25 ms·

Why the iPad and the iPhone don't support multitasking

74 points by pWneD 16y ago

carbocation 16y ago
> "Both the iPad and iPhone, as mobile devices, have limited memory (256MB in the current incarnations) and no hard drive. No hard drive means no swap file." He loses me here. My iPhone has a 32GB SSD hard drive. Sounds like a perfect medium for swap space to me...
- glhaynes 16y ago
  Yeah, that's poor wording. The techie in me was aghast at the idea of Apple shipping iPhones with a full Unixy kernel but with no swap (and minimal background processing -- and for that matter, I wondered why its Objective-C runtime didn't support garbage collection) until I actually laid hands on one and realized how fluid things can be when they don't stutter and stop randomly while swapping in parts of the foreground program. Such jerkiness gives a feel of "computeriness" to the user when running desktop OSes, breaking the feeling of fluid interactivity that one gets with a "real-world" object. It also causes a lot of user anxiety and even errors: it becomes a normal part of the experience to click on an item and then have a second or two of wondering whether the app "heard" you or not. Often followed by more clicks, which end up being misinterpreted when the app finally gets to run again, and now the user's mental model is completely out of sync with the system's state. In the physical world, you never flick a real switch on a panel and then it actually moves a second or two later!
  - astine 16y ago
    "In the physical world, you never flick a real switch on a panel and then it actually moves a second or two later!" I know some old lights which do that.
    - glhaynes 16y ago
      I didn't mean the resulting action might not take a moment, I meant the actual movement of the switch.
  - yason 16y ago
    The jerkiness and stuttering has always been a PC/DOS/Windows issue. Not a computeriness issue, unless you only have computer experience It was in the 80's that PCs couldn't even scroll a line of text without making odd stops at times, it was in the 90's when I was surprised to still keep seeing the phenomenon, and it's these days that I can still see a modern Windows screensaver stutter for no reason. Or just some mouse click taking a few seconds "to deliver". The reason I (and so many other people) so adored the Amiga still late in the 90's is that anything like that was completely unheard of. The computer was just so snappy. Everything happened pretty much immediately. I remember that around 1995 or so there was a web page that had 256 GIF animations playing on it simultaneously. My bare Amiga could run them all smoothly despite me even doing something else in another window. My friend's Pentium pretty much choked on the very same page. Linux desktop is nothing compared to Amiga. BeOS was close but died as well. I want a completely 100% responsive, stutter-free multitasking desktop/ipad/phone because I know it's possible. I don't want to settle for too slow latency or live with the false claim that to be snappy you can only run one application at a time.
- alec 16y ago
  Swapping has been demonstrated to be seriously detrimental to the life expectancy of solid state drives.
  - sjs 16y ago
    Has it? Everything I've read that is not just speculation has concluded that you'd have to constantly write a great deal of data to wear out an SSD, even with a swap partition (or file). http://serverfault.com/questions/23720/should-you-disable-page-file-with-ssd/25620#25620 http://serverfault.com/questions/23720/should-you-disable-pa...
    - jmtulloss 16y ago
      SSD drives have substantially longer life than embedded flash drives since they are SLC, meaning each bit is represented by one cell. Embedded flash devices are MLC, meaning each cell represents multiple bits. Your drive's life expectancy goes down dramatically with each bit you try stuff into a single cell.
      - rictic 16y ago
        Are you sure? I thought most non-enterprise SSDs are MLC.
  - domdelimar 16y ago
    But what's the life expectancy of smartphones and the likes? I wonder if flash storage in them could die so quickly - even before such a device itself would become obsolete. If it's correct that at least Palm's webOS and Maemo dare to swap on flash storages, we shall see soon...
- exit 16y ago
  would anyone care to predict what the memory specs of an iphone-like will be in 5 years?
- bitwize 16y ago
  Obviously you've never used an Amiga. No swap file + no virtual memory + lots of stuff pre-cached onto RAM disk = snappiest user experience ever.
  - romland 16y ago
    It scares me to think that I now days open, without blinking, some JPG that would eat up all the memory available in that poor Amiga. But, ah... lea bbye,a0 move.l (a0),$80 trap #0 rts (to take it back on-topic)
  - domdelimar 16y ago
    Older Palm Treos (up to Treo 600 if I'm not mistaken) had everything in RAM and I remember upgrading to a newer, supposedly better Treo - and everything but the lag was...
- wmf 16y ago
  The N900 has swap, and I think that's why it becomes completely unresponsive from time to time.
- naner 16y ago
  His tweet seemed to indicate that this is a bad idea: http://twitter.com/rlove/statuses/11609100128 http://twitter.com/rlove/statuses/11609100128
  - domdelimar 16y ago
