C128 mode refers to a specific operating mode of the Commodore 128 computer, which allows it to run software designed for the earlier Commodore 64. In this mode, the C128 emulates the C64's hardware and software environment, enabling users to access a vast library of existing C64 programs and games. When the C128 is in C128 mode, it operates with enhanced capabilities, such as improved graphics and sound. This mode also supports multitasking and allows users to run multiple programs simultaneously, making it a versatile choice for both gaming and productivity tasks.