A file with .rom extension is actually a data file; an exact copy of the read-only memory ROM chip for a device, extracted from a video game cartridge or a computer. The purposes of creation a ROM files can be various, such as, software emulation, backing up or archiving ROM data, or updating the firmware on a certain device. Many devices are available to dump video game ROMs into a ROM file, however, more specialized tools and expertise are required for dumping ROMs from other devices such as arcade games.
ROM file format
The ROM file format was designed to contain the data of an exact copy of a video game cartridge, arcade game, computer’s firmware. The term ROM is commonly used when we discuss about emulation, Also the older games or firmware are copied to ROM files on modern computers and these can be used as a piece of software known as an emulator. ROM files are usually pull all data from the read-only memory chips found in cartridge based games or arcade machines using a dedicated device in a process known as dumping.
The ROM files also facilitate the unauthorized copying and redistribution of modern games. Many games development companies blike Nintendo, Capcom, SNK etc uses their on encryption methods to protect their stuff to be copied but companies were failing to protect their games for a long time. Hackers were eventually successful to decrypt the complex encryption method which caused a huge reduction of game sales because the games were freely available to play by using emulation softwares.
Emulation: Video game console emulators usually take ROM images as input files.
Software ROM: Software which is being developed for embedded computers is often written to ROM files for testing on a standard computer.
Digital preservation: There is a significant worry that many early computer and video games may not survive without being transferred to new media. So, those with an interest in preservation are actively seeking older arcade and video games and attempting to dump them to ROM images
Hacks and fan translations: Hacks may range from simple tweaks such as graphic fixes and cheats, to full-blown redesigns of the game, in effect creating an entirely new game using the original as a base.