    What I'd like to know is why this is a bad idea...
- sliverstorm 16y ago
  Perfect? Sounds awful to me. Few things will use up a SSD's wear cycles faster than active swap, and I doubt Apple wants to go out and buy good SSD's with many write cycles. That would eat into profits. (they can cut corners in data storage requirements right now because the drives are written-to/read-from much less often than on a PC, so both longevity and speed are much smaller concerns)
- gte910h 16y ago
  > My iPhone has a 32GB SSD hard drive Embedded engineer here: Solid State Drives do lots of things GREAT. However "being a drive which swap is used on" is not one of them. That's because swap memory is written very often compared to any other portion of the drive. This quickly wears out the drive in that location (and all flash has a limited number of writes, and SSD is a flash technology). There are specific drivers for doing swap on flash devices. But it isn't easy to do well without compromising usable life of the device. IF you're interested in doing virtual memory in an app: http://www.alexcurylo.com/blog/2009/05/14/tip-iphone-virtual-memory/ http://www.alexcurylo.com/blog/2009/05/14/tip-iphone-virtual... is a way to do it, there is a hacked iphone app that also enables it too (don't have a URL offhand). I dis-recommend doing so.
TheAmazingIdiot 16y ago
And in practice, its still wrong. The 3rd party repos have an app called Backgrounding that does precisely that... And no sdlowdown on most apps.
- spudlyo 16y ago
  It's very handy. Sometimes you want to have Safari start loading a slow-to-load page, put it in the background and do something else. Pandora radio is another oft cited example.
- ja27 16y ago
  I jailbroke just so I could run Pandora and Slacker in the background. (Though an updating weather icon and having a background image are nice too.) I'm not sure how Pocket Tunes Radio is able to play in the background, but they've found some Apple-sanctioned solution that works for MP3 and AAC+ streams. Or I can use Safari to start an MP3 stream and it will background just fine. I'm sure Apple could just make a policy decision to let some apps they approve run in the background.
gte910h 16y ago
This guy is just wrong: Apple OS has turned off multitasking for 3rd party apps to maintain battery life. It fully supports it. This is a control situation, where Apple has decided "We want our devices to have good battery life more than we want to allow multitasking".
- jm4 16y ago
  Source?
  - gte910h 16y ago
    Do you hear music in the background while doing other things? Do you see your mail being checked while doing other things? Do you get background notifications while doing other things? Do you get appstore apps downloaded while doing other things? The iphone is fundamentally built on a mach kernel, which supports multitasking. Taking it out, when they already needed to use it for multitasking for the above tasks, is a silly idea. Here is a rundown of other parts of the iPhoneOS kernel: http://www.roughlydrafted.com/2007/07/13/iphone-os-x-architecture-the-mach-kernel-and-ram/ http://www.roughlydrafted.com/2007/07/13/iphone-os-x-archite...
- buster 16y ago
  Best thing about those excuses are: Every other mobile OS supports multitasking and all the smartphones i know have similar battery life. Symbian, Windows, Android, all have multitasking and yet people try to convince me that it, "not needed", "not possible", "makes the device unstable", "drains battery too much" which is just not true. My Android phone lasts at least as long as an iphone and i use multitasking all the day. It's just that the OS was truly made for this and it does it quite well.
  - tumult 16y ago
    If I leave an app running in the background that keeps the net connection open on my Nexus One, the battery goes from 100 to 0 in about 5 hours.
deleted 16y ago
[deleted]
iaskwhy 16y ago
I would be more than happy with no multitasking at all with one exception: sms. And I'm pretty sure that if I include another two apps (safari and mail) on my exception list most people would be okay without multitasking. I don't need a window manager, I need to focus on the app I'm using and the ability to reply (or send) sms and mails and check something on the web without quitting the current app.
- enjo 16y ago
  There are a range of applications, including highly useful ones, that simply needs multi-tasking. Anything that is time based (think calendars, alarm clocks, etc...) really need multi-tasking to work correctly. A host of location aware applications really need multi-tasking to work effectively. I get Apples position. The iPhone is the spiritual successor to the PalmOS. It looks, feels, and works very similarly to it. Even early finger-based applications first made their appearance on the Palm (here's looking at you SnapperMail with your fat finger mode). The Palm had thousands of apps and solved a ton of problems without multi-tasking. So I get it... you can build a really useful device without it. Yet there is so much more you can do with a well thought-out system like Android has. As Android gets more traction (and thus more developer interest) I think your going to see more and more separation between the quality of the apps available on the devices. There are simply going to be killer applications that force Apples hand to stay competitive.
