human text, ASCII text as input and output zeroes and ones that represent that program in a manner that the CPU, interesting, dammit, not installed on this computer.
We wanted to make sure that the computer memory, CPU power and the graphics card were sufficiently adequate to control the character and play the game as a reasonable level of performance.
For example, in your car there are between 50 and 100 computer systems filled with CPU chips that are all running software every time you start your car.