Applications can't be run from an expansion card, and must be in main memory to be executed. In normal operation, when you run an application that has been installed on an expansion card, Palm OS copies that application to main memory to actually run it. When you exit the game normally, the application is deleted from memory to free up the space.

I spent some time testing this week and verified some interesting things about how applications that are installed to an expansion card are handled in various circumstances. If, while running the application, the device is reset (either intentionally or unintentionally), the application is left in main memory and behaves just like you had installed it there, rather than on the card. It stays in main memory and is not deleted when you exit the game.

I also discovered an interesting "side effect" of this situation. I had previously assigned one of my silkscreen icons to Village Sim when I had it installed in main memory. After I uninstalled it and re-installed it to the SD card, the silkscreen icon was reassigned by Palm OS. However, if I launched Village Sim and reset the Palm, the .prc file was left in main memory and the silkscreen icon was again assigned to Village Sim. Once I deleted the .prc file using FileZ, the silkscreen icon was again no longer assigned to Village Sim and the game could be launched only from the card menu - effective "undoing" the main memory installation of the game. Interesting...