ROM image

A ROM image, ROM file, or simply ROM is a computer file which contains a copy of the data from a read-only memory chip, often from a video game cartridge, or used to contain a computer's firmware, or from an arcade game's main board. The term is frequently used in the context of emulation, whereby older games or firmware are copied to ROM files on modern computers and can, using a piece of software known as an emulator, be run on a different device than which they were designed for. ROM burners are used to copy ROM images to hardware, such as ROM cartridges, or ROM chips, for debugging and QA testing.

Creation

ROMs can be copied from the read-only memory chips found in cartridge-based games and many arcade machines using a dedicated device in a process known as dumping. For most common home video game systems, these devices are widely available, examples being the Doctor V64, or the Retrode.

Dumping ROMs from arcade machines, which are highly customized PCBs, often requires individual setups for each machine along with a large amount of expertise.

Copy protection mechanisms

While ROM images are often used as a means of preserving the history of computer games, they are also often used to facilitate the unauthorized copying and redistribution of modern games. Viewing this as potentially reducing sales of their products, many game companies have incorporated features into newer games which are designed to prevent copying, while still allowing the original game to be played. For instance, the GameCube uses non-standard 8 cm DVD-like optical media, which for a long time prevented games stored on those discs from being copied. It was not until a security hole was found in Phantasy Star Online Episode I & II that GameCube games could be successfully copied, using the GameCube itself to read the discs.