Apple is taking a play out of the Palm OS playbook for the iPhone. Unfortunately, it isn't one that'll benefit developers or end users. If a program is out of sight, to the iPhone it is out of mind.

Like with the Palm OS, Apple isn't going to allow developers to create applications that can multitask or run in the background when not directly being used. This means only when a program is on the screen will it be allowed to access the iPhone's memory and processing resources.

So if you go to answer a phone call or check your e-mail, the application you're currently running will shut down.

According to the iPhone Human Interface Guidelines (available to those who sign up for a free account):

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. 

If you are running an application such as AOL Instant Messenger on your iPhone, every time you receive a call or browse away from the application you would be signed out, you would lose any unread messages, and your conversations would end.

Certain applications, like instant messaging software, cannot work optimally or even correctly without multitasking. No matter how vigilant developers are in having their applications save all relevant data before the iPhone shuts them down. Take AOL Instant Messenger, for instance, since it can't run in the background, it won't be able to receive instant messages, just like any desktop IM application would.

The lack of multitasking support is a strange decision on Apple's part, considering one of the many knocks against the ancient - in mobile years - Palm OS is that it can't handle more than one application running at a time. In addition, multitasking long ago became a standard feature in most major smartphone platforms, including with direct iPhone competitors like Windows Mobile and Symbian.

To allow the iPhone to be limited in the same manner as a mobile OS that hasn't been updated in five years isn't the smartest move. After all, isn't Apple always touting the iPhone's version of the Mac OS as the most advanced mobile platform ever created?

Of course, Apple's own iPhone programs can multitask; quite well in fact, as anyone who's used an iPhone can attest to. Much of the "unofficial" iPhone software developed since hackers jailbreaked the iPhone to run third-party software, can too.

With the decision not to allow developers the ability to create official multitasking applications, Apple has inadvertently given the unofficial native iPhone software market thumbs up to keep on going.

As of now, it seems you'll be able to get one type of software, be it apple approved, from the new iPhone App store and another type of application, one that may offer more functionality from those who choose - no thanks to Apple - to go the unofficial route.

[via Brighthand]