One advantage to ROM images is the potential for ROM hacking. 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. Software that emulates a console can be improved with additional capabilities that the original system did not have, such as Spatial anti-aliasing, running in High Definition video resolutions, anisotropic filtering (texture sharpening), audio interpolation, save states, online multiplayer options or the incorporation of cheat cartridge functionality.
Not all emulation is of a questionable nature though. Consoles have legally used the technology to allow the playing of previous generation games.
Sega Smash Pack 1 and 2 for PC used a Windows port of the emulator KGen.
Due to differences in hardware, the Xbox 360 is not natively backwards-compatible with original Xbox games. However, Microsoft achieved backwards-compatibility with popular titles through an emulator. The PlayStation 3 uses physical PlayStation hardware to play original PlayStation titles. In US 60gb models, original PS2 graphics and CPU hardware was also present to run PS2 titles, however the PAL and later US models removed the PS2 CPU, replacing it with software emulation working alongside the video hardware to achieve partial hardware/software emulation. In later releases, backwards compatibility with PS2 titles was completely removed when the PS2 graphics chip was removed and could not be emulated through software alone.
Commercial developers have also turned to emulation as a means to repackage and reissue their older games on new consoles. Square Enix has re-released several Final Fantasy titles on the PlayStation, Game Boy Advance, and DS; while Sega has created collections of Sonic the Hedgehog games. Likely the most notable example of commercial emulation is Nintendo’s Virtual Console, which comes packaged with their seventh-generation system, the Wii. Virtual Console emulates various titles on the NES, SNES, Nintendo 64, Sega Master System, Sega Mega Drive (Genesis in the US), NEC’s TurboGrafx-16 (PC Engine in Japan) and Turbo CD, SNK’s Neo Geo, and Exclusive ones to some regions; Commodore 64 (In Europe and America) and MSX (In Japan), as well as select arcade games.
The Game Boy Advance re-releases of all NES titles in the Classic NES Series line were emulated.