Sending here from the main wiki after a (brief, unanimous) Repair Shop discussion. Up For Grabs.
Needs A Better Name. Now with a crowner for page name!
Some video game systems can play games made for another system. This works without porting the games. It's like a system inside a system.
This feature may provide backwards compatibility, so that a newer system can play games from and older system. A new console or handheld would play not only its launch titles, but also the older games. Another reason is to enjoy handheld games on the big screen, or the other way, to play console games on a handheld.
There are a few ways to make this work:
Extend the hardware in a compatible way, like how the Atari 7800 can play Atari 2600 games.
Put hardware from the old system in the new system, like the Game Boy Color chips inside the Game Boy Advance.
The Atari 2600 wasn't able to play any other console games nor had the hardware for it. However, A LOT of other consoles of the time had the entire hardware of the 2600 (emulation was still unfeasible):
The Atari 7800 uses the same hardware to play both 2600 and 7800 games.
The Colecovision had an add-on, the "Expansion Module", allowing the user to play Atari 2600 games.
The Intellivision II also had an add-on, and many other, less-known consoles had ways to play Atari 2600 games.
First came up the Super Nintendo Entertainment System which, through the Super Game Boy adapter, you were able to use Game Boy cartridges in order to play them on the TV and even enhance them as some games included colour data exclusively for this use.
The Game Boy Advance included the entire hardware of the Game Boy Color inside. There's the ARM processor for new games, and the Z80 processor for old ones. This system also allowed to play the games stretched in order to fit the wider GBA screen. Multiplayer worked in old games, if you used the old link cable, not the new GBA link cable.
The next adapter was the Game Boy Player for the Game Cube. This one was as good as a GBA, playing single-player Game Boy, Game Boy Color and Game Boy Advance games, all on the TV. (Don't confuse it with the Nintendo GameCube-Game Boy Advance link cable.)
Keeping up with it's predecessor, the original and lite variants of the Nintendo DS had a GBA cartridge slot as well as most of its hardware. This played single-player GBA games (but not older Game Boy Color games). The GBA slot also enabled other features in specific DS games, mostly Pokémon ones. The slot and hardware of the GBA were removed in the DSi and the DSi XL.
The Wii is Nintendo's first home console to be completely backwards compatible with it's older sibling, the Game Cube: It had its hardware, controller ports and memory slots. GameCube games can't use Wii remotes or storage, so you did need a GameCube controller and (if you wanted to save) a memory card. Super Smash Bros Melee is just as great on the Wii as on the GameCube. (The Wii doesn't have the GameCube's High Speed Port, so you can't use the Game Boy Player on the Wii. You also can't use any GameCube network adapters, so the very few GameCube games that go online can't do so from the Wii.)
The Wii also introduced Virtual Console, which downloads and emulates games from old consoles. This even included some non-Nintendo consoles. The 3DS and WiiU have their own versions of Virtual Console.
The Wii U keeps Wii compatibility but loses GameCube compatibility. Wii game discs, Wii remotes and so on still work, but you can no longer use GameCube controllers in Wii games.
Thanks to the enormous processing power of modern computers, emulators for PC exist for all consoles up to the sixth generation, albeit with varying degrees of compatibility and requirements. For more information, see our Emulation page, and Emulation on The Other Wiki.
With the move from 68k to PowerPC processors, Mac OS gained a 68k emulator. PowerPC Macs were able to run 68k programs, and programs that mix 68k and PowerPC code. The emulator was generally faster than a 68k Mac, but 68k code was slower than native PowerPC code.
Mac OS X, versions 10.0 through 10.4, used the "Classic" emulator to run Mac OS 9 programs at full speed (though this includes waiting for Mac OS 9 to boot inside Classic). To avoid this emulation, there were also "Carbonized" apps that run in both OS 9 and OS X (without Classic).
Intel Macs, running OS X 10.4 through 10.6, use the "Rosetta" emulator to run PowerPC programs. (Sorry, Rosetta didn't run Classic.) OS X Lion 10.7 can't run Rosetta.
During the era of Mac OS 7, Apple made a DOS Compatibility Card with a 486. Later, OrangePC made similar cards. These NuBus or PCI cards had a 486 or Pentium and booted DOS or Windows. These cards were so expensive, that a whole PC might be cheaper. Later, emulation became feasible (on faster processors like the PowerPC G3), and emulators like Virtual PC appeared.
Windows supports old 16 bit applications on all 32 bit editions. They also support all old 32 bit applications on 64 bit systems. They even include a pile of hacks to mask bugs in old applications. And that's just the support for compiled applications.
The Sega Genesis AKA Mega Drive was an interest example in that it had the Master System's hardware inside but not it's cartridge slot. Thus, the Power Base (a Master System slot and some wires) was made and enabled backwards compatibility.
The Sega Game Gear had a so-called Master Gear Converter, allowing its owners to play Master System/Genesis games on their Game Gear.
The early Play Station 3 had the Emotion Engine (CPU) and the Graphic Synthesizer (GPU) from the Play Station 2 inside, allowing to play PS 2 games on the console. However, as manufacturing costs were too high, the Emotion Engine was eventually removed (2007) and replaced with software for emulation of PS2... which sucked. Eventually, all PS2 compatibility was left out for the 2008 model. PS 1 software emulation is supported across all models.
The Play Station 2 was not only able to play Play Station 1 games (Emulation), but also you were able to use your PS1 memory cards & joysticks.
Homebrewed Playstation Portable consoles are able to play PS1 games as well as other, older consoles.
Due to Google's quite permissive policies for its online store, the Android OS features several emulators, readily available to play on your smartphone or tablet if your device meet the requirements. GBA, PS 1, NES & SNES, N64, GB, Genesis are all among the emulated consoles.
Due to Apple's quite oppressive policies for its online store, the iOS... OS has quite few emulators available if any at all.
Do you know Ben Heck?? If you do, you already know what he has done. If you don't, check his website. He has made up tons of custom consoles like an Atari 2600 with a Play Station 2 inside.
In Minecraft, it is entirely possible to build your own working computer. However, such computers are far too primitive and slow to play games from any existing system.
The FC3 Plus plays NES, SNES and Sega Genesis games all with the same console.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.