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MAME, which is an acronym for Multiple Arcade Machine Emulator, is a computer software program for personal computers designed to faithfully and precisely emulate as many arcade games as possible, with the intent of preserving gaming history and preventing vintage games from being lost or forgotten. MAME has been ported to many different platforms. The X11 port for Unix-like systems is named XMAME. The Mac OS X port is named MacMAME. According to the official MAME web site, the first public MAME release (0.1) was on February 5, 1997, by Nicola Salmoria. As of version 0.109 (actually the 153rd proper release), released September 26, 2006, MAME now supports 3356 unique games and 6253 actual ROM sets (each game may just have the original or have one or more clones as well - see below) and is growing all the time. However, not all of the games in MAME are playable; 707 ROM sets are marked as not working in the current version, and 26 of the 6253 sets are not actual games but BIOS ROM sets.
How MAME works MAME contains several components: a CPU emulator which duplicates the behavior of the CPUs of many original arcade machines; an input emulator which maps arcade buttons, joysticks, and other controls to PC keyboards, joysticks and other devices; and an emulator for the arcade game display and sound equipment. The only thing missing from MAME is the ROM image, which is the program from the original arcade game which made the game run. When MAME is run, it is running the original game from several years ago - just on different hardware. Emulation philosophy The stated aim of the project is to document hardware, and so MAME takes a somewhat purist view of emulation, prohibiting programming hacks that might make a game run improperly or run faster at the expense of emulation accuracy (see UltraHLE, a project aimed to run games at a playable speed). In MAME every emulated component is replicated down to the smallest level of individual registers and instructions. Consequently, MAME emulation is very accurate (in many cases pixel- and sample-accurate), but system requirements can be high. Since MAME runs mostly older games, a large majority of the games run well on a 2 GHz PC. More modern arcade machines are based around fast pipelined RISC processors, math DSPs, and other devices which are difficult to emulate efficiently. These systems may not run quickly even on the most modern systems available; some working games have been estimated to require a 10 GHz processor to run at full speed. The MAME team has not diverged from this purist philosophy to take advantage of 3D hardware available on PCs today. It is a common but incorrect assumption that performance problems are due to some games' use of 3D graphics. However, even with graphics disabled, games using RISC processors and other modern hardware are not emulated any faster. Thus taking advantage of 3D hardware would not speed these games up significantly. In addition, using 3D hardware would make it difficult to guarantee identical output between different brands of cards, or even revisions of drivers on the same card, which goes against the MAME philosophy. Consistency of output across platforms is very important to the MAME team. MAME Releases There are several types of MAME release depending on how frequently users wish to update and the level of code maturity each user feels comfortable running: ROM images In most arcade machines, the data (consisting of the game program, graphics, sounds, etc.) is stored in read-only memory chips (hence the name "ROM"), although other devices such as cassettes, floppy disks, hard disks, laserdiscs, and compact discs are also used. These devices can be read in a process called "dumping" to create computer files containing the same data; these files are often generically called "ROM images" or "ROMs" no matter what kind of device they originally came from. To play a particular game, MAME requires a set of files (called a ROM set) containing all the data from the original machine, however MAME itself does not include any of these files. MAME handles these data files in two ways: CHD (Compressed Hunks of Data) files hold the contents of hard disks or compact discs, and all the other types of game data are stored in ZIP archives, one for each game. There are three types of ROM sets: Rom Naming: A single supported game is usually referred to as a 'Romset', as for the majority of cases each game will consist of multiple 'ROM' files, each of which represents a single device (usually ROM, but sometimes other devices such as PALs) The MAME developers assign each Romset an 8-letter name for identification as well as a description associated with that 8-letter name. hyperpac "Hyper Pacman" MAME expects to find all the ROM images required for the game "Hyper Pacman" in a folder, or ZIP file called hyperpac(.zip) For games which are considered clones, for example hyperpcb "Hyper Pacman (bootleg)" MAME will look in both the parent folder (hyperpac) and the clone folder (hyperpcb) for