Video game console emulator

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This article is about what a console emulator does. For a list of existing emulators, see List of video game emulators.

A video game console emulator is a type of emulator that allows a computing device[fn 1] to emulate a video game console's hardware and play its games on the emulating platform. More often than not, emulators carry additional features that surpass the limitations of the original hardware, such as broader controller compatibility,[fn 2] timescale control, greater performance, clearer quality, easier access to memory modifications (like GameShark), one-click cheat codes, and unlocking of gameplay features. Emulators are also a useful tool in the development process of homebrew demos and the creation of new games for older, discontinued, or more rare consoles.

The code and data of a game are typically supplied to the emulator by means of a ROM file (a copy of game cartridge data) or an ISO image (a copy of optical media), which is created by either regular optical drives reading the data, or specialized tools for game cartridges.[citation needed] Most games retain their copyright despite the increasing time-span of the original system and products' discontinuation; this leaves many[who?] to resort to obtaining games freely across various internet sites rather than legitimately purchasing and ripping the contents (although for optical media, this is becoming popular for legitimate owners). As an alternative, specialized adapters such as the Retrode allow emulators to directly access the data on game cartridges without needing to copy it into a ROM image first.


By the mid-1990s, personal computers had progressed to the point where it was technically feasible to replicate the behavior of some of the earliest consoles entirely through software, and the first unauthorized, non-commercial console emulators began to appear. These early programs were often incomplete, only partially emulating a given system, resulting in defects. Few manufacturers published technical specifications for their hardware, which left programmers to deduce the exact workings of a console through reverse engineering. Nintendo's consoles tended to be the most commonly studied, for example the most advanced early emulators reproduced the workings of the Nintendo Entertainment System, the Super Nintendo Entertainment System, and the Game Boy. Programs like Marat Fayzullin's iNES, VirtualGameBoy, Pasofami (NES), Super Pasofami (SNES), and VSMC (SNES) were the most popular console emulators of this era. A curiosity was also Yuji Naka's unreleased NES emulator for the Genesis, possibly marking the first instance of a software emulator running on a console.[1]

This rise in popularity opened the door to foreign video games, and exposed North American gamers to Nintendo's censorship policies. This rapid growth in the development of emulators in turn fed the growth of the ROM hacking and fan-translation community. The release of projects such as RPGe's English language translation of Final Fantasy V drew even more users into the emulation scene.

Legal issues[edit]

United States[edit]

As computers and global computer networks continued to advance and emulator developers grew more skilled in their work, the length of time between the commercial release of a console and its successful emulation began to shrink. Fifth generation consoles such as Nintendo 64, PlayStation and sixth generation handhelds, such as the Game Boy Advance, saw significant progress toward emulation during their production. This led to an effort by console manufacturers to stop unofficial emulation, but consistent failures such as Sega v. Accolade 977 F.2d 1510 (9th Cir. 1992), Sony Computer Entertainment, Inc. v. Connectix Corporation 203 F.3d 596 (2000), and Sony Computer Entertainment America v. Bleem 214 F.3d 1022 (2000),[2] have had the opposite effect. According to all legal precedents, emulation is legal within the United States. However, unauthorized distribution of copyrighted code remains illegal, according to both country-specific copyright and international copyright law under the Berne Convention.[3][better source needed]

Under United States law, obtaining a dumped copy of the original machine's BIOS is legal under the ruling Lewis Galoob Toys, Inc. v. Nintendo of America, Inc., 964 F.2d 965 (9th Cir. 1992) as fair use as long as the user obtained a legally purchased copy of the machine. To mitigate this however, several emulators for platforms such as Game Boy Advance are capable of running without a BIOS file, using high-level emulation to simulate BIOS subroutines at a slight cost in emulation accuracy.[citation needed]

Official use[edit]

Due to the high demand of playing old games on modern systems, consoles have begun incorporating emulation technology. The most notable of these is Nintendo's Virtual Console. Originally released for the Wii, but present on the 3DS and Wii U, Virtual Console uses software emulation to allow the purchasing and playing of games for old systems on this modern hardware. Though only a small catalog of games are available, the Virtual Console has a large collection of games spanning a wide variety of consoles.[clarification needed] Each game is distributed with a dedicated emulator tweaked to run the game as well as possible. However, it lacks the enhancements that unofficial emulators provide, and many titles are still unavailable.[which?]

