Meaning of "multitasking" on iPhone, iPad, etc
in [UK Mac]
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From: James Taylor on 28 Jan 2010 06:35 I don't own one of these iPhone generation devices, and living out here I've very rarely had a chance to try one, so I'm a bit baffled by how people are using the term "multitasking". In the usual IT lexicon "multitasking" has a very specific meaning when applied to operating systems, and although there are various different technical means by which it is achieved it basically means that programs can be running in memory at the same time and share CPU time. In the case of all Unixes I've encountered this has been "pre-emptive" mutlitasking, where the kernel uses timer interrupts, and I/O event interrupts, to switch regularly between the running processes. As far as I can tell, all Apple devices multitask like this because these days they're all based on some Unix derivative. Perhaps there is a widespread misuse of the term "multitasking" that is being applied to how the GUI makes the OS *appear* to the end user. However, small screen devices such as smart phones (and I remember the various Psion palmtops too) all have a GUI that allows you to switch between the concurrently running apps and each app takes up the full screen while you're using it. You can nevertheless cut'n'paste between apps, or have for example a calendar app pop up an alarm while you're writing an email, or open links received in email in the web browser, etc. I've configured the window manager on my Ubuntu netbook to work like this because it's actually far more convenient on a small screen device than fiddling around with the touchpad to arrange windows, but there is no sense in which Linux could be described as non-multitasking. Indeed even the tiny embedded Linux in OpenWRT is fully multitasking. I have to presume that what people really mean by non-multitasking is a GUI that displays only one application's interface at a time, even if the other applications are still running and thus multitasking in the true sense of the word. However, if so, then I don't understand what they would expect from a small device. Do they really imagine that window management is something they want to be able to do on an iPhone? -- James Taylor
From: Ian McCall on 28 Jan 2010 06:38 On 2010-01-28 11:35:27 +0000, James Taylor <usenet(a)oakseed.demon.co.uk.invalid> said: > I have to presume that what people really mean by non-multitasking is a > GUI that displays only one application's interface at a time, even if > the other applications are still running and thus multitasking in the > true sense of the word. However, if so, then I don't understand what > they would expect from a small device. Do they really imagine that > window management is something they want to be able to do on an iPhone? No - the application is literally terminated. It's what's preventing me, for instance, from running Spotify or SomaFM on the iPhone and then switching to writing mail or reading RSS feeds or whatever. They're not running. Every other phone os can multitask at the applications level, it wouldn't be beyond the wit of Apple to introduce some gesture-based tasking,or maybe pressing the home button twice shows all running apps or something. It's a daft omission. Cheers, Ian
From: yitzhak on 28 Jan 2010 07:05 On 2010-01-28, James Taylor <usenet(a)oakseed.demon.co.uk.invalid> wrote: > I don't own one of these iPhone generation devices, and living out here > I've very rarely had a chance to try one, so I'm a bit baffled by how > people are using the term "multitasking". The iPhone has a hardware button below the screen, which you press whenever an application is running, in order to get back to the 'home' screen, i.e. the screen with all the pretty little icons. If you're running an application, say you're listening to a foreign radio station, and you want to check your e-mail, the radio application will exit if you press the hardware button. That is, the radio will stop. You then have to launch it again and do whatever it requires, to get the radio back. If your iPhone is jailbroken, there is a little 'backgrounder' app that you can install with Cydia, but it wreaks havoc with the battery life. HTH.
From: Woody on 28 Jan 2010 07:17 Ian McCall <ian(a)eruvia.org> wrote: > On 2010-01-28 11:35:27 +0000, James Taylor > <usenet(a)oakseed.demon.co.uk.invalid> said: > > > I have to presume that what people really mean by non-multitasking is a > > GUI that displays only one application's interface at a time, even if > > the other applications are still running and thus multitasking in the > > true sense of the word. However, if so, then I don't understand what > > they would expect from a small device. Do they really imagine that > > window management is something they want to be able to do on an iPhone? > > No - the application is literally terminated. It's what's preventing > me, for instance, from running Spotify or SomaFM on the iPhone and then > switching to writing mail or reading RSS feeds or whatever. They're not > running. > > Every other phone os can multitask at the applications level, it > wouldn't be beyond the wit of Apple to introduce some gesture-based > tasking,or maybe pressing the home button twice shows all running apps > or something. It's a daft omission. It is a daft omission in a lot of cases. Having a jailbroken iPhone, which has multitasking and proswitcher which lets you switch between the applications by pressing and holding the home button, which gives you a view of all apps that you can select, it shows how slick it could be. It would be hard to go back from the multitasking to the singletasking option. One of the immediate things I use it for is reading news on the iPhone. To download a full 200 post update here on the phone takes it quite a while, so I start newstap, go back to what I was doing, and at some point later, the newstap icon has a label on it showing how many posts there are. Without mutitasking I can wait for 30 seconds or so (sometimes longer - it is very slow) on the screen, or go to another scrreen and do it again later when I have got time to wait. Also with multitasking you see that phone iPod and mail are running all the time. I would hope that if apple are stupid enough to prevent it (for whatever their reasons are), other people will come up with a jailbreak to put it back in. -- Woody
From: Richard Tobin on 28 Jan 2010 07:29
In article <7sdb41F6f6U1(a)mid.individual.net>, James Taylor <usenet(a)oakseed.demon.co.uk.invalid> wrote: You're right that the operating system itself provides multi-tasking, but: >I have to presume that what people really mean by non-multitasking is a >GUI that displays only one application's interface at a time, even if >the other applications are still running No, that's not all there is to it. Only Apple can write a program that continues running when it's not the program controlling the display. You can't do background computation, you can't send or listen for data. In effect, the GUI enforces single tasking even though the operating system doesn't. That's why a jailbroken iPhone *can* do real multitasking, by taking control away from the GUI. -- Richard -- Please remember to mention me / in tapes you leave behind. |