Why the iPad and the iPhone don't support multitasking • Hacker News Board

Re: Why the iPad and the iPhone don't support multitasking

#21

Post by sjs » Sun, Apr 04, 2010, 7:18 PM UTC

alec wrote: post #5

carbocation wrote: post #2

> "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...

Swapping has been demonstrated to be seriously detrimental to the life expectancy of solid state drives.

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-pa...

Re: Why the iPad and the iPhone don't support multitasking

#22

Post by enjo » Sun, Apr 04, 2010, 7:20 PM UTC

iaskwhy wrote: post #12

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.

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.

Re: Why the iPad and the iPhone don't support multitasking

#23

Post by orangecat » Sun, Apr 04, 2010, 7:27 PM UTC

orangecat wrote: post #17

tumult wrote: post #13

Earlier quoted context omitted.

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.

I'd bet that app was poorly written and doing something else in the background. An app that is just listening for data from an open connection should be using roughly zero CPU. But we'll try science; I've signed into AIM on my Nexus One and left it running in the background. The battery is at 81% now, I'll report back in an hour.

77% after an hour.

Re: Why the iPad and the iPhone don't support multitasking

#24

Post by jsz0 » Sun, Apr 04, 2010, 7:31 PM UTC

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.

Re: Why the iPad and the iPhone don't support multitasking

#25

Post by bmalicoat » Sun, Apr 04, 2010, 7:59 PM UTC

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?

Re: Why the iPad and the iPhone don't support multitasking

#26

Post by wmf » Sun, Apr 04, 2010, 8:09 PM UTC

carbocation wrote: post #2

> "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...

The N900 has swap, and I think that's why it becomes completely unresponsive from time to time.

Re: Why the iPad and the iPhone don't support multitasking

#27

Post by necubi » Sun, Apr 04, 2010, 8:32 PM UTC

bmalicoat wrote: post #25

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…

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.

Re: Why the iPad and the iPhone don't support multitasking

#28

Post by jcromartie » Sun, Apr 04, 2010, 8:40 PM UTC

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.

Re: Why the iPad and the iPhone don't support multitasking

#29

Post by bmalicoat » Sun, Apr 04, 2010, 8:51 PM UTC

necubi wrote: post #27

bmalicoat wrote: post #25

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…

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 so…

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.

Re: Why the iPad and the iPhone don't support multitasking

#30

Post by tumult » Sun, Apr 04, 2010, 8:54 PM UTC

orangecat wrote: post #23

orangecat wrote: post #17

Earlier quoted context omitted.

I'd bet that app was poorly written and doing something else in the background. An app that is just listening for data from an open connection should be using roughly zero CPU. But we'll try science; I've signed into AIM on my Nexus One and left it running in the background. The battery is at 81% now, I'll report back in an hour.

77% after an hour.

Sign in with the connection currently using WiFi instead of GPRS/3G, and it will keep the WiFi hardware on, which is what kills it. There is no way for a normal user to know that they need to open new, persistent connections over a connection type that uses the cellular modem instead of the WiFi. And Android defaults to using WiFi for new connections if the WiFi hardware is powered on and connected to a network.

The best way to save battery on an Android phone is to turn off WiFi unless you need it at some point during the day. iPhone will stop attempting to do push notifications and the background Apple apps will disconnect if the only available connection is WiFi.

I'd also like to point out that "I bet the app was poorly written" is exactly the situation Apple is currently avoiding until they are confident they have a reasonable technical solution to it.