• What is "ROM"?
• What is "Emulator"?
• What is "BIOS"?
• What is "Plug-in"?
• What is "Mapper"?
• What is "ISO"?
• Why are there several ROMs for one game?
• I often see words like NES, SMD, GBA, PSX, What do they mean?

• How do I use your search system?
• I would like to post news for your site. Can I?
• I would like to help you with site development.
• I could not find either emulators or games for computers, such as ZX Spectrum, Commodore 64, Amiga, etc.

• I discovered my favorite game is not available on your site. Could you get it for me?
• There are some strange symbols in game titles, like [!], [x], (U), etc. What do they mean?
• I downloaded two ROMs with different titles, but it turned out to be the same game. What is it?
• I used GoodGen utility and it said there were more than 6 thousand games for Sega Genesis, though there are only slightly more than a thousand available on your site. You said you had ALL games. Can you explain it?
• I downloaded a ROM, but forgot which console it is for. How can I find that out?
• Why are none of Sega Genesis emulators able to run Virtua Racing game?
• I downloaded and ran a game in emulator, but it looks a lot worse, than it did on the real console.
• Why do 3D graphics "tremble" and "float" in Sony Playstation games I try to run on emulator?

• I didn't manage to run X game or X emulator. Please, help!
• I found a new version of, or new emulator, not available from your site.

ROM is a shortening from English "Read Only Memory". Chips of constant memory are called this way. They are used in cartridges, arcade machines and other devices. These chips contain game code, graphics, and sounds. ROMs are the contains of such chips, extracted to files. These files are usually called "dumps", as a person, who is making ROMs, dumps the data inside chips into a file.

ROMs themselves are useless. The hardware of different types of computers and consoles (that are also computers, designed especially for games) differs a lot, that's why it is not possible to run a program on one computer type, made for another one. To be able to do this people create special programs – emulators.

ROMs may be used for other purposes - there are programs, that let extracting game resources (such as graphics, sounds, etc.) out of them and change these resources (for instance, when translating game into other languages). Also, there are so-called flash-cartridges, that let you running a game on the real console.

As it was stated above, due to difference in computers hardware side, to run a program, you have to emulate an environment that program is supposed for. "Emulators" imitate the internal parts of a computer or a console. If you plan to run a NES (Famicom, Dendy) game on your computer, you will need a NES emulator. First, you will need to run an emulator and after that you can run a game in that emulator.

Emulation, an imitation process of some system – is a very resources-consuming task and may require the performance from your computer, a lot above the performance of the emulated system itself. The more complicated the emulated system and the emulation accuracy are – the more performance is required to run it. Emulation accuracy is the thing that emulated programs (games) compatibility depends on. For instance, if an emulator does not consider some, even smallest, detail of system feature, used in some games, these games will not run, or will work incorrectly, while other games may work perfectly. Also, emulation accuracy affects the sound and video output quality of an emulated game.

Emulators are usually created by amateurs-enthusiasts. Writing an emulator is a very hard work, requiring from the author an experience in coding and knowledge of all the specifications of emulated system. That's why emulators of the same system may differ in both emulation accuracy and computer requirements.

Plug-ins are special additional files, that may interact with a program, realizing parts of its functions. Some emulators have plug-ins support, and plug-ins provide emulation and output of video and sound, work with CD in CD drive or CD image and work with keyboard and gamepads. It lets authors of emulator concentrate on polishing the main code, while more experienced people can work on sound and video emulation side. Authors of plug-ins may experiment, creating plug-ins with different capabilities, more suitable for some special games. The advantage of emulators with plug-ins support is a wide range of available settings to setup an emulator for any computers configurations, while the disadvantage - a process of tuning everything up might seem difficult for some people.

Plug-ins support is widely used in Sony PlayStation emulators, such as PSEmu Pro, ePSXe, PSXeven, etc. Their plug-ins are coded by the universal standard, so they can be used with any of the emulators above. The same system is used in Nintendo 64 emulators.

"Mapper" is a special chip, used in some cartridges. Its purpose is in increasing the memory capacity of cartridges, supported by a console or sometimes increasing the console capabilities (sound and video improvement). The more common console using mappers was NES, there were about a hundred of their types. To run such games with emulator, it is required that this emulator had the support of required mappers. The more mappers emulator supports, the higher its compatibility.

Other consoles either did not use mappers, or there were a lot less types of them and nowadays all of them are supported by most of emulators for these systems.

A game may exist in several versions. It often happens, that games produced for different countries were released a bit different, for instance with logos and other in-game phrases in different languages. Sometimes, games are unofficially modificated for some purposes by pirates or other hackers-amateurs. All known versions of any game are saved to ROM-flies and marked special way (see the question about Good codes). They are marked to let you choose the proper version to play and to be able to see where there is a good version and a bad one (for instance, versions spoiled by pirates). The good and tested copies of original versions, recommended for playing, are marked with [!] in a file name.

We do our best to represent only verified ROMs on our site, the exact copies of original games. Unfortunately, not all of the games are available in good dumps, and in these cases we offer the best dump among available ones – for instance, one of the pirate versions.

