Apple might be planning to allow background processing in a future iPhone, perhaps having decided that its planned push-notification system for the iPhone was not the best solution.
MacRumors has a report out today saying they've "heard" that Apple is thinking about dropping its objection to having iPhone applications run in the background at some point in the future. If you'll recall, Apple announced last June that iPhone users wouldn't be able to run more than one application at the same time in order to preserve battery life and performance, which surprised developers used to creating smartphone applications for other platforms with that capability intact.
Instead, Apple's Scott Forstall announced plans for "a far better solution;" a push-notification service that would route notifications from one application to another over Apple-hosted application servers. This was supposed to allow developers to create an instant-messaging application, for example, that could interrupt your game of Bejeweled with an IM window.
Whatever one thought of the merits of that approach, the service was supposed to be ready by last September. It's now February, and Apple seems to have completely forgotten it ever said such a thing. As usual, it's not clear what is responsible for the holdup, but perhaps such a service has become irrelevant with plans to allow true background processing.
Such a plan would fit in with rumors that the next iPhone is slated to receive an upgrade under the hood, with faster application and graphics processors. The increased horsepower provided by those chips could make it much easier for the iPhone to run multiple applications without a notable performance drag. MacRumors thinks the background processing would be limited for users of the original iPhone and the iPhone 3G, but also thinks the user could select which applications run in the background.
If Apple holds true to the June introduction cycle that has been the case the last two years, we could see this as part of an iPhone 3.0 software release around that time. Even though that would make Apple woefully late in addressing this issue, this solution would be better for users, developers, and Apple, since it wouldn't have to host the notification service.