download software unless the player has all the IOS versions that they require. However, if homebrew is used to forcefully install or run a piece of software when the required IOS does not exist, the user is brought back to the system menu. Nintendo created this system so that new updates would not unintentionally break compatibility with older games, but it does have the side effect that it uses up space on the Wii's internal NAND Flash memory. IOSes are referred to by their number, which can theoretically be between 3 and 255, although many numbers are skipped, presumably being development versions that were never completed. Only one IOS version can run at any given time. The only time an IOS is not running is when the Wii enters GameCube backward compatibility mode, during which the Wii runs a variant of IOS specifically for GameCube games, MIOS, which contains a modified version of the GameCube's IPL. Custom IOSes, called cIOSes, can be installed with homebrew. The main purpose of cIOS is to allow homebrew users to use other homebrew apps such as USB Loader GX (allows games stored in the WBFS file format to be run from a USB stick). User interface The system provides a graphical interface to the Wii's abilities. All games run directly on the Broadway processor, and either directly interface with the hardware (for the hardware common to the Wii and GameCube), or interface with IOS running on the ARM architecture processor (for Wii-specific hardware). The ARM processor does not have access to the screen, and therefore neither does IOS. This means that while a piece of software is running, everything seen on the screen (including the HOME button menu) comes from that software, and not from any operating system or firmware. Therefore, the version number reported by the Wii is actually only the version number of the System Menu. This is why some updates do not result in a change of the version number: the System Menu itself is not updated, only (for example) IOSes and channels. As a side effect, this means it is impossible for Nintendo to implement any functions that would affect the games themselves, for example an in-game system menu (similar to the Xbox 360's in-game Dashboard or the PlayStation 3's in-game XMB). The Wii Menu (known internally as the System Menu) is the name of the user interface for the