These above are shortened titles of different consoles. Using full names, like Sega Genesis or Sony PlayStation in posting news, writing the articles or using in discussions on forums may be tiresome, that's why they thought up common shortenings. Below is a list of the most widespread ones:

32X - Sega 32X, 32-bits add-on device for Sega Mega Drive
GB - Nintendo Game Boy
GBA - Nintendo Game Boy Advance
GBC - Nintendo Game Boy Color
GEN - Sega Genesis
GG - Sega Game Gear
N64 - Nintendo 64
NDS - Nintendo DS
NES - Nintendo Entertainment System, Famicom, Dendy
PC – Personal Computer, usual Personal Computer, be it desktop or laptop
PCE, TG16 - NEC PC-Engine or TurboGrafx-16
PS2 - Sony PlayStation 2
PSP - Sony PlayStation Portable
PSX, PS1, PSOne - Sony PlayStation
SCD - Sega CD, add-on device for Sega Mega Drive, allowing to play games for SegaCD
SMD - Sega Mega Drive
SMS - Sega Master System
SNES - Super Nintendo Entertainment System, Super Famicom

Search system on our site performs a search of a ROM-file by its name or by the title of a game you try to find. It searches among all ROMs for all consoles, represented on our site. The search works very simple: enter a game title (or ROM name) into a search field you try to find and press "Enter" (or click the "Search" button). The system will look for all the games for all the consoles in a database, containing all the words you typed in, both together and separately by each word. Examples:

In search field you typed the word "fire".
The search system will show you following games (the list is shorted):

• Fire_Emblem_(J).zip - separate word "fire".
• Fire_'n_Ice_(U).zip
• GemFire_(U)_[!].zip - the word "fire" as a part of some complex words.
• Hellfire_(J)_[!].zip

Try to use the most important key words and do not use articles "the" and "a (an)". The case is not considerable, so there is no difference if you type words either in lower or in upper case. If the system can not find any ROM, try decreasing the amount of key words and check if they are correct.

For searching NES games there is a game database, available on our site. It lets you search for a game not only by its title, but by separate words from game description, in case you do not know or remember its title.

First, try using our Search system. Possibly, this game is available on our site under different title. It most concerns games for NES (Dendy) – in our country the majority of all games were released by pirates, who often changed the original titles, distributing old games as new ones. Try to search by one of the word from game title, this is the way you will never miss it.

If you look for NES game and do not remember its title, have a look in our Game database, which lets you perform a search by words from game description. If you cannot find a game yourself, raise a question on our forum in the topic "Forgot a game".

The names of ROM-files may have different extensions. In most cases, it's easy to recognize which system a ROM is for. Often an extension matches the shortening of the system this ROM is for. For many systems there are several ROM formats used, of course, with different extensions. Below you can find a list of existing extensions (the list is not full, but covers the majority of the most popular extensions):

.32x - Sega 32x
.a26 - Atari 2600
.a52 - Atari 5200
.a78 - Atari 7800
.crt - Commodore 64 Cartridge
.gb - Game Boy
.gba - Game Boy Advance
.gbc - Game Boy Color
.gen - Sega Mega Drive/Sega Genesis
.gg - Sega Game Gear
.int - Mattel Intellivision
.md - Sega Mega Drive/Sega Genesis
.mx2 - MSX2 Cartridge
.n64 - Nintendo 64
.nds - Nintendo DS
.nes - Famicom/Nintendo Entertainment System
.pce - PC-Engine/TurboGrafx-16
.smc - Super Famicom/Super Nintendo Entertainment System
.smd - Sega Mega Drive/Sega Genesis
.sms - Sega Master System
.v64 - Nintendo 64
.ws - Bandai WonderSwan
.wsc - Bandai WonderSwan Color
.z64 - Nintendo 64

There are also extensions like .bin and .rom. You can't identify the system of these as .bin only means this file contains some kind of data, while .rom means this file is a ROM dump. Such files often contain BIOS for some system. Dumps of games for any of the listed systems may also have .bin and .rom extensions. More often Sega Genesis games are stored in .bin format, as well as some systems discs images (in format bin+cue).

It's the only game for Sega Genesis, for which they applied a special processor called SVP (Sega Virtual Processor), installed in cartridge. It's used for expanding the graphics capabilities of the console, mainly for 3D graphics processing. Due to lack of documentation for this chip and as its internal memory cannot be read, at present its support in emulators is not possible.

Initially, the game Virtua Racing was released on arcade machine Sega Model 1 and only afterwards for Sega 32X and Sega Saturn. All the versions of this game are supported by corresponding emulators for these systems.

It looks as it has to on the screen of a monitor. Monitors image detail is much higher, comparable to TV set, where image has always been a bit blurry. Due to this TV Set feature, neighbor dots image colors are merged, forming additional shades and seeming details. For instance, chess board, consisting of transparent and non-transparent dots will look like semi-transparent image on the screen of TV Set.

To be able to show the image on monitors as it looked on TV Set screen, most of emulators support special graphical filters. These filters offer to change the image in different way – to add blur, interlacing (horizontal lines on the image), or smooth out objects contours. Play with filters a bit and you will choose the one, more suitable for your eyes. You can read how to do it in the documentation for your emulator.

It’s the feature of the console. For 3D graphics acceleration, the console applies simplified calculations, side-effects of which become "trembling" of objects and "floating" and distorted textures. On the screen of the TV Set it's less visible, than it is on computer monitor. However, if you look closely, you can notice this effect on the console as well.

Unfortunately, it is impossible to remove graphics "trembling". The only way is using emulators with plug-ins support – most of DirectX and OpenGL plug-ins are capable of smoothing textures. It lets the image look better than on the real console.

Authors: Eevon, Shiru. Contributors: F1ReB4LL, Колючий, -v-, org. English translation: Boogerman
(с) Emu-Russia, 2008