This is a fascinating and niche topic. To do a "deep post" on MAME (formerly Multi Emulator Super System, though now MAME) ROMs, we have to strip away the legal gray areas and look at the technical archaeology , the preservation philosophy , and the unique hell of protecting arcade hardware.
Why? Because the mission statement changed. The goal is not to play games. The goal is to ensure that when the sun expands and the last PCB has rotted into dust, a future historian can run mame64 pacman and see not just the dots and ghosts, but the logic of the 1980s. mfme roms
MAME uses a "clone" system. The parent ROM ( pacman.zip ) contains all the original code for the Namco hardware. The clone ( pacmanf.zip ) contains only the differences —the code that changes "Puckman" to "Pac-Man" or changes the speed of the ghosts. This is a fascinating and niche topic
You delete the bootleg Street Fighter II where Ken has blonde fireballs because the hacker didn't have the palette table. You delete the prototype Marvel vs. Capcom where the character select screen is a debug grid. You delete the Korean King of Fighters 97 where the blood is turned into gray sweat because of censorship laws. Because the mission statement changed
Every time you play Cadillacs and Dinosaurs or The Punisher in MAME, you are not playing a game. You are tricking a ghost into believing its heart is still beating. The emulator is lying to the code, saying, "Yes, the battery is still at 3.3 volts. Please keep living." Look at your ROM folder. You see pacman.zip (2.3MB) and puckman.zip (2.3MB) and pacmanf.zip (12KB).
Why don't they work? Because they used a TMS34010 DSP chip that runs its own operating system. Or they used a laserdisc player for the background video, and the timings of a spinning optical disc are impossible to emulate without the original servo motor schematics.
