chaotic n-space network fractals | cge | software | philosophy | math | books |home|

Classic Games Emulation | News | Systems | Emulation | Emulators | Games | Links

maintained by


What Is Emulation? And Why Do It?

Specifically, emulation is the process of running software written for one kind of system (e.g. a Nintendo) on another (usually a PC or some other computer system) by mimicking the other system's hardware. Through emulation, we can play Super Mario Bros. 3 on an emulator running under Windows 95, or Asteroids on an emulator in MS-DOS, or Astrosmash on an emulator for a Macintosh, for example.

You may or may not immediately realize the significance of this. Perhaps the greatest advantage is being able to run software for a system that is unavailable. A system might be unavailable because the it is hard to find for sale (say, an old, relatively rare console system like the Vectrex - when was the last time you saw a Vectrex?), or because you own one but it doesn't work, or because you own a system but have it stored somewhere other than where you live. For example, I own three Atari 2600s, but over time the video circuits have decayed badly, and the image quality is so poor that I can barely see a game on a television set. So, instead, I play all my Atari games in an emulator for DOS. Or, as another example, I have never owned an Intellivision, and I would have a difficult time finding one, but because of emulation, I was able to play Astrosmash for the first time last year on my PC. What all this means is that, essentially, emulation allows us to play games or run software we might not otherwise be able to; it expands our capabilities. (The one difficulty is that although emulation allows us to forego owning working hardware, for legal reasons, we still have to own copies of the games in most cases. See How Legal Is Emulation?.) Of course, there are other benfits that come from emulation (some of which I have already mentioned), but this, I think, is the most important right now, and is also the primary focus of this site's discussion of emulation.

How Legal Is Emulation

There are many misconceptions about the legality of emulation. There is nothing inherently illegal about emulation. Having said that, however, there are some related legal issues which are legally murky at best and often clearly illegal. But a studious emulator user can avoid these problems and never break the law by running an emulator.

First, there is usually nothing illegal about an actual emulator; most illegal practices in emulation are due to illegal copying of old software and games. However, there are a few exceptions. The first is when a system requires system ROMs to run. An Atari 2600 emulator is perfectly legal, because there is no ROM code to copy out of the machine. A Commodore 64 emulator, on the other hand, is only legal to run if you own one, because the Commodore 64 has code in its ROMs which is necessary to run it.

Some newer game machines may not be legal to emulate at all because of patents or other intellectual property protection on the hardware. Thus, while it is usually legal to emulate any given system, there may be exceptions. But these situations are not common with older machines.

The biggest legal problem in relation to emulators is illegal ROM copying. ROM stands for "Read Only Memory." They store program code, which, of course, is copyrightable. I already talked above about copying "system ROMs," that is, the ROMs which are required by the system to run. But what I'm talking about here is the software like games and applications. Most game console systems use ROM chips in a cartridge (as in the NES, the Atari 2600, and so on), but the term is often also applied loosely to the copies of disk-based software which are not reallyt RAM (like on the Commodore 64 and other computers). A ROM image is a copy of the ROM that is stored in a file on another system.

Illegal ROM copying is the practice of copying (and distributing) ROM images which one does not own. This is software piracy. Almost all old games are still under copyright. If you do not own a game, it is illegal (and many would say unethical) to use a ROM image of it in an emulator. Illegal ROM copying and use is very prevalent in the emulation world, and I believe it has had a negative influence on it. It has also given companies like Nintendo an excuse to try to crack down on both legal and illegal emulation of Nintendo systems (well, Nintendo seems to think that either is illegal, but the law is not necessarily on their side).

It is often tempting to give in and then download a Super Nintendo emulator and download ROM images of all the Donley Kong Country games, but don't do it! Companies have put money into developing games and, whether we like it or not, they still own the rights to these games and can do with them as they please. Some companies have generously distributed some of their old games for free (see below), and they deserve our support and respect. But if a company chooses not to, it is their prerogative and we must respect their decision. Please, only use ROM images for games you own.

I should point out now that whether you can copy and use a ROM is not always only dependant on whether you own a game or not. Some newer games have license agreements which override simple copyright regulations. Typically, newer software includes a card listing all the things a user agrees to by opening the software or installing it. Under current copyright law, you can make a copy of a game. But a license can prevent even this. That's not to say that all or even most do: Read your license agreements carefully, just like they say you should.

So, what if you don't own any old games? Does that exclude you from running an emulator? Not necessarily. As I already said, some companies have released their games for free, and will allow you to play them, and sometimes distribute them as long as it isn't for profit (see Legalize 8bit ROMs). Also, some authors have written free games that run on old systems (see New Classics! ROM Images).

How to Get Started

How you should start is first dependant on whether you already own a system and some games. If you do, go straight to Emulators or Archaic Ruins' Emulators page, find the system you own and then find an emulator that runs under your operating system. Next, you'll need to find some ROM images. My pages have links to ROM sites, because I am trusting you to only download ROM images of games you own.

If you don't own any games, you'll have to find some free ones first. You can find some by following the links to Free ROMs on the links page. There are lots of free games for many different systems, so you should be able to find one for just about any system. Then go to one of the pages I mentioned above and download an emulator for that system. Just be aware that some systems have system ROMs that they require to run; these are also copyrighted, and if you don't own that system, it would be just as much software piracy to run an emulator for that system.

There are also some emulators that come with games. Most are commercial, but some are available free. One of the free ones is the preview release of the Intellivision emulator the Blue Sky Rangers are developing. There will be a commrecial version, but they have released some games for free on their web site. Telegames sells a reasonably priced Colecovision emulator with several games called Personal Arcade. There are also several other ones available, and some ports (transalations from the old systems to new ones) as well.

About CGE (including contact information)
Created March 28, 1998. Last updated June 7, 1998.