A game backup device, formerly usually called a copier and more recently a flash cartridge, is a device for backing up ROM information from a video game cartridge to a computer file called a ROM image and playing them back on the real hardware. Recently flash cartridges, especially on the Game Boy Advance and Nintendo DS platforms, only support the latter function; they cannot be used for backing up ROM data. Game backup devices also make it possible to develop homebrew software on video game systems. Game backup devices differ from modchips in that modchips are used in conjunction with systems that use generally available media such as CDs and DVDs, whereas game backup devices are used with systems that use cartridges.