the files. Individual ROM files are, where possible, named after labels found on the ROM chips, and the position they are located on the board in the format "label.position". Sega for example use a standard labeling scheme for all the ROMs found on their arcade boards giving each unique ROM chip a unique label. "mpr12380.b2" is a ROM from the Golden Axe romset. This implies that the rom was labeled "mpr12380" and located in position "b2" on the PCB. By using such a naming scheme it makes it easy to use MAME to identify, and often help repair, non-working PCBs. The 8-letter identification tags are less standardized and usually left to the discretion of individual developers, likewise the descriptive long names, although some standards do exist, again often following naming conventions set by the original game manufacturers. Taking Konami's Sunset Riders as an example: Konami gave each revision of their later (mid 90s onwards) games a very specific and clearly visible version number. As these represent an easy way to identify each version of the game, including the region in which it was available and the revision of the code, MAME uses this information to identify each set. UAA is American revision A, while ABD is Asian revision D. For companies where it is less clear sets are often simply labeled as "(set 1)" and "(set 2)". Unreleased games as labeled as "(Prototype)" and non-original versions of games are labeled as "(Bootleg)" Obtaining Roms: Roms can be obtained through a number of methods. 1. Legally, from www.mamedev.org. For Three ROM sets, Gridlee, Robby Roto, and Alien Arena the game's copyright holders have given permission for them to be freely distributed for non-commercial use. 2. By using an EPROM reader, to read the ROMs yourself from your Arcade PCB. 3. Illegally usually through download services or otherwise. Front ends
Legal status of MAME Owning and distributing MAME itself is legal in the US, as it is merely an emulator. Some companies (notably Sony) have attempted in court to prevent emulators from being sold, but they have been ultimately unsuccessful.• As yet, no legal action has been brought against the MAME team. The situation regarding ROM images of games is less clear-cut. Most if not all arcade games are still covered by copyright. Some copyright holders have been indecisive regarding making licensed MAME ROMs available to the public. For example, in 2003 Atari made MAME-compatible ROMs for 27 of its arcade games available through the internet site Star ROMs. However, a status check in March 2006 revealed a reversal of that decision, and the ROMs are no longer being sold there. Other copyright holders have released games which are no longer commercially viable free of charge to the public. Games including Gridlee and Robby Roto have been released by their copyright holders under non-commercial licenses. These games may be downloaded legally from the official MAME web site. However, the majority of games emulated in MAME at this time are copyrighted but no longer commercially available in any form. The legality of distributing or downloading such games depends greatly upon the laws in each country. Many national copyright laws include language which limits offenses to those which cause material harm to copyright holders. An argument could be made that where a game is no longer being manufactured or sold, this could not be the case. A peculiar legal situation exists with regard to games which are covered by copyright but where there no longer exists a copyright holder. Such games are termed orphan works. They are covered by copyright but, since they have no legal owner, do not make money for anybody. Copyright reformers such as Lawrence Lessig believe that such works no longer have a reason to be copyrighted and should be in the public domain. On January 31, 2006, the United States Copyright Office released the results of its study of this issue.• MAME license While MAME is available at no cost, including its source code, it is not open-source software or free software because commercial use and redistribution are prohibited. That is, its license does not meet the conditions of the Open Source Definition, nor is it "free software" as defined by the Free Software Foundation. In particular, MAME may be redistributed in source or binary form, either modified or unmodified, but: "Redistributions may not be sold, nor may they be used in a commercial product or activity." The main goal of this is to prevent arcade operators installing MAME cabinets and profiteering from the works of the original manufacturers of the game. Also, redistributions of modified versions (derivative works) must include the complete corresponding source code (similar to a copyleft). There exist, however, a number of unlicensed builds, including multiplayer builds that support the Kaillera server protocol, or others that add newer games. See also Official MAME sites MAME ports MAME information sites Related Projects | |||||||||||||||||||||||||||||||||
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