  - stcredzero 16y ago
    There are a range of applications, including highly useful ones, that simply needs multi-tasking. Anything that is time based (think calendars, alarm clocks, etc...) really need multi-tasking to work correctly. A host of location aware applications really need multi-tasking to work effectively. Very few apps need completely open ended multitasking. Most apps need very specific capabilities. An API for registering time limited functions with timing, location, and other services would take care of 90% of the needs out there.
    - theBobMcCormick 16y ago
kjhghjmkedfcv 16y ago
Of course there is the official Apple solution. http://technologyexpert.blogspot.com/2010/03/wozniak-carries-two-iphones-to-fix.html http://technologyexpert.blogspot.com/2010/03/wozniak-carries...
tlrobinson 16y ago
Saving the state of an application and terminating it isn't multitasking... you can already do that on the iPhone, and indeed well written iPhone apps will be restored to exactly the state you left them. I care about multitasking for things which actually need to do stuff in the background, like Pandora or IM clients.
jsz0 16y ago
We know from SDK snooping that Apple is working on third party multi-tasking so it's kind of a moot point. The only question is how they're going to do it. I think it's good to acknowledge that a mobile device with limited battery/resources has to multi-task differently than a traditional computer running an OS designed 20-30+ years ago.
bmalicoat 16y ago
The only issue I take here is the iPhone is supposed to not need an instruction manual, everything is supposed to be intuitive. Adding multitasking like the Android means every user becomes an accountant keeping track of what's running and what should be killed. Activity or task managers are most definitely not intuitive. Most apps don't have any business running in the background, saving and resuming states seems to work in most cases especially with smart use of push notifications. I've really only seen a couple compelling use cases and that is Pandora (basically music running in the background for the uninitiated) and the YC Wakemate app. Anyone have any others that couldn't be solved with push?
- necubi 16y ago
  The big issue is that it imposes a high mental cost for switching between applications. If you're browsing on Mobile Safari and you want to look up something in another app, you generally wont, because by the time you get back to Safari you may have lost the page you were visiting and in any case the startup times can be pretty atrocious. On the Pre, which has the best multi-tasking implementation I've seen, these sorts of tasks are a no-brainer. You know that your previous applications is just a couple of swipes away, so you're never afraid to leave it. Constantly shutting down and restarting applications may be good for performance and battery life, but the user experience is hampered.
  - bmalicoat 16y ago
    Well the developer can implement a great experience but the problem is the onus is on them, the OS doesn't do anything to save/resume the state. Some apps, Tweetie for instance, does a great job resuming, others dump you at the front gate and make you watch splash intros which is terrible. So I guess my vote is for built-in support for saving state.
  - blubb 16y ago
    Which is why Safari IS actually multitasking. You can leave it, launch another app, go back to it and be right back where you are. Sometimes Safari doesn't quit and you're back in a millisecond. Other times the OS closes the browser in the background, and you will have to wait a few seconds while Safari reloads the page you were visiting. It's surprising how few people realize that the built-in apps (Mail, iPod, SMS etc) run perfectly in the background. The lack of multitasking is limited to 3rd party apps, which helps explain why most iPhone users never complain too much about the lack of real multitasking.
jcromartie 16y ago
So the android solution is for apps to serialize their state when they are about to be terminated? That's exactly what iPhone apps are expected to do! What we are really talking about here is backgrounding, which is really only appropriate for a small class of apps. Push solves a lot of these cases. The audience for backgrounding without push is mostly power users, and they can jailbreak for that.
stcredzero 16y ago
Apple says they do not support multitasking because it is a hamper to stability and a drain on battery life. That clearly isn’t true—the iPad has plenty of processing power and battery capacity. Rumor is that Apple is going to add multitasking in a future OS release. This rumor likely is true. Is Apple somehow going to make background applications not consume any battery? Of course not. These excuses are straw men. Actually this argument is a straw man. Apple can't make background processes run for free contrary to the laws of thermodynamics. However they can limit the resources they can use through the right API. (Register functions with realtime constraints, and request a "level of service.")
AndrewWarner 16y ago
I have mult-tasking because I jailbroke. Just as he says, Skype keeps getting killed when it's in the background so I can't depend on it for getting calls.

