Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Mobile Multitasking

daringfireball.net

Post reply on HN
Print view View original

11–20 of 68 posts

Re: Mobile Multitasking

#11

Post by ajg1977 »

wvenable wrote: post #6
ajg1977 wrote: post #4

I'm curious why iPhone can't page application memory out to persistent storage (whatever of that 16GB etc you're not using for music) when they're in the background and RAM runs low. That would be the ideal - frozen background apps saved to persistent storage until needed without sitting in RAM. I'm assuming the OS is modern enough that all apps have their own address space so perhaps the hardware doesn't have an MMU…

When an app is swapped to disk, all it's code and data pages are stored. When it's resumed, the code and data pages are loaded back. This isn't so terribly different from relaunching the application (loading the code) and having the app restore it's state (loading the data). In fact, the app can even be more efficient in saving it's own state because it can discard anything it knows it doesn't need. Paging is really…

Paging is a technique to free up RAM. Whether its used to enable interaction with multiple apps, to allow a single app access to more memory than physically exists, or to allow more apps to be frozen in the background is irrelevant. It is neither better nor worse than the system Apple has designed. Its just different.

And yes, an app can manually attempt to restore it's state but a) doing so can be quite tricky (keyboard up, word half-typed) and b) it's puts a heavy onus on developers, many of whom just do not bother.

Re: Mobile Multitasking

#12

Post by jared314 »

mrshoe wrote: post #2

I'm glad that iPhone OS is providing us an excuse to take personal computing a least a few steps down the path to where it should have gone years ago. Users shouldn't have to launch and quit applications. They shouldn't have to save and open documents. State should just persist. Always. If you pull the plug on your box you should be able to plug it back in and all state should be restored within seconds. All applicat…

Task-oriented UI?

Re: Mobile Multitasking

#13

Post by wvenable »

mrshoe wrote: post #2

I'm glad that iPhone OS is providing us an excuse to take personal computing a least a few steps down the path to where it should have gone years ago. Users shouldn't have to launch and quit applications. They shouldn't have to save and open documents. State should just persist. Always. If you pull the plug on your box you should be able to plug it back in and all state should be restored within seconds. All applicat…

If you want to edit a document and then save it as a new document you have to make that choice before you start editing on the iPad. A lot of people are going to destroy a lot of documents that way. It could be a simple fix to still keep the same model but right now it's not very intuitive.

Re: Mobile Multitasking

#14

Post by izendejas »

wvenable wrote: post #5

The close button on Windows Mobile never closed the apps either, it just minimized them. If you ran out of memory, Windows Mobile would close the oldest used application automatically. A great blog post, the Emperor has No Close about this: http://blogs.msdn.com/windowsmobile/archive/2006/10/05/The-E...

If anyone still uses Windows Mobile, I recommend WkTask (not sure it works on 6.5): http://soft.photoracer.net/docs/wktask_en.html

Map a key to launch it. Hit down, then hit close and voila. Can also switch quickly between open apps.

I'm planning to get an android device, but was very disappointed when I played with a droid and learned you can't always kill apps. The culprit in this case was the fandango app. Even after an update, I had to uninstall it because it wasn't responding. Maybe I don't know how to use the app manager?

Re: Mobile Multitasking

#17

Post by allenbrunson »

TimothyFitz wrote: post #16

What's the link between blocks/grand central and multitasking on the iPhone?

none. grand central is a scheme to make it easier to parallelize your code, generally so it can take advantage of two or more cpu cores. not much use on iphone devices, which aren't going to have more than one core for a long time. blocks add closure-like abilities to C. multitasking, in this context, is a way to run two or more third-party apps at once. so, basically, no overlap at all.

Re: Mobile Multitasking

#18

Post by pkulak »

I'm glad he made this point, but he's still not giving Android enough credit. With Android, apps can create a service that can run and do whatever it likes. It's not limited to a couple APIs.

People are pretty jazzed about Skype running in the background, but they are going to be dissapointed when they realize that only means that you can keep the current call running while you leave the app. Skype still won't be able to stay open and listen for incoming calls. Same with chat or IRC apps.

Re: Mobile Multitasking

#19

Post by cpr »

pkulak wrote: post #18

I'm glad he made this point, but he's still not giving Android enough credit. With Android, apps can create a service that can run and do whatever it likes. It's not limited to a couple APIs. People are pretty jazzed about Skype running in the background, but they are going to be dissapointed when they realize that only means that you can keep the current call running while you leave the app. Skype still won't be abl…

Your last paragraph isn't true about VOIP apps, but I can't say more due to the NDA.

Re: Mobile Multitasking

#20

Post by swernli »

pkulak wrote: post #18

I'm glad he made this point, but he's still not giving Android enough credit. With Android, apps can create a service that can run and do whatever it likes. It's not limited to a couple APIs. People are pretty jazzed about Skype running in the background, but they are going to be dissapointed when they realize that only means that you can keep the current call running while you leave the app. Skype still won't be abl…

Not true. The background services offered by the OS allow the apps to still receive calls/IMs etc while not in the foreground. According to Apple press release:

"These services include background audio, so apps like Pandora can play music in the background, and VoIP, so VoIP apps can receive a VoIP call even when the iPhone is asleep or the user is running other apps."

http://www.apple.com/pr/library/2010/04/08iphoneos.html

Post reply on HN