Due to differences in hardware, the Xbox 360 is not natively backwards compatible with original Xbox games.[fn 3] However, Microsoft achieved backwards compatibility with popular titles through an emulator. The PlayStation 3 uses software emulation to play original PlayStation titles.[citation needed] In the North American 60GB models, original PS2 hardware is present to run PS2 titles, however the PAL and later models removed this, replacing it with software emulation working alongside the video hardware to achieve partial hardware/software emulation.[citation needed][clarification needed] In later releases, backwards compatibility with PS2 titles was completely removed along with the PS2 graphics chip, and eventually Sony released PS2 titles with software emulation on the PlayStation Store.[citation needed]

Commercial developers have also used emulation as a means to repackage and reissue older games on newer consoles in retail releases. For example, Sega has created several collections of Sonic the Hedgehog games. Before the Virtual Console, Nintendo also used this tactic, such as Game Boy Advance re-releases of NES titles in the Classic NES Series.[citation needed]

Other uses[edit]

Although the primary purpose of emulation is to make older video-games execute on newer systems, there are several advantages inherent in the extra flexibility of software emulation that were not possible on the original systems.

ROM hacking and modification[edit]

Disk image loading is a necessity for most console emulators, as most computing devices do not have the hardware required to run older console games directly from the physical game media itself. Even with optical media system emulators such as the PlayStation and PlayStation 2, attempting to run games from the actual disc may cause problems such as hangs and malfunction as PC optical drives are not designed to spin discs the way those consoles do.[citation needed] This, however, has led to the advantage of it being far easier to modify the actual game's files contained within the game ROMs. Amateur programmers and gaming enthusiasts have produced translations of foreign games, rewritten dialogue within a game, applied fixes to bugs that were present in the original game, as well as updating old sports games with modern rosters. It is even possible to use high-resolution texture pack upgrades for 3-D games if available and possible.[fn 4]

Enhanced technical features[edit]

Software that emulates a console can be improved with additional capabilities that the original system did not have. These include Enhanced graphical capabilities, such as spatial anti-aliasing, upscaling of the framebuffer resolution to match high definition and even higher display resolutions, as well as anisotropic filtering (texture sharpening).

Emulation software may offer improved audio capabilities (e.g. decreased latency and better audio interpolation), enhanced save states (which allow the user to save a game at any point for debugging or re-try) and decreased boot and loading times. Some emulators feature an option to "quickly" boot a game, bypassing the console manufacturer's original splash screens.

Furthermore, emulation software may offer online multiplayer functionality and the ability to speed up and slow down the emulation speed. This allows the user to fast-forward through unwanted cutscenes for example, or the ability to disable the framelimiter entirely (useful for benchmarking purposes).

Bypassing regional lockouts[edit]

Some consoles have a regional lockout, preventing the user from being able to play games outside of the designated game region. This can be very annoying for console gamers as some games feature sometimes seemingly inexplicable localization differences between PAL and NTSC, such as differences in the time requirements for driving missions and licence tests on Gran Turismo 4,[4][better source needed] and the PAL version of Final Fantasy X requiring players to defeat almost impossible superbosses called Dark Aeons in order to complete the game, as well as making it prohibitively expensive to get Yojimbo to use his killer Zanmato move, compared to the NTSC versions.[original research?] Some games are rendered completely impossible to play in certain regions at all by this, such as certain titles that were only released in Japan, for example.

Although it is usually possible to modify the consoles themselves to bypass regional lockouts, this can cause problems with screens not being displayed correctly and games running too fast or slow, due to the fact that the console itself may not be designed to output to the right format for the game. These problems are overcome on emulators, as they are usually designed with their own output modules, which can run both NTSC and PAL games without issue.[citation needed]

Cheating and widescreen functionality[edit]

Many emulators[which?] make it far easier to load console-based cheats, without requiring potentially expensive proprietary hardware devices such as those used by GameShark and Action Replay. Freeware tools allow codes given by such programs to be converted into code that can be read directly by the emulator's built-in cheating system, and even allow cheats to be toggled from the menu. The debugging tools featured in many emulators also aid gamers in creating their own such cheats. Similar systems can also be used to enable Widescreen Hacks for certain games, allowing the user to play games which were not originally intended for widescreen, without having to worry about aspect ratio distortion on widescreen monitors.

See also[edit]


  1. ^ These target platforms usually have available compilers to allow such emulators to be available.[citation needed] These include (but are not limited to) a personal computer, video game consoles, and Android devices.
  2. ^ One example is PlayStation controllers being used with Nintendo 64 games.
  3. ^ The Xbox architecture is similar to a PC with an x86 architecture, whereas the Xbox 360 is a PowerPC system.
  4. ^ Having these improved textures requires a demanding graphics chipset which is capable of handling such.


  1. ^ "An Interview with Yuji Naka". The Next Level. 15 June 2004. Retrieved 9 June 2014. 
  2. ^ see Midway Manufacturing Co. v. Artic International, Inc., 574 F.Supp. 999, aff'd, 704 F.2d 1009 (9th Cir 1982) (holding the computer ROM of Pac Man to be a sufficient fixation for purposes of copyright law even though the game changes each time played.) and Article 2 of the Berne Convention
  3. ^

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