74 points by pWneD 16y ago

> "Both the iPad and iPhone, as mobile devices, have limited memory (256MB in the current incarnations) and no hard drive. No hard drive means no swap file." He loses me here. My iPhone has a 32GB SSD hard drive. Sounds like a perfect medium for swap space to me...

glhaynes 16y ago
Yeah, that's poor wording. The techie in me was aghast at the idea of Apple shipping iPhones with a full Unixy kernel but with no swap (and minimal background processing -- and for that matter, I wondered why its Objective-C runtime didn't support garbage collection) until I actually laid hands on one and realized how fluid things can be when they don't stutter and stop randomly while swapping in parts of the foreground program. Such jerkiness gives a feel of "computeriness" to the user when running desktop OSes, breaking the feeling of fluid interactivity that one gets with a "real-world" object. It also causes a lot of user anxiety and even errors: it becomes a normal part of the experience to click on an item and then have a second or two of wondering whether the app "heard" you or not. Often followed by more clicks, which end up being misinterpreted when the app finally gets to run again, and now the user's mental model is completely out of sync with the system's state. In the physical world, you never flick a real switch on a panel and then it actually moves a second or two later!
- astine 16y ago
  "In the physical world, you never flick a real switch on a panel and then it actually moves a second or two later!" I know some old lights which do that.
  - glhaynes 16y ago
    I didn't mean the resulting action might not take a moment, I meant the actual movement of the switch.
- yason 16y ago
  The jerkiness and stuttering has always been a PC/DOS/Windows issue. Not a computeriness issue, unless you only have computer experience It was in the 80's that PCs couldn't even scroll a line of text without making odd stops at times, it was in the 90's when I was surprised to still keep seeing the phenomenon, and it's these days that I can still see a modern Windows screensaver stutter for no reason. Or just some mouse click taking a few seconds "to deliver". The reason I (and so many other people) so adored the Amiga still late in the 90's is that anything like that was completely unheard of. The computer was just so snappy. Everything happened pretty much immediately. I remember that around 1995 or so there was a web page that had 256 GIF animations playing on it simultaneously. My bare Amiga could run them all smoothly despite me even doing something else in another window. My friend's Pentium pretty much choked on the very same page. Linux desktop is nothing compared to Amiga. BeOS was close but died as well. I want a completely 100% responsive, stutter-free multitasking desktop/ipad/phone because I know it's possible. I don't want to settle for too slow latency or live with the false claim that to be snappy you can only run one application at a time.
alec 16y ago
Swapping has been demonstrated to be seriously detrimental to the life expectancy of solid state drives.
- sjs 16y ago
  Has it? Everything I've read that is not just speculation has concluded that you'd have to constantly write a great deal of data to wear out an SSD, even with a swap partition (or file). http://serverfault.com/questions/23720/should-you-disable-page-file-with-ssd/25620#25620 http://serverfault.com/questions/23720/should-you-disable-pa...
  - jmtulloss 16y ago
    SSD drives have substantially longer life than embedded flash drives since they are SLC, meaning each bit is represented by one cell. Embedded flash devices are MLC, meaning each cell represents multiple bits. Your drive's life expectancy goes down dramatically with each bit you try stuff into a single cell.
    - rictic 16y ago
      Are you sure? I thought most non-enterprise SSDs are MLC.
- domdelimar 16y ago
  But what's the life expectancy of smartphones and the likes? I wonder if flash storage in them could die so quickly - even before such a device itself would become obsolete. If it's correct that at least Palm's webOS and Maemo dare to swap on flash storages, we shall see soon...
exit 16y ago
would anyone care to predict what the memory specs of an iphone-like will be in 5 years?
bitwize 16y ago
Obviously you've never used an Amiga. No swap file + no virtual memory + lots of stuff pre-cached onto RAM disk = snappiest user experience ever.
- romland 16y ago
  It scares me to think that I now days open, without blinking, some JPG that would eat up all the memory available in that poor Amiga. But, ah... lea bbye,a0 move.l (a0),$80 trap #0 rts (to take it back on-topic)
- domdelimar 16y ago
  Older Palm Treos (up to Treo 600 if I'm not mistaken) had everything in RAM and I remember upgrading to a newer, supposedly better Treo - and everything but the lag was...
wmf 16y ago
The N900 has swap, and I think that's why it becomes completely unresponsive from time to time.
naner 16y ago
His tweet seemed to indicate that this is a bad idea: http://twitter.com/rlove/statuses/11609100128 http://twitter.com/rlove/statuses/11609100128
- domdelimar 16y ago
  What I'd like to know is why this is a bad idea...
sliverstorm 16y ago
Perfect? Sounds awful to me. Few things will use up a SSD's wear cycles faster than active swap, and I doubt Apple wants to go out and buy good SSD's with many write cycles. That would eat into profits. (they can cut corners in data storage requirements right now because the drives are written-to/read-from much less often than on a PC, so both longevity and speed are much smaller concerns)
gte910h 16y ago
> My iPhone has a 32GB SSD hard drive Embedded engineer here: Solid State Drives do lots of things GREAT. However "being a drive which swap is used on" is not one of them. That's because swap memory is written very often compared to any other portion of the drive. This quickly wears out the drive in that location (and all flash has a limited number of writes, and SSD is a flash technology). There are specific drivers for doing swap on flash devices. But it isn't easy to do well without compromising usable life of the device. IF you're interested in doing virtual memory in an app: http://www.alexcurylo.com/blog/2009/05/14/tip-iphone-virtual-memory/ http://www.alexcurylo.com/blog/2009/05/14/tip-iphone-virtual... is a way to do it, there is a hacked iphone app that also enables it too (don't have a URL offhand). I dis-recommend doing so.

