During this era, the MAME team was heavily focused on restructuring drivers to be more logical and shared across similar hardware. This meant that a massive number of ROMs were being renamed, reorganized, and "cloned." The became a standardized collection because it represented a stable, clean slate after a period of chaotic renaming.
: If you are trying to play games that originally used hard drives or CD-ROMs (like Killer Instinct ), you need . These must be placed in a subfolder within your mame 0.119 roms