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TwitchOSX

macrumors 6502a
Original poster
May 2, 2002
508
49
Southern Oregon
iPod Touch here

Heres my issue. I open ESPN ScoreCenter, read a little stuff and then hit the home button to close it and get back to the home screen. Problem is, it doesn't close the program. It leaves it open in the background and I have to double tap the home button to bring up the open apps and then press and hold to wiggle and then hit the X to close the app completely.

So.. after a while I have a ton of apps just running in the background sucking up resources.

While some apps I would LIKE to leave open like Mail or Talkatone (so I can receive calls), most apps I don't want to leave open after I "close" them. Any way to quit an app after I'm done with it? I really don't want Madden NFL 12 staying open. Thats a huge game that sucks a ton of resources. A bunch of stuff left open just makes the iPod laggy.
 

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
Apps in the background don't use resources. They are frozen in the memory and when another program needs more memory, the frozen program is killed.
 

TwitchOSX

macrumors 6502a
Original poster
May 2, 2002
508
49
Southern Oregon
Apps in the background don't use resources. They are frozen in the memory and when another program needs more memory, the frozen program is killed.

They still take SOME resources. The damn thing gets laggy as hell after there are a ton of open apps sucking up memory if that's the case.....
 

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
They still take SOME resources. The damn thing gets laggy as hell after there are a ton of open apps sucking up memory if that's the case.....

They take zero CPU cycles. The memory they do take is quickly released if it is needed. Other then that, they take nothing at all.
 

mrsir2009

macrumors 604
Sep 17, 2009
7,505
156
Melbourne, Australia
They still take SOME resources. The damn thing gets laggy as hell after there are a ton of open apps sucking up memory if that's the case.....

*Sigh*. No, they don't. Go to this page then scroll down to the bottom, where it says "misconceptions about iPhone battery life".

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Then explain why the phone lags when there are multiple apps open.

Might be jailbroken?
 

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
Then explain why the phone lags when there are multiple apps open.

It doesn't lag. What you think is lag is actually a mental effect that is a carry over from desktop operating system, most likely Windows. For when Windows would get low on available ram, it'd start to slow down. You think your iOS device is low on ram, so your mind slows it down. Don't forget, iOS is a UNIX based operating system and on UNIX based operating systems, free ram is wasted ram.
 

goosnarrggh

macrumors 68000
May 16, 2006
1,602
20
It doesn't lag. What you think is lag is actually a mental effect that is a carry over from desktop operating system, most likely Windows.

Wow, do you really not have any recollection of the spinning beachball of death...? Windows definitely isn't the only desktop-class operating system that is susceptible to swap memory thrashing. When it happens on OSX, I find its effects even more cripplingly debilitating than when it happens on Windows.

I know, this is not directly relevant to iOS's multitasking implementation.

Poorly written apps, if they are installed through a jailbreaking process or if they manage to slip through Apple's app vetting process undetected, may needlessly eat up background resources in iOS. But in the vast majority of cases, if not you're jailbroken, Apple will catch most such apps before they make it into the store.
 

TheSuperSteve

macrumors 6502
Jul 4, 2011
404
0
Puerto Rico
It doesn't lag. What you think is lag is actually a mental effect that is a carry over from desktop operating system, most likely Windows. For when Windows would get low on available ram, it'd start to slow down. You think your iOS device is low on ram, so your mind slows it down. Don't forget, iOS is a UNIX based operating system and on UNIX based operating systems, free ram is wasted ram.

You don’t have an iPod touch, do you? Either that or you rarely use it. Otherwise you would realize that the OP is completely correct. Like it or not, the iPod touch slows down when its low on memory. No facts you pull out of head will change that.

To the OP: There is nothing that can be done but close all apps from the multitasking tray when you’re done with them. The iPhone 4S and the new iPad do not suffer from this problem as they both have plenty of memory. The only thing iPod touch owners can really do to fix this is wait until a refresh or shell out the cash for the devices mentioned.
 

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
Wow, do you really not have any recollection of the spinning beachball of death...? Windows definitely isn't the only desktop-class operating system that is susceptible to swap memory thrashing. When it happens on OSX, I find its effects even more cripplingly debilitating than when it happens on Windows.

I know, this is not directly relevant to iOS's multitasking implementation.

Poorly written apps, if they are installed through a jailbreaking process or if they manage to slip through Apple's app vetting process undetected, may needlessly eat up background resources in iOS. But in the vast majority of cases, if not you're jailbroken, Apple will catch most such apps before they make it into the store.

