the user's looking at, or do they free it off and reload it when it is needed - at risk of causing a glitch while the reload happens?

So far as I understand (welcome anybody else who knows better!) what should happen is, when a new App is launched the OS realises there's a shortfall, and so notifies other background Apps and processes, requesting that they free up some memory.  Often they can do so, and just accept that there'll be some reloading of data when they come back to foreground.    If they don't comply, they will be jettisoned - which will equally free up the required memory.  Either way, the new App gets the memory it needs, even though it may have looked like there wasn't enough.

The problem is of course, if all that's left are essential system processes and Apps that are using no appreciable memory, and there's still not enough to run the new App, then you won't get a a quart into a pint pot.  The newly launched App will fail.  It will probably fail ungracefully, because much common coding practice is to not bother checking whether object allocations were successful.

You'll not like me shifting the blame away from Apple, but I am beginning to think the Dev's must take some responsibility too.  As a dev, I get access to early Betas of new iOS releases and plenty of opportunity to test and identify any issues, such as the possibility that iPad 2 may simply not contain enough RAM to run my App in the new iOS.

Of course the fact that system Apps like Safari act up too, defuses the previous argument a little.  And there's also the problem that the Dev may be simply unable to reduce the memory footprint enough.   And then what can he/she do?  It's already installed on the user's iPad and will still be there after the upgrade.   

You're also right that the longer you play a game, the more memory it might use, and not just because the object count increases.  Lots of different models are possible but, for my own Apps, I keep a dictionary  of 'levels solved'.  That dictionary can be written to disk in a matter of milliseconds but sometimes every millisecond counts so in the absence of memory warnings, I might keep it in RAM.  So obviously, it does get bigger and bigger with progress through the game.  But I do actually test each App, a special install with a spoofed worst case dictionary, to make sure it doesn't get to too ridiculous a size.