TheAmazingIdiot 16y ago

And in practice, its still wrong. The 3rd party repos have an app called Backgrounding that does precisely that... And no sdlowdown on most apps.

spudlyo 16y ago
It's very handy. Sometimes you want to have Safari start loading a slow-to-load page, put it in the background and do something else. Pandora radio is another oft cited example.
ja27 16y ago
I jailbroke just so I could run Pandora and Slacker in the background. (Though an updating weather icon and having a background image are nice too.) I'm not sure how Pocket Tunes Radio is able to play in the background, but they've found some Apple-sanctioned solution that works for MP3 and AAC+ streams. Or I can use Safari to start an MP3 stream and it will background just fine. I'm sure Apple could just make a policy decision to let some apps they approve run in the background.

gte910h 16y ago

This guy is just wrong: Apple OS has turned off multitasking for 3rd party apps to maintain battery life. It fully supports it. This is a control situation, where Apple has decided "We want our devices to have good battery life more than we want to allow multitasking".

jm4 16y ago
Source?
- gte910h 16y ago
  Do you hear music in the background while doing other things? Do you see your mail being checked while doing other things? Do you get background notifications while doing other things? Do you get appstore apps downloaded while doing other things? The iphone is fundamentally built on a mach kernel, which supports multitasking. Taking it out, when they already needed to use it for multitasking for the above tasks, is a silly idea. Here is a rundown of other parts of the iPhoneOS kernel: http://www.roughlydrafted.com/2007/07/13/iphone-os-x-architecture-the-mach-kernel-and-ram/ http://www.roughlydrafted.com/2007/07/13/iphone-os-x-archite...
buster 16y ago
Best thing about those excuses are: Every other mobile OS supports multitasking and all the smartphones i know have similar battery life. Symbian, Windows, Android, all have multitasking and yet people try to convince me that it, "not needed", "not possible", "makes the device unstable", "drains battery too much" which is just not true. My Android phone lasts at least as long as an iphone and i use multitasking all the day. It's just that the OS was truly made for this and it does it quite well.
- tumult 16y ago
  If I leave an app running in the background that keeps the net connection open on my Nexus One, the battery goes from 100 to 0 in about 5 hours.

deleted 16y ago

[deleted]

iaskwhy 16y ago

I would be more than happy with no multitasking at all with one exception: sms. And I'm pretty sure that if I include another two apps (safari and mail) on my exception list most people would be okay without multitasking. I don't need a window manager, I need to focus on the app I'm using and the ability to reply (or send) sms and mails and check something on the web without quitting the current app.

