With the unveiling of the iPhone’s SDK, everything seems to have been going swimmingly.
Not so fast, says Apple. It appears that, as of now, the iPhone will not be able to run more than one application made through the SDK, at once.
Only one iPhone application can run at a time, and third-party applications never run in the background. This means that when users switch to another application, answer the phone, or check their email, the application they were using quits. (p. 16)
This is a problem of monumental gravity, as it is highly likely that users will want to run applications, like AIM, in the background while they use another. Granted, Apple has to save RAM in order to make their own iPhone functions, like the iPod or Safari, run smoother.
Yet the point remains, if applications made without the SDK could run simultaneously with not too bad of an effect on the performance of the device, it seems like Apple could let you run, at the very least, two concurrent applications.
The options are still open, end-users! You can still stay Jailbroken, or simply make the transition over to web based apps that run in the background. Who knows? Perhaps later versions of the iPhone will have the processing power to multitask 8 ways from Sunday.
Read [Techcrunch]
You can have multiple applications running at a time on an iPhone – you just need to override the call that exits it when you switch out. Otherwise, how do you think that the talk applications work?
The HIG say that an app *shouldn't* assume it's running in the background, not that it can't.