Mac OS X has virtual memory, iOS does not. Some beach balling is caused by the program swapping its ram to disk. Most other beach balling is caused by a stuck thread or crashed process.

You don’t have an iPod touch, do you? Either that or you rarely use it. Otherwise you would realize that the OP is completely correct. Like it or not, the iPod touch slows down when its low on memory. No facts you pull out of head will change that.

I happen to have an iPod Touch of every generation. I even have multitasking enabled on a iPod Touch 2G with only 128Mb of ram. That iPod has been running for 30+ days non-stop without any slow down caused by lack of ram. My 3Gs with 256Mb of ram is heavily used daily and never suffers from any ram related slow downs.

I suggest you watch the videos posted here and become enlightened: http://www.idownloadblog.com/2012/01/09/ios-multitasking-video/
 

iThinkergoiMac

macrumors 68030
Jan 20, 2010
2,664
4
Terra
Apps in the background don't use resources. They are frozen in the memory and when another program needs more memory, the frozen program is killed.

In an ideal world, absolutely. This isn't always the case. When I played Infinity Blade on my 3rd gen iPod Touch (3GS hardware), I would definitely experience a lower FPS if I didn't quit the other apps first. It was not jailbroken, and it wasn't in my head, as Intell claims it must be. It was measurable and distinct. I know that's not the way it's supposed to be, but that's how it was. My 4S doesn't have this issue, though it is significantly more powerful in all aspects.

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Mac OS X has virtual memory, iOS does not. Some beach balling is caused by the program swapping its ram to disk. Most other beach balling is caused by a stuck thread or crashed process.

Might want to check your facts. According to Apple, iOS has a VM system as integrated as OS X's. Not surprising when you consider that iOS is a scaled-down version of OS X.
 

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
In an ideal world, absolutely. This isn't always the case. When I played Infinity Blade on my 3rd gen iPod Touch (3GS hardware), I would definitely experience a lower FPS if I didn't quit the other apps first. It was not jailbroken, and it wasn't in my head, as Intell claims it must be. It was measurable and distinct. I know that's not the way it's supposed to be, but that's how it was. My 4S doesn't have this issue, though it is significantly more powerful in all aspects.


Might want to check your facts. According to Apple, iOS has a VM system as integrated as OS X's. Not surprising when you consider that iOS is a scaled-down version of OS X.

Watch the video I posted. It is clearly shown that apps in the background and not using any of the 7 backgrounding services do not use any CPU cycles and are killed off as soon as more ram is needed. I do not claim that the slow down must be a mental effect, but the slow down is exacerbated by those who are expecting too much from their device. Sometimes it takes a few seconds to properly close the app when it is told to close by iOS. These few seconds also slightly cause a slow effect.

iOS has virtual memory, but it doesn't have swap. On Mac OS X a swap file is made if the system needs more ram and ram contents are dumped into that file. On iOS this swap file doesn't exist, because iOS doesn't have the ability to make it. If iOS needs more ram is starts killing off apps starting with the one last launched longest ago.
 

iThinkergoiMac

macrumors 68030
Jan 20, 2010
2,664
4
Terra
iOS has virtual memory, but it doesn't have swap. On Mac OS X a swap file is made if the system needs more ram and ram contents are dumped into that file. On iOS this swap file doesn't exist, because iOS doesn't have the ability to make it. If iOS needs more ram is starts killing off apps starting with the one last launched longest ago.

No question there. Just pointing out that saying iOS has no VM is erroneous.
 

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
No question there. Just pointing out that saying iOS has no VM is erroneous.

The terms virtual memory and swap are commonly switched and both accepted terms in the UNIX computing world. They both mean to store ram contents to non-ram storage mediums. iOS does not have this ability. It has fake virtual ram, just like Mac OS X. Right now my Mac's Activity Monitor is saying a few of my processes are using 16,777,216TB of virtual memory, which they clearly are not when my swap used is only 7.25MB. Overall non-swapped virtual memory on iOS/Mac OS X doesn't hold any application data and is more like ghost memory that doesn't really do anything. Only swapped virtual memory does and it is something that iOS cannot do.
 

TheSuperSteve

macrumors 6502
Jul 4, 2011
404
0
Puerto Rico
I happen to have an iPod Touch of every generation. I even have multitasking enabled on a iPod Touch 2G with only 128Mb of ram. That iPod has been running for 30+ days non-stop without any slow down caused by lack of ram. My 3Gs with 256Mb of ram is heavily used daily and never suffers from any ram related slow downs.