enjo 16y ago
There are a range of applications, including highly useful ones, that simply needs multi-tasking. Anything that is time based (think calendars, alarm clocks, etc...) really need multi-tasking to work correctly. A host of location aware applications really need multi-tasking to work effectively. I get Apples position. The iPhone is the spiritual successor to the PalmOS. It looks, feels, and works very similarly to it. Even early finger-based applications first made their appearance on the Palm (here's looking at you SnapperMail with your fat finger mode). The Palm had thousands of apps and solved a ton of problems without multi-tasking. So I get it... you can build a really useful device without it. Yet there is so much more you can do with a well thought-out system like Android has. As Android gets more traction (and thus more developer interest) I think your going to see more and more separation between the quality of the apps available on the devices. There are simply going to be killer applications that force Apples hand to stay competitive.
- stcredzero 16y ago
  There are a range of applications, including highly useful ones, that simply needs multi-tasking. Anything that is time based (think calendars, alarm clocks, etc...) really need multi-tasking to work correctly. A host of location aware applications really need multi-tasking to work effectively. Very few apps need completely open ended multitasking. Most apps need very specific capabilities. An API for registering time limited functions with timing, location, and other services would take care of 90% of the needs out there.
  - theBobMcCormick 16y ago

kjhghjmkedfcv 16y ago

Of course there is the official Apple solution. http://technologyexpert.blogspot.com/2010/03/wozniak-carries-two-iphones-to-fix.html http://technologyexpert.blogspot.com/2010/03/wozniak-carries...

tlrobinson 16y ago

Saving the state of an application and terminating it isn't multitasking... you can already do that on the iPhone, and indeed well written iPhone apps will be restored to exactly the state you left them. I care about multitasking for things which actually need to do stuff in the background, like Pandora or IM clients.

jsz0 16y ago

We know from SDK snooping that Apple is working on third party multi-tasking so it's kind of a moot point. The only question is how they're going to do it. I think it's good to acknowledge that a mobile device with limited battery/resources has to multi-task differently than a traditional computer running an OS designed 20-30+ years ago.

bmalicoat 16y ago

The only issue I take here is the iPhone is supposed to not need an instruction manual, everything is supposed to be intuitive. Adding multitasking like the Android means every user becomes an accountant keeping track of what's running and what should be killed. Activity or task managers are most definitely not intuitive. Most apps don't have any business running in the background, saving and resuming states seems to work in most cases especially with smart use of push notifications. I've really only seen a couple compelling use cases and that is Pandora (basically music running in the background for the uninitiated) and the YC Wakemate app. Anyone have any others that couldn't be solved with push?

necubi 16y ago
The big issue is that it imposes a high mental cost for switching between applications. If you're browsing on Mobile Safari and you want to look up something in another app, you generally wont, because by the time you get back to Safari you may have lost the page you were visiting and in any case the startup times can be pretty atrocious. On the Pre, which has the best multi-tasking implementation I've seen, these sorts of tasks are a no-brainer. You know that your previous applications is just a couple of swipes away, so you're never afraid to leave it. Constantly shutting down and restarting applications may be good for performance and battery life, but the user experience is hampered.
- bmalicoat 16y ago
  Well the developer can implement a great experience but the problem is the onus is on them, the OS doesn't do anything to save/resume the state. Some apps, Tweetie for instance, does a great job resuming, others dump you at the front gate and make you watch splash intros which is terrible. So I guess my vote is for built-in support for saving state.
- blubb 16y ago
  Which is why Safari IS actually multitasking. You can leave it, launch another app, go back to it and be right back where you are. Sometimes Safari doesn't quit and you're back in a millisecond. Other times the OS closes the browser in the background, and you will have to wait a few seconds while Safari reloads the page you were visiting. It's surprising how few people realize that the built-in apps (Mail, iPod, SMS etc) run perfectly in the background. The lack of multitasking is limited to 3rd party apps, which helps explain why most iPhone users never complain too much about the lack of real multitasking.

jcromartie 16y ago

So the android solution is for apps to serialize their state when they are about to be terminated? That's exactly what iPhone apps are expected to do! What we are really talking about here is backgrounding, which is really only appropriate for a small class of apps. Push solves a lot of these cases. The audience for backgrounding without push is mostly power users, and they can jailbreak for that.

stcredzero 16y ago

Apple says they do not support multitasking because it is a hamper to stability and a drain on battery life. That clearly isn’t true—the iPad has plenty of processing power and battery capacity. Rumor is that Apple is going to add multitasking in a future OS release. This rumor likely is true. Is Apple somehow going to make background applications not consume any battery? Of course not. These excuses are straw men. Actually this argument is a straw man. Apple can't make background processes run for free contrary to the laws of thermodynamics. However they can limit the resources they can use through the right API. (Register functions with realtime constraints, and request a "level of service.")

AndrewWarner 16y ago

I have mult-tasking because I jailbroke. Just as he says, Skype keeps getting killed when it's in the background so I can't depend on it for getting calls.