The term BIOS (Basic Input/Output System) was invented by Gary Kildall[REF] and first appeared in the CP/M operating system in 1975,[REF][REF][REF][REF][REF] describing the machine-specific part of CP/M loaded during boot time that interfaces directly with the hardware [REF].
With the introduction of PS/2 machines, IBM divided the System BIOS into real-mode and protected mode portions.