I suggest you watch the videos posted here and become enlightened: http://www.idownloadblog.com/2012/01/09/ios-multitasking-video/

Well aren’t we the smug one? You’re either blind or our definitions of “slowdown” are entirely different. You really don’t see any lag (As in, the OS itself skipping frames of animation, apps taking longer to quit after pressing the home button, apps taking longer to launch) on a second-generation iPod touch? On iOS 4? Really? You don’t see any lag on a fourth-generation iPod touch on iOS 5?

I happen to have both these models and the fourth-generation one is unusably slow when it gets low on ram. I am not imagining things and neither is the OP. Maybe those facts you keep vomiting all over the place are true. But the fact of the matter is that my… and the OP’s iPods are functioning slower than they should. Nothing you say will magically make my iPod touch run faster.
 
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Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
Note I said "no slow downs caused by lack of ram". Meaning my iPod Touch 2G is as fast on uptime 0:00:01 as it is on uptime 24:00:00 even after a day of running various apps. The slow downs it does suffer from are caused by a slow CPU, not lack of ram. I've also found iOS 4.2.1 is slightly faster then 3.1.3 on my iPod Touch 2G. That along with much better battery life in the order of weeks more of standby time better.

My iPod Touch 4G doesn't really slow down much at all, unless I put the Springboard icons into the rearrange mode or play a graphical intensive game. But those problems are caused by the underpowered GPU. Even my iPhone 4 suffers from slow downs when doing those two things, when my 4S doesn't.

I've seen plenty of Apple related problems and have many of my own. One particular one that is a random freezing on iMacs with ATI 2400/2600 video cards caused by a faulty kernel extension that was first used in Mac OS X 10.6.7 and hasn't been fixed yet.
 
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Nermal

Moderator
Staff member
Dec 7, 2002
20,977
4,543
New Zealand
As other people have stated, background apps can still put stress on the device. The most startling example I've seen of this was when I was tethering. I connected my 4S over USB (so it would charge at the same time) and enabled tethering, but still the battery was slowly draining. I noticed this after a few hours, once I got the "20% battery remaining" notification.

At that point, I did double-home and closed all the apps that I didn't need. The effect was almost immediate; the charge indicator turned from red back to white, and continued to increase over the following hours.
 

goosnarrggh

macrumors 68000
May 16, 2006
1,602
20
Mac OS X has virtual memory, iOS does not.
I know that. In fact, I stated it explicitly:
goosnarrggh said:
...this is not directly relevant to iOS's multitasking implementation...
Thank you.

Then, I said that a poorly-written App that managed to slip through Apple's vetting process (or a jailbroken App that specifically bypassed Apple's vetting process) may still needlessly use up iOS resources. You know, there are ways to needlessly use up resources, but have nothing to do with memory thrashing. For example: CPU cycles could be wasted switching into an idle App while it has nothing productive to do. This effect would never happen, of course, with well-written Apps.

Anyway, pedantically, the memory management unit in modern ARM cores tightly binds the concepts of virtual memory (ie memory structure where the logical address is not directly correlated to any particular physical address on any perticular physical medium) with the concepts of memory protection.

iOS most definitely does make use of memory protection, so it must necessarily make use of virtual memory as well.

Each individual process running in a Darwin-based operating system on a 32-bit CPU (such as iOS or OS X) has its own virtual, protected 4GB address space. Some of that virtual 4GB address space is mapped to the operating system, so the same physical memory is mapped into each virtual memory space regardless of which process is running. Some of that 4GB virtual address space may be mapped to some form of physical memory (maybe RAM, maybe a swap file), private to each individual application - and one given allocated virtual address location within one application's virtual address space will very likely point to a totally different physical memory location than the same allocated virtual address location within any other process's virtual address space.

And the vast majority of that 4GB virtual address space may be left unallocated because the process never asked the OS for permission to make use of it.

The fact that iOS never maps any of its virtual memory to a swap file doesn't mean that virtual memory isn't present in the system.
 

Cod3rror

macrumors 68000
Apr 18, 2010
1,809
151
I was going to respond that when you leave your apps, it does slow down, because I've experienced that, and I'd usually close the apps.

However, before that I experimented with leaving the apps open regardless, and for the first hour or so, it did slow down, but now, it's as responsive as with closed apps and I have 8 set(x4) of apps open in the switcher.

So IMO, it's all about how many apps you are using within a short period of time. If you are using 8 apps constantly and not closing them, it'll slow things down, however if you are not using them all at once, things will get sandboxed and it won't make a difference on the performance.

EDIT: Also, there was no drain on battery life, in fact it lasted longer.
 
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