Palm Architecture

Palm devices run Motorola DragonBall MC68328 family of microprocessors which are based on the Motorola MC68EC000 core. They are low speed ranging from 16MHz to 33MHz. They have battery backed RAM to store application data and ROM for the OS. They run PalmOS which has very little security support and lack supervisor mode of running.

Figure 1: Typical Layered Architecutre Of PalmOS device[Mud01]

[width=3.2in]palmarc.eps

The Palm OS has layers: Application, Operating system and the hardware. The application can access the hardware very easily circumventing the OS. For eg to use the color LCD when the OS didn't support any. This Implies that very limited access control can be provided.

The application are generally single threaded, event driven programs. They can use a launch code to request that another application perform an action or modify data.