ROM image

A ROM image, or simply ROM, is a computer file which contains a copy of the data from a read-only memory chip, often from a video games cartridge or from an arcade machine's main board. The term is frequently used in the context of emulation, whereby older games are copied to ROM files on modern computers and can, using a piece of software known as an emulator, be played on the newer computer.

ROM images are also used when developing for embedded computers. Software which is being developed for embedded computers is often written to ROM files for testing on a standard computer before it is written to a ROM chip for use in the embedded system. At present, this article deals mainly with the use of ROM in relation to emulation.

Usage of ROMs

Changing Meaning

ROM chips, while still in use, have been replaced in many instances by optical media such as CD-ROMs and DVD-ROMs, magnetic media such as hard disks and magnetic tapes and, more recently, Flash Memory chips. However, the term ROM has grown to encompass many of these newer media so, for instance, a computer game copied from a magnetic tape may also be referred to as a ROM. Images copied from optical media are also called ISO images, after the standard file system for optical media, ISO 9660.

Dumping ROMs

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. While such devices may be widely available for common home video game systems, dumping ROMs from arcade machines often requires individual setups for each machine along with a large amount of expertise.

Creating ROMs from other media is often considerably easier and can often be performed with off-the-shelf hardware. For example, the creation of ROMs from games stored on magnetic tapes (from, for example, the Sinclair ZX80 computer) generally involves simply playing the magnetic tape using a standard audio tape player connected to the line-in of a PC sound card. This is then recorded to an audio file and transformed into a ROM file using a simple program. Likewise, many CD and DVD games may be copied using a standard PC CD/DVD drive.

Copy prevention mechanisms

While ROM images are often used as a means of preserving the history or computer games, they are also often used to facilitate the unauthorised copying of modern games which are still commercially viable. Seeing this as potentially reducing sales of their products, many game distributors have incorporated features into newer games which are designed to prevent copying, while still allowing the original game to be played. For instance, the Nintendo GameCube used a non-standard 8cm DVD-like optical media which for a long time prevented games from being copied to PCs. It was not until a hole was found in Phantasy Star Online Episode I & II that GameCube games could be successfully copied to a PC.

ROMs and Preservation

The lifespan of digital media is rarely great. While black-and-white photographs may survive for a century or more, many digital media can become unreadable after only a decade. This is beginning to become a problem as early computer systems may be, at the time of writing, fifty or sixty years old while early home video consoles may be nearing forty years old. Due to this aging, there is a significant threat 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 ROMs. When stored on standardised media such as CD-ROMs and DVD-ROMs, they can be copied to future media with significantly reduced effort.

The trend towards mass digital distribution of ROMs, while potentially damaging to copyright holders, may also have a positive effect on preservation. While over time many original copies of older games may deteriorate, be broken or thrown away, a copy in ROM form may be distributed throughout the world, allowing games which would otherwise have been lost, a more robust survival.

Collecting ROMs

Like many other items such as Stamps and Coins, ROMs are also collected by many people. The motives for doing this vary from a desire to preserve the history of computer and video games to obsessive collectors. Those who desire to collect all ROMs have been derided by the team behind the MAME emulator as PokéROMs, in a reference to the Pokémon fad, Gotta Collect 'em All.

Given this desire by many people to collect ROMs, there are many projects on the internet which dump ROMs, catalogue them or provide tools to verify the correctness and completeness of ROM collections. For instance, the TOSEC and Good Tools projects produce regularly updated databases of games and other software for various old computers and video games consoles.

Internet Distribution of ROMs

The trading of ROMs over the internet is extremely widespread. Many methods are used for such distribution, including:

• BitTorrent
• Direct Connect hubs
• eMule
• IRC DCC
• Usenet binaries

Although the large size of newer games makes the distribution of more than one game at a time impractical, it is often the case for older games that many thousands of games may be distributed together as a collection. For example, the entire Good2600 set of 2,687 Atari 2600 games could be downloaded in around two minutes over a broadband connection.

Hacks & Fan Translations

Once games have been made available in ROM format, it is often trivial for users to make modifications to the games. This may take the form of modifying graphics, changing the levels or even translating the game into a language in which it was not originally made available.

Hacks can often take the form of humourous modifications to games, as is the case with a hack of the NES version of Mario Brothers, entitled “Afro Mario Brothers” which featured the famous brothers wearing Afro haircuts.

A large scene has developed to translate games. Many games receive a release in one part of the world but not in another. For example, many RPG games which are released in Japan go unreleased in the west. For games where there is an obvious demand in other countries, a group of fan translators will often translate the game themselves. For example, the game Tales of Phantasia was officially released in Japan only. The game's on-screen text was translated into English by the group DeJap Translations. Further to this, a project called Vocals of Phantasia was setup to go one step further and translate the actual speech from the game.

Legal Status of ROMs

ROMs themselves are not illegal per se. This section gives a general discussion of the legal status of ROMs as regards the various uses to which they may be put, though this should not be construed as legal advice.

Games owned by the user

In most countries, it is entirely legal for an individual to personally make backup copies of a game they own. Individuals may make backup copies for various reasons, perhaps as insurance against losing the game or as redundancy in the even that the original game's medium becomes unreadable. See the section on ROMs and Preservation.

Officially Licensed ROMs

It is, of course, legal to purchase a ROM image which has been licensed to you by the rights holder. For example, Atari now make 27 of their original arcade games available in ROM format which is compatible with the MAME emulator through the online ROM retailer Star ROMs.

Freely Licensed ROMs

The vast majority of computer & video games from the history of such games are no longer manufactured. As such, the copyright holders of some games have offered free licenses to those games, often on the condition that they be used only for non-commercial purposes. For example, two of the games emulated in MAME, Gridlee and Robby have been made available under such licenses. As such, they are made freely available from the MAME Home Page. More recent examples include Id Software's release of the source code to Doom, Quake, Quake II and Quake III Arena under the GNU General Public Licence.

Unlicensed ROMs

While some games which no longer make any profit fit into the category above, the vast majority are no longer available in any form. The legality of obtaining such games varies from country to country. Some countries have special exceptions in copyright laws or case law which permit (or discourage less) copying when an item is not available for legal purchase or when the copying is for non-commercial or research purposes, while other countries may make such practices firmly illegal. There is often a distinction drawn between distribution and downloading, with distribution being seen as the greater offence.

Abandonware

Some emulation enthusiasts state that ROM trading is legal with regard to games which are no longer commercially available since those games have been abandoned by their copyright holders so have become Abandonware. However, this concept has no legal basis. Copyrights, unlike Trademarks, can not become abandoned through lack of use.

Commercial Distribution

Commercial distribution of copyrighted games without the consent of the copyright holder is generally illegal in almost all countries, with those who take part in that activity being liable for both criminal and civil penalties.

Online auction sites, such as eBay have sometimes been used by sellers to sell unauthorised copies of games which are advertised as legitimate copies. Such sellers, in addition to violating copyright laws, may also be liable for prosecution for fraud and/or false advertising.

Enforcement

There have been few convictions and lawsuits related to ROM trading. Criminal convictions tend to be related to high-profile Warez groups which trade combinations of recent films and Computer Games. In contrast, the ROM scene tends to concentrate mostly on older games. Given the lack of continuing profit from most older games, the grievances of games companies rarely exceed sending a Cease and Desist order which compels the recipient to stop distributing the copyrighted works in question. Many have argued that it would be irrational for a company to spend money prosecuting for games that they are no longer making profit from, as there would be no damages to speak of.

See also

• Emulator
• Console emulator
• In-circuit emulator
• Binary translation
• Fan translation
• Disk image