Action Replay is a game modifier for the Nintendo DS system that allows users to use a number of codes, cheats and other modifiers with their DS game cartridges. The device is fully updatable, but doing so requires the application interface. Since this program is meant to be executed on a Windows based computer, Mac users are forced to use a virtual system program to run Windows on their Mac OS based computers so that they may update their Action Replay cartridges. Writer Bio