While vendors such as Citrix and Wyse have worked hard to foster the perception that the iPhone has what it takes to be a desktop virtualization end-point, the limitations imposed by the 3.5 inch display are painfully visible. Now with the iPad just around the corner screen size is no longer a problem, but this doesn't mean that Windows on the iPad is assured of success. Setting aside the obvious ergonomic limitations that the lack of physical keyboard imposes, perhaps the most significant shortcoming of the iPad the lack of support for multitasking. Accepting that one of the primary selling points of the iPhone/iPad is the availability of countless numbers of applications, it's doesn't take much to understand that users might want multitasking. However, while the iPhone 3.X operating system does offer preemptive multitasking. Apple have hobbled it so that multitasking support is restricted only to those applications that Apple grants approval to (in reality this means a subset of Apple developed applications). Which leads to the rather bizarre situation where the only way to get unrestricted multitasking on an iPad is to use it as a thin-client connected back to a remote desktop.
Application developers have for the most part worked hard to overcome this limitation by exploiting the OS to the full so that application state can be remembered between sessions - something that does go a long way to ease the pain of restarting an application from scratch. However, for any application that performs remote control this is not really enough. While the application state can be remembered the remote connection is always dropped, delaying the restart and increasing the chances that the remote session might be reset.
Last year with the launch of the iPhone 3GS there was significant speculation that the introduction of more memory and a faster processor would see Apple loosening the shackles and allowing more applications to take advantage of the operating system's multitasking abilities but this hope was never fulfilled. It should be no surprise then that with an iPhone 4.0 upgrade in the works for this summer stories are starting to surface that Apple will finally allow third-party apps to run in the background.
As AppleInsider explains:
From a user-facing perspective, Apple plans to deliver a multi-tasking manager that leverages interface technology already bundled with its Mac OS X operating system, according to those same people. It was requested that specifics be withheld at this time, as the iPhone Software 4.0 remains under development and reportedly has a quite 'way to go' before it's ready for prime time.
There's no information on the possibility of Apple extending this privilege to all applications, indeed given just how resource intensive some applications can be it would be foolhardy for Apple to relinquish all control especially if it compromised either the security or battery life of the iPad. Still it does provide hope for those of those who might consider an iPad as a suitable platform for accessing server hosted virtual desktops yet are frustrated by the current limitations that lack of multitasking support imposes.
If Apple fails to deliver, we can be assured that Citrix and VMware's desktop virtualization marketeers will be racing each other to announce that the they can make the iPad multitask even if Apple can't.