Mebibit

The mebibit is a multiple of the bit, a unit of information, prefixed by the standards-based multiplier "mebi" (symbol "Mi"), a binary prefix meaning 220. The unit symbol of the mebibit is Mibit.
This unit is most useful for measuring RAM and ROM chip capacity.
The mebibit is closely related to the megabit which equals 106 bits = 1,000,000 bits.
Throughout the 1980s and 1990s, video game manufacturers sometimes reported the amount of internal cartridge read-only memory (ROM) on packaging in megabits, where 1 megabit equaled 128 kibibyte and 8 megabits were 1 mebibyte of ROM, containing game instructions and data.